Pediatric Movement Disorders - Myoclonus

Mechanism

The mechanism of myoclonus is not well understood. Cortical myoclonus is possibly a disorder of decreased inhibition in the cortex. The frequent association with seizure disorders suggests that there may be a common cause for myoclonus and some types of epilepsy. However, the reason for the reduced inhibition is not known. The mechanism of subcortical and spinal myoclonus is even less well understood. A group of disorders called "startle syndromes" probably involves hyperexcitability of the normal brainstem startle circuits and decreased inhibition in spinal circuits. This may due to a mutation in the receptor for the neurotransmitter glycine.