Concurrent Validity and Reliability of Inertial Sensor-Based Wearables for Quantifying Spatial-Temporal Gait...

This systematic review examined the validity and reliability of wearable inertial sensor systems to quantify spatiotemporal gait parameters in post-stroke adults, a population in which gait asymmetry and altered motor control challenge accurate measurement. Sixteen studies involving 300 participants were included. Spatial parameters gait speed, cadence, and step/stride length showed consistently good-to-excellent agreement with reference systems (ICC 0.85-0.98; 95% LoA ±0.03-0.08 m/s for gait speed, ±4-10 steps/min for cadence, and ±3-8 cm for step/stride length) and high test-retest reliability. Temporal parameters demonstrated greater heterogeneity, with larger errors and lower concordance (ICC 0.40-0.85; LoA ±0.04-0.12 s), particularly for swing time (ICC 0.40-0.70; LoA up to ±0.15 s). Paretic-side measurements showed 10-20% lower concordance and 30-50% wider limits of agreement compared with the non-paretic side, although within-subject reliability remained moderate to high. No consistent influence of sensor number on measurement accuracy was observed. Overall, wearable inertial sensors provide robust estimates of spatial gait parameters, whereas temporal outcomes especially swing time remain limited due to challenges in gait event detection under stroke-related biomechanical alterations. These findings highlight the need for standardized protocols and improved algorithms to enhance comparability across studies and support broader clinical adoption.