Brain connectivity modulation after exoskeleton assisted gait in chronic hemiplegic stroke survivors: a pilot study

OBJECTIVE: to investigate electroencephalographic (EEG) connectivity short-term changes, quantified by node strength (NS) and betweenness centrality (BC), induced by a single trial of exoskeleton assisted gait in chronic stroke survivors. DESIGN: Study design was randomized cross-over. Sixtyfour channels EEG were recorded before gait (baseline, BL), after unassisted overground walking (UW) and overground exoskeleton assisted walking (EXO). Coherence was estimated for alpha1, alpha2 and beta frequency ranges. Graph analysis assessed network model properties: NS and BC. RESULTS: Nine participants were included in final analysis. In the group (4 participants) with a left-hemisphere stroke lesion (dominant hemisphere), over the vertex NS increased in alpha1, alpha2 and beta bands, and BC decreased in alpha2 both after UW and exoskeleton assisted walking. In the group (5 participants) with a right-hemisphere lesion (non-dominant hemisphere), NS increased in alpha1 and alpha2 over the contralesional sensorimotor area and ipsilesional prefrontal area after EXO, compared to BL and UW. CONCLUSION: A single session of exoskeleton training provides short-term neuroplastic modulation in chronic stroke. In participants with a non-dominant hemisphere lesion, exoskeleton training induces activations similar to those observed in able-bodied participants, suggesting a role of lesion lateralization in networks' reorganization.