Sleep-induced masticatory myoclonus: a rare parasomnia associated with insomnia.
Tonic and rhythmic activity of the masticatory muscles accompanied by a loud and grating or clicking sound characterizes bruxism, a well-recognized parasomnia. We describe a 63-year-old man who complained of insomnia due to repeated tongue nibbling during sleep. Nocturnal polysomnographic recordings showed brief (50-100-ms) myoclonic jerks of myloioideus and masseter muscles occurring during phase 1 of sleep and leading to troublesome tongue nibbling with arousal of the patient. Hypnograms showed reduction of phase 2 and absent phases 3-4 and REM. Different pharmacological treatments including clomipramine, benzodiazepines, and carbamazepine were ineffective. A purposive interdental plate was placed to prevent jaw closings during sleep: masticatory myoclonus still persisted, but it did not provoke arousals; insomnia disappeared and night hypnograms improved.
Aguglia
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Institute of Neurological Sciences, School of Medicine, University of Reggio Cal., Catanzaro, Italy.
Gambardella
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Quattrone
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D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology; D006801:Humans; D008297:Male; D008410:Masticatory Muscles / Q000503:physiopathology*; D008875:Middle Aged; D009207:Myoclonus / Q000503:physiopathology*; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology