This book reviews how we can record the human brain's response to sounds, and how we can use these recordings to assess hearing. These recordings are used in many different clinical situations--the identification of hearing impairment in newborn infants, the detection of tumors on the auditory nerve, the diagnosis of multiple sclerosis. As well they are used to investigate how the brain is able to hear--how we can attend to particular conversations at a cocktail party and ignore others, how we learn to understand the language we are exposed to, why we have difficulty hearing when we grow old. This book is written by a single author with wide experience in all aspects of these recordings. The content is complete in terms of the essentials. The style is clear; equations are absent and figures are multiple. The intent of the book is to make learning enjoyable and meaningful. Allusions are made to fields beyond the ear, and the clinical importance of the phenomena is always considered.

Experiment 1 investigated how auditory evoked potentials change as stimulus rate increases from the transient to the steady state range. Only the 13 Hz response-produced a frequency-amplitude characteristic with a prominent peak in response amplitude at 40 Hz. A new signal processing procedure, based on the Hotelling T2 statistic but applied in a procedure similar to a spectrogram, was used to show dynamics in the steady-state response which were not observable in the time-domain averages.

Written for auditory clinicians and researchers alike, this is the first monograph on this important area of auditory science that traces the international research effort from its origins in the 1970s to the present day. Comprising contributions from experts in a range of disciplines including auditory physiology, engineering, medicine and audiology, the book presents comprehensive and authoritative coverage of the generation and recording of the ASSR and the clinical applications of the response.

Written by experts with extensive clinical and scientific experience, this comprehensive textbook presents the state of the art in auditory evoked potentials. Opening chapters explain the nature of electrical fields that generate surface recorded potentials, summarize the imaging modalities that complement evoked potential studies, and review acoustics and instrumentation. Major sections examine the anatomy and physiology of the auditory periphery, brainstem, and cortex and the principles and clinical applications of auditory, myogenic, visual, somatosensory, and vestibular evoked potentials. Chapters present hands-on laboratory exercises and clinical case studies. A full-color insert includes 3D images from multi-channel evoked potentials and functional imaging.

In order to identify neurophysiological correlates of the changes in the level of conciousness associated with general anesthesia, the 40 Hz auditory steady-state response (ASSR), the electroencephalogram (EEG) and the N1 and P3 components of the transient auditory evoked potential were recorded before anesthesia (pre-induction), at the onset of anesthesia (induction), during surgical anesthesia, at the time of emergence and during recovery from anesthesia. The amplitude of the ASSR, was reduced significantly during late induction and dropped below noise levels during surgical anesthesia. It increased during emergence and further increased during recovery although the amplitude during recovery was significantly less than pre-induction values. Total EEG power increased significantly after induction. The EEG median frequency and 95% quantile frequency decreased significantly during surgery and increased significantly during emergence. Muscle artifacts could account for many of the EEG changes. The results for the transient auditory evoked potential indicated that, except during emergence, detection was associated with clear N1 and P3 waves whereas undetection was not. The lack of either N1 and P3 for detection during emergence perhaps occurred because the patients were not yet fully conscious. (Abstract shortened by UMI.).