Mild parkinsonian signs (MPS) are reported to be associated with increased risk of dementia, Parkinson's disease, parkinsonism, and vascular lesions of white matter and are also a significant predictor of mortality. Although more than 20% of subjects aged 60 years and older suffer from MPS in Japan, it is often unrecognized and underestimated by patients and medical physicians. We used neuropsychological methods to examine cognitive function and depressive symptoms in subjects with MPS.
We performed a population-based study in Ama-cho, a rural island town in western Japan. Participants included 951 subjects aged 65 years and older, 613 of whom completed all questionnaires, neurological examinations, and neuropsychological assessments and were included in the data analysis. Subjects were assessed for depression and subjective cognitive impairment using the Geriatric Depression Scale (GDS-15), Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and modified Unified Parkinson's Disease Rating Scale (mUPDRS).
Of the 613 participants, 143 were diagnosed with MPS. GDS scores were significantly higher in the MPS group compared with the motor control group, while MMSE scores were significantly lower.
We demonstrated that MPS correlate with both depressive symptoms and cognitive impairment.