H-reflex recovery curve and reciprocal inhibition of H-reflex of the upper limbs in patients with spasticity secondary to stroke.

The H-reflex recovery curve of the lower limb is considered a useful test for the diagnosis of spasticity, and recently the reciprocal inhibition of the H-reflex has proven to be abnormal in patients affected with spasticity. We studied the H-reflex recovery curve and the reciprocal inhibition of the H-reflex in the upper limb of a group of 33 patients with different degrees of spasticity secondary to stroke. Results were compared with those of 25 controls. The aim of this study was to investigate if the two tests showed any direct correlation with the degree of spasticity and, furthermore, with other clinical measures that are present in patients with spasticity as part of an upper motoneuron syndrome (i.e., changes in muscle tone, reflexes, force, etc.). The results showed an abnormality of both tests in most patients (decrease of the three phases of inhibition in the reciprocal inhibition test and increase of the late facilitation part of the H-reflex recovery curve), and these abnormalities seem mostly to be related to muscle tone, most important being the degree of correlation between tone and changes in abnormality of the H-reflex recovery curve (P < 0.03).