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Segmental facial myoclonus in Moebius syndrome
Author(s) -
Bonanni Paolo,
Guerrini Renzo
Publication year - 1999
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/1531-8257(199911)14:6<1021::aid-mds1019>3.0.co;2-3
Subject(s) - myoclonus , electromyography , corneal reflex , medicine , facial nerve , electroencephalography , facial muscles , palsy , anatomy , psychology , reflex , neuroscience , audiology , physical medicine and rehabilitation , anesthesia , pathology , alternative medicine
Moebius syndrome is characterized by sixth and seventh nerve palsy and is usually the result of bilateral hypoplasia or aplasia of the respective brain stem nuclei. There have been no reports of involuntary facial movements associated with this malformative complex. We report on a 6‐year‐old boy affected by Moebius syndrome with asymmetric involvement and segmental facial myoclonus with onset at age 2 years, affecting the side with partially conserved motility. Clinical presentation included congenital peripheral palsy of the right seventh cranial nerve and left‐sided rhythmic rising of the upper lip and eyebrow. Surface‐electromyography (EMG) of the left levator labii and frontalis muscles showed rhythmic bursting (duration: 150–450 ms; frequency: 1–3 Hz). Electroencephalographic (EEG)–polygraphic recordings and burst‐locked EEG averaging failed to show any consistent EEG activity preceding the EMG bursts. Study of the blink reflex, somatosensory and motor‐evoked potentials showed findings consistent with pontine pathology. Segmental facial myoclonus, although extremely rare in children, must be differentiated from several other paroxysmal motor manifestations associated with structural lesions involving the brain stem.