Carli G, Caminiti S P, Galbiati A, Marelli S, Casoni F, Padovani A, Ferini-Strambi L, Perani D
School of Psychology, Vita-Salute San Raffaele University, Milan, Italy.
In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Eur J Neurol. 2020 Jul;27(7):1285-1295. doi: 10.1111/ene.14215. Epub 2020 Apr 11.
Isolated rapid eye movement sleep behaviour disorder (iRBD) is a parasomnia, recently recognized as a risk factor for progression to Parkinson's disease, dementia with Lewy body and multiple system atrophy. Biomarker studies in iRBD are relevant due to lack of evidence in this condition. The identification of biomarkers able to predict progression to synucleinopathy diseases is critical for iRBD. Fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging might provide information about ongoing neurodegenerative processes. In the present study, we tested for presence of brain hypometabolism patterns as biomarkers of neurodegeneration in single iRBD individuals.
We recruited 37 subjects with polysomnography-confirmed iRBD, with neuropsychological assessment and available FDG-PET scan. Images were analysed with a validated statistical parametric mapping procedure, providing individual hypometabolism maps.
According to the neuropsychological evaluation, 22 subjects with iRBD had normal cognition and 15 subjects showed impairments, particularly in visuoperceptive/visuospatial and memory domains. One-fifth of the cases were impaired on the Qualitative Scoring of Pentagon Test. In 32 iRBD cases, FDG-PET statistical parametric maps revealed significant cerebral hypometabolism, namely in the occipital lobes (n = 5), occipital and cerebellar regions (n = 13), occipitoparietal regions (n = 13) and a selective cerebellar hypometabolism (n = 1). Five cases had normal FDG-PET scans.
These imaging findings indicate that brain neurodegenerative processes are present and already detectable in iRBD. The different hypometabolism patterns in the single individuals may reflect specific early pathophysiological events due to the underlying synucleinopathy, with a specific neural vulnerability for the occipital cortex that might pre-date a risk of progression towards dementia with Lewy body.
孤立性快速眼动睡眠行为障碍（iRBD）是一种异态睡眠，最近被认为是进展为帕金森病、路易体痴呆和多系统萎缩的危险因素。由于iRBD缺乏相关证据，因此对其进行生物标志物研究具有重要意义。识别能够预测进展为突触核蛋白病的生物标志物对iRBD至关重要。氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）成像可能会提供有关正在进行的神经退行性过程的信息。在本研究中，我们测试了单个iRBD个体中脑代谢减低模式作为神经退行性变生物标志物的存在情况。
我们招募了37名经多导睡眠图证实为iRBD的受试者，进行了神经心理学评估并获得了FDG-PET扫描结果。使用经过验证的统计参数映射程序对图像进行分析，生成个体代谢减低图。
根据神经心理学评估，22名iRBD受试者认知正常，15名受试者存在认知障碍，尤其是在视觉感知/视觉空间和记忆领域。五分之一的病例在五角形测试定性评分中受损。在32例iRBD病例中，FDG-PET统计参数图显示大脑存在明显的代谢减低，具体为枕叶（n = 5）、枕叶和小脑区域（n = 13）、枕顶叶区域（n = 13）以及选择性小脑代谢减低（n = 1）。5例FDG-PET扫描结果正常。
这些影像学结果表明，iRBD中存在脑神经退行性过程且已可检测到。个体中不同的代谢减低模式可能反映了由于潜在的突触核蛋白病导致的特定早期病理生理事件，枕叶存在特定神经易损性，这可能早于进展为路易体痴呆的风险。
