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.