Brain and Mind Center, School of Medical Sciences, University of Sydney, Forefront Parkinson's Disease Research Clinic, Sydney, Australia.
Neurology department, Université Clermont-Auvergne, Clermont-Ferrand University Hospital, EA7280, Clermont-Ferrand, France.
J Neurol. 2021 Sep;268(9):3371-3380. doi: 10.1007/s00415-021-10498-6. Epub 2021 Mar 11.
Current neuroimaging research has revealed several brain alterations in idiopathic REM sleep behaviour disorder (iRBD) that mirror and precede those reported in PD. However, none have specifically addressed the presence of changes across the reward system, and their role in the emergence of impulse control disorders (ICDs). We aimed to compare the volumetric and functional connectivity characteristics of the reward system in relation to the psychobehavioral profile of patients with iRBD versus healthy controls and PD patients.
Twenty patients with polysomnography confirmed iRBD along with 17 PD patients and 14 healthy controls (HC) underwent structural and functional resting-state brain MRI analysis. Participants completed the questionnaire for impulsive-compulsive disorders in PD (QUIP), the short UPPS-P impulsive behaviour scale, as well as neuropsychological testing of cognitive function.
A higher percentage of iRBD patients reported hypersexuality, compared to HC and PD (p = 0.008). Whole-brain and striatal voxel-based morphometry analyses showed no significant clusters of reduced grey matter volume between groups. However, iRBD compared to HC demonstrated functional hypoconnectivity between the limbic striatum and temporo-occipital regions. Furthermore, the presence of ICDs correlated with hypoconnectivity between the limbic striatum and clusters located in cuneus, lingual and fusiform gyrus.
Altered functional connectivity between the limbic striatum and posterior cortical regions was associated with increased hypersexuality in iRBD. It is possible that this change may ultimately predispose individuals to the emergence of ICDs when they receive dopaminergic medications, after transitioning to PD.
目前的神经影像学研究揭示了特发性 REM 睡眠行为障碍（iRBD）中的几种大脑改变，这些改变与 PD 中报道的改变相似并先于后者。然而，目前尚无研究专门针对奖励系统的变化及其在冲动控制障碍（ICD）出现中的作用。我们旨在比较 iRBD 患者与健康对照者和 PD 患者的奖赏系统的体积和功能连接特征与心理行为特征的关系。
20 例经多导睡眠图证实的 iRBD 患者、17 例 PD 患者和 14 例健康对照者（HC）接受了结构和功能静息态脑 MRI 分析。参与者完成了 PD 冲动-强迫障碍问卷（QUIP）、简短 UPPS-P 冲动行为量表以及认知功能神经心理学测试。
与 HC 和 PD 相比，iRBD 患者报告性欲亢进的比例更高（p=0.008）。全脑和纹状体基于体素的形态计量学分析显示，各组之间的灰质体积无明显减少的簇。然而，与 HC 相比，iRBD 患者的边缘纹状体与颞枕叶区域之间的功能连接性降低。此外，ICD 的存在与边缘纹状体与楔前叶、舌回和梭状回之间的连接功能降低有关。
边缘纹状体与后皮质区域之间的功能连接改变与 iRBD 中性欲亢进增加有关。当他们在向 PD 过渡后接受多巴胺能药物治疗时，这种变化可能最终使个体更容易出现 ICD。
