Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa.
Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
Transl Psychiatry. 2018 Apr 12;8(1):75. doi: 10.1038/s41398-018-0105-y.
Electroencephalography (EEG) has been proposed as a neurophysiological biomarker to delineate psychotic disorders. It is known that increased delta and decreased alpha, which are apparent in psychosis, are indicative of inappropriate arousal state, which leads to reduced ability to attend to relevant information. On this premise, we investigated delta/alpha frequency activity, as this ratio of frequency activity may serve as an effective neurophysiological biomarker. The current study investigated differences in delta/alpha frequency activity, in schizophrenia (SCZ), bipolar I disorder with psychotic features and methamphetamine-induced psychosis. One hundred and nine participants, including individuals with SCZ (n = 28), bipolar I disorder with psychotic features (n = 28), methamphetamine-induced psychotic disorder (MPD) (n = 24) and healthy controls (CON, n = 29). Diagnosis was ascertained with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th Edition disorders and current medication was recorded. EEG was undertaken in three testing conditions: resting eyes open, resting eyes closed and during completion of a simple cognitive task (visual continuous performance task). EEG delta/alpha frequency activity was investigated across these conditions. First, delta/alpha frequency activity during resting eyes closed was higher in SCZ and MPD globally, when compared to CON, then lower for bipolar disorder (BPD) than MPD for right hemisphere. Second, delta/alpha frequency activity during resting eyes open was higher in SCZ, BPD and MPD for all electrodes, except left frontal, when compared to CON. Third, delta/alpha frequency activity during the cognitive task was higher in BPD and MPD for all electrodes, except left frontal, when compared to CON. Assessment of EEG delta/alpha frequency activity supports the delineation of underlying neurophysiological mechanisms present in psychotic disorders, which are likely related to dysfunctional thalamo-cortical connectivity. Delta/alpha frequency activity may provide a useful neurophysiological biomarker to delineate psychotic disorders.
脑电图（EEG）已被提议作为一种神经生理学生物标志物来描绘精神病障碍。众所周知，在精神病中明显增加的 delta 和减少的 alpha 表明唤醒状态不当，这导致了对相关信息的关注能力降低。在此前提下，我们研究了 delta/alpha 频率活动，因为这种频率活动的比值可能是一种有效的神经生理学生物标志物。本研究调查了精神分裂症（SCZ）、伴有精神病特征的双相 I 障碍和甲基苯丙胺引起的精神病中 delta/alpha 频率活动的差异。共有 109 名参与者，包括精神分裂症患者（n=28）、伴有精神病特征的双相 I 障碍患者（n=28）、甲基苯丙胺引起的精神病患者（MPD，n=24）和健康对照组（CON，n=29）。使用《精神障碍诊断与统计手册》第 4 版的结构临床访谈确定诊断，并记录当前的用药情况。在三种测试条件下进行 EEG：睁眼静息、闭眼静息和完成简单认知任务（视觉连续表现任务）时。研究了这些条件下的 EEG delta/alpha 频率活动。首先，与 CON 相比，闭眼静息时 SCZ 和 MPD 的 delta/alpha 频率活动在全球范围内更高，而与 MPD 相比，右半球的 BPD 则更低。其次，与 CON 相比，睁眼静息时 SCZ、BPD 和 MPD 所有电极的 delta/alpha 频率活动均升高，除左额部外。第三，与 CON 相比，认知任务时 BPD 和 MPD 所有电极的 delta/alpha 频率活动均升高，除左额部外。评估 EEG delta/alpha 频率活动支持描绘精神病障碍中存在的潜在神经生理学机制，这些机制可能与丘脑皮质连接功能障碍有关。Delta/alpha 频率活动可能是描绘精神病障碍的有用神经生理学生物标志物。
