Archives of Physical Medicine and Rehabilitation · Jun 20, 2026
Subregion-Specific Prefrontal Activation Predicts Fall Risk and Fall Timing in Older Adults With Mild Cognitive Impairment
By Baek CY
OBJECTIVE: To investigate whether time-varying prefrontal cortex (PFC) activation during dual-task (DT) walking is associated with fall risk and time to first fall in older adults with mild cognitive impairment (MCI). DESIGN: Prospective longitudinal cohort study. SETTING: Community-based assessment with 12-month follow-up. PARTICIPANTS: One hundred ten community-dwelling older adults with MCI (N=110). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Oxygenated hemoglobin changes in PFC subregions during DT walking were measured using functional near-infrared spectroscopy. Baseline global cognition and functional mobility were assessed. The primary outcomes were fall occurrence and time to first fall during 12 months of prospective follow-up. Associations with fall risk and time to first fall were examined using multivariable logistic regression, Cox proportional hazards models with time-varying coefficients, and Kaplan-Meier analyses, adjusting for age, sex, and global cognition. RESULTS: During follow-up, 39 participants (35.5%) experienced ≥1 fall. Greater early-phase dorsolateral PFC (DLPFC) activation during DT walking was independently associated with higher odds of falling (odds ratio, 2.36; 95% CI, 1.02-5.59; P=.048) and shorter time to first fall (hazard ratio, 3.00; 95% CI, 1.49-6.04; P=.002). This association attenuated significantly over time, supported by a significant DLPFC-by-time interaction (hazard ratio, 0.24; 95% CI, 0.15-0.40; P<.001). Slower timed Up and Go performance was also independently associated with higher fall risk and shorter time to first fall. CONCLUSIONS: Exaggerated early-phase DLPFC activation during cognitively demanding walking represents a time-sensitive neural prognostic marker of fall vulnerability in older adults with MCI. Integrating cortical activation measures with functional mobility assessment may enhance fall risk stratification in clinical and community settings.