Modulation of soleus stretch reflexes during walking in people with chronic incomplete spinal cord injury.

Modulation of soleus stretch reflexes during walking in people with chronic incomplete spinal cord injury. Exp Brain Res. 2019 Jul 15;: Authors: Thompson AK, Mrachacz-Kersting N, Sinkjær T, Andersen JB Abstract In people with spasticity due to chronic incomplete spinal cord injury (SCI), it has been presumed that the abnormal stretch reflex activity impairs gait. However, locomotor stretch reflexes across all phases of walking have not been investigated in people with SCI. Thus, to understand modulation of stretch reflex excitability during spastic gait, we investigated soleus stretch reflexes across the entire gait cycle in nine neurologically normal participants and nine participants with spasticity due to chronic incomplete SCI (2.5-11 year post-injury). While the participant walked on the treadmill at his/her preferred speed, unexpected ankle dorsiflexion perturbations (6° at 250°/s) were imposed every 4-6 steps. The soleus H-reflex was also examined. In participants without SCI, spinal short-latency "M1", spinal medium latency "M2", and long-latency "M3" were clearly modulated throughout the step cycle; the responses were largest in the mid-stance and almost completely suppressed during the stance-swing transition and swing phases. In participants with SCI, M1 and M2 were abnormally large in the mid-late-swing phase, while M3 modulation was similar to that in participants without SCI. The H-reflex was also large in the mid-l...
Source: Experimental Brain Research - Category: Neuroscience Authors: Tags: Exp Brain Res Source Type: research