Section 5: Cerebrovascular Diseases
- 5.1. Transient Ischemic Attacks
- 5.2. Cerebrovascular Accidents
A summary of the current fitness-to-drive guidelines (Cerebrovascular Diseases) for medical practitioners from Australia (1998) and Canada (2000) is presented in Table 13.
5.1 Transient Ischemic Attacks
Transient ischemic attacks (TIAs) are brief episodes of stroke-like symptoms that last less than 24 hours. TIAs are thought to be caused by temporary dysfunction of a portion of the brain caused by transient ischemia and are more common in the older population (Earnest and Cohen, 1990). Permanent cerebral damage does not occur with TIAs. TIAs are an important warning symptom and are a risk factor for a cerebrovascular accident. Approximately 20 to 30 percent of individuals experiencing a first TIA will have a completed stroke within three years (Mohr and Pessin, 1986).
There are an estimated 30,000 to 150,000 TIAs each year but accurate estimates are difficult because of the likelihood of under reporting (American Academy of Neurology, 1997).
Transient Ischemic Attacks and Driving Literature Review
The symptoms of TIA depend on the vessel involved. Earnest and Cohen (1990) provide a description of symptoms based on carotid artery involvement and vertebrobasilar involvement. Those symptoms are presented in Table 10.
Many of the neurological sequelae of TIAs, clearly, can have important implications for driving. There are, however, few studies available on the relationship between TIAs and increased risk of motor vehicle crashes. Rehm and Ross (1995) prospectively evaluated drivers 60 years of age and older with unexplained motor vehicle crashes presenting to their trauma center over a one-year period. Of the 79 drivers (aged 60-98), 73 percent were at-fault in the crash. Of those patients with a syncope etiology, eight percent were deemed due to TIA. Although there is a paucity of literature investigating the relationship between TIAs and motor vehicle crash risk, most medical guidelines recommend driving cessation following a single TIA or recurrent TIAs until the cause has been identified.
Table 10 Summary of Transient Ischemic Attack Symptoms by Vascular Supply
(Reproduced from Earnest, M.P., & Cohen, J.A. (1990). Cerebrovascular disease. In R.W. Schrier (Ed.), Geriatric medicine (pp. 109-118), with permission from W.B. Saunders Company, Philadelphia)
Bilateral facial or limb sensory symptoms
Hemianopsia or total blindness