Synchronous positive and negative myoclonus due to pontine hemorrhage.

We report a case of synchronous positive and negative myoclonus following pontine hemorrhage. Constant synchronous jerking of the eyes, tongue, face, mandible, larynx, pharynx, and diaphragms persisted during sleep. Jerking of limb muscles occurred during volitional activities, but not at rest. Inability to sustain glottic adduction during phonation contributed to severe dysarthria. Electromyography (EMG) revealed positive myoclonus of the branchial musculature with synchronous negative myoclonus in a generalized distribution. Treatment with trazodone reduced the ocular myoclonus but worsened the dysphagia. We suggest that a single neural rhythm generator may produce both positive and negative myoclonus.