BCI for Hemiparetic Upper Extremities in Patients Due to Stroke

Brain-computer Interface (BCI) Based Closed-loop Training for Hemiparetic Upper Extremities in Patients Due to Stroke: A Randomized Controlled Study

Non-invasive brain-computer interface (BCI) technology is one of the new training approaches to achieve motor restoration through a closed-loop system from brain activity through event-related desynchronization (ERD) after motor imagery (MI) or movement attempt to peripheral feedback triggered by an external hepatic device. Often, it is unclear whether the BCI intervention itself or the assistance of the external device leads to neural responses and functional gains.

This study adopts a closed-loop BCI system involving ERD induced by MI. Functional electrical stimulation (FES) and virtual reality (VR) are simultaneously delivered as feedback. The aim is to investigate the efficacy of closed-loop BCI training combined with FES and VR on the recovery of the hemiparetic upper extremity of individuals with chronic stroke.

Chronic stroke survivors are being recruited and randomly allocated into 3 groups: (1) BCI-FES-VR - participants look at an external screen displaying the VR avatar participant's arms while performing wrist dorsiflexion MI in random order (left or right). The BCI system detects the ERD of the motor area corresponding to correct MI. Then, visual feedback with the VR and motor-tactile feedback with the discharge of the FES is delivered; (2) BCI-FES - same procedure as group 1, but the difference is that the participant's hands replace the VR system; (3) BCI-VR - same procedure as group 1, but the FES is removed. Each session requires 240 MI trials with a training duration of 10 sessions in a 3-week interval.

Motor and MI assessments are being conducted at post-assessment and at a 3-week follow-up.

The findings of this study will provide significant new information regarding neurophysiological motor relearning mechanisms, which could inform the development and evaluation of BCI-based treatment for individuals with stroke and impact the field of translational neuroscience.

Inclusion Criteria:

1. Have a diagnosis of ischemic or hemorrhagic stroke to unilateral hemisphere, confirmed by neuroimaging examinations, i.e., brain CT or MRI;
2. Chronic phase of stroke, i.e., time after stroke onset more than 6 months;
3. ≥ 18 years old;
4. With severe to moderate levels of hemiparetic upper limb impairment due to stroke, i.e., from levels 1 to 5 in the Functional Test for the Hemiplegic Upper Extremity (FTHUE)
5. Able to give informed written consent to participate in the study.

Exclusion Criteria:

1. Previous diagnosis of any neurological disease excluding stroke;
2. Presence of any sign of cognitive problems (Abbreviated Mental Test < 6)
3. Modified Ashworth score > 2 in wrist extensor muscle in the hemiparetic upper extremity after stroke (Bohannon and Smith, 1987) or with severe pain that hinders upper extremity movement
4. With other notable impairments of the upper extremity not caused by stroke (e.g., fracture, Rheumatoid Arthritis, or congenital deformity, etc.)