Background Mild parkinsonian signs are important clinical symptoms related to the decline of motor and cognitive functions. We aimed to identify predictors for the incidence of mild parkinsonian signs in older Japanese by conducting an 8-year longitudinal community-based cohort study.
Methods Participants aged 65 years or older, living in Ama-cho, a rural island town in western Japan, underwent a baseline assessment of motor function, cognitive function, depression score, the Pittsburgh Sleep Quality Index (PSQI), the Tanner questionnaire, and cerebral white matter lesions on brain magnetic resonance imaging from 2008 to 2010, and then underwent a follow-up neurological examination from 2016 to 2017. Mild parkinsonian signs were defined according to a modified Unified Parkinson’s Disease Rating Scale score.
Results Of the 316 participants without mild parkinsonian signs at baseline, 94 presented with incident mild parkinsonian signs at follow-up. In addition to an absence of exercise habits, a higher score on the Tanner questionnaire, PSQI, and deep white-matter hyperintensity Fazekas scores were significant independent predictors for incidence of mild parkinsonian signs.
Conclusion We suggest multiple factors related to incidence of mild parkinsonian signs. Vascular lesions and sleep disorders are associated with a pathogenesis of mild parkinsonian signs, the Tanner questionnaire is useful for early detection of subclinical mild parkinsonian signs, and exercise has a possibility of being associated with preventing onset of mild parkinsonian signs.