NEUROPSYCHOLOGICAL DRIVING FITNESS TESTS FOR BRAIN-DAMAGED SUBJECTS

Objective: The study was carried out to evaluate and develop simple to ols to assess the driving fitness of brain-damaged patients. Design: F our neuropsychological tests (predictors) were validated against an op en-road driving test (criterion standard), which is used by the Depart ment of Adaptations of the Dutch Driving Licensing Agency for assessin g disabled drivers. Setting: The predictor tests were conducted in the involved scientific institute; the criterion standard involved partic ipation in normal traffic. Patients: The subject group consisted of 33 men and 5 women who had recovered to a stabilized level from traumati c brain injuries. All had valid driving licenses when they were injure d and they were considered to be potentially able to recommence drivin g. The subjects had a mean reported driving experience of 109.200km (S D = 86.300km). All subjects were recovered from a brain trauma with an average coma duration of 33 days (SD = 51 days). They were tested at least 1 year after the accident. All subjects had normal or corrected- to-normal vision and none used medications that, according to existing medical criteria, interfere with normal psychomotor or cognitive func tioning. Ages at the time of the injury were between 17 and 55 years ( mean, 29.8; SD, 10.9). Main Outcome Measures: Pearson product moment c orrelations (and explained variances) were calculated between the four predictor tests (a Perceptual Speed test, the WAIS Symbol-Digit Subst itution subtest, a Tracking-Reaction dual task, and a Time Estimation task) and the open-road criterion standard. Results: The results indic ated that performance on both the Perceptual Speed task and the Time E stimation task were significantly correlated with driving performance (p < .05). When combined with coma duration and driving experience, th e Perceptual Speed and Tracking-Reaction tests together explained 35.3 % (r = .59) of the variance in on-road driving performance. Conclusion : The amount of variance in open-road driving performance that could b e accounted for by these tests was insufficient to completely replace an open-road driving fitness assessment. Also, based on other experime ntal documentation, it is concluded that more integral, domain-specifi c tests leg, based on driving simulation) need to be developed. (C) 19 96 by the American Congress of Rehabilitation Medicine and the America n Academy of Physical Medicine and Rehabilitation.