This study validates four simple neuropsychological tests as tools to assess the driving fitness of brain-damaged patients: (1) a Perceptual Speed test; (2) the Wechsler Adult Intelligence Scale (WAIS) Symbol-Digit Substitution subtest; (3) a Tracking-Reaction dual task; and (4) a Time Estimation task. These tasks focus on perceptual and attentional deficiencies that most brain-damaged patients show. Subjects performed both the laboratory tests and an on-road driving test. The results indicated that, for brain-damaged patients, performance on both the Perceptual Speed task and the Time Estimation task were significantly correlated with driving performance. Neither of the tests, however, predicted on-road driving to a degree that would justify replacing the on-road driving test that is currently used to assess the driving fitness of brain-damaged patients. When combined with coma duration and driving experience, the Perceptual Speed and Tracking-Reaction tests together could explain 35.3% of the variance in on-road driving performance. More detailed analyses showed that also a combination ofthese test scores did not justify enough to replace on-road driving fitness assessment. All in all, assessing driving fitness of brain-injured persons with the to-be-validated laboratory tests was not justified by the present results. As a consequence alternative tests (for instance using low-cost driving simulators) need to be developed. (A)
Abstract