Repeated sessions of functional repetitive transcranial magnetic stimulation increases motor cortex excitability and motor control in survivors of stroke
Affiliations: [a] Department of Physical Therapy & Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, USA | [b] Department of Health & Exercise Science, Colorado State University, CO, USA | [c] Department of Occupational Therapy, Colorado State University, CO, USA
Correspondence:
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Address for correspondence: Crystal L. Massie, 100 Penn Street, AHB 100 Physical Therapy and Rehabilitation Science Department, University of Maryland School of Medicine, Baltimore, MD 21201, USA. Tel.: +1 410 706 7770; Fax: +1 410 706 6387; E-mail: [email protected]
Abstract: Objective:To determine the impact of a single-session of repetitive transcranial magnetic stimulation (rTMS) and an rTMS intervention on neurophysiology and motor control in survivors of stroke. Methods:Twelve stroke survivors were randomized into functional-rTMS or passive-rTMS conditions. Measures of short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), and force steadiness (coefficient of variation, CV) at 10 and 20% of maximum voluntary contraction were assessed at baseline and after a single-session of rTMS (post single-session), and again following an intervention of 8 rTMS sessions (2 sessions per day; post-intervention). Functional-rTMS required subjects to exceed a muscle activation threshold assessed by surface electromyography to trigger each rTMS train; the passive-rTMS group received rTMS while relaxed. Results:ICF scores significantly increased following the single-session of functional-rTMS compared to the decrease following passive-rTMS. The increase in APB SICI and ICF scores following the intervention was significantly greater for the functional-rTMS group compared to the decreases following passive-rTMS. The groups were significantly different in the CV of force (20%) following the single-session of rTMS, and in the 10 and 20% tasks following the intervention. The functional-rTMS group increased steadiness overtime, whereas the passive group demonstrated a return to baseline following the intervention session. No differences were observed in first dorsal interosseus (FDI) measures (SICI and ICF) between groups. Conclusions:The functional-rTMS protocol enhanced cortical excitability following a single-session and after repeated sessions and improved steadiness, whereas the passive stimulation protocol tended to decrease excitation and no improvements in steadiness were observed.
Keywords: Rehabilitation, motor control, transcranial magnetic stimulation, repetitive transcranial magnetic stimulation, force
