title: Functional repetitive transcranial magnetic stimulation increases motor cortex excitability in survivors of stroke.
abstract: OBJECTIVE
  To 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.
  
  
  METHODS
  Eighteen 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.
  
  
  RESULTS
  Significant 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).
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  Functional-rTMS promoted greater excitability changes and selectively modulated agonist muscle activity.
authors.affiliation: Physical Therapy and Rehabilitation Science Department, University of Maryland School of Medicine, Baltimore, MD 21201, USA. cmassie@som.umaryland.edu
authors.forename: Crystal L
authors.initials: CL
authors.lastname: Massie
authors.forename: Brian L
authors.initials: BL
authors.lastname: Tracy
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Malcolm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D017741:Survivors; D050781:Transcranial Magnetic Stimulation / Q000379:methods*