Post-stroke injured cerebral cortex: frequency analysis of the desynchronization of its sensorimotor rhythms during motor intent

During a motor intent, desynchronization of sensorimotor rhythms of the cerebral cortex takes place. This physiological phenomenon, called event related desynchronization (ERD), is used for the development of Brain Computer Interfaces (BCI) for motor recovery. Stroke survivors suffering complete or partial loss of mobility usually require therapy for motor rehabilitation. The damage of the sensorimotor cortex that follows a stroke can compromise the brain rhythms that encode motor states. Therefore, this study assessed the ERD behavior during movement and motor intent in post-stroke patients. Eight electroencephalogram channels were recorded in seven chronic ischemic stroke patients during rest and movement or motor intent of their hands. The spectra of the coefficient of determination r² were estimated between 8 and 30 Hz. The median of r² reached 0.05 during motor intent of the corresponding affected hand; so it is a real value to be taken into account in BCI developments for people who have suffered a stroke. However, there was no evidence of a common pattern for the ERD. It was also observed that stroke survivors have discrimination capacity in the injured hemisphere during the motor intent of their affected limb.