Electrodermal responses to unannounced perturbations during walking on a treadmill in fall-prone older adults – preliminary results

Introduction: Treadmill-based perturbation training (PBT) simulates gait perturbations and trains reactive dynamic balance responses under safe conditions and can reduce falls in daily life of older adults. Electrodermal activity (EDA) responses, an indicator of emotional arousal, decreases across six perturbations in young, healthy adults, suggesting adaptation. EDA was not yet measured during perturbed walking in older adults or across multiple sessions. Hence, the EDA trajectory during PBT and conventional treadmill training (CTT) in older adults with and without cognitive impairment (CI) is compared.

Methods: 33 of 100 targeted fall-prone participants aged ≥ 70 years, with and without CI, were examined. During the training, the participants receive nine training sessions with either PBT or CTT, respectively. EDA responses are assessed during the 3rd and last session, applying eight perturbations. Analysis focuses on phasic EDA responses following perturbations and on the tonic EDA level during the 5 seconds before each perturbation onset and at equivalent times in CTT. EDA will be compared descriptively across sessions and training types.

Results: In the 3rd session, tonic EDA was 5.15 ± 2.39 µS in the PBT and 2.60 ± 1.35 µS in the CTT group. In the last session, tonic EDA was higher in the PBT (5.15 ± 2.39 µS) compared with the CTT (2.64 ± 1.58 µS). In the PBT, phasic EDA responses decreased slightly from 3rd session (0.28 ± 0.29 µS) to last session (0.25 ± 0.22 µS).

Conclusions: Increased EDA tonic levels in the PBT group suggest greater emotional arousal compared with CTT. Persistently elevated EDA may indicate ongoing concerns or stress. Recognizing and monitoring emotional arousal may help improve the safety, acceptability, and individualization of PBT. Future research should explore whether EDA can be used as a biomarker to adapt training intensity and to identify older adults who benefit from PBT.