A pilot study of psychometric properties of the Beijing version of Montreal Cognitive Assessment in patients with idiopathic Parkinson's disease in China.

Cognitive dysfunction is one of the most critical clinical manifestations of Parkinson's disease (PD), and its accurate and efficient diagnosis is crucial for treatment. We evaluated the psychometric properties of the Beijing version of the Montreal Cognitive Assessment (BJ-MoCA) in 123 Chinese patients with idiopathic PD. The internal consistency and convergent validity of the BJ-MoCA were examined and psychometric characteristics of BJ-MoCA scores were analyzed in PD patients with ''normal'' Mini-Mental State Examination (MMSE) scores. More than half (56.9%) of the patients with normal MMSE scores showed cognitive impairment in multiple cognitive domains, including visuospatial and executive functions, naming, attention, language, delayed recall, and orientation. The impaired delayed recall was less likely to occur in newly diagnosed patients, and the orientation ability in patients with early onset was rarely affected. The multivariate regression analysis revealed that the age of symptom onset and disease severity were independent predictors of cognitive impairment. Thus, the current findings demonstrate that the BJ-MoCA is a reliable tool for screening cognitive dysfunction in Chinese patients with idiopathic PD. It is more sensitive than the MMSE for screening early cognitive decline in non-memory dysfunction.