Quantified electrographic scales on 10 pre-term healthy newborns followed up to 40-43 weeks of conceptional age by serial polygraphic recordings.

Full-term newborns with seizures exhibit EEG patterns that appear reliable in predicting neurological outcome in almost 75% of the cases in a prospective investigation. These patterns are unreliable for over 25% of infants with seizures and even more so for term and pre-term babies with other complications. Observations that such newborns often show maturational delay in various physiological and/or behavioral parameters, raises the issue of whether indices other than specific EEG patterns might prove reliable in predicting prognosis. As a prerequisite for testing such an hypothesis in prospective investigations of term and pre-term babies with 'risk' factors other than seizures, it appears necessary to obtain quantification of these parameters in normals. Hence a longitudinal study was designed to obtain simultaneously 3 parameters in a control group of newborns born after 30-32 weeks of gestational age, followed with serial polygraphic recordings at weekly intervals until a conceptional age of 43 weeks. The selected parameters were purposefully restricted to three that can be obtained and measured easily in routine recordings without need for more complex instrumentation and analysis. These were: the percentage of interhemispheric synchrony between bursts of 'trace alternant'; the number of spindle-delta complexes ('brushes') during 5 min of REM and NREM sleep; and the concordance between various parameters during the same 5 min epochs. The range of these indices was thus established in a group of normal prematures followed prospectively. Establishing such normative data will allow greater inter-study reliability, and form the basis for other prospective studies of infants 'at risk' to investigate whether those that lag behind the norm in these indices when followed serially during the newborn period differ prognostically from those who recover and reach expected norms for conceptional age.