Validity of Center of Pressure Path Length Measured Using a Wii Balance Board for Fall Risk Screening in Community-Dwelling Older Adults

Background/Objectives: Falls among older adults are a major public health concern. Although instrumented posturography provides objective balance and fall-risk assessment, its cost and limited portability restrict widespread use. This study aimed to examine the construct and concurrent validity of center of pressure (COP) path length measured using a Wii Balance Board (WBB) in relation to a clinically established posturographic fall-risk construct in community-dwelling older adults and to explore its discriminatory performance across multiple sensory postural conditions. Methods: Sixty adults aged ≥ 65 years participated in this cross-sectional study. COP path length was measured using a WBB under eight postural conditions and compared with the Fall Index derived from a conventional posturography system (Tetrax^Ⓡ). Functional performance was assessed using the Four Square Step Test and the Five Times Sit-to-Stand test. Pearson correlation, receiver operating characteristic (ROC), and exploratory regression analyses were performed. Results: COP path length showed significant positive correlations with the Tetrax^Ⓡ Fall Index across all conditions (r = 0.349–0.561, p < 0.01) and with functional performance tests under most postural conditions (p < 0.05), except for the Normal stability, Open eyes (NO) condition. ROC analysis demonstrated acceptable-to-good discriminatory performance for classifying Tetrax^Ⓡ Fall Index-based risk status (AUC = 0.783–0.865), with the NO condition showing the highest discriminatory capability (AUC = 0.865). Exploratory regression models based on selected postural conditions explained 12.1–40.7% of the variance in the reference Fall Index. Conclusions: COP path length measured using a WBB demonstrated construct validity and acceptable discriminatory capacity in relation to a conventional posturographic fall-risk construct in community-dwelling older adults. These findings support the exploratory feasibility of simplified WBB-based balance assessment approaches for community and clinical screening contexts. Further longitudinal studies incorporating prospective fall outcomes are required to establish predictive validity and broader clinical applicability.