Department of Neuroscience, University of Turin Medical School, and National Institute of Neuroscience, Turin, Italy.
J Psychiatry Neurosci. 2012 Jul;37(4):259-66. doi: 10.1503/jpn.110030.
In spite of the large number of studies on schizophrenia, a full understanding of its core pathology still eludes us. The application of the nonlinear theory of electroencephalography (EEG) analysis provides an interesting tool to differentiate between physiologic conditions (e.g., resting state and mathematical task) and normal and pathologic brain activities. The aim of the present study was to investigate nonlinear EEG activity in patients with schizophrenia.
We recorded 19-lead EEGs in patients with stable schizophrenia and healthy controls under 4 different conditions: eyes closed, eyes open, forward counting and backward counting. A nonlinear measure of complexity was calculated by means of correlation dimension (D2).
We included 17 patients and 17 controls in our analysis. Comparing the 2 populations, we observed greater D2 values in the patient group. In controls, increased D2 values were observed during active states (eyes open and the 2 cognitive tasks) compared with baseline conditions. This increase of brain complexity, which can be interpreted as an increase of information processing and integration, was not preserved in the patient population.
Patients with schizophrenia were taking antipsychotic medications, so the presence of medication effects cannot be excluded.
Our results suggest that patients with schizophrenia present changes in brain activity compared with healthy controls, and this pathologic alteration can be successfully studied with nonlinear EEG analysis.
尽管有大量关于精神分裂症的研究，但我们仍未能完全理解其核心病理学。脑电图（EEG）非线性分析理论的应用为区分生理状态（如静息状态和数学任务）以及正常和病理脑活动提供了一种有趣的工具。本研究旨在探讨精神分裂症患者的脑电非线性活动。
我们在 4 种不同条件下记录了稳定期精神分裂症患者和健康对照者的 19 导 EEG：闭眼、睁眼、正向计数和反向计数。通过关联维数（D2）计算非线性复杂性度量。
我们将 17 例患者和 17 例对照纳入分析。与对照组相比，患者组的 D2 值较大。在对照组中，与基线条件相比，活跃状态（睁眼和 2 项认知任务）下 D2 值增加。这种大脑复杂性的增加可以解释为信息处理和整合能力的提高，但在患者群体中并未得到保留。
精神分裂症患者正在服用抗精神病药物，因此不能排除药物作用的存在。
我们的研究结果表明，与健康对照组相比，精神分裂症患者的大脑活动存在变化，这种病理性改变可以通过非线性 EEG 分析成功研究。
