Severe Brain Metabolic Decreases Associated with REM Sleep Behavior Disorder in Dementia with Lewy Bodies

Article type: Research Article

Authors: Iaccarino, Leonardo^{a; 1} | Marelli, Sara^{b; c; 1} | Iannaccone, Sandro^d | Magnani, Giuseppe^e | Ferini-Strambi, Luigi^{b; c; *} | Perani, Daniela^{a; c; f; g; h}

Affiliations: [a] Vita-Salute San Raffaele University and Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy | [b] Department of Clinical Neurosciences, San Raffaele Scientific Institute, Neurology, Sleep Disorders Center, Milan, Italy | [c] Vita-Salute San Raffaele University, Faculty of Psychology, Milan, Italy | [d] Department of Clinical Neurosciences, San Raffaele Scientific Institute, Neurorehabilitation Unit, Milan, Italy | [e] Department of Neurology, San Raffaele Scientific Institute, Neurology, Milan, Italy | [f] CERMAC, Vita-Salute San Raffaele University, Milan, Italy | [g] Istituto di Bioimmagini e Fisiologia Molecolare C.N.R., Segrate, Italy | [h] Nuclear Medicine Unit, San Raffaele Scientific Institute, Milan, Italy

Correspondence: [*] Correspondence to: Luigi Ferini-Strambi, MD, PhD, Director, Sleep Disorders Center, University Vita-Salute San Raffaele, Via Stamira D’Ancona, 20, 20127 Milan, Italy; Full Professor of Neurology, Sleep Disorders Center, Università Vita-Salute San Raffaele, Milan, Italy. Tel.: +39 02 2643 3363; Fax: +39 02 2643 3394; E-mail: ferinistrambi.luigi@hsr.it.

Note: [1] These authors contributed equally to this work.

Abstract: Background/Objective: To evaluate the prevalence of REM sleep behavior disorder (RBD) in a sample of Dementia with Lewy Bodies (DLB) and Alzheimer’s Disease (AD) patients and compare the patterns of brain glucose metabolism in DLB patients with or without the sleep disturbances. Methods: In this retrospective study, the presence of probable RBD was ascertained for 27 clinically diagnosed DLB patients and 11 AD patients by a self-administered RBD Single-Question Screen (RBD1Q), followed by a sleep structured interview by experts in sleep disorders blinded to clinical information. For 18F-FDG-PET metabolic comparisons, we considered an additional 13 DLB patients with negative history for sleep disturbance. We performed DLB within-group comparisons covarying for age and disease duration. Results: The RBD1Q questionnaire identified 20 out of 27 DLB RBD+ and 7 out of 27 DLB RBD–. None of the AD patients was positive to RBD1Q test. 18F-FDG-PET hypometabolism at the single- and group-level tested by means of an optimized SPM approach revealed the typical DLB metabolic pattern. Each DLB patient showed a predominant occipital hypometabolism. The SPM voxel-based comparisons revealed significant brain metabolic differences, namely a more severe metabolic decrease in DLB RBD+ in the dorsolateral and medial frontal regions, left precuneus, bilateral superior parietal lobule and rolandic operculum, and amygdala. Discussion: We found a high prevalence of RBD in DLB and none in AD, as identified by the RBD1Q questionnaire, indicating its utility in clinical practice. DLB patients with or without RBD show different hypometabolism patterns that might reflect differences in underlying pathology.

Keywords: Brain metabolism, dementia, dementia with Lewy bodies, ¹⁸F-FDG-PET, REM sleep behavior disorder, sleep

DOI: 10.3233/JAD-151000

Journal: Journal of Alzheimer's Disease, vol. 52, no. 3, pp. 989-997, 2016