Validity of the Mini-Mental State Examination and the Montreal Cognitive Assessment in the Prediction of Driving Test Outcome Ann M. Hollis, OTR/L,* Haley Duncanson, MA,*† Lissa R. Kapust, LICSW,*‡ Patricia M. Xi, MA,* and Margaret G. O’Connor, PhD*‡
OBJECTIVES: To evaluate the effectiveness of two cognitive screening measures, the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA), in predicting driving test outcome for individuals with and without cognitive impairment. DESIGN: Retrospective cohort study. SETTING: A clinical driving evaluation program at a teaching hospital in the United States. PARTICIPANTS: Adult drivers who underwent assessment with the MMSE and MoCA as part of a comprehensive driving evaluation between 2010 and 2014 (N = 92). MEASUREMENTS: MMSE and MoCA total scores were independent variables. The outcome measure was performance on a standardized road test. RESULTS: A preestablished diagnosis of cognitive impairment enhanced the validity of cognitive screening measures in the identification of at-risk drivers. In individuals with cognitive impairment there was a significant relationship between MoCA score and on-road outcome. Specifically, an individual was 1.36 times as likely to fail the road test with each 1-point decrease in MoCA score. No such relationship was detected in those without a diagnosis of cognitive impairment. CONCLUSION: For individuals who have not been diagnosed with cognitive impairment, neither the MMSE nor the MoCA can be reliably used as an indicator of driving risk, but for individuals with a preestablished diagnosis of cognitive impairment, the MoCA is a useful tool in this regard. A score on the MoCA of 18 or less should raise concerns about driving safety. J Am Geriatr Soc 63:988–992, 2015.
Key words: older driver; driving evaluation; neuropsychological tests
From the *Department of Neurology, Beth Israel Deaconess Medical Center; †Suffolk University; and ‡Harvard Medical School, Boston, Massachusetts. Address correspondence to Ann M. Hollis, Cognitive Neurology Unit, 330 Brookline Ave., Boston, MA 02215. E-mail: [email protected]
JAGS 63:988–992, 2015 © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society
rowing numbers of older drivers has given rise to concerns about the driving safety of those who may be compromised by physical and cognitive impairments. Physicians and other health professionals are often asked to determine whether an individual retains the capacity to operate a motor vehicle safely. Many are reluctant to advise on driving, because they do not have the expertise or time to make this important decision during an office visit.1 They also lack a reliable means of assessing critical factors indicating a need for referral to a comprehensive driving evaluation.2 Clinicians frequently use screening tasks to determine cognitive vulnerabilities relevant to safe driving. The Mini-Mental State Examination (MMSE)3 is often used to assess cognitive status. The utility of the MMSE as a predictor of road test outcome has been examined, but studies have provided mixed results.4 A number of studies have demonstrated that the MMSE is helpful in the prediction of driving safety,5–7 but other studies have not found an association between MMSE score and driving outcome.8–11 The current study examined whether a preestablished diagnosis of cognitive impairment affects the predictive validity of the MMSE in this regard. Health providers are increasingly using an alternate mental status test, the Montreal Cognitive Assessment (MoCA),12 to screen for cognitive impairment. It is slightly more difficult, and as a result, MoCA scores tend to be lower than MMSE scores. The usefulness of the MoCA as a predictor of driving safety has not been firmly established. A study examining the relationship between cognitive performance, perceptions of driving, and self-reported driving practices of healthy older adults found that the MoCA was not helpful in this regard.13 A preliminary study found that the MoCA and the MMSE were equally effective in predicting on-road performance,14 but this comparison was based on only 47 individuals and did not consider the asymmetry between MMSE and MoCA scores. Nor did it investigate whether an established diagnosis of cognitive impairment affected this relationship.
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The current study focused on two well-established cognitive screening measures that healthcare providers across the country commonly use. Although these tests were not designed to assess driving safety, they are integrated into clinical practice, and given their ease of administration, they may be ideal for the identification of at-risk drivers who need further assessment at a driving clinic. Ninety-two individuals who completed the MMSE and MoCA as part of a comprehensive driving evaluation were examined. Raw scores were compared to obtain specific cut-scores that discriminate between safe and unsafe drivers. Asymmetry between test scores was then corrected for using a previously developed algorithm.15 This method allows for direct comparison of these two screening measures. Whether an established diagnosis of cognitive impairment modified the association between screening measures and driving competence was also examined. Evidence-based findings from the current study will provide clear objective criteria to assist physicians and other health providers in making informed recommendations about the driving safety of their patients. Findings may facilitate the differentiation of individuals appropriate for referral to a comprehensive driving evaluation from those who do not need this type of intervention.
METHODS Performance on the MMSE and the MoCA was examined in relation to road test performance in a group of individuals referred to a hospital-based driving evaluation program (DriveWise).16 The assessment included a review of medical and driving history, mental status screening, evaluation of physical and perceptual functions, and a 1-hour standardized road test. The medical diagnosis was used to determine whether an individual had a prior history of a condition associated with cognitive impairment. Historical information about driving was obtained to assess frequency, pattern, and emotional significance of driving. This information is clinically relevant because it provides the DriveWise team with important information to guide recommendations. Over the past two decades, 587 people have undergone DriveWise assessments; 41% have passed the examination.
Participants A chart review was conducted of DriveWise evaluations between 2010 and 2014. Ninety-two charts met the inclusion criteria for this investigation, namely that the participant completed the evaluation, was English speaking, and had had the MoCA and MMSE administered. Forty-nine participants were male (53%), and the average age was 74.6 14.5. Participants varied with respect to reason for referral. Forty-three (46%) were referred because of neurological conditions such as mild cognitive impairment, early-stage Alzheimer’s disease, and Parkinson’s disease. Another 26 (28%) were referred because of medical conditions such as stroke or musculoskeletal disorders. All participants in this group had normal MMSE scores of 25 or greater. A further 14 (16%) were referred because of family concerns about driving. None of these people had a previous diagnosis of dementia; 13 of them scored between
MMSE & MOCA IN PREDICTION OF DRIVING OUTCOME
27 and 30 and one scored 24 on the MMSE. Nine participants (10%) did not have a clinical diagnosis and had been referred solely on the basis of advanced age. Only one participant in this group had a low score (