Driving with Parkinson’s disease: Cut points for clinical predictors of on-road outcomes

Abstract

Background. Parkinson’s disease (PD) is a common neurodegenerative disorder that impacts a person’s fitness to drive. Practitioners require a sensitive and predictive battery of clinical tests to identify at-risk drivers. Purpose. This study aimed to identify clinical predictors and their optimal cut points, sensitivity, specificity, and predictive values of on-road outcomes in drivers with PD. Method. Participants ( N = 101) underwent a comprehensive driving evaluation. We identified predictors of pass/fail outcomes through logistic regression and computed optimal cut points through receiver operating characteristic curves and corresponding Youden indexes. Findings. The Trail Making Test Part B (Trails B; sensitivity = .89, specificity = .74; positive predictive value [PPV] = .71; negative predictive value [NPV] = .91) and contrast sensitivity (sensitivity = .82, specificity = .63; PPV = .61; NPV = .84) emerged as significant predictors. The optimal cut point for the Trails B was 108 s (area under the curve = .86). Implications. Occupational therapists can benefit from implementing Trails B and contrast sensitivity screening as part of in-office screening of potentially at-risk drivers with PD.