Validity and reliability of the Traffic Sign naming test (TSNT) and written exam for driving decisions (WEDD) as measures of fitness to drive among older adults

Importance: Occupational therapists need valid and reliable tools to help determine fitness to drive of older drivers with medical conditions such as dementia. Objective: To establish the validity and reliability of the Traffic Sign Naming Test (TSNT) and Written Exam for Driving Decisions (WEDD) as measures of fitness to drive of adults with and without dementia. Design: Cross-sectional. Setting: Washington University Medical School in St. Louis in collaboration with the Rehabilitation Institute of St. Louis. Participants: Older drivers diagnosed with dementia (n = 130) and without dementia (n = 34). Drivers with dementia required a physician referral indicating a medical need for a driving evaluation, a diagnosis of dementia, and an Alzheimer Detection 8 score of 2. Drivers without dementia were required to be age 55 yr or older and not meet criteria for dementia. Outcomes and Measures: Participants completed a comprehensive driving evaluation (CDE) that included clinical measures of vision, motor, and cognition; TSNT; and WEDD. The outcome measure was performance on a standardized on-road assessment. Results: The TSNT's interrater reliability was determined to be strong (k =.80). The TSNT and WEDD demonstrated convergent validity with cognitive measures (p <.001) and discriminant validity with visual and motor measures in the CDE. The TSNT (area under the curve [AUC] =.74) and WEDD (AUC =.71) had fair ability to predict failure on a standardized on-road assessment. Conclusion and Relevance: TSNT and WEDD are recommended for use by occupational therapists in combination with other performance measures when determining fitness to drive or need for a CDE.