Scalp electrical recording during paralysis: Quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG
- 作者：Emma M. Whitham ; Kenneth J. Pope ; Sean P. Fitzgibbon ; Trent Lewis ; C. Richard Clark ; Stephen Loveless ; Marita Broberg ; Angus Wallace ; Dylan DeLosAngeles ; Peter Lillie ; Andrew Hardy ; Rik Fronsko ; Alyso
- 关键词：Neuromuscular blockade ; Very high frequency ; Gamma oscillations ; EEG ; Spectra ; Auditory odd-ball
- 刊名：Clinical Neurophysiology
- 出版年：2007
- 期刊代码：61_13882457
- 类别：med
- 出版时间：August 2007
- 卷：118
- 期：8
- 页码：1877-1888
- 文件大小：1263 K
摘要
To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks.
Methods
Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings.
Results
EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis.
Conclusions
Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated.
Significance
This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation.