Stroboscopic Vision-induced Sensory Reweighting During Postural Control

Abstract

Human postural control is achieved by dynamic reweighting of sensory inputs among visual, vestibular, and somatosensory systems in accordance with an external environment. However, due to experimental limits, little is known how partially disrupted visual inputs affect postural control. PURPOSE: The purpose of this study was to explore the effects of stroboscopic glasses on postural control. METHOD: 24 healthy people (M: 12, F:12, Height: 172.1±7.8, weight: 67.5±10.4) performed balance tests (jump landing balance and single leg balance) with 3 sets of 10 second, respectively. While the jump landing test has three conditions (eyes-open (EO), and high and low strobe vision (HSV, and LSV) respectively), the single-leg balance has four conditions (EO, HSV, LSV, and eyes-closed (EC)). These two balance tests will be implemented on a firm surface and a foam surface. Main outcome measure were dynamic postural stability index (DPSI) and the center of pressure (COP) excursion with 2 directions (anterior-posterior (A/P) and medial-lateral (M/L)). For the surface conditions, student-t test was used. For DPSI and COP excursion, an analysis of variance with repeated measures was performed to determine difference in balance performance between these visual conditions. RESULT: In the jump landing balance, DPSI was greater on the foam than the firm (p = .0474). Likewise, in the single leg balance, CoP excursion was greater in both A/P and M/L on the foam than the firm (p < .0001). For the vision conditions, in the jump landing balance, DPSI was greater in HSV and LSV than EO (p = .0100 and p = .0013, respectively). In the single leg balance, CoP excursion was greater in EC, HSV, and LSV than EO (p < .0001). Additionally, CoP excursion in EC was greater than HSV and LSV (p = .0012 and p = .0093, respectively). In the single leg balance, both HSV and LSV showed greater interaction with foam in both A/P and M/L than the firm (6% up to 22%). CONCLUSION: The effects of stroboscopic glasses on postural control were less than the effects of eye-close. The subjects seemed to rely more on visual inputs to stabilize posture in an unstable condition. The stroboscopic glasses, that can adjust visual inputs, may be used to measure the reliance of visual inputs in those who have reduced or altered somatosensory function.