AUTHOR=Yue Zan , Xiao Peng , Wang Jing , Tong Raymond Kai-yu 

TITLE=Brain oscillations in reflecting motor status and recovery induced by action observation-driven robotic hand intervention in chronic stroke

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 17 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2023.1241772

DOI=10.3389/fnins.2023.1241772

ISSN=1662-453X

ABSTRACT=Hand rehabilitation in chronic stroke remains challenging, and finding markers that could reflect motor function would help to understand and evaluate the therapy and recovery. The present work explored whether brain oscillations in different electroencephalogram (EEG) bands could indicate the motor status and recovery induced by action observation driven brain-computer interface (AO-BCI) robotic therapy in chronic stroke. The neurophysiological data of 16 chronic stroke patients who received 20-session BCI hand training is the basis of the study presented here. Resting state EEG was recorded during the observation of non-biological movements, while the task stage EEG was recorded during the observation of biological movements in training. The motor performance was evaluated using Action Research Arm Test (ARAT) and upper extremity Fugl-Meyer Assessment (FMA), and significant improvements (p<0.05) on both scales were found on patients after the intervention. Averaged EEG band power EEG power in the affected hemisphere presented negative correlations with scales pre-training, however, no significant correlations (p>0.01) were found both in the pre-training and post-training stage. After comparing variation of oscillations over training, we found patients with good and poor recovery show different trends in delta, low beta and high beta variation and only patients with good recovery presented significant changes in EEG band power after training (delta band, p<0.01). Importantly, motor improvements in ARAT correlate significantly with the task EEG power changes (low beta, c.c =0.71, p=0.005; high beta, c.c =0.71, p=0.004) and task/rest EEG power ratio changes (delta, c.c =-0.738, p=0.003; low beta, c.c =0.67, p=0.009; high   beta, c.c =0.839, p=0.000). These results suggest that, in chronic stroke, EEG band power may not be good indicators in reflecting motor status. However, ipsilesional oscillations changes in delta and beta band provide potential biomarkers related to the therapeutic-induced improvement of motor function in effective BCI intervention, which may be useful in understanding the brain plasticity changes and contribute to evaluating therapy and recovery in chronic stage motor rehabilitation.