Presumed rapid eye movement behavior disorder in Machado-Joseph disease (spinocerebellar ataxia type 3).

Rapid eye movement behavior disorder (RBD) is a recently recognized sleep disorder in which patients are occasionally not paralyzed during the dream portions of sleep. When not idiopathic, this state has been associated primarily with parkinsonian conditions but also with a small number of medications and other neurodegenerative disorders. Dopamine deficiency may play a role in some patients. This report describes the occurrence of a syndrome that appears to be RBD in 6 of 7 patients followed with Spinocerebellar ataxia type 3 (Machado-Joseph disease). Polysomnography was normal in 1 patient. Two of these patients had had single photon emission computed tomographic imaging of the dopamine transporter 1 year previously.