Vibration training after chronic spinal cord injury: Evidence for persistent segmental plasticity.
H-reflex paired-pulse depression is gradually lost within the first year post-SCI, a process believed to reflect reorganization of segmental interneurons after the loss of normal descending (cortical) inhibition. This reorganization co-varies in time with the development of involuntary spasms and spasticity. The purpose of this study is to determine whether long-term vibration training may initiate the return of H-reflex paired-pulse depression in individuals with chronic, complete SCI. Five men with SCI received twice-weekly vibration training (30Hz, 0.6g) to one lower limb while seated in a wheelchair. The contra-lateral limb served as a within-subject control. Paired-pulse H-reflexes were obtained before, during, and after a session of vibration. Untrained limb H-reflex depression values were comparable to chronic SCI values from previous reports. In contrast, the trained limbs of all 5 participants showed depression values that were within the range of previously-reported Acute SCI and Non-SCI H-reflex depression. The average difference between limbs was 34.98% (p=0.016). This evidence for the return of H-reflex depression suggests that even for people with long-standing SCI, plasticity persists in segmental reflex pathways. The spinal networks involved with the clinical manifestation of spasticity may thus retain adaptive plasticity after long-term SCI. The results of this study indicate that vibration training may hold promise as an anti-spasticity rehabilitation intervention.
Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, 52242, United States.
Chu-Ling
CL
Yen
Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, 52242, United States.
Colleen L
CL
McHenry
Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, 52242, United States.
Michael A
MA
Petrie
Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, 52242, United States.
Shauna
S
Dudley-Javoroski
Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, 52242, United States. Electronic address: richard-shields@uiowa.edu.
Richard K
RK
Shields
D000328:Adult; D002908:Chronic Disease; D006181:H-Reflex; D006801:Humans; D007866:Leg / Q000294:innervation / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009473:Neuronal Plasticity; D013119:Spinal Cord Injuries / Q000503:physiopathology / Q000534:rehabilitation*; D014732:Vibration; D055815:Young Adult
H-reflex; Paralysis; Post-activation depression; Pre-synaptic inhibition; Spasticity