Development and assessment of a neuropsychological battery to aid in predicting driving performance.

PURPOSE

This study was conducted to select a neuropsychological battery that correlated with driving simulator skills, thus enabling practitioners to provide information to older patients and their families about driving risks.

METHODS

The study was conducted in two phases. In Phase 1, a survey inquiring as to the kinds of neuropsychological tests currently used to screen patients for driving was sent to 292 licensed neuropsychologists. Of these 292 surveys, 125 (43%) were returned. We used the responses to develop a battery of nine tests, including eight neuropsychological tests and one other cognitive measure: (1) the Seashore Rhythm Test, (2) Logical Memory (Immediate [I] and Delayed [II]) of the Wechsler Memory Scale-Revised (WMS-R), (3) WMS-R Visual Reproduction (Immediate [I] and Delayed [II]), (4) Trails A and B, (5) Digit Span, (6) Digit Symbol, (7) Block Design, (8) Visual Form Discrimination, and (9) a Zoo Map Test. The complete battery included 12 measures. In Phase 2, 22 licensed drivers were recruited ranging in age from 67 to 91 years (14 males and 8 females). The Mini-Mental Status Exam (MMSE) was administered to all subjects. Scores on this test served as a criterion cutoff for placement into a group of subjects with suspected dementia (Group 1, MMSE score below 25) or a group of control subjects (Group 2, with a MMSE score of 25 or above). None of the patients had any gross motor difficulties. Following screening, subjects were administered the neuropsychological battery, a driving simulator test, and a Driving Habits Interview.

RESULTS

Data revealed a significant difference between the performance of Groups 1 and 2 on the driving simulator test in two distinct areas, staying within one's lane boundaries and speed. The suspected dementia subjects had significantly more lane boundary crossings than the control subjects and drove at significantly slower speeds. Ten neuropsychological measures correlated with driving simulator performance. The number of lane boundary crossings correlated with the greatest number of neuropsychological tests, with more lane boundary crossings correlated with poorer performance on the neuropsychological tests. In particular, Trails A, Trails B, and Logical Memory (Immediate) correlated with the largest number of driving measures.

CONCLUSION

Preliminary findings show that commonly used neuropsychological tests correlated with driving simulator skills as measured with a driving simulator. Because the driving simulator has been shown to be correlated with actual on-road driving, one may hypothesize that these neuropsychological tests may be predictive of on-road driving. This research is important in defining an appropriate battery to screen for driving skills in patients with known or suspected dementia.