title: Neuropsychological and radiological assessments of two cases with apparent idiopathic rapid eye movement sleep behaviour disorder.
abstract: We examined two male patients (64 and 70 years old) with rapid eye movement sleep behaviour disorder (RBD) using cognitive tests, myocardial (123)I-metaiodobenzylguanidine (MIBG) scintigraphy, and dopamine positron emission tomography (PET) imaging. One patient had impaired social cognition and decision-making skills and reduced MIBG reuptake, and dopamine PET imaging indicated striatal terminal loss. The other patient had normal social cognition and reduced MIBG reuptake, but no abnormalities were detected by dopamine PET imaging. Both patients reported constipation. This study supports the hypothesis by Braak et al. [Mov Disord 2006;21:2042-2051] that impairment of the amygdala and striatum occurs at the same stage as α-synucleinopathy, and the findings suggest that autonomic dysfunctions such as reduced MIBG reuptake and constipation are the earliest symptoms of RBD. Detailed neuropsychological and radiological assessments of these 2 cases revealed that idiopathic RBD could develop in various clinical situations and include cognitive and autonomic changes. Further longitudinal studies with larger sample sizes will help understand the neuropsychology and pathophysiology of RBD.
authors.affiliation: Department of Neurology, Showa University School of Medicine, Tokyo, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Koyama
authors.forename: Mutsutaka
authors.initials: M
authors.lastname: Kobayakawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Tachibana
authors.forename: Yuri
authors.initials: Y
authors.lastname: Masaoka
authors.forename: Ikuo
authors.initials: I
authors.lastname: Homma
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishii
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kawamura
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging*; D003071:Cognition; D003657:Decision Making; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D020187:REM Sleep Behavior Disorder / Q000000981:diagnostic imaging* / Q000523:psychology*; D011877:Radionuclide Imaging; D021641:Recognition, Psychology