Mimicking slipping responses using a novel mechanical perturbation algorithm

• Published in: Gait & posture Vol. 106; pp. S293 - S294
• Main Authors: Geissmann, Marina, Moessner, Sandra, Filli, Linard
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2023
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2023.07.079

Falls are a major cause of injuries in older adults leading to hospitalization, reduced mobility and substantial healthcare expenses [1,2]. Most falls occur while walking due to unexpected perturbations, such as slips and trips [3]. Gait disturbances can be elicited by a one-sided acceleration or deceleration on a split-belt treadmill [4,5]. The time point of perturbation onset within the gait cycle is a key factor influencing the magnitude of the recovery response [6]. Currently, there is no standardized perturbation algorithm to mimic slipping responses. The objective of this study is to develop a gait perturbation that closely mimics the experience of slipping during daily activities. This novel perturbation will be compared to two abundant gait perturbations with respect to the reactive response and gait recovery in healthy participants. Forty-four healthy subjects will be included and divided into two age groups (young: 18-40 years (n=22); old: 60-80 years (n=22)). Three different one-sided perturbation algorithms will be compared: 1) Belt deceleration triggered at foot strike [4] 2) Belt acceleration when the hallux marker of the to-be-perturbed leg is crossing the same marker of the contralateral leg in sagittal plane [5] 3) Belt deceleration reaching its minimum speed in the early loading phase. Overall 30 perturbations (10 of each algorithm) will be applied in a pseudo-randomized order with equal acceleration/deceleration intensity and identical minimal/maximal speed. Margin of stability in the anterior-posterior direction (MoS AP) at foot strike serves as the primary endpoint. Secondary outcome measures include a range of kinematic, functional and subjective (i.e. questionnaire) parameters with the aim of comprehensively assessing the effects of the different perturbations. As the study will start in a few weeks, the findings presented in this abstract are based on preliminary results obtained from a single young pilot subject (female, 23 years). The initial gait disturbance (Post1-2), as measured by MoS AP, was most pronounced in response to algorithm 3 (-0.252±0.194m, -0.128±0.061m) compared to algorithm 1 (-0.150± 0.066m, -0.083± 0.053m) and algorithm 2 (-0.086±0.019m, -0.080±0.033m) (Fig. 1). However, time for gait recovery was similar across all the three perturbation algorithms, with the MoS AP returning to baseline values after six to seven steps. Fig. 1. MoS AP (mean ± SD and single data points per perturbation) before (Base), one step before (Pre) and 10 steps (Post1-10) after perturbation for each onset algorithm. [Display omitted] All of the perturbation algorithms elicited a noticeable gait disturbance and subsequent recovery response. The newly developed algorithm 3 showed the greatest impact on the gait pattern and was perceived as most realistic with regards to slipping. However, further data is necessary to accurately compare the effects of various perturbation algorithms.