The Montreal Cognitive Assessment and Neurobehavioral Cognitive Status Examination are useful for screening mild cognitive impairment in Japanese patients with Parkinson's disease

Aim: Diagnosis of mild cognitive impairment (MCI) in Parkinson's disease (PD; PD-MCI) can be difficult. We examined whether the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and the Neurobehavioral Cognitive Status Examination (COGNISTAT-J) were suitable to screen PD-MCI. Methods: A total of 50 patients with PD and PD with dementia, took the Mini-Mental State Examination (MMSE), MoCA-J and COGNISTAT-J (except 3 patients) tests. Impairment in each cognitive domain on the tests was then compared between groups. Results: Of 25 patients with a high MMSE score of 27 or above, 13 had a MoCA-J score of below 25, and showed significantly lower scores than 12 patients with MoCA-J scores of 25 or above in the visuospatial, executive and memory domains of MoCA. Of the 25 patients with a high MMSE score, seven had four or more impaired subtests of the 10 subtests of COGNISTAT-J. The seven patients showed significantly lower scores in the subtests of construction, calculation and similarity compared with the 18 patients with less than four impaired subtests. In patients with a high MMSE score and less than four impaired subtests on the COGNISTAT-J, construction and memory were more impaired. Executive, visuospatial and memory abilities are characteristically impaired in PD-MCI, therefore both MoCA-J and COGNISTAT-J detected characteristics of PD-MCI in patients with a high MMSE score. Conclusion: Both MoCA and COGNISTAT are sensitive tools for screening for PD-MCI.