Vanhatalo Sampsa, Voipio Juha, Kaila Kai
Department of Clinical Neurophysiology, University of Helsinki, Finland.
Clin EEG Neurosci. 2005 Oct;36(4):311-7. doi: 10.1177/155005940503600411.
A variety of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and magnetoencephalography (MEG), have been established during the last few decades, with progressive improvements continuously taking place in the underlying technologies. In contrast to this, the recording bandwidth of the routine clinical EEG (typically around 0.5-50 Hz) that was originally set by trivial technical limitations has remained practically unaltered for over half a decade. An increasing amount of evidence shows that salient EEG signals take place and can be recorded beyond the conventional clinical EEG bandwidth. These physiological and pathological EEG activities range from 0.01 Hz to several hundred Hz, and they have been demonstrated in recordings of spontaneous activity in the preterm human brain, and during epileptic seizures, sleep, as well as in various kinds of cognitive tasks and states in the adult brain. In the present paper, we will describe the practical aspects of recording the full physiological frequency band of the EEG (Full-band EEG; FbEEG), and we review the currently available data on the clinical applications of FbEEG. Recording the FbEEG is readily attained with commercially available direct-current (DC) coupled amplifiers if the recording setup includes electrodes providing a DC-stable electrode-skin interface. FbEEG does not have trade-offs that would favor any frequency band at the expense of another. We present several arguments showing that elimination of the lower (infraslow) or higher (ultrafast) bands of the EEG frequency spectrum in routine EEG has led, and will lead, to situations where salient and physiologically meaningful features of brain activity remain undetected or become seriously attenuated and distorted. With the currently available electrode, amplifier and data acquisition technology, it is to be expected that FbEEG will become the standard approach in both clinical and basic science.
在过去几十年间，已经建立了多种神经成像技术，如功能磁共振成像（fMRI）、正电子发射断层扫描（PET）和脑磁图（MEG），并且基础技术也在不断取得进步。与此形成对比的是，常规临床脑电图（EEG）的记录带宽（通常约为0.5 - 50 Hz）最初是由微不足道的技术限制所设定的，在过去半个多世纪里几乎没有改变。越来越多的证据表明，显著的EEG信号会出现并且可以在传统临床EEG带宽之外被记录下来。这些生理和病理EEG活动的频率范围从0.01 Hz到几百Hz，并且已经在早产儿大脑的自发活动记录中、癫痫发作期间、睡眠期间以及成人大脑的各种认知任务和状态中得到证实。在本文中，我们将描述记录EEG全生理频段（全频段EEG；FbEEG）的实际操作方面，并回顾目前关于FbEEG临床应用的现有数据。如果记录设置包括提供直流稳定电极 - 皮肤界面的电极，那么使用市售的直流（DC）耦合放大器就很容易实现FbEEG的记录。FbEEG不存在以牺牲其他频段为代价而偏袒任何一个频段的权衡情况。我们提出了几个观点，表明在常规EEG中去除EEG频谱的较低（超低频）或较高（超高频）频段已经并将导致这样的情况：大脑活动的显著且具有生理意义的特征仍未被检测到，或者变得严重衰减和扭曲。凭借目前可用的电极、放大器和数据采集技术，可以预期FbEEG将成为临床和基础科学中的标准方法。
