Hippocampal perfusion predicts impending neurodegeneration in REM sleep behavior disorder

Neurology. 2012 Oct 31. [Epub ahead of print]

Dang-Vu TT, Gagnon JF, Vendette M, Soucy JP, Postuma RB, Montplaisir J.

Source

From the Center for Advanced Research in Sleep Medicine (T.T.D.-V., J.-F.G., M.V., R.B.P., J.M.), Hôpital du Sacré-Cœur de Montréal; Department of Exercise Science and Center for Studies in Behavioral Neurobiology (T.T.D.-V.), Concordia University, Montréal, Canada; Cyclotron Research Centre (T.T.D.-V.), University of Liege; Department of Neurology (T.T.D.-V.), Centre Hospitalier Universitaire de Liège, Belgium; Department of Psychology (J.-F.G.), Université du Québec à Montréal; Montreal Neurological Institute (P.S.), McGill University, Montréal; Department of Nuclear Medicine (J.P.-S.), Centre Hospitalier de l'Université de Montréal; Department of Neurology (R.B.P.), Montreal General Hospital; and Department of Psychiatry (J.M.), University of Montreal, Canada.

Abstract

OBJECTIVES:

Patients with idiopathic REM sleep behavior disorder (IRBD) are at risk for developing Parkinson disease (PD) and dementia with Lewy bodies (DLB). We aimed to identify functional brain imaging patterns predicting the emergence of PD and DLB in patients with IRBD, using SPECT with (99m)Tc-ethylene cysteinate dimer (ECD).

METHODS:

Twenty patients with IRBD were scanned at baseline during wakefulness using (99m)Tc-ECD SPECT. After a follow-up of 3 years on average, patients were divided into 2 groups according to whether or not they developed defined neurodegenerative disease (PD, DLB). SPECT data analysis comparing regional cerebral blood flow (rCBF) between groups assessed whether specific brain perfusion patterns were associated with subsequent clinical evolution. Regression analysis between rCBF and clinical markers of neurodegeneration (motor, color vision, olfaction) looked for neural structures involved in this process.

RESULTS:

Of the 20 patients with IRBD recruited for this study, 10 converted to PD or DLB during the follow-up. rCBF at baseline was increased in the hippocampus of patients who would later convert compared with those who would not (p < 0.05 corrected). Hippocampal perfusion was correlated with motor and color vision scores across all IRBD patients.

CONCLUSIONS:

(99m)Tc-ECD SPECT identifies patients with IRBD at risk for conversion to other neurodegenerative disorders such as PD or DLB; disease progression in IRBD is predicted by abnormal perfusion in the hippocampus at baseline. Perfusion within this structure is correlated with clinical markers of neurodegeneration, further suggesting its involvement in the development of presumed synucleinopathies.

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