Use of the MMSE in the Prediction of Driving Fitness: Relevance of Specific Subtests

OBJECTIVES To examine the association between performance on subtests of the Mini-Mental State Examination (MMSE) and driving competence in people with cognitive impairment (CI) as well as those with no cognitive impairment (NCI). DESIGN Retrospective observational study. SETTING Participants referred for a DriveWise evaluation at Beth Israel Deaconess Medical Center in Boston, Massachusetts, were included in the study. PARTICIPANTS A total of 419 participants referred for a DriveWise evaluation was studied. The average age of the sample was 77.69 years. In this study, people with an MMSE score lower than 25 were included in the CI group; 41% of participants had CI. MEASUREMENTS All participants underwent mental status screening with the MMSE, and all underwent a 45-minute road test modeled after the Washington University Road Test adapted for use in Boston streets. RESULTS In both groups, poor road test performance was associated with low scores on the MMSE. In drivers with CI, MMSE total score and performance on the attention subtest were significantly lower for those who failed the road test. In drivers with NCI, the MMSE total score and orientation subtests were significantly lower for those who failed the road test. CONCLUSIONS Clinicians working with older people should know that the MMSE is an effective tool to screen for driving safety, but MMSE subtests are differentially sensitive to driving safety in people with and without CI. Poor performance on specific MMSE subtests may prompt further evaluation of driving competence with a road test. J Am Geriatr Soc 67:790-793, 2019.