Rhythmic involuntary lingual movements (lingual myoclonus): study of 4 cases.

Abstract

Four children with rhythmic lingual movements resembling palatal myoclonus in rate and character are reported. The movements did not interfere with swallowing or crying and varied in frequency from 60 to 130/min. The contractions of the tongue produced side to side or up and down movements or intermittent protrusion of the tongue. In one patient the disorder was confined to the tongue, in one was associated with opsoclonus and myoclonus of the facial and extremity muscles and in one patient each with involvement of the jaw and the right upper limb. The movements were intermittent in one child, disappeared during sleep in two and spontaneous remission of the involuntary movements occurred in all. Electroencephalograms (EEG) carried out while the patients were having the involuntary movements excluded an epileptic basis for the disorder. The presumptive etiological diagnosis included acute viral encephalitis in two, subacute encephalitis in one and brainstem encephalitis in one. The rate, rhytmicity and persistance of the malady without evident seizure activity in the EEG justify the term lingual myoclonus akin to palatal myoclonus in these patients.