Abstract Details

Title Early in vivo signatures of neurodegeneration at individual level in isolated REM behaviour disorder

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) P2 - Poster Session 2 (5:30 PM-6:30 PM)

Poster/Presentation
Number 9-028

Objective This study assessed the pattern of brain hypometabolism, at individual level, in subjects with isolated REM behaviour disorder (iRBD), also considering clinico-neuropsychological features.

Background

IRBD is recognized as a clinical manifestation of the synucleinopathy spectrum. IRBD biomarkers of underlying brain pathology need to be identified.

Design/Methods

We recruited thirty-one polysomnography-confirmed iRBD subjects, with [18F]FDG-PET scan and available clinico-neuropsychological evaluation. Single-subject [18F]FDG-PET images were analysed by means of an optimized SPM procedure, providing patterns of hypometabolism at single-subject level. Regional hypometabolism was correlated with neuropsychological measures. The presence of brain metabolic subtypes within iRBD group was investigated using hierarchical cluster analysis (HCA).

Results According to the National normative standards, iRBD subjects showed selectively impaired copy of Rey-Osterrieth complex figure (22.58% of patients), and Rey Auditory Verbal Learning test immediate recall (16.13% of patients). Hypometabolism patterns suggestive of neurodegeneration were present in the majority of iRBD patients, with a common occipital hypometabolism. Occipital brain dysfunction correlated with worse visuoperceptual performances, as measured by Qualitative Scoring of Pentagon Test (QSPT) of MMSE (p<0.05). Two subgroups emerged from the HCA, namely 10 iRBD with selective occipital hypometabolism and 21 iRBD subjects with an occipito-cerebellar hypometabolism. Although the two subgroups were clinically comparable, the latter was characterized by worse scores in phonemic fluency and digit span forward tests (p<0.05).

Conclusions The patterns of brain hypometabolism found in iRBD are consistent with the brain vulnerabilities reported in the synucleinopathy spectrum, namely Parkinson diseases dementia, Lewy body dementia and multiple system atrophy. Occipital and cerebellar hypometabolism might reflect the possible pathological substrate of an early α-synuclein-specific neurodegeneration, also correlated to specific visuoperceptive impairments. Our findings suggest the use of [18F]FDG-PET SPM single-subject analysis for the identification of iRBD endophenotypes in clinical settings, crucial for its possible prognostic value, which should be confirmed by follow-up studies.

Authors/Disclosures
PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Sara Marelli	No disclosure on file
	No disclosure on file
Luigi Ferini-Strambi, MD	Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bioprojet. Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for lundbeck. Dr. Ferini-Strambi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for idorsia. Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Italfarmaco. Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi. Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Bruno Farmaceutici. Dr. Ferini-Strambi has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier Sleep Medicine.
Daniela Perani	No disclosure on file

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