Brain plasticity following MI-BCI training combined with tDCS in a randomized trial in chronic subcortical stroke subjects: a preliminary study

Abstract

Brain-computer interface-assisted motor imagery (MI-BCI) or transcranial direct current stimulation (tDCS) has been used in stroke rehabilitation, though their combinatory effect is unknown. We investigated brain plasticity following a combined MI-BCI and tDCS intervention in chronic subcortical stroke patients with unilateral upper limb disability. Nineteen patients were randomized into tDCS and sham-tDCS groups. Diffusion and perfusion MRI, and transcranial magnetic stimulation were used to study structural connectivity, cerebral blood flow (CBF), and corticospinal excitability, respectively, before and 4 weeks after the 2-week intervention. After quality control, thirteen subjects were included in the CBF analysis. Eleven healthy controls underwent 2 sessions of MRI for reproducibility study. Whereas motor performance showed comparable improvement, long-lasting neuroplasticity can only be detected in the tDCS group, where white matter integrity in the ipsilesional corticospinal tract and bilateral corpus callosum was increased but sensorimotor CBF was decreased, particularly in the ipsilesional side. CBF change in the bilateral parietal cortices also correlated with motor function improvement, consistent with the increased white matter integrity in the corpus callosum connecting these regions, suggesting an involvement of interhemispheric interaction. The preliminary results indicate that tDCS may facilitate neuroplasticity and suggest the potential for refining rehabilitation strategies for stroke patients.

EEG Spectral Generators Involved in Motor Imagery: A swLORETA Study

“…Although it could be argued that performing MI and MI during BCI activates different neural networks, it has been shown that they activate a common large and distributed cortical and subcortical network including motor, premotor, supplementary and posterior parietal cortex ( Marchesotti et al, 2017 ). From another new perspective, recent studies suggest that the transcranial direct-current stimulation increases MI-BCI accuracy ( Ang et al, 2015 ; Hong et al, 2017 ). In this way, it has been shown that tDCS applied on motor cortex and cerebellum ten minutes before right-hand MI enhanced the accuracy of a classifier trained with the related mu and beta spectral power ( Angulo-Sherman et al, 2017 ).…”

Intra- and Inter-subject Variability in EEG-Based Sensorimotor Brain Computer Interface: A Review

“…The structural and functional changes in neural substrates induced by MI-based training with transcranial direct current stimulation or transcranial magnetic stimulation provide further evidence for the induction of neuroplasticity that is essential for motor recovery (Hong et al, 2017;Johnson et al, 2018). Because the induction of plasticity by rehabilitation varies across subjects (Leamy et al, 2014;Vallence et al, 2015), subject-specific training sessions may be required.…”

Role of Rehabilitation in Neural Plasticity

“…Voxel-wise CBF analysis and behavioural correlation [13]. (a) CBF of all the patients (tDCS and sham groups together) is lower especially in the ipsilesional hemisphere compared to the control at the baseline.…”