Sensory reweighting of postural control requires distinct rambling and trembling sway adaptations

Eryn D Gerber; Chun-Kai Huang; Sanghee Moon; Hannes Devos; Carl W Luchies

doi:10.1016/j.gaitpost.2024.04.028

Sensory reweighting of postural control requires distinct rambling and trembling sway adaptations

Gait Posture. 2024 Apr 26:112:16-21. doi: 10.1016/j.gaitpost.2024.04.028. Online ahead of print.

Authors

Eryn D Gerber¹, Chun-Kai Huang², Sanghee Moon³, Hannes Devos², Carl W Luchies⁴

Affiliations

¹ Biodynamics Research Laboratory, University of Kansas, Lawrence, KS, USA.
² Department of Physical Therapy, Rehabilitation Science, and Athletic Training, School of Health Professions, University of Kansas Medical Center, Kansas City, KS, USA; Mobility Core, University of Kansas Center for Community Access, Rehabilitation Research, Education and Service, Kansas City, KS, USA.
³ Department of Kinesiology, College of Health and Human Services, University of New Hampshire, NH, USA.
⁴ Biodynamics Research Laboratory, University of Kansas, Lawrence, KS, USA; Department of Mechanical Engineering, School of Engineering, University of Kansas, Lawrence, KS, USA. Electronic address: luchies@ku.edu.

PMID: 38723391
DOI: 10.1016/j.gaitpost.2024.04.028

Abstract

Background: Implementation of the Sensory Organization Test (SOT) under the rambling-trembling (RM-TR) framework allows for an examination of both individual sensory contributions and compensatory mechanisms, a valuable insight in research and clinical settings. Such investigation could substantially improve our ability to assess and treat fall risk in older adults and people living with neurological disorders.

Research question: How are RM and TR components of sway influenced by SOT-induced challenges in healthy adults?

Methods: Twenty-three healthy adults (27.4±8 years; 10 male) volunteered to participate in this cross-sectional study. Each participant completed a VR-based SOT program, which included six conditions with varied visual environments (normal, blacked-out, conflict) and support surfaces (stable, unstable foam), while a force plate captured forces at the plantar surface. Center of pressure (COP) was calculated and decomposed into RM-TR components. For each time series, range, root-mean-square (RMS) and sample entropy (SampEn) were extracted. Individual contributions of somatosensation, vision, and vestibular sense, as well as the preference ratio, were calculated. Repeated measures ANOVA were used to compare the effects of time series type (COP, RM, TR) and SOT condition. Paired t-tests were used to assess the difference in preference ratio between RM and TR components.

Results and significance: TR sway behavior was impacted significantly by the sensory challenges induced by the SOT procedure, while RM was largely unaffected. Such findings are characteristic of healthy individuals, capable of competently re-weighting sensory input, but still facing challenge-based adaptations. Additionally, the mediolateral SampEn preference ratio was higher in TR compared to RM, indicating potential differences in compensation strategies between supraspinal and spinal/peripheral control mechanisms. These findings serve as a foundation for future RM-TR analyses using SOT procedures, aiding in our ability to implement targeted diagnostic and treatment methods, ultimately reducing the incidence of falls in aging and individuals with neurological conditions.

Keywords: Center of pressure; Postural sway; Rambling-trembling; Sample entropy; Sensory Organization Test.