Nonlinear Cognitive-physical Relationships and EEG Markers in Motoric Cognitive Risk Syndrome

다국어 초록 (Multilingual Abstract)

This study examined the nonlinear relationship between cognitive and physical function in community-dwelling older adults to identify suggestive gait-speed thresholds within this cohort. It also characterized the neurophysiological features of Motoric Cognitive Risk Syndrome (MCR) and determined predictors of MCR. A cross-sectional study recruited 62 adults aged 65 years or older. Cognitive function was assessed using the MMSE, SDST, and PAL, while physical function was evaluated through gait speed, TUG, SPPB, the 6MWT, and handgrip strength. Resting-state EEG was recorded for five minutes with eyes closed using a 19-channel wireless system. MCR was defined as the co-occurrence of cognitive impairment and slow gait. Gait speed showed a nonlinear relationship with cognition, with MMSE declining below approximately 1.0 m/s and PAL improving up to about 1.2 m/s. Individuals with MCR exhibited elevated frontal theta/beta ratios, indicating attentional and executive dysfunction. MCR prevalence was 24.2%, and older age and lower skeletal muscle index were significant predictors. These findings suggest that gait- speed thresholds reflect graded cognitive vulnerability and that elevated theta/beta ratios may serve as neurophysiological markers. Integrating gait assessment and EEG indicators may enhance early identification of cognitive- motor risk in older adults.