EMG contamination of EEG: spectral and topographical characteristics
EMG contamination of EEG: spectral and topographical characteristics
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DOI：
10.1016/s1388-2457(03)00093-2
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发表时间：
2003-09-01
影响因子：
4.7
通讯作者：
Wolpaw, JR
中科院分区：
文献类型：
--
作者：
Goncharova, II;McFarland, DJ;Wolpaw, JR
目的：肌电图 (EMG) 污染通常是脑电图 (EEG) 记录中的一个问题，特别是对于那些依赖于 EEG 特征自动测量的基于 EEG 的脑机接口等应用。作为开发识别和消除脑电图肌电图污染的方法的重要前奏，这项研究定义了整个头皮上额肌和颞肌肌电图的光谱和地形特征。它描述了平均数据和个体差异范围。方法：在 25 名健康成年人中，在放松期间以及在额肌或颞肌的限定收缩（最大的 15%、30% 或 70%）期间记录来自 64 个头皮和 4 个面部位置的信号。结果：在平均数据中，肌电图具有从 0 到 > 200 Hz 的广泛频率分布。正面 20-30 Hz 处振幅最大，颞侧 40-80 Hz 处振幅最大。颞肌谱还在 20 Hz 附近显示出较小的峰值。这些光谱成分集中衰减和展宽。即使收缩较弱（15%），在平均数据中 > 12 Hz 的频率和某些个体中 > 8 Hz 的频率下，在顶点附近也可检测到 EMG（P < 0.001）。结论：从头皮记录的额肌或颞肌 EMG 具有在个体之间存在很大差异的频谱和地形特征。 EMG 频谱通常在 Beta 频率范围内有峰值，类似于 EEG Beta 峰值。 意义：虽然 EMG 污染在靠近活动肌肉的头皮周边最严重，但即使是微弱的收缩也会产生 EMG，从而掩盖或模仿整个头皮的 EEG α、mu 或 Beta 节律。识别和消除这种污染可能需要从一组适当的周边头皮位置进行记录。 (C) 2003 年国际临床神经生理学联合会。由爱思唯尔爱尔兰有限公司出版。保留所有权利。
Objective: Electromyogram (EMG) contamination is often a problem in electroencephalogram (EEG) recording, particularly, for those applications such as EEG-based brain-computer interfaces that rely on automated measurements of EEG features. As an essential prelude to developing methods for recognizing and eliminating EMG contamination of EEG, this study defines the spectral and topographical characteristics of frontalis and temporalis muscle EMG over the entire scalp. It describes both average data and the range of individual differences.Methods: In 25 healthy adults, signals from 64 scalp and 4 facial locations were recorded during relaxation and during defined (15, 30, or 70% of maximum) contractions of frontalis or temporalis muscles.Results: In the average data, EMG had a broad frequency distribution from 0 to > 200 Hz. Amplitude was greatest at 20-30 Hz frontally and 40-80 Hz temporally. Temporalis spectra also showed a smaller peak around 20 Hz. These spectral components attenuated and broadened centrally. Even with weak (15%) contraction, EMG was detectable (P < 0.001) near the vertex at frequencies > 12 Hz in the average data and > 8 Hz in some individuals.Conclusions: Frontalis or temporalis muscle EMG recorded from the scalp has spectral and topographical features that vary substantially across individuals. EMG spectra often have peaks in the beta frequency range that resemble EEG beta peaks.Significance: While EMG contamination is greatest at the periphery of the scalp near the active muscles, even weak contractions can produce EMG that obscures or mimics EEG alpha, mu, or beta rhythms over the entire scalp. Recognition and elimination of this contamination is likely to require recording from an appropriate set of peripheral scalp locations. (C) 2003 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.