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Published on: May 24, 2017
Restoration of frequency-dependent depression of the H-reflex by passive exercise in spinal rats
N B Reese1, R D Skinner, D Mitchell
1Department of Physical Therapy, University of Central Arkansas, Conway, AR 72205, USA.
Study Design:
Hyper-reflexia, measured as a decrease of low frequency-dependent depression of the H-reflex, is known to occur in both humans and animals after spinal cord injury (SCI). Previous studies have shown that passive exercise for 3 months could be used to restore low frequency-dependent depression of the H-reflex after SCI.
Objective:
To determine the effects of various periods of time on the ability of passive exercise to restore low frequency-dependent depression of the H-reflex.
Setting:
Spinal Cord Injury Mobilization Program of the Center for Translational Neuroscience, the research arm of the Jackson T Stephens Spine and Neuroscience Institute, Little Rock, AR, USA.
Methods:
Adult rats underwent complete spinal cord transection at the T10 level. The hindlimbs were passively exercised in different groups of rats for 1 h/day, 5 days/week for 15, 30, 45, 60, or 90 days, and low frequency-dependent depression of the H-reflex was tested.
Results:
Statistically significant low frequency-dependent depression of the H-reflex was evident by 30 days of exercise, although numerical reductions were seen even at 15 days. There was a linear decrease in low frequency-dependent depression of the H-reflex with duration of passive exercise.
Conclusions:
Passive exercise can restore frequency-dependent depression of spinal reflexes in a time-dependent manner if used following complete spinal transection.
