Excessive fragmentary myoclonus is a movement disorder diagnosed by electromyographic (EMG) measurements, which tracks muscle contractions. Contractions in the muscle are subtle and may not always be visible. Therefore, the electric potentials of these contractions must be visualized by an EMG. Excessive fragmentary myoclonus occurs during NREM sleep. At least five myoclonus recordings per minute must be observed to be a diagnostic criterion.
