Concurrent validity of wearable inertial sensors for postural sway assessment during quiet standing compared with force plates: a systematic review and meta-analysis

Abstract

Abstract Wearable inertial sensors are increasingly used for postural sway assessment, but their concurrent validity with force plates during quiet standing has not been quantitatively synthesized. This systematic review and meta-analysis (PROSPERO: CRD42024596870) pooled concurrent validity estimates for inertial-sensor-derived sway parameters against simultaneous force-plate measurements in healthy and clinical populations. PubMed, Embase, and Cochrane Central were searched up to October 2, 2024, without language restrictions and in accordance with PRISMA guidelines. Correlation coefficients from 22 studies ( n = 761; age range 7–85 years), including healthy adults and individuals with Parkinson’s disease, multiple sclerosis, or vestibular disorders, were pooled using random-effects meta-analysis with Fisher’s z-transformation. Strong pooled correlations were found for sway area (eyes-open: r = 0.80, 95% CI 0.57–0.91; eyes-closed: r = 0.82, 95% CI 0.51–0.94), path length ( r = 0.75, 95% CI 0.57–0.86; r = 0.85, 95% CI 0.75–0.91), RMS amplitude ( r = 0.77, 95% CI 0.54–0.89; r = 0.74, 95% CI 0.28–0.93), and total power ( r = 0.84 in both conditions). Sway velocity showed the weakest associations ( r = 0.45–0.53). Heterogeneity was substantial across outcomes (I² = 71–94%), and overall strength of evidence was moderate. The lumbosacral region was the most frequently studied sensor location and is biomechanically plausible for quiet-standing assessment. When force plates are unavailable, this placement may be useful for estimating selected sway parameters. However, because the current evidence is based mainly on correlations, formal agreement studies are still needed before inertial-sensor-derived measures can be considered interchangeable with force-plate-derived measures.