Autonomic Responses During Kinesthetic Motor Imagery in Healthy Adults: A Multimodal Assessment Using HRV and EDA

This study aimed to examine autonomic nervous system responses during motor imagery (MI) in healthy adults, using different autonomic markers that reflect cardiac vagal activity and electrodermal activity. 24 healthy individuals were included in this study. Demographic data were assessed using a demographic data form, and MI ability was assessed using mental chronometry, mental rotation, and the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20). Heart rate (HR), heart rate variability (HRV), and electrodermal activity (EDA) were recorded during each 5-min relaxation and MI sessions. HR and HRV were measured using a Polar H10 device, while EDA was measured using the BIOPAC MP36 system. During MI, decreased HRV parameters reflecting cardiac vagal activity, such as Root Mean Square of Successive Differences (RMSSD) and high frequency (HF) band power, were observed (p < 0.05 for all). In addition, significant increase was found in EDA values reflecting electrodermal activity during MI (p < 0.001). Residualized HR was strongly positively correlated with KVIQ-Visual scores (r = 0.511), moderately positively correlated with KVIQ-Total (r = 0.497) and Left-hand accuracy (r = 0.441) scores, while a moderately negative correlation was found between residualized HR and Left-hand reaction time (r = -0.466) (p < 0.05 for all). In conclusion, when assessing MI sessions and MI ability, it is important to use different autonomic indicators (e.g., HRV and EDA) together. The findings suggest that autonomous responses observed during MI may reflect different physiological mechanisms, offering significant implications for the potential use of autonomous biomarkers in MI-based rehabilitation interventions.