The influence of cognitive impairment on driving performance in multiple sclerosis

OBJECTIVE: To examine the influence of impaired cognitive processing on measures of driving skills in persons with MS. METHODS: Twenty-eight subjects with documented MS were divided into two groups-with [MS(+), n = 13] and without [MS(-), n = 15] cognitive impairment-based on neuropsychological performance. Healthy control (HC) subjects (n = 17) matched on age and driving experience were also studied. Driving-related skills were compared between the groups based on performance on two computerized driving tests: the Useful Field of Vision (UFOV) and the Neurocognitive Driving Test (NDT). RESULTS: The MS(+) group performed significantly worse than both the MS(-) and HC groups in the latency to perform several driving-specific functions on the NDT, but no overall group differences were observed in actual errors on the NDT. On the UFOV, when compared to MS(-) and HC subjects, the MS(+) group demonstrated poorer performance on two of the three subtests. Additionally, a significantly higher percentage of MS(+) individuals were rated within the high risk (probability of crash involvement) category, relative to the MS(-) and HC groups. CONCLUSIONS: Cognitive impairment can negatively affect driving-related skills in persons with MS and should be considered in the determination of driving ability.