Greater prefrontal cortical activation is associated with higher balance confidence in older adults

Fear of falling (FoF) is a prevalent and consequential concern among older adults, often associated with impaired mobility, cognitive decline, and reduced quality of life. Traditionally conceptualized as a psychological response to prior falls, FoF is increasingly recognized as a neurobehavioral phenomenon reflecting dysregulated cognitive-motor integration. In particular, the prefrontal cortex (PFC)-responsible for executive control, attentional regulation, and anticipatory motor planning-has emerged as a key neural substrate underlying FoF. This study investigated the association between PFC activation and balance confidence, a continuous correlate of FoF, in 308 community-dwelling older adults aged ≥ 60 years. Prefrontal oxygenated hemoglobin (HbO) was measured using functional near-infrared spectroscopy (fNIRS) during a verbal fluency task, a standardized cognitive paradigm eliciting PFC engagement without motor interference. Balance confidence was assessed using the validated Korean version of the Activities-specific Balance Confidence (ABC) scale. Subgroup analyses stratified by fall history, age, sex, and educational attainment were conducted to explore heterogeneity by known vulnerability factors. Higher regional HbO levels were significantly associated with higher ABC scores, reflecting greater balance confidence and lower FoF. This association was most pronounced in the right lateral and lower PFC regions (e.g., Right Lateral: β = 1.41, p = 0.0062; Lower Right: β = 1.41, p = 0.0007), and remained robust after adjusting for demographic and clinical covariates. Subgroup analyses revealed stronger associations among individuals with a history of falling, aged ≥ 75 years, women, and those with lower education. For example, in participants with prior falls, Right Hemisphere HbO was strongly correlated with ABC scores (β = 2.06, p = 0.020), suggesting greater cortical recruitment in response to heightened threat perception. We found that greater PFC activation was associated with higher balance confidence in older adults, particularly in those at elevated risk of falling. This relationship may reflect adaptive cortical engagement supporting postural assurance in vulnerable populations.