Marzano Cristina, Ferrara Michele, Sforza Emilia, De Gennaro Luigi
Department of Psychology, Sapienza University of Rome, Italy.
Curr Pharm Des. 2008;14(32):3446-55. doi: 10.2174/138161208786549326.
In the last two decades quantitative electroencephalogram (EEG) analysis has been widely used to investigate the neurophysiological characteristics of insomnia. These studies provided evidence in support of the hypothesis that primary insomnia is associated with hyperarousal of central nervous system and altered sleep homeostasis. However, we have here underlined that these results have intrinsic methodological problems, mainly related to constraints of standard assessment in clinical research. We have proposed that future studies should be performed on larger samples of drug-free patients, using within-subjects designs and longitudinally recording patients adapted to sleep laboratory. All these methodological improvements will allow to partial out the contribution of individual differences, pharmacological influences and first-night effects on EEG frequencies. Moreover, we have discussed the potential relevance of recent findings from basic research concerning local changes during physiological sleep, which could be extended to the study of insomnia. We have suggested that, if normal sleep exhibits specific regional characteristics, also disorders in initiating and maintaining sleep should be characterized by local changes. The extension of this theoretical framework to the study of insomnia could provide new insights on the underlying pathophysiological mechanisms. As a first step toward the integration of knowledge from basic and clinical research focused on local sleep changes, here we showed some preliminary data from sleep onset recordings of patients with paradoxical insomnia. This approach supports the heuristic potential of our proposal, pointing to a local functional impairment in the process of synchronization in insomniac patients compared to normal subjects, the former exhibiting more beta and less delta and sigma power on anterior scalp locations than the latter.
在过去二十年中，定量脑电图（EEG）分析已被广泛用于研究失眠的神经生理特征。这些研究为原发性失眠与中枢神经系统过度觉醒及睡眠稳态改变相关这一假说提供了证据支持。然而，我们在此强调，这些结果存在内在的方法学问题，主要与临床研究中标准评估的局限性有关。我们提出，未来的研究应在更大样本的未用药患者中进行，采用受试者内设计，并纵向记录适应睡眠实验室环境的患者。所有这些方法学上的改进将有助于排除个体差异、药物影响和首夜效应在脑电频率上的作用。此外，我们还讨论了基础研究中有关生理睡眠期间局部变化的最新发现的潜在相关性，这些发现可能扩展到失眠研究中。我们认为，如果正常睡眠具有特定的区域特征，那么起始和维持睡眠的障碍也应以局部变化为特征。将这一理论框架扩展到失眠研究中，可能会为潜在的病理生理机制提供新的见解。作为整合聚焦于局部睡眠变化的基础研究和临床研究知识的第一步，我们在此展示了矛盾性失眠患者入睡记录的一些初步数据。这种方法支持了我们提议的启发式潜力，表明与正常受试者相比，失眠患者在同步过程中存在局部功能障碍，前者在前额头皮位置表现出比后者更多的β波功率以及更少的δ波和σ波功率。
