Modulatory effects of locomotor training on extensor spasticity in individuals with motor-incomplete spinal cord injury.

PURPOSE: Sparse data exist about effects of locomotor training on spasticity in individuals with spinal cord injury (SCI). We investigated changes in spastic responses in individuals with motor-incomplete SCI (MISCI) associated with locomotor training and examined properties of a biomechanical measure of clonus severity, plantar flexor reflex threshold angle (PF RTA).

METHODS

In 18 individuals with chronic MISCI, we assessed biomechanical and electrophysiologic measures of extensor spasticity and their relationship with walking speed before and after 12 weeks of body-weight supported locomotor training. Measures included PF RTA, plantar flexor (ankle clonus) and quadriceps spasm duration, soleus H-reflex, and ankle muscle electromyography. PF RTA validity was assessed by measuring PF RTA and clonus duration in 40 individuals with SCI and 10 non-disabled individuals.

RESULTS

Locomotor training was associated with decreased PF RTA (p = 0.06), ankle clonus (p = 0.09) and quadriceps spasm (p = 0.05). PF RTA discriminated between non-disabled individuals and individuals with SCI and was moderately correlated with walking speed, soleus H/M ratio, and quadriceps spasm duration.

CONCLUSIONS

In persons with spastic paresis due to MISCI, locomotor training was associated with decreased spasticity as measured by decreased plantar flexor excitability, ankle clonus, and quadriceps spasm.