Abstract
Reciprocal Ia inhibition in stroke patients was investigated before and after walking with and without Ankle Foot Orthotics (AFO). Five patients (mean: 47.6 years) with spastic hemiplegia due to cerebrovascular disease who can walk independently allowed soleus surface recording of H-reflex before and after treadmill walking at 1 km/h for 15 min. For test stimuli, the tibial nerve was stimulated at the popliteal fossa, and for conditioning stimuli, the common peroneal nerve was at the level of caput fiblae with the intensity of the lowest threshold for M wave. Time interval between test and conditioning stimuli were 0, 1, 2, and 3 msec. Statistical comparisons were made using with repetition in ANOVA and probability values less than 0.05 considered significant. Reciprocal Ia inhibition in spastic patients was reduced or abolished every conditioning test interval before and after walking. Although two cases showed reciprocal IA inhibition started 2 msec conditioning test interval at the rest, they had been facilitated H-reflex after walking. However, there was a tendency to decrease H-reflex amplitude after treadmill walking with AFO compared to before task.
We have found that reciprocal Ia Inhibition maintained in normal subjects after treadmill walking, but not in spastic hemiplegic patients. We have considered that it might be important for gait training or motor control of spastic patients to be maintained reciprocal Ia inhibition or distribute input volley with AFO. We would continue further investigation, and would like to examine the relationship between the effects of reciprocal Ia inhibition by AFO and function changes of the neurological organization, such as reciprocal inhibition conjunctions.
