Soleus H-reflex recruitment is not altered in persons with chronic spinal cord injury.
OBJECTIVE
To determine whether spasticity in persons with spinal cord injury (SCI) is associated with elevated monosynaptic reflex excitability.


METHODS
One-way experimental.


METHODS
Research laboratory.


METHODS
Convenience sample of 9 subjects (8 men, 1 woman) with chronic and complete SCI and 20 persons (14 men, 6 women) with no neurologic impairment. Subjects with SCI exhibited lower-extremity spasticity as indicated by velocity-dependent increased resistance to passive muscle stretch, abnormally brisk deep tendon reflexes, involuntary lower-extremity flexion and/or extension spasms, and clonus.


METHODS
Soleus H-reflex recruitment curves were elicited in all subjects.


METHODS
Soleus H-reflex threshold (HTH), gain (HGN), and amplitude (HPP).


RESULTS
There was no difference between subjects with and without SCI in HTH, HGN, or HPP.


CONCLUSIONS
Spasticity in people with chronic and complete SCI was not associated with increased excitability of the connections between Ia afferent projections and motoneurons. Factors extrinsic to these connections may have a role in spasticity caused by SCI.
Schindler-Ivens
Sheila M
SM
Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA. s-schindler-ivens@northwestern.edu
Shields
Richard K
RK
D000328:Adult; D016022:Case-Control Studies; D002908:Chronic Disease; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009128:Muscle Spasticity / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D012494:Sampling Studies; D013119:Spinal Cord Injuries / Q000503:physiopathology*