Palatal myoclonus--its remote influence.

Four patients with palatal myoclonus were examined electromyographically. Surface EMG was recorded simultaneously from several myoclonic muscles and the correlation between their rhythmic discharges was shown. The possible existence of a remote influence of palatal myoclonus was tested by recording soleus and anterior tibial H-reflexes and seeking a correlation of their amplitudes with the rhythm of palatal myoclonus. Two cases, both with additional severe spasticity in the legs, showed rhythmic variation of the soleus H-reflex amplitude corresponding with that of their palatal myoclonus. This suggests that the neural mechanism generating the visible myoclonus has much more extensive effects.