Monitoring of Stimulus-Induced 40Hz Brain Oscillations


Gerhard Litscher  (Ed.)


Pabst Science Publishers



ISBN: 3933151368




Book Review




The book provides a systematic overview of the current status of monitoring auditory stimulus induced 40Hz brain oscillations in humans. Its ten chapters are written by oustanding scientists from around the world in the fields of neuroscience, biomedical engineering, critical care medicine, anesthesiology, neurology, neuroanesthesiology, surgery, biophysics, communication science, and neurophysiology.

The book is a valuable source for a various audiences interested in brain oscillations, such as researchers, physicians, engineers, medical students, nursing students, nurses and other health care professionals as well as scientists in other areas, such as biomedical engineering, informatics or medical computer science.




Recording and processing of electroencephalograms and evoked potentials is an ever-changing science. The new possibilities are of interest to scientists in this field as well as to clinicians regularly confronted with neurophysiologic monitoring.

This book was conceived as a collaborative effort between scientists, physicians, and engineers to integrate and advance the recording of brain oscillations in clinical practice.

Since Robert Galambos and coworkers first reported auditory stimulus-induced 40Hz oscillations in humans in 1981, many new discoveries in neurophysiology have been made. These rapid developments have been made possible by many technological advances in neuroscience.

Innovation is the key to progress in neuromonitoring. Revolutionary advances in basic neuroscience together with improvements in electrophysiological recording techniques - which for example permit the amplification of the electrical activity directly on the surface of the scalp - is essential for monitoring brain oscillations.

This book covers aspects from basic neurophysiology to the manifold clinical applications of 40Hz steady-state potentials in anesthesia and intensive care medicine. I thank all the authors for their excellent contributions.

Gerhard Litscher  

Graz, October 1998




Book review  Elizabeth A.M. Frost


Since Galambos first described oscillations in reference to characteristic, sinus waves formed by acoustic stimulation of the auditory pathway, using a frequency of 40Hz in 1981, many studies have followed. Although the mechanism of the 40Hz response has not been clarified, it is believed that the thalamus-midbrain area is the site of generation of these stimulus induced potentials of middle latency. 


Over the past 10 years, many investigators have used this monitor as a gauge of depth or awareness during anesthesia. Other studies have examined the responses of postraumatic patients and those comatose in the intenisve care unit and have determined that loss of the signal correlates with a very poor prognosis. Indeed, the monitor may be a better indicator of adverse outcome than CT scan, or Glasgow Coma Scale score. Although electroencephalographic recordings are better at predicting quality of life, low or absent 40Hz potentials recorded immediately after trauma showed 100 % specificity and sensitivity for poor outcome. 


This small book provides a systematic review of the current status of monitoring auditory stimulus induced 40Hz brain oscillation in humans. The 10 chapters have been contributed by researchers from many fields including anesthesiologists, neurophysiolgists, biomedical engineers, and communications scientists among others. The autors come mainly from Italy and Austria and, hence, English may not be their first language. Thus there are several instances where the reader may find himself re-examining sentences for understanding because of misspellings (e.g., scull), missed articles, or even verbs. Also, there is considerable repetition. Transient auditory evoked potentials and steady state auditory evoked potentials are given almost verbatim explanations in several chapters as are the effects of anesthetic agents on 40Hz brain oscillations. No attempt has been made to standardize transatlantic spelling. 


Some of the chapters (e.g., Experimental Gamma (40Hz) Oscillation) might make for rather heavy reading for the clinical anesthesiologist - no doubt because the authors are physiologists and engineers. Other chapters that contain case histories are interesting and quite understandable. Illustrations (some in color) are plentiful and most helpful. 

Altough the book is marketed as a valuable source for, among others, medical and nursing students and informatics of medical computer science, I believe that it has a rather narrower audience of neuroscientists. 


All in all, the book does cover most aspects fo this monitoring technique from basic neurophysiology and the clinical applications of 40Hz steady state potentials in anesthesia and intensive care to future trends. No attempt has been made to address cost benefit ratios - perhaps because such mundane matter appear still be be a concern more in the U.S. than in Europe.


Elizabeth A.M. Frost, J. Neurosurg. Anesth. 11(3): 223, 1999.