The effects of electrical stimulation of VL and sub-VL on muscle tonus

VL and sub-VL were electrically stimulated at 1-mm intervals and the influence on three muscles (anterior tibial muscle, gastrocnemius muscle and soleus muscle) of the contralateral limb was studied by the method of RE-EMG. The effect of VL and sub-VL stimulation was examined on ether clonus as an indicator of hyperactive muscle, especially for spasticity. The results are summarized as follows: 1. Clonus was apparently suppressed by electrical stimulation in an area (F, 10.0 mm; L, 4.0 mm; D, from +2 to -2; there was especially marked suppression of clonus by stimulation in sub-VL. 2. On electrical stimulation of the lateral third of VL, hypertonicity of anterior tibial muscle (T), hypotonicity of gastrocnemius muscle (G), and also hypotonicity of soleus muscle (S), was observed on stimulation of the middle third, T, G, S, and of the medial third, no effect was observed. 3. Electrical stimulation of the anterior part of VL showed T, G, S, and electrical stimulation of the posterior part of VL showed T, G, S.