Nonmotor and Dopamine Transporter Change in REM Sleep Behavior Disorder by Olfactory Impairment
- Author:
Jee Young LEE
1
;
Eun Jin YOON
;
Yu Kyeong KIM
;
Chae Won SHIN
;
Hyunwoo NAM
;
Jae Min JEONG
;
Han Joon KIM
;
Beomseok JEON
Author Information
- Publication Type:Original Article
- Keywords: Idiopathic REM sleep behavior disorder; Olfaction; Parkinson's disease; Dopamine transporters; Positron emission tomography
- MeSH: Brain; Cognition; Cohort Studies; Constipation; Dopamine Plasma Membrane Transport Proteins; Dopamine; Humans; Magnetic Resonance Imaging; Parkinson Disease; Positron-Emission Tomography; Prospective Studies; Putamen; Raphe Nuclei; REM Sleep Behavior Disorder; Sleep, REM; Smell; Substantia Nigra
- From:Journal of Movement Disorders 2019;12(2):103-112
- CountryRepublic of Korea
- Language:English
- Abstract: OBJECTIVE: It is unclear whether the decline in dopamine transporters (DAT) differs among idiopathic rapid eye movement sleep behavior disorder (iRBD) patients with different levels of olfactory impairment. This study aimed to characterize DAT changes in relation to nonmotor features in iRBD patients by olfactory loss. METHODS: This prospective cohort study consisted of three age-matched groups: 30 polysomnography-confirmed iRBD patients, 30 drug-naïve Parkinson's disease patients, and 19 healthy controls without olfactory impairment. The iRBD group was divided into two groups based on olfactory testing results. Participants were evaluated for reported prodromal markers and then underwent 18F-FP-CIT positron emission tomography and 3T MRI. Tracer uptakes were analyzed in the caudate, anterior and posterior putamen, substantia nigra, and raphe nuclei. RESULTS: Olfactory impairment was defined in 38.5% of iRBD patients. Mild parkinsonian signs and cognitive functions were not different between the two iRBD subgroups; however, additional prodromal features, constipation, and urinary and sexual dysfunctions were found in iRBD patients with olfactory impairment but not in those without. Tracer uptake showed significant group differences in all brain regions, except the raphe nuclei. The iRBD patients with olfactory impairment had uptake reductions in the anterior and posterior putamen, caudate, and substantia nigra (p < 0.016 in all, adjusted for age), which ranged from 0.6 to 0.8 of age-normative values. In contrast, those without olfactory impairment had insignificant changes in all regions ranging above 0.8. CONCLUSION: There was a clear distinction in DAT loss and nonmotor profiles by olfactory status in iRBD.
