Assessment of Balance Instability by Wearable Sensor Systems During Postural Transitions

Abstract

Several studies have demonstrated beneficial effects of real-time biofeedback for improving postural control. However, the application for daily activities, which also include postural transitions, is still limited. One crucial aspect is the time point of providing feedback, and thus its reliability. This might depend on the sensor system used, but also on how the threshold is defined.This study investigates which wearable sensor system and what kind of threshold is more reliable in a situation of a postural transition. To this end, we compared three sensor systems regarding their accuracy in timing in a stable and unstable Postural Transition in 16 (9 female) healthy young adults: a multiple Inertial Measurement Unit system (IMU), a pressure Insole system (IS), and a combination of both systems (COMB). Further, we contrasted two threshold parameters for each system: a Quiet Standing-based threshold (QSth) and a Limits of Stability-based threshold (LoSth).Two-way Repeated Measures ANOVAs and Wilcoxon tests (α−level : 0.05) indicated highest accuracy in the COMB LoSth, though with small differences to the IS LoSth. The LoSth showed more accurate timing than the QSth, especially in medio-lateral direction for IS and COMB.Consequently, for providing a reliable timing for a potential biofeedback applied by a wearable device in everyday life situations, such as during postural transitions, application should focus on pressure Insoles and a functional stability threshold, such as the LoS-based threshold.

Does vibrotactile biofeedback for postural control interfere with cognitive processes?

“…For the first study, to trigger vibrotactile biofeedback, the threshold was defined as 1.2 times the absolute mean tilt angle assessed during baseline sway measurements for AP and ML (body sway-based threshold), respectively. In the second study, instead of a body sway-based threshold, we implemented a Limits-of-Stability-based threshold, as in a previous study, we have found this to better capture postural instability [51].…”

Analysis of Human Gait Cycle With Body Equilibrium Based on Leg Orientation

“…Hessfeld et al explored examples of the wearable sensor system and type of threshold are more dependable in a postural shift scenario. Comparison of three sensing systems: pressure insoles system (IS), multiple inertial measurement unit systems (IMU), and a combination of both systems to provide reliable timing for potential biofeedback applied by a wearable device in daily activities [22]. Saboor et al discussed the two slashing technologies that are essential to contemporary gait analysis.…”