The practice of neonatal electroencephalography combines clinical medicine and biomedical technology. It is based on the understanding of both the general principles of electroencephalography (EEG) interpretation and aspects unique to the neonatal period, but it is limited by a gap in our knowledge between well-characterized features of some neonatal EEG findings and those that have yet to be clearly defined by clinical investigations. In considering these factors, we have written Atlas of Neonatal Electroencephalographyto be a single-source reference concerning neonatal EEG based on available information. Through the text, tables, and the samples of EEG recordings, we have tried to present a comprehensive view of the clinical practice of neonatal EEG for neurologists and clinical neurophysiologists, for trainees in neurology and clinical neurophysiology, and for electroneurodiagnostic technologists.
This atlas consists of chapters concerning the approach to visual analysis, artifacts of noncerebral origin, age-dependent normal findings, patterns of uncertain diagnostic significance, abnormal EEG findings, and seizures. Chapters consist of explanatory text, tables, a list of figures, and the samples themselves with their legends. We have presented information based on the available referenced literature from a diverse group of clinical investigators. However, in considering the aspects of neonatal EEG for which no studies are available and for which unresolved controversies persist, we have provided our own opinions. These have been formulated within our group, based on our collective experience, which spans more than 50 years. In addition, over the years, we have written a number of articles and reviews on neonatal electroencephalography, and we have also drawn from these works (Hrachovy, 2000; Kellaway and Hrachovy, 1981; Mizrahi, 1986; Hrachovy et al, 1990; Mizrahi and Kellaway, 1998).
This atlas has been produced at a time when many laboratories are replacing analog recording devices with digital instrumentation. Thus, we have presented a mixture of EEG samples derived from pen-and-ink and from digital, computer-based recordings. All of our samples are shown as they were recorded in the course of clinical practice in our laboratory or at the bedside in the neonatal intensive care unit without modification. Unless otherwise indicated in figure legends, the recording parameters for all EEG channels on all samples are sensitivity, 7 µV/mm; high-frequency filter, 70 Hz; low-frequency filter, 0.5 Hz; 60 Hz filter on; paper speed 30 mm/sec (analog recordings) and 10 sec/screen (digital recordings). In addition, because bedside EEG-video monitoring is becoming more available for neonates, we have provided technical information concerning this method of monitoring.
In presenting samples, we have emphasized specific components of the neonatal EEG. Our hope is that the Atlas of Neonatals Electroencephalography will allow the neurophysiologist to be able to recognize within a clinical recording the individual elements we have presented so as to determine their significance.
The neurophysiologist should understand the age-dependent characteristics of the neonatal EEG as well as the potential factors that may effect the developing central nervous system. Thus, throughout we have emphasized the age-dependent nature of both normal and abnormal findings of the neonatal EEG and the need to correlate them with clinical data. The most valuable report of the findings of a neonatal EEG is one with clinical relevance—a report that attempts to answer the clinical questions raised by the referring physician.