Regional cerebral blood flow changes in patients with idiopathic REM sleep behavior disorder.

Background:  Recent studies have shown an association between rapid eye movement sleep behavior disorder (RBD) and neurodegenerative disorders, especially alpha-synucleinopathies. Objective:  We investigated regional cerebral blood flow (rCBF) changes using single photon emission computed tomography (SPECT) in patients with idiopathic RBD (iRBD), to determine functional brain alterations associated with the disorder. Methods:  The SPECT data of 24 patients with iRBD were compared with those of 18 age-matched normal controls using statistical parametric mapping 2. Results:  We found decreased rCBF in the parietooccipital lobe (precuneus), limbic lobe, and cerebellar hemispheres in patients with iRBD, which is commonly seen in patients with Lewy body disease (Parkinson’s disease and dementia with Lewy bodies) or multiple system atrophy. Conclusion:  Our SPECT study suggests that iRBD can be a presymptomatic stage of alpha-synucleinopathies.