The EEMG--a practical index of cortical activity and muscular relaxation.

M. H. Harmel, F. F. Klein, D. A. Davis

Research output: Contribution to journalArticlepeer-review


In a continuing study of the EEG as a monitor of cortical activity during anesthesia using a time-domain wave analyzer, the contamination of the EEG by scalp muscle activity was observed. A measure of this EMG activity was extracted from the combined EEG/EMG wave obtained from two electrodes placed over the left frontalis muscle and right mastoid process. Clinical work with this variable showed that the EMG can serve both as a reliable guide to patient muscular relaxation and an indicator of unacceptable muscle contamination of the EEG. This extracted variable in conjunction with the analyzed EEG has served as a valid indicator in the assessment of the anesthetic state. The system has been successfully employed in the management of nearly 1000 surgical patients.

Original languageEnglish (US)
Pages (from-to)97-102
Number of pages6
JournalActa Anaesthesiologica Scandinavica, Supplement
StatePublished - 1978
Externally publishedYes

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine


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