The electroencephalogram of the full-term newborn: review of normal features and hypoxic-ischemic encephalopathy patterns.

OBJECTIVE: The objective of this study is to specify, by reference to the normal newborn, the current contribution of the electroencephalogram (EEG) to the diagnosis and prognosis of hypoxic-ischemic encephalopathy (HIE) in the full-term newborn. Both digitized traditional EEG and cerebral function monitoring will be considered. DISCUSSION: A good knowledge of the EEG features of the sleep-wake cycle (SWC) is a prerequisite. We first describe the main features of normal and pathological EEGs. Very early recordings (before 6hours of life) are needed to indicate any required neuroprotective (hypothermia) and other (sedation, anticonvulsivants) treatments. CONCLUSIONS: Between the normal or near-normal tracings, which are associated with a good prognosis, and the very pathological ones (inactive, paroxysmal), which are associated with a poor vital or neurological prognosis, the interpretation of "intermediate" tracings--mainly represented by other types of discontinuous tracings--must take into account characteristics such as bursts and discontinuities, postnatal age, evolution of successive tracings, and treatments.

Electroencephalography in premature and full-term infants. Developmental features and glossary.

Following the pioneering work of C. Dreyfus-Brisac and N. Monod, research into neonatal electroencephalography (EEG) has developed tremendously in France. French neurophysiologists who had been trained in Paris (France) collaborated on a joint project on the introduction, development, and currently available neonatal EEG recording techniques. They assessed the analytical criteria for the different maturational stages and standardized neonatal EEG terminology on the basis of the large amount of data available in the French and the English literature. The results of their work were presented in 1999. Since the first edition, technology has moved towards the widespread use of digitized recordings. Although the data obtained with analog recordings can be applied to digitized EEG tracings, the present edition, including new published data, is illustrated with digitized recordings. Herein, the reader can find a comprehensive description of EEG features and neonatal behavioural states at different gestational ages, and also a definition of the main aspects and patterns of both pathological and normal EEGs, presented in glossary form. In both sections, numerous illustrations have been provided. This precise neonatal EEG terminology should improve homogeneity in the analysis of neonatal EEG recordings, and facilitate the setting up of multicentric studies on certain aspects of normal EEG recordings and various pathological patterns.

Electroencephalography (EEG) recording techniques and artefact detection in early premature babies.

Electroencephalography (EEG) recording techniques in early premature babies are not very different from those used for full-term neonates. Here, we emphasise the most important points: asepsis precautions, full knowledge of the clinical data and drug therapies, fundamental role of a well-trained technician in supervising the EEG recording and monitoring the baby. We discuss the best electrode positions, the most informative montages, and their standardisation between neurophysiological laboratories. Artefact detection constitutes an important aspect of EEG signal analysis in preterm babies of less than 30 weeks. It is obviously necessary to discriminate between meaningful information and artefacts. The complexity of the signal in neonates makes artefact detection difficult. We present some characteristic features and describe some methods for eliminating them. We underline the positive aspect of some artefacts and their clinical use. We emphasise the crucial role of the technicians.

Pathological features of neonatal EEG in preterm babies born before 30 weeks of gestationnal age.

Pathological features on very premature EEG concern background abnormalities and abnormal ictal and nonictal patterns. Positive rolandic sharp waves keep an important place regarding diagnosis and prognosis of white-matter lesions. Background abnormalities, that may be classified as acute-stage or chronic-stage abnormalities, give essential complementary information. These abnormal patterns remain precocious markers of cerebral lesions and are complementary to cerebral imaging. Analysis of these abnormalities has always to take into account medication received by the baby during the recording and that could modify the EEG.

[Electroencephalography (EEG) recording techniques and artifact detection in early premature babies]. / Technique d'enregistrement et identification d'artefacts chez le grand prématuré

EEG recording techniques in early premature babies are not very different from those used for full-term neonates. Here, we emphasise the most important points: asepsis precautions, full knowledge of the clinical data and drug therapies, the fundamental role of a well-trained technician in supervising the EEG recording and monitoring the baby. The best electrode positions, the most informative montages and their standardisation between neurophysiological laboratories, are suggested. Artifact detection constitutes an important aspect of EEG signal analysis in preterm babies of less than 30 weeks. It is obviously necessary to discriminate between meaningful information and artefacts. The complexity of the signal in neonates makes artifact detection difficult. We present some characteristic features and describe some methods for eliminating them. We underline the positive aspect of some artifacts and their clinical use. We emphasise the crucial role of the technicians.

[Pathological patterns in neonatal EEG before 30 weeks of gestational age]. / Les aspects pathologiques de l'EEG du nouveau-né prématuré avant 30 semaines d'âge postmenstruel.

Pathological features on very premature EEG concern background abnormalities and abnormal patterns. Positive rolandic sharp waves keep an important place regarding diagnosis and prognosis. Background abnormalities give essential complementary informations. Unusual patterns (abnormal localisation or morphological aspect, high amplitude) remain early markers of cerebral lesions. Analysis of these pathological features must always take into account treatment given to the baby, which can by itself modify the EEG.