fNIRS-BCI Neurofeedback in Stroke Rehabilitation

Patients will perform kinesthetic motor imagery of the affected upper extremity in response to auditory cues from the BCI system. The averaged oxygenated hemoglobin (HbO) level, extracted from optimal channels identified during the localizer session, will serve as signal intensity. This intensity, quantified as percent signal change relative to baseline, will trigger neurofeedback when reaching a predefined threshold. Visual feedback, delivered via the digital mirror therapy system, will guide patients to perform observational imitation tasks using bilateral upper extremities. Each session will include 5-6 movements tailored to the patient's functional performance. After observational imitation training, patients will practice functional adaptation tasks in a virtual environment, where they apply learned movements to functional activities. Sessions will last approximately 75 minutes.

In the sham group, patients will wear a similar headset equipment as those in the BCI group. However, the visual feedback provided through the digital mirror therapy system will not be based on their own brain activity. Instead, it will be derived from the brain activity of a participant in the BCI group using the simulation mode of Turbo-Satori. Patients in the sham group will receive constant visual feedback, with a fixed duration of 60 seconds for motor imagery, regardless of their actual brain signals. Like the BCI group, patients will be instructed to use kinesthetic motor imagery and imitate the movement when receiving visual feedback, and practice functional adaptation tasks after observational imitation training. The sham training will also last for around 75 minutes per session.