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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 99mTc–ethylene cysteinate dimer (ECD).
Methods: Twenty patients with IRBD were scanned at baseline during wakefulness using 99mTc-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: 99mTc-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.
GLOSSARY
- DLB=
- dementia with Lewy bodies;
- DSM-IV-TR=
- Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision;
- ECD=
- ethylene cysteinate dimer;
- FM=
- Farnsworth-Munsell;
- FWHM=
- full width at half maximum;
- IRBD=
- idiopathic REM sleep behavior disorder;
- MCI=
- mild cognitive impairment;
- MSA=
- multiple system atrophy;
- PD=
- Parkinson disease;
- RBD=
- REM sleep behavior disorder;
- RBDEv=
- REM sleep behavior disorder with clinical evolution;
- RBDSt=
- state of isolated REM sleep behavior disorder;
- rCBF=
- regional cerebral blood flow;
- UPDRS=
- Unified Parkinson Disease Rating Scale;
- UPSIT-12=
- University of Pennsylvania Smell Identification Test 12 items
Footnotes
Study funding: Supported by the Canadian Institutes of Health Research and by the Fonds de recherche du Québec–Santé.
Go to Neurology.org for full disclosures. Disclosures deemed relevant by the authors, if any, are provided at the end of this article.
Editorial, page 2296
Supplemental data at www.neurology.org
- Received April 25, 2012.
- Accepted July 27, 2012.
- © 2012 American Academy of Neurology
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