Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke

Abstract

Background Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Methods Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist grading of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities Specific Balance Confidence Scale, respectively. Results There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. Conclusion This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke.

A Perspective on Objective Measurement of the Perceived Challenge of Walking

“…There are several potential directions for future research in this area. Our prior work (Chatterjee et al, 2018; Clark et al, 2018) supports the measurement of skin conductance to assess the perceived challenge of walking, which could be expanded to assess prediction of future adverse mobility outcomes such as falls. We have also shown evidence of a rehabilitation induced reduction of SNS activity during complex walking.…”

“…We have also reported skin conductance measurement of SNS response to complex walking in adults with chronic post-stroke hemiparesis. In this population, higher magnitude of SNS activity measured by skin conductance was shown to be associated with worse task performance across 17 walking tasks, as quantified by speed of movement or performance grading by a physical therapist (Clark et al, 2018). This finding supports that SNS activity scales with the challenge level of the task.…”

“…Task-related SNS response was measured by skin conductance (SCL and SCR), and the data were analyzed in accordance with our previously published work (Chatterjee et al, 2018; Clark et al, 2018). Skin conductance signals were recorded using a commercially available portable data acquisition unit (Flexcomp Infiniti; Thought Technologies Ltd, Montreal, QC, Canada).…”

“…Future research could also add to the existing evidence of an association between self-report and the perceived challenge of walking. Prior evidence showing that skin conductance can be used to categorize the difficulty level of tasks (Clark et al, 2018) might be extended to the development of an ecologically valid walking task battery for the assessment of complex walking impairment. Another promising topic may be the measurement of skin conductance in real-time to optimize task challenge level during rehabilitation.…”

Closed-Loop Cognitive Stress Regulation Using Fuzzy Control in Wearable-Machine Interface Architectures

“…While heart rate also provides insight about the internal arousal state, it carries information associated with cardiac activity [29], [32]. As skin conductance signal carries information about sympathetic nervous system, we focus on this physiological signal for our further analysis [33]. In the presence of external (e.g.…”