Opsoclonus myoclonus ataxia (OMA) is a syndrome that includes opsoclonus along with diffuse or focal body myoclonus and truncal titubation with or without ataxia and other cerebellar signs.
- Opsoclonus is a disorder of ocular motility characterized by spontaneous, arrhythmic, conjugate saccades occurring in all directions of gaze without a saccadic interval.
- Myoclonus is a clinical sign that is characterized by brief, shock-like, involuntary movements caused by muscular contractions or inhibitions.
Patients with OMA are sometimes described as having dancing eyes and feet. Although OMA can be paraneoplastic in origin, it can also result from viral infections, post-streptococcal pharyngitis, metabolic disorders, metastases, and intracranial hemorrhage [1,2].
This topic discusses opsoclonus myoclonus ataxia. An overview of paraneoplastic syndromes and other paraneoplastic disorders are discussed separately. Other disorders causing myoclonus are also discussed separately. (See "Overview of paraneoplastic syndromes of the nervous system" and "Paraneoplastic syndromes affecting peripheral nerve and muscle" and "Paraneoplastic syndromes affecting the spinal cord and dorsal root ganglia" and "Classification and evaluation of myoclonus" and "Symptomatic (secondary) myoclonus" and "Treatment of myoclonus".)
OMA is rare; one prospective study in the United Kingdom estimated an incidence of 0.18 cases per million per year . OMA affects mainly young children with a mean age of 1.5 to 2 years [3,4]. Some series, but not others, have found a higher prevalence in girls. A female predominance is characteristic of most, but not all, autoimmune disorders .