Abstract: ObjectiveTo investigate the changes and relevance of H reflex and spasticity after cervical or thoracic spinal cord injury (SCI).MethodsH reflex of 13 healthy adults as controls and 30 SCI patients (subacute, n=18; chronic, n=12) was measured twice from soleus muscle once a month. In the same time, the evaluation of spasm was performed by the modified Ashworth scale.ResultsThere was no significant difference in the mean H_max amplitude and H_max/M_max ratio between different SCI stages(P>0.05). However, the mean H_max amplitude of the patients was smaller than that of controls(P<0.01). During subacute stage there was quadratic correlation between the mean H_max amplitude and spasticity, H_max/M_max ratio and spasticity. But there was linear correlation between H_max/M_max ratio and spasticity during chronic stage.ConclusionThere was closer relation between spasticity and Hmax/Mmax ratio after spinal cord injury. However, the quantitative evaluation need to be proved by larger samples.

Key words: spinal cord injury, H reflex, H_max/M_max ratio, modified Ashworth scale