Comparing the Montreal Cognitive Assessment with Mini‐Mental State Examination in Japanese Parkinson's disease patients

Abstract Background and Aim The Montreal Cognitive Assessment (Mo CA ) is the most suitable measure for screening cognitive impairment in Parkinson's disease ( PD ). However, the utility of the Mo CA has not been documented sufficiently, especially in Asian populations. The present multicenter study included a large number of Japanese patients, and compared Mini‐Mental State Examination ( MMSE ) and Mo CA scores in PD patients. Methods We carried out a cross‐sectional study. Idiopathic PD patients ( n = 304; age 70.6 ± 8.3 years (mean ± SD); disease duration 6.6 ± 5.1 years; Hoehn and Yahr stage 2.7 ± 0.7) were registered at 13 participating hospitals, and their clinical/neurological/cognitive features were examined using Japanese versions of the MMSE and Mo CA . Results The MMSE and Mo CA scores were 26.3 ± 3.6 (range 12–30) and 20.9 ± 5.0 (range 5–30), respectively, and showed a strong correlation ( R 2 = 0.74, P < 0.001) with each other. A MMSE score of <26 was observed in 35% of the participants. A Mo CA score of <21 had 89% sensitivity and 83% specificity, comparable with a MMSE score of <26. The two scores were correlated with age ( R 2 = 0.12 and 0.20, respectively; P < 0.0001), but not with Hoehn and Yahr stage or disease duration. Conclusions One‐third of the patients had a MMSE score of <26, a diagnostic criterion of PD with dementia. A Mo CA score of <21 seemed comparable with a MMSE score of <26. The two scores were correlated with age, rather than severity of motor symptoms, suggesting that cognitive decline might be independent of motor decline in PD .