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ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

30 licensed drivers age 61-89 (mean = 72.2), recruited by word of mouth from studies of normal aging (n=17), medical and dementia clinics (n=9), and from the community (n=4)

26 males, 4 females

3 subjects had dementia of the Alzheimer=s Type; 3 others had dementia of the Vascular Type

The MMSE was given prior to an on-road test. MMSE score of 30 is the best possible score.

The road test was 10 miles long and took 45 minutes. An instructor sat in the front seat and two research raters sat in the back seat. Seven closed course tasks and 68 in-traffic scored tasks were rated by scoring 5 relevant behaviors for each task (scanning the environment, lateral position of the vehicle, anterior/posterior position of the vehicle (following too closely), speed, and use of turn signals. The test route began on residential streets in low traffic, and progressed to busy streets, congested city traffic, and freeway driving. The test focused on tasks known to be difficult to older drivers, such as left turns at busy intersections and merging into fast-moving traffic. Failing any behavior resulted in a failure of the task. Scores were calculated by averaging the two raters scores for each item, summing the averaged scores, and dividing by the number of tasks completed. This resulted in in-traffic scores that ranged from 0 to 1.

Other cognitive tests included traffic sign recognition (not described in the report); Verbal and Visual memory subscales of the Wechsler Memory Scale; Trail-Making Part A; and computer-generated simple and complex reaction time tests developed by the Neurobehavioral Evaluation System.

Harvard Medical School, Boston, MA.

Clinical evaluations; closed-course driving route; in-traffic road test

$In traffic scores ranged from 0.0 to 0.91 (mean = .67). Four subjects for whom the road test was aborted because of dangerous driving behavior received a score of 0.

$MMSE scores ranged from, 4 to 30 (mean = 26.2).

$MMSE scores for subjects with dementia ranged from 4 to 25 (mean = 14.8).

$One subject w/ dementia had a MMSE score of 25.

$Five of the 6 subjects who scored 24 or less on MMSE had diagnoses of dementia.

$The correlation between MMSE score and in-traffic score was .72, and significant at the p<.01 level. Adjusting for age resulted in no change in the correlation.

$Although there was a strong correlation between the MMSE and driving performance, the MMSE alone was deemed inadequate to predict driving performance. The MMSE scores of the four subjects who failed the road test were 4, 16, 21, and 24. Of the subjects who passed the road test, the lowest MMSE score was 14.

$The correlations between the in-traffic scores and the other cognitive tests are as follows, with age-adjusted correlations in parentheses:

Traffic Sign Recog. 0.65** (0.69**)
Visual Memory 0.54** (0.50**)
Verbal Memory 0.51** (0.37*)
Trails A 0.52** (0.33*)
Simple RT -.25 (-.12)
Complex RT -0.70** (-0.58**)
*p<.05
**p<.01

Odenheimer, Beaudet, Jette, Albert, Grande, and Minaker (1994)

ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

67 patients diagnosed with Alzheimers (met the NINCDS-ARDA criteria were met for diagnosis of probable Alzheimer=s) recruited from the Alzheimer=s Clinic of the University of Kansas Medical Center (mean age = 71.3, s.d.= 8.3);

100 elderly, non-spousal controls (mean age = 64.6, s.d. 9.4)

The study was conducted to determine if the impaired mental skills in Alzheimer=s disease may adversely affect driving ability.

A 40-question survey was administered that asked about whether the subject was still driving, and if not, why; car size; miles traveled per month and roadway types; whether the subject drove in inclement weather; usual time of day chosen for driving; usual speed in relation to speed limit; and number of accidents per year in the past 10 years. Family members corroborated AD patients= responses. The Mini-Mental State Exam was also administered.

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FINDINGS (Cont=d)

The accident rate per million vehicle miles of travel was calculated for the 3 years prior to the study for the 19 AD subjects and 98 normal controls still driving.

AD =262
Controls = 14
National Accident Rate All Drivers age 55+ = 5.7
All drivers in Kansas and Missouri = 3.7 and 3.2

The accident rate for AD patients was significantly different from each other group. There was no significant difference between the accident rate for the controls and state or national averages.

Alzheimer=s Clinic of the University of Kansas

46 of the AD subjects had stopped driving due to self or other=s safety concerns, 1 stopped for failing a driver=s test, and 1 stopped for other reasons. Only 2 control subjects had stopped driving (own safety concern and broken hip).

The mean MMSE score for all AD patients was 17.3 (s.d.= 7.1) and for controls 29.4 (s.d.=0.79). This difference was significant.

The mean MMSE score for the 19 AD patients still driving was 22.3 (s.d. = 2.8) and for AD patients who stopped driving 15.3 (s.d. = 7.4).This difference was significant.

The mean number of accidents/person/year for the entire AD group was 0.106 +/- 0.351 after disease onset, and 0.053 +/- 0.224 for the years prior to the disease.

The control group had 0.055 +/- 0.241 accidents/person/year for the 10 years of the study.

Dubinsky, Williamson, Gray, and Glatt (1992).

ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

101 licensed drivers (39 females and 62 males) age 72-90 (mean age = 78.3) who were members of a preexisting study cohort engaged in longitudinal studies of a community-dwelling cohort of older people (at Buck Center for Research in Aging)

The 11-item (30 point) MMSE was given in Novato as part of the Buck Center for Research in Aging. Possible errors can occur in the 6 general cognitive domains of orientation (items 1 and 2); registration (item 3), attention/calculation (item 4), recall (item 5), language (items 6-10), and visuospatial perception/praxis (item 11-copying a figure of 2 intersecting pentagons).

An on-road driving exam was given by the project driving instructor (owner/operator of a driving school in San Francisco) based on the California Driving Performance Evaluation (DPE), and using the same scoresheet as used for the MDPE given in San Jose by these researchers. (see On-road Performance Measures of Driving Safety: California MDPE at the end of this Compendium). A weighted error score was calculated as total # of unweighted errors, plus twice the sum of critical and hazardous errors. Concentration errors were also noted.

Critical errors = errors which would in normal circumstances cause test termination (turning from improper lane, dangerous maneuver, examiner intervention needed).

Hazardous errors = dangerous maneuver or examiner intervention.

Concentration errors = subject unable to proceed to field office at end of test, or drove past the street on which the field office was located and did not recognize their error.

Novato, Marin County California; Buck Center for Research in Aging

MMSE correct responses were not significantly correlated with road test weighted errors, but MMSE correct responses did significantly correlate with concentration errors on the road test (r=0.09, p=0.359). MMSE Aerror areas,@ the number of cognitive domains represented on the MMSE on which at least one error was made correlated 0.27 (p=0.006) with road test weighted errors and 0.29 (p=0.003) with concentration errors. The binary Apass/fail@ score on the pentagon item did not relate to road test weighted errors (r=0.0007, p=0.994).

Janke and Hersch (1997)

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PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

Matched pair case-control study, with close (1 year) age matching conducted in Sweden

$ 37 drivers age 65+ (mean age 75.5) with temporarily-suspended licenses due to crashes (23 drivers) or other moving violations (14 drivers). Moving violations were: speeding (2), running stop sign (4), running red light (4) run off the road (4). Mean distance driven/yr = 12000 km; # males = 30, # females = 7

$ 37 matched controls age 65+ (mean age 74.8) with no license suspensions within the past 5 yrs; mean # miles driven = 9200 km; # males = 30, # females = 7

The MMSE Score was obtained as a global index of cognitive functioning.

Other tests included:

Immediate memory was tested by a 5-item recall test, where the subject was required to name and recall 5 objects viewed on a desk after a 10-minute period (the items were not listed in this review). The delayed recall score was 1 point per correct item. If the subject failed, the procedure was repeated for up to 3 times.

Visuoconstruction abilities were assessed by having the subjects copy a cube without time limit. Scoring: 2 points for correct or minor errors only, with 3-dimensional view correct; 1 point for presence of 3-dimensional view but with errors; 0 points if no 3-d view present.

The severity of cognitive and functional impairment was judged using the Clinical Dementia Rating Scale (CDR).

Static Visual Acuity was measured using a standard letter chart at 4 m.

Subjects underwent blood tests, MRI, and EEG testing

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FINDINGS (Cont=d)

$ Cardiovascular disease was 2.7 times more frequent among s=s with crashes than s=s with other moving violations.

$ High diastolic blood pressure occurred more often in crash group compared to controls.

Hospital clinic

(Unit of Traffic Medicine, Section of Geriatric Medicine, Department of Clinical Neuroscience & Family Medicine, Karolinska Institutet, Stockholm, Sweden)

$ Questionable (CDR=0.5 ) and mild (CDR = 1) dementia were found significantly more often in the case group than in the matched control group (49% vs 11%, p=.003).

$ Subjects in case group (suspensions + crashes) had significantly lower MMSE score (p=.019), lower immediate memory task performance (p=.010) and poorer performance on the cube copying task (p=.010) compared to matched controls.

$ There were no significant differences between cases and controls on visual acuity measure (nor on EEG abnormalities, brain infarctions, neurological signs, white matter hyperintensities, number of prescribed drugs, blood pressure, physician reported cardiovascular disease, or blood tests--sedimentation rate, hemoglobin, leukocytes, platelets, thyroid-stimulating hormone, vitamin B12, folic acid, creatinine, glutamyl transferase, glucose, cholesterol, and triglyceride level.)

$ Comparison of the 23 case subjects with crashes and the 29 control subjects with no crashes in the past 5 years showed that the crashed drivers had more incidence of dementia/CDR>0 (p<.001), worse cube copying (p<.015), poorer 5-item recall (p<.003), lower MMSE (p<.019), and more EEG abnormalities.

$ Mean MMSE of case S=s with crashes = 27.5; but 78% of drivers with crashes had MMSE greater than 25. Thus, MMSE score of 23-25 has low sensitivity in crash prediction.

Johansson, Bronge, Lundberg, Persson, Seideman, and Viitanen (1996)

Johansson (1997)

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PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

283 community-dwelling individuals age 72 to 92 (mean age = 77.8) from the Project Safety cohort living in New Haven, CT who drove between 1990 and 1991. 57% were males.

The MMSE was given as part of a battery of tests.

The outcome variable was self-reported involvement in automobile crashes, moving violations, or being stopped by police in the year following administration of the test battery.

New Haven, CT. Subjects were interviewed and given the assessments in their homes by a trained research nurse.

Persons with borderline cognitive impairment (MMSE score of 23-25) were more likely to have adverse events (traffic accident, violation, or stopped by police) in the year following examination than those with higher or lower scores (relative risk 2.0, 95% CI, 1.1-3.7). The authors examined the components of the MMSE individually and by cognitive domain (orientation, memory, attention, language, and visuospatial ability), and found that the item most closely associated with adverse events was impaired design copying (24% of persons who could not correctly copy the intersecting pentagons had events compared with 8% of those who could {relative risk 3.0, CI, 1.6-5.6}).

A multivariate analysis adjusting for driving frequency and housing type found the following factors to be associated with the occurrence of adverse events: poor design copying on the MMSE (relative risk 2.3, 95% CI, 1.5 to 5.0), fewer blocks walked--0 versus > 1 (relative risk 2.3, 95% CI 1.3 to 4.0) and more foot abnormalities--3 to 8 versus 0 to 2 (relative risk 1.9, 95% CI, 1.1 to 3.3).

Combining these 3 factors to assess their ability to predict adverse driving events showed that if no factors were present, 6% of drivers had adverse events; if 1 factor was present, 12% had events; if 2 factors were present, 26% had events; and if all 3 factors were present, 47% had events.

Marottoli, Cooney, Wagner, Doucette, and Tinetti (1994)

ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Mini-Mental State Evaluation (MMSE)

N/A

A consensus statement was generated by 22 researchers meeting in Borlange Sweden, aimed at providing advice to primary care physicians concerning the assessment of cognitive status in relation to driving. Although consensus could not be reached concerning the issue of a cutoff score on the MMSE, it was determined by the majority (with some reservation) that some cut-off levels can be cautiously proposed in the context of decisions concerning future driving.

Meeting in Borlange Sweeden

$Cutoff scores must be considered as being relative, forming a small part of the basis of making decisions about driving, and secondary to a clinical evaluation.

$MMSE score 10, accompanied by a diagnosis of dementia, indicates a suficiently low level of cognitive functioning to justify recommending immediate cessation of driving.

$MMSE score of 11-17, accompanied by a diagnosis of dementia, suggests severe cognitive impairment; the patient should be referred for specialized assessment unless the clinician feels that it is unnecessary.

$MMSE score of 18-23 indicates mild impairment; decisions concerning possible assessment should be based on the functional level of the patient. If the functional level is stable, then a periodic follow up is recommended. If functional deterioration is present, then specialized assessment is recommended

$For patients without diagnosis of dementia, score of 17 or less and scores of 18-23 with accompanying signs of functional deterioration should be indications for specialized assessment.

$Some participants could not accept this suggested use because:

$Risk of designating false positives; low scores are related to illiteracy, aphasia, depression, and resistive behavior; may not correctly assess mental status of patient.

$MMSE does not assess poor judgment and impulse control; persons with scores above the cutoff may be inappropriately viewed as safe drivers.

$Use may be wasteful adding nothing more to eval. of competence than clinical observation of general functioning.

Lundberg, Johansson, Ball, Bjerre, Blomqvist, Braekhus, Brouwer, Blysma, Carr, Englund, Friedland, Hakamies-Blomqvist, Klemetz, O=Neill, Odenheimer, Rizzo, Schelin, Seideman, Tallman, Viitanen, Waller, and Winblad (1997).

ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Short Blessed Cognitive Screen

3,238 drivers ages 65+, who applied for renewal of North Carolina driver=s license

Originally a 26-item test (Orientation-Memory-Concentration) test of cognitive impairment, it was shortened to a 6-item test, and has been shown to reliably discriminate among mild, moderate, and severe cognitive deficits. This test requires identification of current year and month, identifying time within one hour, counting backwards from 20 to 1, saying months in reverse order, and repeating a name and address that the test administrator has told the subject just before asking current time. Weighted scores on the test range from 0 (no errors) to 28 (maximum errors). Scores of 0-8 indicate normal or minimal cognitive impairment; 9-19 moderate impairment; and 20 and above severe impairment.

Dependent variable: involvement in a police-reported motor vehicle crash during the three-year period immediately preceding license renewal

Eight NC driver=s license offices, representing a mix of urban and rural locations in the western, central, and eastern portions of the State.

Performance declined significantly as a function of increasing age (number of errors increased with increasing age).

90% of the sample scored normal or minimally impaired, 9.3% scored moderately impaired, 0.7% scored severely impaired. Prevalence of impairment increased with increasing age.

Results of single variable models for the association of each cognitive test measure with recent prior crash involvement using continuous test scores (Chi Square Tests) showed that the Short blessed test was not significant.

Multivariate Poisson Regression Models were employed to control for effects of age, race, driving exposure, etc, and included Trails A, Trails B and Short Blessed. All three models fit the data adequately, although the Short Blessed was the least significant of the variables with an associated p-value of 0.48 (odds ratio 1.10, 95% confidence interval 1.01-1.19 for association of cognitive test with recent prior crash involvement).

The Short Blessed test was less sensitive to reduced cognitive function than the two Trails tests employed in this research, even though it is supposed to be relatively sensitive to milder levels of impairment. The short answer format may make it less appropriate for driver=s license settings, compared to the more performance-based Trail Making and AARP Reaction Time Tests.

Stutts, Stewart, and Martell (1996, 1997)

ATTENTION/

PERCEPTION/

COGNITION

Mental Status:

Short Blessed Cognitive Screen

$ Healthy elderly controls (n=13); mean age = 73.5; CDR score =0

$ Subjects with very mild dementia (n=12) ; mean age = 72.5; CDR score = 0.5

$ Subjects with mild dementia (n=13); mean age = 73.4; CDR score = 1.0

Subjects came from the Washington University Longitudinal Studies population

Dementia severity measured w/ Washington University=s Clinical Dementia Rating

The Short Blessed Cognitive Test was given prior to the on-road driving exam. This test is scored from 0 (no cognitive impairment) to 28 (maximum impairment).

The in-vehicle, on-road driving ability of participants was scored independently by a driving instructor (blind to study design and dementia status of the subjects), and an unblinded occupational therapist (Principal Investigator). The vehicle was a standard model car w/ automatic transmission and equipped with dual brake pedals. Each subject drove for 1 hour on a pre-designed route using urban streets and highways, that included common driving situations (stop signs, traffic signals, left turns at intersections, entering and exiting an interstate highway, changing lanes, merging, diagonal and parallel parking). Subjects drove in low volume conditions. A gestalt Apass/fail@ rating was given by each observer in the vehicle.

Washington University Alzheimer=s Disease Research Center.

The mean Short Blessed Test scores were:

Control group (CDR=0): 0.3 +/- 0.8

Very mild (CDR=0.5): 2.1 +/- 1.9

Mild (CDR = 1.0): 12.4 +/- 7.9

Five subjects--all in the CDR 1 stage--@failed@ the in-car on-road test. There was 100% agreement between the driving instructor and principal investigator in their pass/fail ratings for all 38 drivers. The ability to follow the driving instructor=s directions, the demonstration of appropriate decision-making (>judgment=) in traffic, and interpretation of traffic signs were highly correlated with overall driving performance. Other behaviors demonstrated by subjects who Afailed@ the in-car exam included coasting to a near stop in the midst of traffic, drifting into other lanes of traffic, stopping abruptly without cause, simultaneously pressing the brake and accelerator while driving, delay in changing lanes when an obstacle appeared, and failure to understand why other drivers signaled them in frustration or exaggeration.

The correlation between the pass/fail outcome on the road test and performance on the Short Blessed Test was significant at the p<.001 level.

Hunt, Morris, Edwards, and Wilson (1993)

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COGNITION

Perceptual Speed:

Cue Recognition

(DORON Driver Analyzer)

$ 102 Areferred@ subjects aged 60-91 (34 of which were identified as probably being cognitively impaired to some degree). 47% of the noncognitively impaired referred drivers had visual impairment noted on their record, and 24% of the cognitively impaired had a visual disability noted). The drivers were referred to the DMV for reexamination due to a medical condition (by physician, optometrist, ophthalmologist), a series of licensing test failures, a flagrant driving error (police referral), or some other indicator of driving impairment.

$ 33 paid Avolunteers@ aged 56-85, recruited through signs posted at study site or word of mouth.

Three-part test administered via noninteractive driver simulator system (Doron Precision Systems= L-300 Series Driver Analyzer). A familiarization session allowed for RT testing (press brake to lights flashing in a certain configuration on console). Cue Recognition presents car icons generally facing away from the subject and rapidly and suddenly changing their positions on a wide projection screen. When Aaction cue@ occurs (icon faces forward to the side) the subject is to release the accelerator, and within 5 s, brake or turn wheel in appropriate direction. For Cue 1: action cue is car facing toward subject; subject must brake. For Cue 2: action cue is car faces to left or right and subject must turn wheel in that direction. Cue 3 is a mix of trials from Cue 1 and Cue 2. Release of accelerator from stimulus initiation is timed, and score is output in distance traveled at 55 mi/h from stimulus presentation to accelerator release. Speed of braking or wheel turn is irrelevant.

Three tiers of analyses were conducted in this research: (1) logistic regressions to determine what combination of tests, observations, or survey variables, with what weightings, would best predict whether a subject was a volunteer or referral; (2) multiple linear regressions were conducted to arrive at the best linear combination of variables for predicting performance on road tests; and (3) comparisons were made between cognitively impaired and cognitively non-impaired referral drivers to determine whether there were differences in performance on nondriving tests and driving tests.

(See On-road Performance Measures of Driving Safety: California MDPE at the end of this Compendium).

California DMV Field Office

Referral group performed significantly worse than the volunteer group (correlations: Cue 1 and group = .363; Cue 2 and group = .415; Cue 3 and group = .541; total errors and group = .410).

Note: These variables were also significantly correlated with age (Correlations: Cue 1 and age = .313; Cue 2 and age = .416; Cue 3 and age = .508; total errors and age = .379)

Cue 1, Cue 2, and Cue 3 average distances, total errors, and average RT (Doron orientation exercise) correlated significantly with weighted error score on the road test as follows:

Total Errors: r = .4382, p< .000
Average RT: r = .3297, p<.005
Cue 1 dist: r = .4777, p<.000
Cue 2 dist: r = .4656, p<.000
Cue 3 dist: r = .3584, p<.002

A multiple linear regression model using knowledge test score, Auto Trails time, Doron Cue Recognition 2 score, MultiCAD Static Contrast Sensitivity time with the high contrast 20/80 target, and MultiCAD Static Acuity time for correct responses at 20/80 accounted for 56.4% of the variance in performance on the road test (weighted road test error score).

The cognitively impaired group performed significantly more poorly on Cue 2 , Cue 3 , reaction time, and total errors than the cognitively nonimpaired referrals.

Janke & Eberhard (1998)

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PERCEPTION/

COGNITION

Perceptual Speed:

Cue Recognition

(DORON Driver Analyzer)

101 licensed drivers (39 females and 62 males) age 72-90 (mean age = 78.3) who were members of a preexisting study cohort engaged in longitudinal studies of a community-dwelling cohort of older people (at Buck Center for Research in Aging)

Three-part test administered via noninteractive driver simulator system (Doron Precision Systems= L-300 Series Driver Analyzer). A familiarization session allowed for RT testing (press brake to lights flashing in a certain configuration on console). Cue Recognition presents car icons generally facing away from the subject and rapidly and suddenly changing their positions on a wide projection screen. When Aaction cue@ occurs (icon faces forward to the side) the subject is to release the accelerator, and within 5 s, brake or turn wheel in appropriate direction. For Cue 1: action cue is car facing toward subject; subject must brake. For Cue 2: action cue is car faces to left or right and subject must turn wheel in that direction. Cue 3 is a mix of trials from Cue 1 and Cue 2. Release of accelerator from stimulus initiation is timed, and score is output in terms of time--rather than distance traveled at 55 mi/h, as described for San Jose testing-- from stimulus presentation to accelerator release. Recognition time was available only if the correct (steering or braking) response followed accelerator release.

Speed of braking or wheel turn is irrelevant.

An on-road driving exam was given by the project driving instructor (owner/operator of a driving school in San Francisco) based on the California Driving Performance Evaluation (DPE), and using the same scoresheet as used for the MDPE given in San Jose by these researchers. (See On-road Performance Measures of Driving Safety: California MDPE at the end of this Compendium). A weighted error score was calculated as total # of unweighted errors, plus twice the sum of critical and hazardous errors. Concentration errors were also noted.

Critical errors = errors which would in normal circumstances cause test termination (turning from improper lane, dangerous maneuver, examiner intervention needed).

Hazardous errors = dangerous maneuver or examiner intervention.

Concentration errors = subject unable to proceed to field office at end of test, or drove past the street on which the field office was located and did not recognize their error.

Novato, Marin County California; Buck Center for Research in Aging

The correlations between response time for each Cue Recognition test and weighted road test score were not significant (r=.00 for Cue 1, f=0.20 for Cue 2, and r=0.22 for Cue 3).

It should be noted that there were hardware problems at this test site, resulting in many missing data occurrences; and many subjects anticipated critical stimuli and responded before a response window was available in the software, resulting in response time readouts of Azero@.

Janke and Hersch (1997)

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COGNITION

Selective Attention:

Auditory Selective Attention Test

72 drivers (58 males and 14 females) ages 28-59, divided into 2 accident groups:

$ no accidents in the previous 10 years

$ 1 or more accidents in the past 10 years

Subjects were volunteers from a large northeastern utility firm, who had been drivers for the firm during the previous 10 years.

Auditory Selective Attention Test: presented 24 dichotic messages simultaneously to the S=s ears. A tone presented at the beginning of each trial indicated which ear (right or left) would be presented with the relevant information. Sixteen pairs of letters and numbers were then presented, followed by another tone, and then three pairs of numbers. The S was required to report aloud the digits appearing in the channel that was indicated as being relevant. Scores on the test were the total number of errors made on the test including failure to report a number or letter (omission) on the relevant channel, report of an incorrect competing message number or letter (intrusion error) on the irrelevant channel, and errors on trials following a cue to switch channel attention (switching error).

Visual Selective Attention Test: constructed for this study to approximate a visual counterpart of the Auditory Test, and was presented to s=s via CRT microcomputer.

Group Embedded Figures Test: a measure of perceptual style ability (field dependence vs field independence) was obtained, in which a S must perceptually extract a target geometric figure embedded within an irrelevant stimulus context.

It was predicted that poorer performance on measures of selective attention would be significantly related correlated with higher motor vehicle accident frequency, and that performance on the auditory and visual selective attention tests would be positively correlated. It was also hypothesized that drivers who were found to be field dependent would show a higher motor vehicle accident rate. Also, it was predicted that the measures of selective attention would be positively correlated with the measure of perceptual style.

University laboratory: all S=s were tested individually in small experimental rooms that were quiet, comfortable, and well-lighted.

$ None of the following variables were significantly correlated with crash frequency: gender, age, number of miles driven daily, or tenure with utility company.

$ For both measures of selective attention, the accident group showed significantly poorer performance, as evidenced by their higher error frequency. For both selective attention tests, omission errors (failure to report a presented number or letter) and switching errors (errors on trials following a cue to switch channel attention) were significantly correlated with accident frequency. Intrusion errors (report of an incorrect competing message number or letter) on the auditory selective attention test were also positively correlated with accident involvement.

$ The total number of figures correctly identified with the Group Embedded Figures Test was higher for the no-accident group, but performance on this test was only marginally related to accident involvement (p<0.10).

$ Switching errors on both measures of selective attention were found to have the highest correlation with accident involvement of all the measures in the predictor battery.

Correlations: Visual attention switching errors and total number of accidents = 0.40 (p<0.0001); auditory selective attention and total number of accidents = 0.43 (p<0.0001).

Avolio, Kroeck, and Panek (1985)

ATTENTION/

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COGNITION

Selective Attention:

Auditory Selective Attention Test

1,475 ITT Hartford Insurance Co. policyholders for whom past driving histories were available through insurance records, divided into two groups based on the presence or absence of recent at-fault accidents. Driver age ranged between 50 and 80+ and was distributed as follows:

$ 26 percent of the sample were between 50-64,

$ 54 percent were between 65-74,

$ 20 percent were over 75.

Participants were active drivers who had (generally) been pre-screened for risk in the insurance underwriting process. Also, participants who came in for testing appeared confident in their driving abilities.

A measure of auditory selective attention was obtained using the Auditory Selective Attention Test (ASAT), which includes a series of dichotic messages heard through a stereo headset (Arthur, 1991). In this test, each message is presented in two parts and consists of a series of pairs of numbers and letters. A modification from its usual format required subjects to manually record responses on an answer sheet, instead of giving them orally to the experimenter.

Insurance and motor vehicle department records provided information about the following variables: at-fault accidents, non-fault accidents, non-accident claims, violations and convictions, miles driven, age, gender and marital status.

Testing rooms in hotels in 15 cities throughout Connecticut, Florida, and Illinois

The Auditory Selective Attention Test did not correlate significantly with at-fault accidents. ASAT data from only Connecticut (initial testing) correlated significantly (r=0.24) with at-fault accidents with a simple accident/no accident criterion. Testing conducted in Florida and Illinois did not show the same relationship. The authors note that the ASAT is an auditory test that requires a quiet test environment, which may not have been true of the hotel room test sites in these two states. Testing rooms at times became crowded and noisy, and administration proved to be difficult at times, and there was missing data as site staff tended to eliminate this test on heavily scheduled days.

Brown, Greaney, Mitchel, and Lee (1993)

ATTENTION/

PERCEPTION/

COGNITION

Selective Attention:

Auditory Selective Attention Test

Student volunteers from Texas A&M University.

Postdictive (1988) sample contained 214 S=s, mean age = 19.19 years, 70% females, 30% males

Predictive sample (1990) contained 142 s=s, mean age = 19.18 years, 68% females, 32% males.

Locus of control-- a measure of personality --measured by the Montag Driving Internality and Driving Externality scales (Montag and Comrey, 1987),and auditory selective attention, a measure of information processing, measured using the Auditory Selective Attention Test were used to predict driving accidents.

The ASAT is a dichotic listening task, where 24 dichotic messages are presented simultaneously to subjects via stereo headphones (Gopher and Kahneman, 1971). Each message consists of a pair of single English letters or digits ranging from 0 to 9. The ASAT was scored as the total number of errors. The MDIE was scored as a single scale, with a higher score reflecting a more internal locus of control.

The number of accidents was self-reported in 1988 to date; in 1990, number of accidents between 1988-1990 was self-reported.

University Laboratory

ASAT was significantly correlated with 1988/90 total (r=0.24, p<0.01), at-fault (r=0.20, p<0.01), and not-at-fault (r=.15, p<0.05) accidents. It was also significantly related to 1988 total (r=0.19, p<0.01) and at-fault (r=0.23, p<0.001) accidents. ASAT was also significantly correlated with 1990 not-at-fault accidents (r=0.20, p<0.01).

The only significant correlation for the Montag Driving Internality and Driving Externality (MDIE) scale was for 1990 not-at-fault accidents

(r=-0.15, p<0.05). The relationship was in the Awrong@ direction: an internal locus of control was associated with elevated accident rates. The MDIE was not associated with accident involvement in either the postdictive or predictive design.

Selective attention was not related to locus of control. The correlation between these 2 measures was 0.05 (p>0.05).

Arthur and Doverspike (1992).

ATTENTION/

PERCEPTION/

COGNITION

Selective Attention:

Auditory Selective Attention Test

Meta Analysis: 149 usable data points from 32 articles. The number of data points per predictors was:

Predictor    # of r=s

Selective attention 13
Perceptual style 12
Choice & complex RT 5
Cognitive ability 10
Age 8
Education 7
General activity level 40
Regard for authority 13
Level of distress 13
Locust of control 13

Selective attention was operationalized as scores on the Auditory Selective Attention Test (Arthur, Barrett, & Doverspike, 1990) or the Dichotic Listening Test (Mckenna et al. 1986). Data points for selective attention comprised omission, intrusion, and switching errors.

The 13 studies contained 1,101 drivers. These studies used a professional driver sample and archival criterion data.

Meta-Analysis

Results showed a significant correlation between selective attention and automobile accidents (mean r=0.257, p<0.05). The 95% confidence interval ranged from a lower limit of r=0.205 to an upper limit of r=0.317. The results indicated that although a significant amount of unexplained variance remained (43%), the 57% of total variance accounted for was relatively high. Better selective attention was associated with lower levels of accident involvement.

In addition, marginally favorable results were obtained for higher regard for authority (r=0.155), an internal locus of control (r=0.196), and higher cognitive ability (r=0.117). The better the performance on these tests, the lower the levels of accident involvement.

 

Arthur, Barrett, and Alexander (1991)

ATTENTION/

PERCEPTION/

COGNITION

Selective Attention:

Auditory Selective Attention Test

39 repeat-accident professional bus drivers ages 22-32, with at least 2 moderately severe accidents

78 control professional bus drivers in the same age range; half with a zero-accident history; half with a low accident rating

The test used Gopher and Kahneman=s test. Messages were presented by earphones, and subjects were required to repeat all relevant digits as soon as they heard them. The test lasted 25 minutes. In addition, subjects completed a brief form of Raven=s (1956) Progressive Matrices Test (a short intelligence test).

The test was completed in 1969. Accident records for the sample were obtained for the period of two years prior to the completion of the Auditory Selective Attention Test (1967-1969), and were used to assess the reliability of the test as a predictor of accidents in professional bus drivers.

______________________________________________

FINDINGS (cont=d)

$The effects of a selection cutoff at a score of 16 errors in Part 2 were evaluated as an aid to the rejection of a group of applicants who were most likely to be accident prone. The effects of the rules (including the elimination of stereotyped error individuals) were estimated for the entire driving population, by extrapolation from the study results. The results are as follows:

sample accept reject invalid total
Acc. free 486 14 27 527
Intermed. 386 12 88 482
Acc. Prone 45 26 7 78
Total 913 52 122 1087

Although caution was extended because the study was posdictive rather than predictive, and the cutoff was chosen to fit the present data, the estimates suggest that the use of the ASAT as an aid in decisions about hiring could lead to a 15-25% reduction in the number of accident-prone drivers accepted, at a relatively negligible cost in the rejection of potentially safe drivers.

Testing was conducted during work hours at the local bus station (using employees of the Egged Bus Company, Israel), where they provide interurban and urban bus service.

$The association between accident scores for 2 successive years and performance of the ASAT was significant . Correlations between components of the ASAT (errors of omission in Part 1, errors of intrusion in Part 1, and errors in incorrect reports in Part 2) and the accident criterion were all significant.

$Part 2 of the test measures the speed and effectiveness with which attention is redirected to a relevant channel after an orientation cue. When 24 subjects who had an extremely high frequency of all three types of errors (stereotyped patterns of errors where they ignored reorientation tone between Part 1 and 2) were eliminated form the analysis, the validity of the correlation with Part 2 performance and accident performance was improved (r=.46 for errors in Part 2). When the 2 categories of relatively safe drivers were combined and compared to the unsafe group, the point-biserial correlation between accident frequency and the number of errors in Part 2 was 0.51.

$The intelligence test did not discriminate significantly between the accident groups, and had a low correlation with the attention test (.33 with Part 2 errors).

Kahneman, D and Ben-Ishai, R. (1973).

ATTENTION/

PERCEPTION/

COGNITION

Sustained Attention:

Continuous Performance Task -X

Continuous Performance Task-AX

 

17 subjects (age 57-97; mean age = 75)

6 females and 11 males.

8 S=s were referred from local mental disorder clinics or from local physicians because of possible dementia and associated driving problems.

9 S=s were community residents who did not have suspected dementia or driving problems.

Both tests were administered via personal computer.

The continuous performance task-X is a measure of sustained attention and assesses subjects' vigilance. Subjects were required to respond with a bar press every time the letter "X" was visualized in a sequence of letters continuously presented over a 5-minute period, where each letter had a 2-second duration. Scores included the number of correct responses, errors of omission, errors of commission, and average reaction time.

The continuous performance task-AX was identical to the task-x test described above, except the subject was required to respond to an "X" only if it was preceded by an "A".

An on-road driving assessment was performed with the subject driving with a certified driving examiner in a dual-brake vehicle. Simple maneuvers were first performed in a parking lot, then subjects joined the flow of traffic and traveled over a prescribed route in moderate to heavy traffic. Subjects were scored on the basis of errors or omissions that correspond to points on the State of New York road test exam; higher scores indicate poorer performance. Therefore a total score was used as well as a determination of whether the subject met or exceeded state standards ("pass") or failed to meet standards ("fail"). In addition, a pass/fail rating was given for the subjects' performance in steering control, braking, acceleration, judgment in traffic, observation skills, and turning skills (particularly left turning).

Clinical tests: University Laboratory

On-road driving evaluation: parking lot and in-traffic (moderate to heavy traffic situations)

$Results of the driving exam indicated that eight subjects passed, eight failed (scored 19 or more errors on the on-road exam), and one could not complete the exam because of poor vision. The analyses conducted in this study compared the subjects who met the driving exam standards with the eight who did not. There was no significant difference in average age of subjects who passed the exam compared to those who failed. Drivers who failed drove significantly fewer miles, however. The group that failed the on-road exam made significantly more errors of omission on the continuous performance-AX test (mean errors = 5.86), than those who passed the on-road exam (mean errors = 0.86). They also made more omission errors on the continuous performance-X tasks (8.0 mean errors compared to 0.83). These differences failed to reach significance due to the large variability in this small sample.

$A regression analysis to determine which variables predict driving status was not possible, because some subjects did not complete all measures and because the sample size was relatively small. An exploratory analysis using total score on the road test as the criterion measure and using five preselected variables determined that age, total time on Trail Making Test, and the number of omission errors on the continuous performance AX test were possible predictors, and when average reaction time is added, account for 93% of the variance in the road test scores.

$Of the 8 persons referred for possible dementia, 5 failed the road test, 2 passed the test, and 1 was unable to complete the evaluation.

Cushman (1992)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

Benton Visual Retention Test

(Copy Test)

 

$ Healthy elderly controls (n=13); mean age = 73.5; CDR score =0

$ Subjects with very mild dementia (n=12) ; mean age = 72.5; CDR score = 0.5

$ Subjects with mild dementia (n=13); mean age = 73.4; CDR score = 1.0

Subjects came from the Washington University Longitudinal Studies population

Dementia severity measured w/ Washington University=s Clinical Dementia Rating

The Benton Copy Test (form D) was administered prior to the on-road driving exam. This test measures visuoperceptual function (Benton, 1963). The test involves a ten-card series with each card containing several (usually 3) line drawings in the horizontal plane. The cards are shown for 10 seconds, after which the subject must draw figures from memory.

An examiner may also require simple copying of the figures, to assess the accuracy of the subject=s drawings, when memory is not involved. The test was scored on the basis of the number of correct drawings.

The in-vehicle, on-road driving ability of participants was scored independently by a driving instructor (blind to study design and dementia status of the subjects), and an unblinded occupational therapist (Principal Investigator). The vehicle was a standard model car w/ automatic transmission and equipped with dual brake pedals. Each subject drove for 1 hour on a pre-designed route using urban streets and highways, that included common driving situations (stop signs, traffic signals, left turns at intersections, entering and exiting an interstate highway, changing lanes, merging, diagonal and parallel parking). Subjects drove in low volume conditions. A gestalt Apass/fail@ rating was given by each observer in the vehicle.

Washington University Alzheimer=s Disease Research Center.

Five subjects--all in the CDR 1 stage--@failed@ the in-car on-road test. There was 100% agreement between the driving instructor and principal investigator in their pass/fail ratings for all 38 drivers. The ability to follow the driving instructor=s directions, the demonstration of appropriate decision-making (>judgment=) in traffic, and interpretation of traffic signs were highly correlated with overall driving performance. Other behaviors demonstrated by subjects who Afailed@ the in-car exam included coasting to a near stop in the midst of traffic, drifting into other lanes of traffic, stopping abruptly without cause, simultaneously pressing the brake and accelerator while driving, delay in changing lanes when an obstacle appeared, and failure to understand why other drivers signaled them in frustration or exaggeration.

The correlation between the pass/fail outcome on the road test and performance on the Benton Copy Test was significant at the p<.008 level.

Hunt, Morris, Edwards, and Wilson (1993)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

Motor-Free Visual Perception Test

105 drivers licensed in Nebraska, aged 65-88 (mean age = 71.4). 54 were females (mean age = 70.5 years); 51 were males (mean age = 72.2 years). All subjects were volunteers, and were paid $25.00 for participating. 36 had taken a driver education course in the past 10 years.

Visual perception was assessed using the motor-free visual perception test (MVPT) designed by Colarusso and Hammil (1972). This test is composed of 36 questions, divided into five groups, that assess the following aspects of visual perception: spatial relationship; visual discrimination; figure ground; visual closure; and visual memory. Two scores were obtained for each subject for each of the five visual-perception measures; the response-time score was the mean time required for the subjects to answer questions pertaining to the given measure, and the error score was the number of questions answered correctly. Overall response-time and error scores were also computed.

The driving performance of the subjects was evaluated using the on-street driving performance measurement (DPM) technique developed by Vanosdall and Rudisill (1979). The subjects were evaluated by a driver education expert trained in the use of the DPM technique, while they drove in their own cars. The DPM route was a 19-km circuit designed to evaluate the subjects in the situations that are most often involved in the accidents of older drivers. Therefore, their performance was evaluated at 7 intersections where they were required to make left turns at 5 intersections and right turns at the other 2 intersections. Four of the left turns were made from left-turn lanes onto four-lane divided arterial streets in suburban areas, and one was made from a left turn lane onto a two-lane one-way street in an outlying business district.

Cognitive measures: University laboratory.

Driving measures:

business district and residential street networks

Among the visual perception factors, the following scores correlated significantly with the driving performance measure (correlation coefficient in parentheses): spatial relationships error score (.21), visual discrimination error score (.26), visual discrimination response-time score (-0.22), figure-ground response-time score (-0.28), visual closure response-time score (-0.38), overall error score (.26), and overall response-time score (-0.32). As percent of correct responses increased on the visual perception tests, performance on the driving test increased; as the reaction time scores increased, performance on the driving test decreased.

Definitions:

Spatial relationships: the ability to orient one=s body in space and perceive the positions of objects in relation to oneself and other objects.

Visual discrimination: the ability to discriminate dominant features in different objects.

Figure-ground: ability to distinguish an object from its background.

Visual closure: ability to identify incomplete figures when only fragments are presented.

Visual memory: ability to recall dominant features of one stimulus item or to remember the sequence of several items.

Tarawneh, McCoy, Bishu, and Ballard (1993)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

Motor-Free Visual Perception Test

42 patients with Alzheimer=s Disease (mean age = 72.2 years); 81 normal elderly controls (mean age = 69.1 years)

Dementia S=s were recruited from the Dementia Research Clinic (DRC) or the Alzheimer=s Disease Research Center (ADRC) of the Johns Hopkins University School of Medicine; or from referring physicians and local chapters of the Alzheimer=s Assoc. Non-demented S=s were recruited from among friends of Drc or ADRC patients and from the community. Control S=s were screened for psychiatric illness.

Cognitive tests included:

Mini-Mental State Examination [(MMSE), Folstein, Folstein, and McHugh, 1975], Logical Memory and Visual Reproduction subtests (immediate) from the Wechsler Memory Scale-Revised; Category Fluency test (Issacs & Kennie, 1973); Standardized Road Map Test of Directional Sense (Money, 1976); Trail Making A and B (Reitan, 1958); Hopkins Verbal Learning Test (Brandt, 1991); Spatial recognition Span Test (Moss, Albert, Butters, & Payne, 1986); Motor-Free Visual Perception Test (Colarusso & Hammill, 1972); and simple, two-choice, and four-choice reaction time tests.

$Driving performance was evaluated using the Doron L225 DrivoTrainer and Driver Analyzer system. Two 15 min Adriver-point-of-view@ films (Cue recognition task and ADrive to the City@). Drivers were required to brake, steer left or steer right to specific action cues in Cue recognition. In Drive to the City, appropriate performance is recorded under 5 categories: maintaining appropriate speed, use of turn signal, force applied to brake, use of accelerator, and position of steering wheel.

$The number of actual crashes, violations, and near misses was obtained for the previous 2 years from control subjects, and from a family member of AD patients.

_______________________________________________

FINDINGS (Cont=d)

$With ACue Recognition@ as the dependent variable for the larger number of control subjects, age alone explained 26% of the variance. Visual Memory-immediate, # errors on Road Map test, Category Fluency, and visual closure subscore on Motor-Free Visual Perception test jointly accounted for 45% of the variance. Adding age increased the R2 by 1%.

$Considering miles driver/yr and # of crashes and near misses reported on questionnaire, AD patients in the highest mileage category (5,000-7,500) had considerably lower rates (< half) of both crashes and near misses than AD patients who drive <2,000 mi and those who drove 2,000-4,000 mi/yr. However, this group also performed worse in the simulator than the higher mileage AD drivers. This was interpreted that AD patients make an effort to compensate for deteriorating driving skills by driving less, but this is not an adequate strategy. For controls, # of reported crashes was equal for each mileage category.

Johns Hopkins University School of Medicine

$Driver simulator performance measures correlated strongly with Visual Memory immediate scores, & Visual Closure subscore of the Motor-Free Visual Perception Test for both AD and control subjects.

$Errors on the standardized Road-Map Test of Directional Sense, completion time on Trails B, and Spatial Recognition span correlated with simulator driving performance only for control subjects.

$Multiple regression results for AD patients using ADrive to the City@ performance as the dependent variable (DV) showed that MMSE alone accounted for 22% of the variance. Logical Memory-immediate, Trails A time, and the visual closure subscore of the MVPT jointly accounted for 54% of the variance. Adding the MMSE to this set of variables did not account for any additional variance.

When ACue Recognition@ was the DV, MMSE alone accounted for 21% of the variance; four-choice RT alone accounted for 33% of the variance, and jointly they accounted for 34% of the variance.

$For the control S=s with ADrive to the City@ as the DV, 2 sets of variables explained the variance (due to a smaller set of S=s completing the Spatial Recognition Span Test): For the group N=78, age alone accounted for 23% of the variance, and Visual Memory-immediate, # of errors on Road-Map test, and Trails A accounted for 33%. With age, these variables explained 41% of the variance. For the control S=s N=59, age explained 26%; and Visual memory immediate, # errors on Road Map Test, Spatial Recognition span, and Category Fluency jointly accounted for 38% of the variance. Together with age, these variables accounted for 45%.

Keyl, Rebok, Bylsma, Tune, Brandt, Teret, Chase, and Sterns (manuscript under review)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

Motor-Free Visual Perception Test

7 Spinal Cord Injured (and rehabilitated) subjects with a mean age of 27;

10 Traumatic Brain Injured (and rehabilitated) subjects with a mean age of 29 years;

The SCI and TBI subjects were representative of disabled clients referred by rehabilitation agencies to driving evaluators as driving candidates

The control (able-bodied) group consisted of 8 Introductory Psychology class students, with a mean age of 19 years.

The psychometric predictors included:

- Motor WAIS (WAIS Picture Arrangement, Block Design, and Digit Symbol subtests)

- Non Motor WAIS (WAIS Arithmetic and Picture Completion subtests)

- Motor-Free Visual Perception Test

- Baylor Adult Visual Perception Test

- Trail making A and B

- Symbol Digit Modalities Test

- Driver Performance Test (knowledge and judgment test using videotaped scenes of potentially dangerous driving situations)

The criterion measure involved expert ratings of performance driving in a full-size vehicle on a closed course.

Rehabilitation Center

The able-bodied subjects drove better than the spinal-cord injured subjects, who drove better than the head-injured subjects. All of the psychometric measures except the MVPT correlated significantly with driving performance. The correlation between the MVPT and driving performance was -.382.

Schweitzer, Gouvier, and Horton (1987)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

WAIS-R Picture Completion Test

121 licensed drivers forming groups composed of :

$ 47 normal/nondemented elderly (mean age 72.9)

$ 29 middle-aged/nondemented controls (mean age 40.6)

$ 45 cognitively impaired drivers (mean age 73.3)

$ 28 with mild dementia

$ 8 with moderate dementia

$ 9 with cognitive impaired but not meeting the criteria for dementia

Test consists of 20 cards printed with pictures and bound in a booklet. The experimenter tells the subject,@ I am going to show you some pictures in which there is some important part missing. Look at each picture and tell me/show me what is missing.@ A maximum exposure of 20 s is allowed for each card. If the subject does not indicate the missing part, item is scored as a failure and the next card is presented. If the subject responds incorrectly, the next card is presented, even if the full 20 s has not elapsed.

[6 other psychometric tests were included in this study: letter cancellation, stroop, choice reaction time, Trail Making Part B, WAIS-R comprehension subtest, and Direct Assessment of Functional Status]

Two operational level dependent measures were collected using the Computerized Driving Assessment Module (CDAM): simulator brake reaction time and simulator steering accuracy. The brake RT measure comprised the average of three trials, where the subject was instructed to maintain a "speed" of 50 kph while monitoring a screen for the appearance of a STOP sign. RT corresponded to the interval between the appearance of the word STOP and the time the brake pedal was fully depressed. Steering accuracy was computed by summing the areas of deviation between the curve describing the position of computer generated lights and the curve generated by the steering actions of the driver.

Maneuvering level measures were assessed on the Motor Vehicle Branch (MVB) Road Test and on a measure of stopping distance in response to a moving hazard.

Strategical level measures were related to the accuracy of subjects' self appraisals and comprised the Cone Avoidance Task and a comparison between self-ratings and collateral ratings of driving problems. The cone avoidance task required a subject to maneuver a test vehicle through a course of traffic cones, hitting as few as possible.

Cognitive battery given at Clinic for Alzheimer=s Disease and Related Disorders (University Hospital, Vancouver B.C.), CDAM testing performed at a local Rehab Center, MVB Road test conducted by license examiners on a class 5 course. Cone Avoidance test conducted on off-road course.

Performance on the Picture Completion Test was only significantly correlated with Brake Time performance in the simulator (correlation = -.41, p<.05). On the simulator brake RT test, the demented had a significantly longer mean reaction time than either of the control groups, while the normal elderly and mid-age controls did not show significantly different performance on this task. The only other psychometric measure significantly related to driving performance was Trail Making, which was only correlated with steering deviation on the driving simulator. In both cases, the psychometric tests accounted for less than 25% of the variance in driving behavior.

A note of interest: Although the demented had on average, 10 more demerit points than the normal elderly on the MVB road test, 75% of the demented drivers passed the road test.

There was no significant correlation between these two tests and performance on the motor vehicle branch test, or on stopping distance or cone avoidance.

Tallman, Tuokko, and Beattie (1993)

ATTENTION/

PERCEPTION/

COGNITION

Visual Perception:

WAIS-R Picture Completion Test

7 Spinal Cord Injured and rehabilitated subjects (SCI) with a mean age of 27;

10 Traumatic Brain Injured and rehabilitated subjects (TBI) with a mean age of 29 years;

The SCI and TBI subjects were representative of disabled clients referred by rehabilitation agencies to driving evaluators as driving candidates

The control (able-bodied) group consisted of 8 Introductory Psychology class students, with a mean age of 19 years.

The psychometric predictors included:

- Motor WAIS (WAIS Picture Arrangement, Block Design, and Digit Symbol subtests)

- Non Motor WAIS (WAIS Arithmetic and Picture Completion subtests)

- Motor-Free Visual Perception Test
- Baylor Adult Visual Perception Test
- Trail making A and B
- Symbol Digit Modalities Test (Smith, 1968)
- Driver Performance Test (Weaver, 1984)

The DPT is a knowledge and judgment test using videotaped scenes of potentially dangerous driving situations. Separate scales assess capacity for search, identification, prediction, decision making, and execution of correct maneuver. The test measures capacity for polysensory information processing, integration, and motoric output.

The criterion measure involved expert ratings of performance driving in a full-size vehicle on a closed course.

Rehabilitation Center

The able-bodied subjects drove better than the spinal-cord injured subjects, who drove better than the head-injured subjects.

Correlations between each measure and the criterion were:

Motor WAIS = 0.807
Digit-Symbol (WAIS) = 0.782
Trails = 0.668
Baylor = 0.632
Non motor WAIS = 0.706
Symbol-Digit = 0.839
Motor-Free Visual Perception = -0.382
DPT = 0.847

All of the psychometric measures except the MFVPT correlated significantly with driving, and the correlations exceeded the a=0.005 level of probability.

Multiple regression analyses using only 2 predictors, the DPT and Non Motor WAIS (Picture Completion and Arithmetic) variables yielded an R2 of .81 (accounting for 81% of the variance in driving performance)

Schweitzer, Gouvier, and Horton (1987)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

92 brain or spinal-cord injured patients from the Center for Outpatient Rehabilitation in Knoxville, TN

61% stroke

21% traumatic brain injury

6% spinal cord injury

Battery includes computerized and standardized psychometric tests. Standardized, nonautomated tests included:

$ WAIS-R Picture Completion Test

$ WAIS-R Digit Symbol Test

$ Trail-Making Test Parts A & B

Computerized items were presented on an Atari 800 computer. Test software was adapted from Bracy=s (1982, 1985) Cognitive Rehabilitation Programs (BCRP) for brain-injured and stroke patients, marketed through Psychological Software Service, Inc. (PSS). Computerized tests included:

$Visual Reaction Differential Response - Computer screen is bisected by vertical line; a small dark square appears in random locations with random inter-trial interval. S pushes joystick toward side of screen on which square appears. DV=response time, variance, errors, and latencies in each visual quadrant. Measures attention, concentration, reaction time.

$Visual Reaction Differential Response Reversed - Same as above, but S must push joystick in opposite direction. Measures attention, concentration, reaction time, dynamic cognitive processing, simple decision making. Radio in backroom provides auditory distractors.

$Visual Discrimination Differential Response II - Three squares are presented on screen. S fixates on center square and moves joystick toward square that turns same color as center square. Measures rapid decision-making & stimulus discrimination/response differentiation.

$Visual Scanning III - Two columns of alpha characters are shown, one on each side of screen. Starting in left column, a character group is highlighted, and S must find matching character group in right column and move cursor to it. Procedure repeats for 20 trials using alternative sides for initial stimulus. Measures ability to shift attention from one stimulus set to another and back.

Other tests included:

$Keystone Driver Vision Tester - far visual acuity, color vision

$ Keystone Perimeter Field of Vision - measures up to 90 degrees on each side of fixation point.

A road test is given to assess basic vehicle control, attitute, reactions under pressure/stress, direction-following, safety awareness, destination finding, problem solving.

Lakeshore Systems Services, Center for Outpatient Rehabilitation.

Knoxville, TN

The 10 tasks yield 27 response measures. A score termed AGeneral Driving Index AGDI27" was defined as the mean standard score of all 27 items.

$ Internal consistency reliability of the CBDI was 0.95 (Cronbach=s alpha)

$ Correlation between performance on CBDI (GDI27) and road test performance was significant (2=86, Cramer=s V=0.97, p<.0001).

$ Of the 44 patients who passed the CBDI, 42 passed the road test (95.5%).

$ Of the 48 patients who failed the CBDI, only 6 were allowed to take the road test. All 6 patients Aconvincingly@ failed the road test.

Engum, Pendergrass, Cron, Lambert, and Hulse (1988)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

121 brain-injured patients at Fort Sanders Regional Medical Center in Knoxville, TN

(Cerebral vascular accident and traumatic head injury victims)

See: Engum, Pendergrass, Cron, Lambert, and Hulse (1988). Ten assessment tasks yield 27 response measures dealing with such cognitive/behavioral skills as attention, concentration, rapid decision-making, stimulus discrimination/response differentiation, visual scanning and acuity, and attention shifting.

Two scores were calculated for each patient: (1) the overall General Driver=s Index (GDI27) defined as the mean standard score of all 27 variables; and (2) the short form Abbreviated Driver=s Index (ADI10), defined as the mean standard score of those 10 items with the highest corrected part-whole correlations.

The 10 best items with corrected part-whole correlations (which measure how closely a given item correlates with all other items excluding itself) were:

$ Trails B Time

$ WAIS Digit Symbol (N correct)

$ Visual Reaction Differential Response: joy Stick to square (ave. time)

$ Visual Reaction Differential Response: joy stick to square (Q1 time)

$ Visual Reaction Differential Response: joy stick to square (Q3 time)

$ Visual Reaction Differential Response Reverse: joy stick away (ave time)

$ Visual Reaction Differential Response Reverse: joy stick away (Q1 time)

$ Visual Reaction Differential Response Reverse: joy stick away (Q3 time)

$ Visual Reaction Differential Response Reverse: joy stick away (Q4 time)

$ Left Visual Scanning III (time)

Both the GDI27 and ADI10 have a mean of 50 and a standard deviation of 10, with scores above 50 indicating greater levels of disability.

Patients were given the CBDI and then an on-road driving test.

Fort Sanders Regional Medical Center in Knoxville, TN

$Short form ADI10 scores and long form GDI27 scores were very closely related [r(GDI27, ADI10)=0.97 (p<.001)]

$Above average scores on the CBDI (>50 indicates more deficit) were more likely to occur in patients who failed the road test, while below average scores (< 50 indicates less deficit) were more likely to occur in patients who passed the road test.

$63 of 121 patients passed the on-road exam. Patients who passed had average GDI27 and ADI10 standard scores of 45.

$Patients who failed the on-road exam had average standard scores of 55

$An indeterminate region with standard scores ranging from 47-52 has an overlap of passing and failing distributions. A patient with a standard score in this Azone of uncertainty@ is almost equally likely to have passed or failed in the examiner=s opinion.

$Patients who obtained a standard GDI27 score of 47 or below passed the on-road test 100% of the time.

$Patients who obtained a standard GDI27 score of 53 or above failed the on-road test 100% of the time.

$The following decision-making criteria are suggested: standard scores of 46 or less are clearly passing; standard scores of 47-52 are borderline; and standard scores of 53 or greater are clearly failing.

Borderline test scores on the CBDI are not definitive and an examiner should judge these cases with information independent of the CBDI, such as a road test, behavioral observations, or other neuropsychological tests.

Engum, Lambert, Womac, and Pendergrass (1988).

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

Double-blind validity study using 175 brain-injured patients

See: Engum, Pendergrass, Cron, Lambert, and Hulse (1988). Ten assessment tasks yield 27 response measures dealing with such cognitive/behavioral skills as attention, concentration, rapid decision-making, stimulus discrimination/response differentiation, visual scanning and acuity, and attention shifting.

Subjects undergo examination on the CBDI and then are assessed on the road.

Fort Sanders Regional Medical Center in Knoxville, TN

The relationship between CBDI performance (pass, borderline, fail) and the on-road evaluation outcome (pass, fail) was significant (r=0.81, p<.0001).

Of the 42 patients who received a favorable Apass@ decision based on CBDI performance, 40 passed the on-road exam.

Only 7 of the 39 patients who received an unfavorable Afail@ rating on the CBDI passed the on-road test.

Patients who passed the road test passed significantly more CBDI items (mean = 17.1) than those who failed the road test (mean = 6.3).

Patients who failed the road test failed significantly more CBDI items (mean = 11.7) than those who passed the road test (mean = 1.7)

Patients who passed the road test produced a CBDI protocol with much less scatter or within-subject variability (mean = 16.76) than those who failed the road test (mean = 82.33)

Engum, Lambert, Scott, Pendergrass, and Womac (1989).

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

232 patients from rehab centers: (121 members of the original normative sample, plus 111 added to constitute the restandardization sample)

61 patients with left cerebral vascular accidents

60 patients with right cerebral vascular accidents

71 patients with traumatic head injuries

9 patients with spinal cord injuries

31 patients with other disabling and debilitating neurological disorders

(multiple sclerosis, Gullian-Barre syndrome, Alzheimer=s disease, myasthenia gravis, intrinsic & extrinsic tumors of the brain, Parkinson=s disease, toxic encephalopathy)

See: Engum, Pendergrass, Cron, Lambert, and Hulse (1988). Ten assessment tasks yield 27 response measures dealing with such cognitive/behavioral skills as attention, concentration, rapid decision-making, stimulus discrimination/response differentiation, visual scanning and acuity, and attention shifting.

Restandardized normative tables support a new General Driver=s Index (GDI28), a composite summary of the original 27 CBDI items, plus a measure of within-subject variability. Norms also support the Abbreviated Driver=s Index (ADI10), a validity check on GDI28, which is based on the 10 most valid CBDI items in relation to road test performance. (Although there is a strong relationship between ADI10 and GDI28 scores, it is recommended that the ADI10 alone not be used for decision making). New norms also narrow the zone of uncertainty.

Subjects undergo examination on the CBDI and then are assessed on the road.

Center for Outpatient Rehabilitation in Knoxville, TN; Fort Sanders Regional Medical Center in Knoxville, TN; and North Alabama Rehabilitation Hospital in Huntsville, AL

$CBDI norms are based on 232 patients; however, only 180 completed road test. 52 patients were not allowed to take the road test due to extreme levels of disability.

$Of the 180 patients who completed the road test, 119 passed and 61 failed.

$GDI28 scores of 47 and below are clearly passing (accounting for 95 of 119 patients who passed road test and 4 of 61 who failed road test);

$GDI28 scores of 48-51 are borderline (accounting for 24 of 119 patients who passed road test and 23 of 61 who failed road test);

$GDI28 scores of 52 and above are clearly failing (accounting for none of the drivers who passed the road test and 34 of 61 patients who failed

$The probability of a patient with GDI28 scores of 51 and above passing the road test is below 23%

$42 nonpatients passed an average of 25.3 items, compared to 20.85 items for patients who passed the road test, 8.8 for patients who failed the road test, and 9.2 for patients for whom no road test was allowed.

$The 10 CBDI items most closely related to road test score are:

$WAIS-R Digit Symbol, n correct

$Trails A, time

$Trails B, time

$Visual Reaction Differential Response Reversed (VRDRR), average time

$VRDRR, Q2 time

$VRDRR, Q4 time

$Visual Reaction Differential Response II, % correct

$Visual Scanning III, match cols left, time

$Visual Scanning III, match cols right, time

$Individual=s variance across items

Engum and Lambert (1990)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

215 rehabilitation patients

(mean age = 47.8 years)

59 patients with left cerebral vascular accidents

58 patients with right cerebral vascular accidents

63 patients with traumatic head injuries

9 patients with spinal cord injuries

26 patients with other disabling and debilitating neurological disorders

(multiple sclerosis, Gullian-Barre syndrome, Alzheimer=s disease, myasthenia gravis, intrinsic & extrinsic tumors of the brain, Parkinson=s disease, toxic encephalopathy)

41 control subjects

(mean age = 31.15 years)

Licensed drivers without any reported history of brain injury or other neurological disorder. Also, no license suspensions or revocations, and no restrictions on driving privileges.

 

See: Engum, Pendergrass, Cron, Lambert, and Hulse (1988). Ten assessment tasks yield 27 response measures dealing with such cognitive/behavioral skills as attention, concentration, rapid decision-making, stimulus discrimination/response differentiation, visual scanning and acuity, and attention shifting.

Study objectives were to determine whether the CBDI would discriminate between 3 discrete groups: (1) those brain-injured persons whose residual cognitive impairments preclude them from driving; (2) those brain-injured individuals who have recovered sufficient cognitive function that they should be allowed to resume driving; and (3) normal control subjects without brain damage.

Subjects undergo examination on the CBDI and then are assessed on the road.

5 summary scores were calculated from the CBDI:

$GDI27 - the average of the patient=s 27 CBDI item scores

$within subject variance

$number of items passed

$number of items borderline

$number of items failed

________________________________________________

FINDINGS (Cont=d)

$22 of the 27 item scores and all summary scores correlated significantly with age; older patients produced larger (poorer) scores

$After removing the confounding effects of age, 20 of 27 item scores and 4 of 5 summary scores continued to differentiate patients from controls. Five of the 7 that failed to differentiate pertained to number of errors (various Visual Reaction and Scanning tests)

$Average GDI27 performance for controls (42.09) was superior to that of patients passing road test (45.75), which was, in turn, superior to patients who failed road test (54.23)

$Controls failed less than 2 of 27 CBDI items. Patients failed from 0 to 27 items. 40.5% of patients failed 8 or more items; 40.9 % of patients failed less than 2 items.

$Controls passed 18 to 27 items. 31.6% of patients passed 18 or more items (judged fit to drive). 32.1% of patients passed less than 8 items (judged cognitively impaired and unfit to drive)

Center for Outpatient Rehabilitation in Knoxville, TN; Fort Sanders Regional Medical Center in Knoxville, TN; and North Alabama Rehabilitation Hospital in Huntsville, AL.

$Based on CBDI performance, 118 patients were judged safe to drive and 97 were judged to be unsafe. Only 45 of the 97 patients judged unsafe were allowed to take the road test.

$Of the 163 patients who took the road test (118 + 45), 109 passed and 54 failed.

$All 5 summary scores, plus 25 of the 27 item scores significantly discriminated the 215 brain-injured patients from the 41 normal controls (p<.05)

$The 109 patients who passed the road test performed significantly better on all 27 items of the CBDI, and 4 of the 5 summary scores than the 54 patients who failed the road test (p<.01). The sole exception was for the number of borderline items, which was unrelated to road test performance.

$The control group performed significantly better on the CBDI (on 21 of the 27 items and all 5 summary scores) than the patient group who passed the road test (109 patients){p<.05]

$The control group performed significantly better on the CBDI (on 19 of the 27 items and all 5 summary scores) than the patient group who Apassed@ the CBDI/ judged safe to drive (118 patients). [p<.05]

$The control group performed significantly better on the CBDI (on 21 of the 27 items and all 5 summary scores) than the patient group who Apassed@ the CBDI and passed the road test [p<.05]

$5 of the 7 items that failed to discriminate controls from passing patients on the CBDI pertained to the number of errors on a task rather than upon the speed and fluidity with which tasks were performed

Engum, Lambert, and Scott (1990)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Behavioral Driver=s Inventory (CBDI)

232 rehabilitation patients (from the restandardization sample) and 42 control subjects in 4 age categories:

youth (age 26 or less)

adult (27-45)

middle aged (46-62)

elderly (age 63 and older)

Diagnoses:

61 patients with left cerebral vascular accidents

60 patients with right cerebral vascular accidents

71 patients with traumatic head injuries

9 patients with spinal cord injuries

31 patients with other disabling and debilitating neurological disorders

(multiple sclerosis, Gullian-Barre syndrome, Alzheimer=s disease, myasthenia gravis, intrinsic & extrinsic tumors of the brain, Parkinson=s disease, toxic encephalopathy)

See: Engum, Pendergrass, Cron, Lambert, and Hulse (1988). Ten assessment tasks yield 27 response measures dealing with such cognitive/behavioral skills as attention, concentration, rapid decision-making, stimulus discrimination/response differentiation, visual scanning and acuity, and attention shifting.

Analysis Objective: to determine the differential effects of age and diagnosis upon cognitive status as related to driving safety.

Variables: age group

Diagnosis (LCVA, RCVA, head trauma, other neurological condition, spinal cord injury)

CBDI performance (pass, fail, borderline)

Road test status (pass, fail, deferred)

Neuropsychologist=s decision (pass, fail)

Subject status (patient, control)

Subjects undergo examination on the CBDI and then are assessed on the road.

_______________________________________________

FINDINGS (Cont=d)

$CBDI performance was the most sensitive to organicity or neuropsychological impairment of all patient variables. Older patients suffering left and right CVA or w/ other degenerative neuropsychological conditions who fail the CBDI and/or the road test, have a high morbidity index and a pessimistic prognosis for driving. But traumatically brain injured, spinal cord injured, and young patients who fail the CBDI are unstable neuropsychologically, and may be capable of making rapid gains due to rehab and spontaneous recovery (and many may resume driving after rehab). Middle-aged stroke patients are average on the stability index, and although may experience improvement in cognitive function, the age-limited recovery tends to restrict some of the gains.

Center for Outpatient Rehabilitation in Knoxville, TN; Fort Sanders Regional Medical Center in Knoxville, TN; and North Alabama Rehabilitation Hospital in Huntsville, AL

$Left CVA patients are less likely to pass the road test than the average patient, and more likely to obtain borderline CBDI scores.

$Traumatically brain-injured patients are more likely to pass the road test than the average patient, and less likely to obtain borderline or failing CBDI scores. Also more likely to receive a passing recommendation from neuropsychologist.

$Right CVA patients are more likely to fail the CBDI than the average patient, and more likely to receive a failing recommendation from the neuropsychologist.

$Equations with weighted coordinates were derived to calculate

(1) an organicity index (cognitive status; measure of operational skills required for safe operation of motor vehicle),

(2) a stability index (to determine if a presently unqualified individual may be able to drive at some point in the future; the reduced probability of long term cognitive change in rehabilitation), and

(3) a morbidity index (a global summary of all patient characteristics inc. CBDI performance, age, diagnosis, neuorpsych judgment, road test performance; the weighted sums of organicity and stability). Higher scores are pathological while lower scores are benign. Future versions of the CBDI software will calculate organicity, stability, and morbidity indices.

Lambert and Engum (1992)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Cognitive Screen

(ADrivAble Testing, Ltd.@)

Test development research: 279 drivers across three groups:

176 patients referred to a clinic with suspected decline in mental abilities (majority were diagnosed with Alzheimer=s) with mean age = 72;

70 mature healthy drivers volunteered for the research (mean age = 69);

33 young (age range 30-40; mean age = 36) healthy controls also volunteered.

Validation research: 431 drivers

(no other descriptive info provided about this sample)

The (cognitive) competence screen is presented on a touch screen computer, & takes 20-30 min to administer. Tasks require multiple mental abilities and integration and shifting among these abilities. Tests include: a selective attention task; an assessment of judgment/decision making using a Gap Task (designed by research team); visual attention (using a version of UFOV (Ball et al., 1994); a spatial working memory task; a simple and choice reaction time test; and Weaver=s Driving Video (selected & revised driving scenarios). Two competence scores are generated: The high cutoff score identifies the performance level necessary to accurately predict that the driver would pass the road test; the low cut-off score identifies the performance level below which accurate predictions of failing road-test performance can be achieved. The road test would only need to be administered to those who score in the mid range on the competence screen (and, depending on the jurisdiction, for those who fail the competence screen but want a road test as due process)

A road test was administered by 2 experienced driving instructors from the Canadian Automobile Association. Testing was conducted in a mid-sized American car equipped with dual brakes. Definition and scoring of errors was as follows:

$Hazardous or potentially catastrophic driving errors: errors committed by drivers who are no longer competent to drive (e.g., wrong-way on a freeway, stop at green light), and would result in a crash if examiner did not intervene or traffic did not adjust

$Discriminating driving errors: potentially dangerous errors that signal declining driving skill (e.g., poor positioning on turns and straight aways, observational errors)

$Non-Discriminating driving errors: errors made equally often by good and bad drivers, reflecting bad habits as opposed to declining ability (e.g., rolled stops and speed errors). Drivers are not penalized for non-discriminating errors. Discriminating errors are documented and scored in terms of their severity (5, 10, or 51 points). Hazardous errors were renamed as Criterion errors and the commission results in an automatic fail. A combined criterion of one or more criterion errors and/or discriminating point total exceeding criterion, results in a failure on the road test.

Neuropsych. and Rehab. Med. Dept, Northern Alberta Regional Geriatric Program

Subjects in the development research were used to develop road test procedures and scoring. The majority of the drivers who failed the road test received low scores on the cognitive screen; the majority of the drivers who passed the road test received high scores on the cognitive screen.

Validation Research: The cut-off scores identified in the original research for the competence screen were 94% accurate in predicting actual pass/fail performance on the road test. Only 33% of those tested had Competence Screen scores falling below the high and low cut-off scores. Analysis of the road test errors revealed the same categories of errors and verified the effectiveness of the road test for revealing the errors among unsafe drivers. Using the joint criterion, all of the young normal drivers passed the road test, approximately 95% of the mature control group drivers passed the road test, and only 25% of the cognitively impaired (patient) group passed the road test.

The Competency Screen resulted in a 5% error in predicted road test performance: it predicted a pass for 29 of the 33 drivers who passed the road test, and predicted a fail for 33 of the 34 drivers who failed the drive test. The screen reduced the number of drivers who needed to be tested by 67%. Only 33% of the drivers in the sample received an indeterminate score on the competence screen: 54% of the indeterminate drivers passed the road test and 45% failed the road test.

DriveAble Testing, March 1997; Dobbs, 1997

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Driving Advisement System (DAS)

Visuo-motor (pursuit tracking); movement speed; speed of information processing; consistency of performance; laterality; acquisition (learning) of procedures; self-modulation (impulse control); and meta-cognition (self-appraisal)

$ 60 licensed drivers aged 18-86 deemed to be safe drivers and free from serious neurological impairment (standardization sample)

$ 60 traumatic brain injury and cerebrovascular accident survivors 60 traumatic brain injury and cerebrovascular accident survivors

___________________________

PROCEDURES (Cont=d)

False alarms are also recorded on trials where the gas pedal is released before the "B" appears.

Performance is compared to comprehensive driving evaluations in driving rehab centers, and may include an on-road exam.

The choice reaction time test builds on the simple reaction time test by adding an equal number of "H" (horn) and "B" (brake) stimuli, in an unpredictable sequence. The object is to be as quick as possible without making errors in pedal activation. The reversing choice reaction time test builds on the procedures used in the choice reaction time segment. On a random half of the trials, a sign appears in the center of the screen that says, "pedals reversed." When this happens, the person must press the brake pedal when an "H" appears, and press the horn pedal when a "B" appears. The program switches unpredictably between the "ordinary" mode and the "pedals reversed" mode, demanding rapid adjustment.

A more comprehensive protocol that uses the same IBM compatible system as the EDS. The DAS is an hour long protocol designed for advising persons who seek to resume driving following brain injury, caused by head injury or stroke. The DAS software costs $500.00 and the foot pedals are an additional $200.00. Its procedures address the complexity of information processing, and breaks responses down into a decision and an execution component. As the task demands increase in complexity, the choice component of reaction time is expected to increase, but not the execution component. Momentary contact switches are activated by three pedals, laid out on a floor plate with a middle gas pedal, a left brake pedal, and a right horn pedal; the horn and brake pedal are equidistant from the gas pedal. A steering wheel senses rotation of approximately 270. There are five parts to the appraisal: self appraisal; a pursuit tracking task ("On the Road"); a simple reaction time procedure ("Brake"); a choice reaction time task ("Decide"); and a reversing choice reaction time task ("Inhibit"). In the self-appraisal portion, ratings are obtained for eight parameters: reaction time, decision speed, movement speed, speed of adaption, consistency, concentration, field of vision, and impulse control. After each parameter is explained carefully, the subject uses the steering wheel to move a marker that represents his/her present status on a display in comparison to "other safe drivers." In the pursuit tracking task, the display contains an abstract representation of a road with a small rectangular block representing the vehicle, which can only be moved laterally. The road itself changes, creating an illusion of movement. The subject's task is to hold down the gas pedal to keep the vehicle moving along the road and to use the steering wheel to maintain the vehicle in the center of the road. Modifiable parameters include speed of progress, roadway width, roadway curviness, length of course, amount of preview of the roadway above the vehicle. In the simple reaction time test, the subject holds down the accelerator until the letter "B" appears either in the right or left signal box. Then, s/he moves the foot from the gas to the brake as quickly as possible, and replaces the foot on the gas to resume driving. Resumption time (brake to gas), choice time (appearance of B to release of gas), and execution time (release of gas to press of brake) are measured in 100ths of a second.

Gaylord Hospital (Wallingford, CT)

The execution times of the standardization group in "Brake," Decide," and "Inhibit," do not increase with increasing task complexity and substantiates that these times are reflective of motor functioning and not mental processing. In contrast, the choice times increased with increasing complexity. Gianutsos and Campbell (1988) have found that the DAS measures correlated with an on-the-road assessment (pass/fail criterion) in a group of 60 traumatic brain injury and cerebrovascular accident survivors slightly better than the Porto Clinic Glare (a device used in predriving assessments typically conducted in occupational therapy settings, that screens visual acuity, visual fields, depth, glare recovery, color vision, and reaction time in approximately 20 min. Performance criteria are based on performance of Marine recruits). Additionally, the DAS and Doron simulator correlate well with the outcome of a comprehensive evaluation (Gianutsos and Campbell, 1991).

Gianutsos et al. (1992)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Easy DriverJ

170 Subjects: age range 15-91, 89M 81F

Older and younger groups divided at 55 yrs. old for analysis of preferred speed, and divided at 65 yrs. for traffic event RT.

Computer-video display and recording system Easy DriverJ which runs from a Macintosh microcomputer and a standard large-screen color TV monitor, with a dual pedal control unit (brake and accelerator). Drivers view driving scenarios while they operate brake and accelerator pedals to drive at preferred speeds under various conditions, and to brake in response to events occurring in the video. Scenarios include traffic events in which drivers may respond to the onset of brake lights in a lead vehicle or rapid closures of gaps between vehicles, intrusions of other vehicles and pedestrians (high and low illumination conditions), stop signs and traffic signals, and tennis balls (small, high contrast target) or basketballs (large, low contrast target, used in day and in dusk conditions) rolling into the road in suburban residential areas (indicating possible incursion of child). Drivers proceed at their own pace in several scenarios including highway driving in excellent road conditions in light traffic, wet snow/rain, heavy rain, and night driving with oncoming headlight glare.

Independent Variables:

$ Preferred driving speed: Speed in MPH for:

1. 4 lane road, dry

2. 2 lane road, wet

3. Heavy Rain

4. Headlight Glare

$ RT to Traffic Events: critical events included:

1. Stopped schoolbus

2. Lead vehicle brakes, city driving

3. Lead vehicle brakes, rural

4. Pedestrian Incursion, day

5. Pedestrian Incursion, night

6. Hit ped. (pedestrian stands in road, scene stops with ped directly in front of car hood)

7. Basketball in road, day (low contrast)

8. Basketball in road, dusk

9. Tennis ball in road, day (high contrast)

$ Simple RT measure: RT measured to traffic light changing from green to red.

Dependent variable: Global Accident Risk (GAR) =Total number of reported at-fault crashes for each driver, with the addition of up to 3 more points for self-reported medical or driving problems (dizziness, attentional lapses, severe arthritis, poor vision, and poor vehicle control). The resulting range of scores was 0-13.

Data collected at 4 sites in Fla, Vermont, NYU, and suburban NYC.

$ Performance differences between 109 older S=s (aged 55-95) and 61 younger S=s (aged 15-54) included slower driving speeds by older S=s, particularly in the poor visibility conditions and under headlight glare conditions; longer (but not signif.) simple RT; longer RT=s to traffic events such as braking in response to lead vehicle brake lights, a ped., and the basketball (dusk) scenarios; late braking by 40-90 year olds in response to a school bus pulling into their lane; and lack of response by a substantial number of older S=s to the tennis ball and basket ball (dusk) scenarios.

$ Two S=s age 74 and 75 accidentally depressed the gas pedal in response to the hit ped. and tennis ball scenarios, rather than the brake.

$ Although difference in RT not significant, a mean diff. of 75 msec translates to a stopping dist. of 4.4 ft at 40 mi/h.

$ Using GAR score as a criterion, mult. regress. anal. were performed to determine which scenarios would best predict driving perf. Using scores for hit ped., schoolbus, and tennis ball scenarios, plus simple RT for the entire sample, a multiple R=.39 was obtained, accounting for 12-15% of the variance of GAR scores.

$ Regress. anal. performed separately for older and younger S=s using 65 years as the criterion age split. For the older S=s, RTs from hit ped., tennis ball, basketball (dusk) and city brakes yielded an R=.47, accounting for 22% of the var. in GAR scores. For young S=s, schoolbus, hit ped., & tennis ball yielded an R=.41, accounting for 16% of the variance.

Schiff & Oldak (1993)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Elemental Driving Simulator (EDS)

(Tracking, simple reaction time, complex reaction time, divided attention, complex visual perception, judgment)

1,475 ITT Hartford Insurance Co. policyholders for whom past driving histories were available through insurance records, divided into two groups based on the presence or absence of recent at-fault accidents. Driver age ranged between 50 and 80+ and was distributed as follows:

$ 26 percent of the sample were between 50-64,

$ 54 percent were between 65-74,

$ 20 percent were over 75.

Participants were active drivers who had (generally) been pre-screened for risk in the insurance underwriting process. Also, participants who came in for testing appeared confident in their driving abilities.

A quasi-driving simulator which includes a steering wheel, accelerator and turn signal, provided scores on three subtests. These subtests included a basic steering experience; a steering experience combined with using a turn signal when prompted with an on-screen stimulus; and a complex experience in which the turn signal task stimulus reverses the appropriate response. Phase 1 is a preview tracking task which requires the subject to steer a simulated vehicle which moves at a fixed pace in the center position of the driving lane. Measures of lateral position are taken 8 times per second. In Phase II, a two-choice RT test is added to the steering task, where as the road advances, a small, one-character stimulus face appears unpredictably on either side of the roadway. The subject must turn the signal lever on the steering column toward the face as soon as possible, while maintaining a steady position in the center of the road. Reaction times are stored along with the steering measures. In Phase III, a contingency is introduced into the reaction time test such that when the face is flashing ("hazard"), the subject must away from it, and when it is steady, the subject must signal toward the face.

Insurance and motor vehicle department records provided information about the following variables: at-fault accidents, non-fault accidents, non-accident claims, violations and convictions, miles driven, age, gender and marital status.

Testing rooms in hotels in 15 cities throughout Connecticut, Florida, and Illinois

Performance on the EDS yielded a low but significant correlation with at-fault accidents (r = -.09, p .05). Sample selection bias (policy holders with poor functional capabilities may have declined to participate) and testing under noisy conditions (hotel sites) may have contributed to the low correlations. Additionally, a higher correlation may have been attained if an important procedure had been followed in test administration (according to the test developer). The EDS should be administered as a one-on-one test with a test administrator trained in its use. Each phase should be preceded by sufficient practice to ensure that the subject is comfortable with the task. The theory is that driving is a highly practiced task, and the subjects should be encouraged to continue in the practice mode until they feel they have reached their best level of performance. Also, this approach contributes to the clinical acceptance, as people believe they have been given the fairest possible chance. In this study, time was a limited commodity, and therefore subjects were "rushed in and out," with little practice. This resulted in not obtaining good baseline steering practice and therefore a subset of the subjects were unable to complete all three phases of the test.

Brown, Greaney, Mitchel, and Lee (1993)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Elemental Driving Simulator (EDS)

(Tracking, simple reaction time, complex reaction time, divided attention, complex visual perception, judgment)

$ 50 normatively-aged drivers (average age 41)

$ 1145 community residing older drivers

(average age = 69)

$ 82 drivers seeking driver rehabilitation related to a CNS disorder

(average age = 37)

IBM-compatible PC, a 10-inch diameter steering wheel controlling a 150K linear potentiometer with turn signal, and a momentary contact foot pedal. Apart from the computer, the EDS costs about $2,000 and includes a full day of training. Testing requires about 20 minutes, although 30 minutes should be scheduled to allow for sufficient practice by the poorest performing segment. The system is elemental in its technical simplicity and in its simulation of the elements of driving-related cognitive abilities. It is employed to assess people with known or suspected cognitive impairment. The assessment protocol begins with a self-appraisal of cognitive abilities related to driving: steering control, speed of reaction, self-control (impulsivity), field of view, consistency, and adjustments to changes and complexity. Each of these areas is then assessed in increasingly complex simulated steering tasks. Phase 1 is a preview tracking task which requires the subject to steer a simulated vehicle which moves at a fixed pace in the center position of the driving lane. Measures of lateral position are taken 8 times per second. In Phase II, a two-choice RT test is added to the steering task, where as the road advances, a small, one-character stimulus face appears unpredictably on either side of the roadway. The subject must turn the signal lever on the steering column toward the face as soon as possible, while maintaining a steady position in the center of the road. Reaction times are stored along with the steering measures. In Phase III, a contingency is introduced into the reaction time test such that when the face is flashing ("hazard"), the subject must away from it, and when it is steady, the subject must signal toward the face.

The rehab sample received a comprehensive driving evaluation that included medical and driving history, vision screening, EDS, Doron simulator, and a road test. A pass or fail decision was made about each individual.

Gaylord Hospital (Wallingford, CT)

The performance of the 50 normatively-aged drivers was more consistent and substantially better than that of 1145 community residing older drivers and the group of 82 drivers seeking driver rehabilitation related to a CNS disorder. As a group, the older drivers performed almost as poorly in terms of steering ability, two-choice simple reaction time, and in complex reaction time as the rehabilitation patients who failed their driving exam. The failers were always worse than the passers, however the difference in performance was significant only for steering unsteadiness.

Case examples have shown also that observations of actual on-road performance are consistent with conclusions based on the EDS; persons who perform poorly on the EDS have been observed to exhibit lane drifting, poor steering control, failure to make head checks, impulsivity, and difficulty in making adjustments during a 1.5 hr drive.

Gianutsos (1994)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

University of Illinois/Atari

Interactive Driving Simulator

6 subjects w/ hemianopic visual field deficits, 2F 4M age 53-80 (mean 71 yrs)

7 Older controls 3F, 4M age 62-83 (mean 70)

Data collected from 31 younger controls in an earlier study also analyzed

Interactive driving simulator [developed in collaboration with Atari Corp (Milpitas, CA)], is composed of a seat, steering wheel, gas and brake pedals, and an automatic transmission. The visual display consists of three 62.5 cm color monitors displaying a 160 horizontal viewing field and a 35 vertical viewing field of a computer-generated environment to a driver sitting 57.5 cm from the center screen. Stimuli are computer-generated images of a simulated roadway with traffic, signs, and painted roadway lines. The video scene was updated 20 times per second. Simulator performance MOEs included

$ Mean speed (in MPH)

$ Average slowing and stopping to traffic signals

$ Number of lane boundary crossings

$ Mean Break pedal pressure

$ Mean Gas pedal pressure

$ Number of simulator accidents

$ Lane position

$ Steering angle

$ Vehicle angle to the road

Six staged driving simulator challenges required visuocognitive/motor skills to avoid an accident; three of these were intersections with cross traffic.

Eye and Head Movement recorded for each subject

Self report of accidents over the previous five years was also collected for each subject

_____________________________________________

FINDINGS (Cont=d)

$ simulator accidents occurred only for 2 subjects in the older normally-sighted group.

$ Two of the four older subjects who had real world accidents also had the longest slowing times, the longest stopping times, and the most accidents in the driving simulator.

$ no signif. diff. between mean brake pedal pressure among the 3 groups, but greater variability in brake pedal pressure for both older groups, compared to normally sighted younger controls.

Univ. Illinois at Chicago

Eye Center

$ significantly more lane boundary crossings for the older patient group, but no significant differences between the older and younger control groups this performance measure (p<.01);

$ greater variability in lane position among the older patient group with no consistent differences in absolute lane position between the two control groups (p<.05);

$ greater deviations in steering angle by both groups of older drivers compared to the younger control group, but no significant differences between the older patient and older control group on this measure;

$ no significant differences between the three groups in their vehicle angle to the road performance measure;

$ longer slowing times by 4 older controls and 3 older patients when compared to the younger controls, but no differences in mean slowing times between the two older groups, due to a large variability among individuals;

$ prolonged stopping times by both older driver groups when compared to the younger control group;

$ slower avg. speeds exhibited by both older groups when compared to the younger group, but no differences in mean speed between the older patients and older control subjects;

$ lower avg. pedal pressure and greater variability in accelerator pedal pressure by both older groups in comparison to the younger group, but no differences between the 2 older groups on this measure;

Szlyk, Brigell, & Seiple (1993)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

University of Nevada, Las Vegas (UNLV) subtests:

Form Detection

(speed of discriminating between forms);

Visual Tracking (tracking and stopping a moving stimulus);

Cognitive Overload (divided attention)

1,475 ITT Hartford Insurance Co. policyholders for whom past driving histories were available through insurance records, divided into two groups based on the presence or absence of recent at-fault accidents. Driver age ranged between 50 and 80+ and was distributed as follows:

$ 26 percent of the sample were between 50-64,

$ 54 percent were between 65-74,

$ 20 percent were over 75.

Participants were active drivers who had (generally) been pre-screened for risk in the insurance underwriting process. Also, participants who came in for testing appeared confident in their driving abilities.

$form detection: the ability to discriminate between forms presented outside the center of the visual field

$visual tracking: the ability to track a moving object presented outside the central field of vision

$cognitive overload: form detection task coupled with visual tracking task.

Computer tests were administered on a Macintosh Plus microcomputer with a number pad. Subjects were seated in front of the computer monitor at a distance of 24 inches. Task instructions were provided by the computer and were followed by short practice sessions. Form detection task: a square or a cross appeared in 1 of 10 locations around the perimeter of the screen. S=s were to press the AK@ key if they saw a square, and the AD@ key if they saw a cross. The size (2.2 x 2.2 cm or 1 x 1 cm), type (square or cross), and location of the stimulus varied randomly, Stimulus duration was constant at 500 ms. Visual tracking task: a small white cross (1 x 1 cm) randomly appeared in 1 of 4 locations around the screen. A square (1 cm x 1 cm) simultaneously appeared 7 cm away from the cross. The cross moved towards the square at 1 of 2 speeds (7 or 14 cm per s). S=s were to stop the cross by pressing the space bar as soon as it was completely enclosed by the square. The direction and speed of movement varied randomly. Cognitive overload task: a trial started with a fixation point immediately followed by the presentation of a cross moving toward a square in the center of the screen. The S was to stop the cross when it was completely enclosed by the square. While the cross was moving, a square or cross appeared in 1 of 10 locations near the edge of the screen. S=s were to press the AD@ key for a cross and the AK@ key for a square. The speed of tracking was constant at 14 cm/s. The kind and size of the stimulus in the detection task varied randomly.

Insurance and motor vehicle department records provided information about the following variables: at-fault accidents, non-fault accidents, non-accident claims, violations and convictions, miles driven, age, gender and marital status.

Testing rooms in hotels in 15 cities throughout Connecticut, Florida, and Illinois

The UNLV Tests produced correlations for 2 subtests: Form Detection mean time (r=0.10) and the Visual Tracking accuracy in the Cognitive Overload task (r=0.09) were predictive of at-fault accidents.

Brown, Greaney, Mitchel, and Lee (1993)

ATTENTION/

PERCEPTION/

COGNITION

Multiple Capabilities:

Washington University Visual Attention Tests

 

Participants recruited from Alzheimer=s Disease Research Center (ADRC) at Wash. Univ. School of Medicine

58 healthy elderly control subjects, mean age = 76.8; Clinical Dementia Rating =0

65 subjects with Dementia of the Alzheimer=s type (DAT), mean age = 73.7; Divided into 2 groups: 36 Ss with Clinical Dementia Rating = 0.5 (very mild DAT) and 29 Ss with CDR = 1.0 (mild DAT)

All S=s had corrected acuity of at least 20/50

Three computerized tests of visual attention were employed to study the relationship between specific aspects of visual attention and driving skills in DAT:

The UFOV task (Visual Attention Analyzer) was used as a measure of early attentional processing, and the size of the functional field of view available for target identification was used to examine relationships with on-road driving performance and dementia severity.

A visual monitoring task measured the ability to detect infrequent changes in a visual display (vigilance), where S=s had to respond when a target AX@ occurred in a series of scrolling AO@s while monitoring one or two lines on a computer screen. In the visual monitoring task, 2 types of errors were possible: errors of omission (missing the target) and errors of commission (false alarming in the absence of the target).

A visual search task was used to examine the ability to select a target that was either present or absent in an array of distractors. There were two types of errors: miss errors (responding that a target is not present in the array when it really is present), and false alarm errors (responding that a target is present in the array, when it really is not present)

S=s were administered the on-road, in-traffic driving test (see On-road Performance Measures of Driving Safety: Washington University Road Test at the end of this Compendium). Driving performance (Ahigh@ vs Alow@) was based on a median split on drive test scores.

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FINDINGS (Cont=d)

$In the visual search task, there was no difference in miss or false alarm errors for Ss with high vs low drive test scores in CDR 0 and CDR 0.5 groups, but a large increase in false alarm errors was shown for CDR 1 poor-performing drivers compared to CDR 1 Ss who performed well on the drive test.

Washington University School of Medicine

Road test conducted on urban medical school and urban highways and streets

$Percent reduction in UFOV was greatest in the mildly demented Ss (CDR = 1), particularly for CDR 1 Ss who also showed poorer performance on the drive test. The reduction in UFOV for mildly demented Ss with low (poor) drive performance scores was 90%, compared to 60% for mildly demented Ss with high (good) driving performance. The larger reductions in UFOV for Ss with low drive scores occurred primarily in the selective attention component of the UFOV task, where the S must localize a peripheral target embedded in an array of distractors. Percent UFOV reduction for very mildly demented Ss (CDR = 0.5) was 40% for Ss who performed poorly on the road test, and 32% for Ss who performed well on the road test. For non-demented Ss (CDR = 0), there was little difference in UFOV reduction as a function of drive performance (28% reduction for good performers and 30% reduction for poor performers).

$In the visual monitoring task, there was no differentiation in miss or false alarm errors for Ss with high vs low drive scores in either the healthy control group (CDR = 0) or the very mild DAT group (CDR = 0.5). There was a large increase in false alarm errors for CDR 1 individuals (mildly demented) with poor driving performance (@ 20 errors) compared to CDR 1 Ss with good driving performance (@ 5 errors).

Duchek, Hunt, Ball, Buckles, and Morris (1997)