From the Psychiatry Department, School of Medicine, University of Valladolid, Valladolid, Spain (Molina, Lubeiro); the Psychiatry Service, Clinical Hospital of Valladolid, Valladolid, Spain (Molina, Martín-Santiago); the Neurosciences Institute of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain (Molina); the Imaging Processing Laboratory, University of Valladolid, Valladolid, Spain (de Luis Garcia); the Biomedical Engineering Group, University of Valladolid, Valladolid, Spain (Gomez-Pilar, Núñez); the Neurophysiology Service, Clinical Hospital of Valladolid, Valladolid, Spain (Iglesias-Tejedor); the Psychiatry Service, Doce de Octubre University Hospital, Madrid, Spain (Holgado-Madera, Sanz-Fuentenebro); the Psychiatry Service, Cruces Hospital, Bilbao, Spain (Segarra-Echeverría, Recio-Barbero); and the Psychiatry Service, Santiago Apostol Hospital, Vitoria, Spain (Haidar, Fernández-Sevillano).
J Psychiatry Neurosci. 2020 Sep 1;45(5):322-333. doi: 10.1503/jpn.190032.
The synchronized activity of distributed neural assemblies — reflected in the electroencephalogram (EEG) — underpins mental function. In schizophrenia, modulation deficits of EEG spectral content during a P300 task have been replicated. The effects of treatment, chronicity and specificity in these deficits and their possible relationship with anatomic connectivity remain to be explored.
We assessed spectral entropy modulation of the EEG during a P300 task in 79 patients with schizophrenia (of those, 31 werein their first episode), 29 patients with bipolar disorder and 48 healthy controls. Spectral entropy values summarize EEG characteristics by quantifying the irregularity of spectral content. In a subsample, we calculated the network architecture of structural connectivity using diffusion tensor imaging and graph-theory parameters.
We found significant spectral entropy modulation deficits with task performance in patients with chronic or first-episode schizophrenia and in patients with bipolar disorder, without significant pre-stimulus spectral entropy differences. The deficits were unrelated to treatment doses, and spectral entropy modulation did not differ between patients taking or not taking antipsychotics, lithium, benzodiazepines or antidepressants. Structural connectivity values were unrelated to spectral entropy modulation. In patients with schizophrenia, spectral entropy modulation was inversely related to negative symptoms and directly related to verbal memory.
All patients were taking medication. Patients with bipolar disorder were euthymic and chronic. The cross-sectional nature of this study prevented a more thorough analysis of state versus trait criteria for spectral entropy changes.
Spectral entropy modulation with task performance is decreased in patients with schizophrenia and bipolar disorder. This deficit was not an effect of psychopharmacological treatment or structural connectivity and might reflect a deficit in the synchronization of the neural assemblies that underlie cognitive activity.
分布式神经集合的同步活动——反映在脑电图（EEG）中——是心理功能的基础。在精神分裂症中，P300 任务期间 EEG 频谱内容的调制缺陷已经得到了复制。这些缺陷的治疗、慢性和特异性以及它们与解剖连接的可能关系仍有待探索。
我们评估了 79 例精神分裂症患者（其中 31 例为首发）、29 例双相情感障碍患者和 48 例健康对照者在 P300 任务期间 EEG 的频谱熵调制。频谱熵值通过量化频谱内容的不规则性来总结 EEG 特征。在一个子样本中，我们使用弥散张量成像和图论参数计算结构连接的网络结构。
我们发现，慢性或首发精神分裂症患者以及双相情感障碍患者在任务表现时存在明显的频谱熵调制缺陷，而在刺激前没有明显的频谱熵差异。这些缺陷与治疗剂量无关，服用或不服用抗精神病药物、锂、苯二氮䓬类或抗抑郁药的患者之间的频谱熵调制没有差异。结构连接值与频谱熵调制无关。在精神分裂症患者中，频谱熵调制与阴性症状呈负相关，与言语记忆呈正相关。
所有患者都在服用药物。双相情感障碍患者病情稳定且为慢性。本研究的横断面性质阻止了对频谱熵变化的状态与特征标准进行更彻底的分析。
精神分裂症和双相情感障碍患者在任务表现时的频谱熵调制降低。这种缺陷不是精神药理学治疗或结构连接的影响，可能反映了支持认知活动的神经集合同步的缺陷。
