Symptoms include: *<unk>  (rapid, involuntary, multivectorial (horizontal and vertical), unpredictable, conjugate fast eye movements without intersaccadic quick rotation of the eyes intervals) *<unk>  (brief, involuntary twitching of a muscle or a group of muscles) * cerebellar ataxia, both truncal and appendicular * aphasia (a language disorder in which there is an impairment of speech and of comprehension of speech, caused by brain damage) * mutism (a language disorder in which a person does not speak despite evidence of speech ability in the past, often part of a larger neurological or psychiatric disorder) * lethargy * irritability or malaise * drooling * strabismus (a condition in which the eyes are not properly aligned with each other) * vomiting * sleep disturbances * emotional disturbances (including fits of rage) About half of all<unk>  cases occur in association with neuroblastoma (a cancer of the sympathetic nervous system usually occurring in infants and children). Disease course and clinical subtypes In most cases,<unk>  starts with an acute flare-up of physical symptoms within days or weeks, but some less obvious symptoms such as irritability and malaise may begin weeks or months earlier.
Opsoclonus myoclonus syndrome
Benign hereditary chorea
Parkinson-plus syndrome
Progressive supranuclear palsy
Sydenham's chorea
Huntington's disease-like syndrome
Post-encephalitic parkinsonism
Paroniria