Dario Arnaldi1, Sanne K Meles2, Alessandro Giuliani3, Silvia Morbelli4, Remco J Renken5, Annette Janzen6, Geert Mayer6,7, Cathrine Jonsson8, Wolfgang H Oertel6,9, Flavio Nobili1, Klaus L Leenders2, Marco Pagani10,11,12. 1. Department of Neuroscience (DINOGMI), Clinical Neurology, University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy. 2. Department of Neurology, University of Groningen, University Medical Center Groningen, The Netherlands. 3. Environment and Health Department Istituto Superiore di Sanità, Rome, Italy. 4. Department of Health Sciences (DISSAL), Nuclear Medicine, University of Genoa and IRCCS Ospedale Policlinico San Martino Genoa, Italy. 5. Department of Neuroscience, Neuroimaging Center, University of Groningen, The Netherlands. 6. Department of Neurology, Philipps-Universität Marburg, Marburg, Germany. 7. Hephata Klinik, Schwalmstadt, Germany. 8. Medical Radiation Physics and Nuclear Medicine, Imaging and Physiology, Karolinska University Hospital, Stockholm, Sweden. 9. Institute for Neurogenomics, Helmholtz Center for Health and Environment, München, Germany. 10. Institutes of Cognitive Sciences and Technologies, CNR, Rome, Italy. 11. Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden. 12. Department of Nuclear Medicine, University of Groningen, University Medical Center Groningen, The Netherlands Department of Neurology and JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Aachen University, Aachen, Germany.
Abstract
BACKGROUND/ OBJECTIVE: Idiopathic REM sleep behavior disorder (iRBD) often precedes Parkinson's disease (PD) and other alpha-synucleinopathies. The aim of the study is to investigate brain glucose metabolism of patients with RBD and PD by means of a multidimensional scaling approach, using18F-FDG-PET as a biomarker of synaptic function. METHODS: Thirty-six iRBD patients (64.1±6.5 y, 32 M), 72 PD patients, and 79 controls (65.6±9.4 y, 53 M) underwent brain 18F-FDG-PET. PD patients were divided according to the absence (PD, 32 subjects; 68.4±8.5 y, 15 M) or presence (PDRBD, 40 subjects; 71.8±6.6 y, 29 M) of RBD. 18F-FDG-PET scans were used to independently discriminate subjects belonging to four categories: controls (RBD no, PD no), iRBD (RBD yes, PD no), PD (RBD no, PD yes) and PDRBD (RBD yes, PD yes). RESULTS: The discriminant analysis was moderately accurate in identifying the correct category. This is because the model mostly confounds iRBD and PD, thus the intermediate classes. Indeed, iRBD, PD and PDRBD were progressively located at increasing distance from controls and are ordered along a single dimension (principal coordinate analysis) indicating the presence of a single flux of variation encompassing both RBD and PD conditions. CONCLUSION: Data-driven approach to brain 18F-FDG-PET showed only moderate discrimination between iRBD and PD patients, highlighting brain glucose metabolism heterogeneity among such patients. iRBD should be considered as a marker of an ongoing condition that may be picked-up in different stages across patients and thus express different brain imaging features and likely different clinical trajectories.
BACKGROUND/ OBJECTIVE:Idiopathic REM sleep behavior disorder (iRBD) often precedes Parkinson's disease (PD) and other alpha-synucleinopathies. The aim of the study is to investigate brain glucose metabolism of patients with RBD and PD by means of a multidimensional scaling approach, using18F-FDG-PET as a biomarker of synaptic function. METHODS: Thirty-six iRBD patients (64.1±6.5 y, 32 M), 72 PDpatients, and 79 controls (65.6±9.4 y, 53 M) underwent brain 18F-FDG-PET. PDpatients were divided according to the absence (PD, 32 subjects; 68.4±8.5 y, 15 M) or presence (PDRBD, 40 subjects; 71.8±6.6 y, 29 M) of RBD. 18F-FDG-PET scans were used to independently discriminate subjects belonging to four categories: controls (RBD no, PD no), iRBD (RBD yes, PD no), PD (RBD no, PD yes) and PDRBD (RBD yes, PD yes). RESULTS: The discriminant analysis was moderately accurate in identifying the correct category. This is because the model mostly confounds iRBD and PD, thus the intermediate classes. Indeed, iRBD, PD and PDRBD were progressively located at increasing distance from controls and are ordered along a single dimension (principal coordinate analysis) indicating the presence of a single flux of variation encompassing both RBD and PD conditions. CONCLUSION: Data-driven approach to brain 18F-FDG-PET showed only moderate discrimination between iRBD and PDpatients, highlighting brain glucose metabolism heterogeneity among such patients. iRBD should be considered as a marker of an ongoing condition that may be picked-up in different stages across patients and thus express different brain imaging features and likely different clinical trajectories.
Entities:
Keywords:
18F-FDG-PET; Parkinson’s disease; REM sleep behavior disorder; synucleinopathy