Background and Aim
The Montreal Cognitive Assessment (MoCA) is the most suitable measure for screening cognitive impairment in Parkinson's disease (PD). However, the utility of the MoCA 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 MoCA scores in PD patients.
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 MoCA.
The MMSE and MoCA scores were 26.3 ± 3.6 (range 12–30) and 20.9 ± 5.0 (range 5–30), respectively, and showed a strong correlation (R2 = 0.74, P < 0.001) with each other. A MMSE score of <26 was observed in 35% of the participants. A MoCA score of <21 had 89% sensitivity and 83% specificity, comparable with a MMSE score of <26. The two scores were correlated with age (R2 = 0.12 and 0.20, respectively; P < 0.0001), but not with Hoehn and Yahr stage or disease duration.
One-third of the patients had a MMSE score of <26, a diagnostic criterion of PD with dementia. A MoCA 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.