# Rapid functional reorganization of the targeted contralesional hemisphere induced by one week of noninvasive closed-loop neurofeedback guides motor recovery in post-stroke patients with chronic motor impairment: a phase I trial

## TL;DR

A brain-computer interface linked to a robotic exoskeleton helps stroke patients regain arm movement by enhancing brain activity on the undamaged side.

## Contribution

A noninvasive closed-loop system using BCI and exoskeleton training promotes rapid motor recovery in chronic stroke patients.

## Key findings

- Seven days of training led to significant and sustained motor improvement in affected upper limbs.
- The system safely upregulates contralesional motor cortex activity without adverse effects.

## Abstract

Post-stroke hemiplegia of the upper extremities continues to pose a significant therapeutic hurdle. Contralesional uncrossed corticospinal pathways (CST) are involved in the recovery processes.

We test the safety, and preliminary efficacy of targeted upregulation of uncrossed CST excitability through self-modulation of cortical activities via noninvasive brain-machine interaction training (Registered with the University Hospital Medical Information Network: UMIN000017525). In this single-arm prospective trial, eight individuals with persistent severe post-stroke motor disability voluntarily actuated their affected shoulder using a brain-computer interface (BCI) bridging the contralesional motor cortex (M1) and an exoskeleton robot. While patients attempted to elevate the affected arm, scalp electroencephalogram (EEG) signals over the contralesional M1 were processed online to provide them with feedback on M1 excitability.

Here we show that the BCI reconstructs neural pathways, allowing arm elevation without any adverse effects. As evidenced by an increase in primary outcome measure (Fugl- Meyer Assessment, p < 0.05, d = 1.24), seven days of consecutive system use results in rapid, sustained, and clinically significant improvement in motor function when removed from the system and promotes contralesional M1 functional remodeling.

This closed-loop system is safe, feasible, and a promising intervention that recruits intact neural resources to allow patients to recover upper-extremity motor abilities.

During a stroke, blood flow to the brain is blocked resulting in damage to parts of the brain. This study examines a method to support recovery of arm function in individuals with severe post-stroke paralysis. The approach aimed to enhance activity in intact brain pathways on the side opposite the side damaged by the stroke. Participants engaged in training with a brain-computer interface linked to a robotic exoskeleton. While attempting to lift their impaired arm, their brain activity was monitored and used to facilitate the movement. After seven consecutive days of training, participants demonstrated clear and sustained improvements in their ability to move the paralysed limb, without any adverse effects. These findings indicate that targeted modulation of preserved brain networks may represent a safe and promising strategy to improve upper-limb recovery in people living with long-term stroke-related disability.

Takasaki et al. evaluate whether closed-loop upregulation of the contralesional motor cortex activity in the post-stroke patients promotes recovery of arm motor function. The brain-computer interface-based rehabilitation reorganizes the uncrossed corticospinal pathways in the chronic phase to improve arm movement.