Two Cases of Stimulus Sensitive Spinal Myoclonus

ABSTRACT

Myoclouns is a complicated and poorly-understood phenomenon caused by many pathological conditions. Myoclonus which is triggered by sensory stimuli has been termed reflx myoclonus and divided into cortical, reticular and spinal types depending on the generator sites. Segmental myoclonus of spinal origin consists of synchronous rhythmical jerks confined to a group of muscles supplied by either one segment or several contiguous segments of the spinal cords. We present two cases of spinal reflex myoclonus. One was 50 years old female who showed complex myoclonic jerks involving the abdominal wall and paraspinal muscibs resembling 'belly dance'. The other was 26 years old male who showed intermittent synchronous upper cervical axial muscle contractions. In both cases, jerks were increased with certain stimuli, but disappeared during sleep. They showed normal EEGs and absence of enhancement of SSEPS.