Clinical Testing of Invasive Spinal Cord Stimulation and Evaluation of Its Physiological Effects Using the Electroencephalography

The aim of the study is to identify the nature of brain network dysfunctions and assess the recovery of their function based on resting-state electroencephalography (EEG) recordings during rehabilitation using spinal cord stimulation (SCS). The study aims to gather information on the role of brain neuroplasticity during the use of effective SCS programs with implanted electrodes in participants with partial or complete spinal cord injury at various levels. Participants are enrolled according to inclusion criteria. Before the procedure for implanting multichannel electrodes, resting-state EEG recordings are performed. Then, multichannel electrodes are implanted into the epidural space of the spinal cord below the level of injury. After the implantation, another resting-state EEG recording is conducted before the stimulator is turned on for the first time. Once the optimal SCS program is selected (for the suppression of spastic syndrome or volitional motor control), periodic resting-state EEG recordings are made: before stimulation, during stimulation, and after stimulation. Before the participant is discharged, a final resting-state EEG recording is performed with the stimulator turned on. Scheduled postoperative monitoring will be conducted for up to 2 weeks. SCS is initiated on the second day after the surgical procedure. The participant is instructed on the use of the stimulator. The optimal program is selected within commonly accepted ranges of stimulation parameters (frequency, amplitude, pulse width) based on maximum efficacy. Researchers expect that effective SCS scenarios will result in progressive alterations in the quantitative metrics of resting-state EEG throughout the rehabilitation period. The data obtained may be used to optimize rehabilitation protocols and develop personalized approaches for recovery after spinal cord injury. Within the motor imagery paradigm, following the selection of the program for volitional motor control, participants are instructed to sequentially imagine movements of the limbs (general flexion and extension of the left arm, general flexion and extension of the right arm, general flexion and extension of the left leg, and general flexion and extension of the right leg) in response to auditory and visual cues displayed on a computer screen. After imagining these movements, participants are required to physically perform the same movements. Recordings are made with the stimulator both turned off and on. Throughout the entire recording period, EEG is continuously recorded from the participant. The primary aim of this recording is to investigate the desynchronization of the mu rhythm.