EEG-based neurofeedback training with shoulder exoskeleton robot assistance triggered by the contralesional primary motor cortex activity in poststroke patients with severe chronic hemiplegia

Introduction/Background: Recent clinical studies have shown that electroencephalogram- (EEG) based neurofeedback training promotes functional recovery of finger movements in poststroke patients (Pichiorri F et al., Ann Neurol. 2015). However, impairment of shoulder elevation in poststroke severe chronic hemiplegia is a debilitating condition with no evidence-based, accessible treatment. To verify motor recovery evidence of neurofeedback training with our shoulder exoskeleton robot, this study reports upper extremity section of Fugl-Meyer assessment (FMA-UE) associated with the evaluation of up-conditioning of contralesional corticospinal pathways. Material and method: Eight poststroke patients with severe hemiplegia in the chronic stage were recruited (FMA-UE score = 16.8 ± 4.4). Patients engaged in 1 hour daily training for 7 consecutive days (Fig. 1), and clinical and neurophysiological measurements were performed 1 day before and after the intervention. FMA-UE was used for the primary outcome measure. A 128-channel whole-head EEG was used to assess the hemispheric lateralization of event-related desynchronization (ERD). Single-pulse transcranial magnetic stimulation (TMS) was applied to the contralesional primary motor cortex to assess the corticospinal excitability in 6 tested patients. Results: All participants finished the intervention without adverse events. FMA-UE was significantly improved after the intervention (paired t-test, P < 0.01). All patients demonstrated improved FMA-UE (mean change = 6.6 ± 3.2) and 6 of 8 patients exceeded the minimal clinically important difference that is set to 5. From the group analysis of hemispheric lateralization of ERD, the contralesional ERD became stronger after interventions (Wilcoxon signed-rank test, P < 0.01). Motor evoked potentials became more apparent after interventions in 3 of the 6 tested patients. Conclusion: The results from this study demonstrated targeted up-conditioning of contralesional corticospinal pathways and efficacy of neurofeedback training with our shoulder exoskeleton robot.