Traditional brain-computer interface (BCI) systems have focused on applications for patients with structurally intact cortices. A large body of research has shown that activity in primary motor cortex contralateral to the hand of interest is tuned to hand position, movement direction and speed, and that this activity can control a multiple degree-of-freedom BCI system. Although the contralateral motor cortex seems to be an ideal control signal in traditional BCI applications, a different cortical signal would be necessary in motor-impaired hemiplegic stroke survivors who suffer damage contralateral to the affected limb. Stroke is the most common neurological disorder in the United States with approximately 795,000 strokes per year and approximately 15 million annually worldwide. Of these new strokes, 15-30% of patients are left permanently disabled and 20% require institutional care after their stroke. Previous work from our lab showed neural activations ipsilateral to hand movements in motor-intact patients monitored with subdural electrocorticography (ECoG). Additionally, these activations occurred 160ms prior to activations related to contralateral motor activations, were located in premotor cortex instead of primary motor cortex, and occurred in a differentiable spectral range from activity related to contralateral hand movements. Not only did this study show a differentiable physiology related to ipsilateral hand movements, but ipsilateral activations were used to control a BCI system with performance comparable to BCI systems developed using contralateral motor activations. This project seeks to investigate the applications of ipsilateral motor signals for BCI systems in hemiplegic stroke survivors. Initial work has used scalp electroencephalography (EEG) recordings and demonstrated the presence of ipsilateral motor-related activations that can be separably discriminated from contralateral activations as well as the use of these ipsilateral activations for BCI control. The lab will continue to investigate the use of ipsilateral motor signals for BCI control as well as the potential for using BCI systems for motor rehabilitation in chronic stroke survivors.
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