Source: Frontiers in Neurology. 12 (no pagination), 2021. Article Number: 749798.
Date of Publication: 04 Nov 2021.
Author: Dionisio A.; Gouveia R.; Castelhano J.; Duarte I.C.; Santo G.C.; Sargento-Freitas J.; Duecker F.; Castelo-Branco M.
Objectives: Transcranial magnetic stimulation, in particular continuous theta burst (cTBS), has been proposed for stroke rehabilitation, based on the concept that inhibition of the healthy hemisphere helps promote the recovery of the lesioned one. We aimed to study its effects on cortical excitability, oscillatory patterns, and motor function, the main aim being to identify potentially beneficial neurophysiological effects.
Material(s) and Method(s): We applied randomized real or placebo stimulation over the unaffected primary motor cortex of 10 subacute (7 +/- 3 days) post-stroke patients. Neurophysiological measurements were performed using electroencephalography and electromyography. Motor function was assessed with the Wolf Motor Function Test. We performed a repeated measure study with the recordings taken pre-, post-cTBS, and at 3 months’ follow-up.
Result(s): We investigated changes in motor rhythms during arm elevation and thumb opposition tasks and found significant changes in beta power of the affected thumb’s opposition, specifically after real cTBS. Our results are consistent with an excitatory response (increase in event-related desynchronization) in the
sensorimotor cortical areas of the affected hemisphere, after stimulation. Neither peak-to-peak amplitude of motor-evoked potentials nor motor performance were significantly altered.
Conclusion(s): Consistently with the theoretical prediction, this contralateral inhibitory stimulation paradigm changes neurophysiology, leading to a significant excitatory impact on the cortical oscillatory patterns of the contralateral hemisphere. These proof-of-concept results provide evidence for the potential role of continuous TBS in the neurorehabilitation of post-stroke patients. We suggest that these changes in ERS/ERD patterns should be further explored in future phase IIb/phase III clinical trials, in larger samples of post-stroke patients.