Myorhythmia

A rare movement disorder characterized by repetitive, rhythmic, slow (1-4 Hz), tremor-like or jerky muscle contractions, predominantly involving cranial and limb muscles, typically present at rest and during action, and usually associated with structural lesions in the brainstem or thalamus. Possible causes are stroke, Whipple's disease, autoimmune encephalitis, infectious encephalitis (listeria, syphilis), multiple sclerosis, traumatic brain injury, Wilson's disease, CNS lymphoma, or metabolic conditions.