| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3044618 | Clinical Neurophysiology | 2013 | 8 Pages |
ObjectiveTo determine if repetitive transcranial magnetic stimulation (rTMS) applied to the motor cortex with simultaneous voluntary muscle activation, termed functional-rTMS, will promote greater neuronal excitability changes and neural plasticity than passive-rTMS in survivors of stroke.MethodsEighteen stroke survivors were randomized into functional-rTMS (EMG-triggered rTMS) or passive-rTMS (rTMS only; control) conditions. Measures of short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), force steadiness (coefficient of variation, CV) at 10% of maximum voluntary contraction, and pinch task muscle activity were assessed before and after rTMS. Functional-rTMS required subjects to exceed a muscle activation threshold to trigger each rTMS train; the passive-rTMS group received rTMS while relaxed.ResultsSignificant interactions (time × condition) were observed in abductor pollicis brevis (APB) SICI, APB ICF, CV of force, and APB muscle activity. Functional-rTMS decreased APB SICI (p < 0.05) and increased ICF (p < 0.05) after stimulation, whereas passive-rTMS decreased APB muscle activity (p < 0.01) and decreased CV of force (p < 0.05). No changes were observed in FDI measures (EMG, ICF, SICI).Conclusion(s)Functional-rTMS increased motor cortex excitability, i.e., less SICI and more ICF for the APB muscle. Passive stimulation significantly reduced APB muscle activity and improved steadiness.SignificanceFunctional-rTMS promoted greater excitability changes and selectively modulated agonist muscle activity.
► Functional-rTMS (repetitive transcranial magnetic stimulation simultaneously delivered during a voluntary muscle contraction) promoted greater cortical excitability changes than passive-rTMS. ► Survivors of stroke had a refinement in the level of muscle activity and force fluctuations following passive-rTMS. ► Functional-rTMS preferentially modulated the agonist/primary muscle group which may have important clinical implications for stroke rehabilitation.
