POLYSOMNOGRAPHIC QUANTIFICATION OF BIOELECTRICAL MATURATION IN PRETERM AND FULL-TERM NEWBORNS AT MATCHED CONCEPTIONAL AGES

We analyzed the relationship between normal neonatal EEG features and gestational age and conceptional age, and evaluated the normal aspects of EEG maturation in preterm babies compared to term babies. We repor t 46 newborns, divided into two groups. Group I consisted of 11 newbor ns with gestational age between 30 and 32 weeks, followed with weekly polysomnograms until they reach 42 weeks' conceptional age. Group II ( control) consisted of 35 newborns with gestational ages of 34 weeks (n = 5), 36 weeks (n = 10), 38 weeks (n = 10) and 40 weeks (n = 10) eval uated with one polysomnogram in their first 24-48 h of life. In each e xamination one 5 min epoch in REM and NREM sleep was analyzed to quant ify the number of delta brushes, the presence of frontal and temporal sharp transients, the presence of delta frontal rhythmic activity, the grade of concordance between EEG patterns and sleep stages, the perce nt of interhemispheric synchrony and the duration of interburst interv al. The age dependent variability of the EEG patterns was evaluated du ring the subsequent weeks with group comparisons at weeks 34, 36, 38 a nd 40. Our results show that the number of delta brushes and the durat ion of the interburst interval decrease as gestational and conceptiona l age increase. The percent of interhemispheric synchrony increases wi th gestational and conceptional age. The presence of frontal sharp tra nsients and delta frontal rhythmic activity suggest that the newborn i s fullterm. The presence of temporal sharp transients suggest a preter m newborn. The degree of concordance between behavioral sleep patterns and EEG was more helpful in recognizing sleep stages than in estimati ng gestational or conceptional age. Although the EEG patterns were com parable between the groups at the same age, analyses of the behavioral patterns of concordance in NREM sleep showed that newborns in Group I had a more immature behavior than newborns in Group II. Our results a lso suggest that extrauterine life of preterm babies does not seem to accelerate EEG maturation but may influence the acquisition of behavio ral patterns during NREM sleep. (C) 1997 Elsevier Science Ireland Ltd.