A closed-loop brain-computer interface triggering an active ankle-foot orthosis for inducing cortical neural...

Area of Science:

• Neuroscience
• Rehabilitation Engineering
• Biomedical Engineering

Background:

• Stroke often leads to motor impairments, necessitating effective rehabilitation strategies.
• Cortical neuroplasticity is crucial for motor function recovery after neurological injury.
• Brain-computer interfaces (BCIs) offer a promising avenue for augmenting rehabilitation.

Purpose of the Study:

• To introduce a brain-computer interface (BCI) driven motorized ankle-foot orthosis (BCI-MAFO).
• To demonstrate the BCI-MAFO's efficacy in inducing cortical neuroplasticity in healthy subjects.
• To assess the potential of this BCI-MAFO system for stroke rehabilitation.

Main Methods:

• A BCI system detected imagined dorsiflexion movements from scalp EEG using movement-related cortical potentials (MRCPs).
• A manifold-based method (locality preserving projection) achieved online motor imagery detection with a 73.0 ± 10.3% true positive rate.
• Detected motor imagery triggered a motorized ankle-foot orthosis (MAFO) to elicit passive dorsiflexion.

Main Results:

• A significant increase in motor-evoked potential (MEP) size was observed immediately after and 30 minutes post-intervention (p = 0.009), indicating cortical plasticity.
• The lack of change in short-latency stretch reflex components suggested the induced plasticity was cortical, not spinal.
• Control conditions (imagining only or random MAFO triggering) did not yield significant changes in MEP size.

Conclusions:

• The BCI-MAFO system provides a rapid and effective method for inducing cortical plasticity.
• This technology holds significant potential for improving motor function rehabilitation in stroke survivors.
• The findings support the use of BCI-driven interventions for enhancing neural recovery.