Evaluation of two assessment tools in predicting driving ability of senior drivers.

Objective: To evaluate Motor Free Visual Perceptual Test (MVPT) and Clock Drawing Task (clock test) as quick assessment tools in predicting driving capability of senior drivers for an on-road driving test.

Design: Senior drivers (> or = 55 yrs) referred for evaluation and recommendation for license renewal were given the MVPT, clock test, and an on-road driving test. Receiving operating characteristic (ROC) analysis and stepwise multivariate logistic regression (SMLR) were used to develop a probability model to differentiate between capable and incapable senior drivers.

Results: Data for 232 seniors who had completed all written tests and the on-road driving test were analyzed. Of the 232 seniors, 131 (56%) were classified as capable and 101 (44%) as incapable drivers on the road test. Mean scores for capable and incapable drivers were MVPT 32.0 +/- 4.0 vs. 28.4 +/- 4.6 and mean clock test score 3.5 +/- 0.8 vs. 2.7 +/- 1.2, and mean processing time was 7.1 + 6.5 vs. 10.6 + 5.5. The means of the three measurements were significantly different between the two groups (P value <0.001). ROC curve analysis revealed an optimal cut point of > or = 32 for MVPT score with 60% sensitivity and 83% specificity. The optimal cut point for clock test scores is > or = 3 with 70% sensitivity and 65% specificity. The optimal cut point for processing times is < or = 6.27 secs with 60% sensitivity and 80% specificity. SMLR showed that the most significant predictor of seniors' driving capabilities are the MVPT test scores and clock test scores.

Conclusion: MVPT and clock test tools are significant predictors of driving capability on an on-road driving test.