Spasticity, as one component of the upper motorneuron syndrome has been one of the most troublesome obstacles to the successive rehabilitation of motor function. Moreover, the objective diagnosis and the quantification of the extent of spasticity have been the interesting issues to be solved.

In the present study, to control spasticity systemically, we used a GABA derivative (i.e baclofen) to ten subjects who had symptomatic spasticity due to spinal or cerebral lesion fir 4 weeks. And then we examined H/M ratio weekly to observe the effect. The result obtained as follows:

1) The basal H/M ratio of the spastic, 16 limbs of 10 subjects, was 0.476±0.161, significantly larger than the standard normal value.

2) The percentile changes of the H/M ratio after 1,2,3 and 2 weeks during the medication, were accordingly -20.1±26.2, -21.0±25.4%, -23.4±23.8% and -32.8±19.6%, so the significant serial decrement of the H/M ratio with clinical improvement of spasticity could be observed.

3) The H/M ratio change of the spinal spasticity was not significantly larger than that of the cortical spasticity.

4) The H/M ratio change in spastic hemiplegia showed the decrement in affected side as well as in unaffected side.

5) Of the spastic symptoms, resistance to the passive movement showed improvement in 80%, in contrast to the ankle clonus, which had the improvement only in 40%.