Department of Informatics, Bioengineering, Robotics and System engineering (DIBRIS), University of Genoa, Genoa, Italy.
Clinical Neurology, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Children's Sciences (DINOGMI), University of Genoa, Genoa, Italy.
Sleep. 2022 Jan 11;45(1). doi: 10.1093/sleep/zsab232.
Increased phase synchronization in electroencephalography (EEG) bands might reflect the activation of compensatory mechanisms of cognitive decline in people with neurodegenerative diseases. Here, we investigated whether altered large-scale couplings of brain oscillations could be linked to the balancing of cognitive decline in a longitudinal cohort of people with idiopathic rapid eye-movement sleep behavior disorder (iRBD).
We analyzed 18 patients (17 males, 69.7 ± 7.5 years) with iRBD undergoing high-density EEG (HD-EEG), presynaptic dopaminergic imaging, and clinical and neuropsychological (NPS) assessments at two time points (time interval 24.2 ± 5.9 months). We thus quantified the HD-EEG power distribution, orthogonalized amplitude correlation, and weighted phase-lag index at both time points and correlated them with clinical, NPS, and imaging data.
Four patients phenoconverted at follow-up (three cases of parkinsonism and one of dementia). At the group level, NPS scores decreased over time, without reaching statistical significance. However, alpha phase synchronization increased and delta amplitude correlations decreased significantly at follow-up compared to baseline. Both large-scale network connectivity metrics were significantly correlated with NPS scores but not with sleep quality indices or presynaptic dopaminergic imaging data.
These results suggest that increased alpha phase synchronization and reduced delta amplitude correlation may be considered electrophysiological signs of an active compensatory mechanism of cognitive impairment in people with iRBD. Large-scale functional modifications may be helpful biomarkers in the characterization of prodromal stages of alpha-synucleinopathies.
脑电图（EEG）频段中相位同步的增加可能反映了神经退行性疾病患者认知能力下降的代偿机制的激活。在这里，我们研究了在特发性快速眼动睡眠行为障碍（iRBD）的纵向队列中，大脑振荡的改变的大范围耦合是否与认知下降的平衡有关。
我们分析了 18 名 iRBD 患者（17 名男性，69.7±7.5 岁），他们在两个时间点（时间间隔 24.2±5.9 个月）接受了高密度脑电图（HD-EEG）、突触前多巴胺成像以及临床和神经心理学（NPS）评估。因此，我们在两个时间点量化了 HD-EEG 功率分布、正交幅度相关和加权相位滞后指数，并将其与临床、NPS 和成像数据相关联。
四名患者在随访时出现了表型转化（帕金森病三例，痴呆一例）。在组水平上，NPS 评分随时间下降，但无统计学意义。然而，与基线相比，在随访时，alpha 相位同步增加，delta 振幅相关性降低。这两种大范围网络连接指标都与 NPS 评分显著相关，但与睡眠质量指数或突触前多巴胺成像数据无关。
这些结果表明，alpha 相位同步的增加和 delta 振幅相关性的降低可能被认为是 iRBD 患者认知障碍的主动代偿机制的电生理标志。大范围的功能改变可能是 alpha-突触核蛋白病前驱期特征的有用生物标志物。
