Massed practice versus massed practice with stimulation: effects on upper extremity function and cortical plasticity in individuals with incomplete cervical spinal cord injury.
OBJECTIVE
To determine the effect of massed practice (MP) versus massed practice combined with somatosensory stimulation (MP+SS) on cortical plasticity and function in persons with incomplete tetraplegia.


METHODS
Ten subjects were assigned to either MP or MP+SS. Median nerve stimulation (500 ms train, 10 Hz, 1 ms pulse duration) was delivered at the intensity eliciting a motor threshold response. Training sessions were 5 d/week for 3 weeks at 2 h/session. Outcome measures included 1) motor-evoked potentials (MEPs) elicited via transcranial magnetic stimulation (TMS), motor threshold (MT) and MEP amplitude at 1.2 MT; 2) maximal pinch grip force; 3) Wolf Motor Function Test (WMFT) and Jebsen Hand Function Test.


RESULTS
The MP+SS group demonstrated significant improvements (P < 0.05) in pinch grip strength (190%), WMFT scores (52%), and Jebsen test scores (33%), whereas the MP group demonstrated significant improvement (P < 0.05) only in Jebsen test scores (11%). No significant changes were detected in cortical excitability in the MP+SS or MP group.


CONCLUSIONS
The findings of this preliminary study suggest that MP+SS results in greater increases in pinch strength and timed functional test scores than MP. Optimal stimulation paradigms and training methods are needed to further test this strategy.
Beekhuizen
Kristina S
KS
The Miami Project to Cure Paralysis, University of Miami School of Medicine, Miami, FL 33136, USA.
Field-Fote
Edelle C
EC
D000368:Aged; D002574:Cervical Vertebrae; D004599:Electric Stimulation Therapy / Q000379:methods*; D019054:Evoked Potentials, Motor; D005260:Female; D006225:Hand / Q000294:innervation / Q000502:physiology; D018737:Hand Strength; D006801:Humans; D008280:Magnetics / Q000627:therapeutic use*; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged; D009043:Motor Activity; D009473:Neuronal Plasticity / Q000502:physiology*; D010865:Pilot Projects; D011782:Quadriplegia / Q000503:physiopathology / Q000534:rehabilitation / Q000628:therapy; D013003:Somatosensory Cortex / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology / Q000534:rehabilitation / Q000628:therapy*