Study of the activation in sensorimotor cortex and topological properties of functional brain network following focal vibration in healthy subjects and subacute stroke patients: an EEG Study

Abstract Modulatory effects of cerebral cortex and cerebral networks are of utmost importance in rehabilitation since they can induce plastic changes. Previous studies have proved that focal vibration (FV) can modulate the activities of sensorimotor cortex in healthy subjects (HS). In this study, we studied the modulation of FV on the sensorimotor cortex and cerebral network in HS and subacute stroke patients (SSP). An experiment was conducted to investigate alpha and beta motor-related power desynchronization (MRPD), and topological properties of cerebral network during FV of 75Hz applied over biceps muscle of right limb of 10 HS and 10 SSP with right hemiplegia. Electroencephalography (EEG) was recorded in the following phases: before FV, in the control condition and three sessions of FV. EEG analysis showed that MRPD of contralesional primary sensorimotor cortex (contralesional S1-M1) in the beta2 band (18-21Hz) for SSP, but MRPD of bilateral S1-M1 in the beta1 (13-18Hz) and the beta2 band for HS, had a significant decrease during three FV sessions. Moreover, MRPD of contralesional S1-M1 was significantly lower than MRPD of ipsilesional S1-M1 during FV. Besides, a significant increase of global efficiency (E) and decrease of characteristic path length (L) were identified in the beta1 band for SSP, which was different from a significant increase of L for HS. The phenomenon indicated that FV could enhance the excitability of contralesional S1-M1 and alter topological properties of functional brain network for SSP, which is different from HS. This indication contributes to explaining acute central adaptations caused by FV.