Behavioural changes and bioelectric brain maturation of preterm and fullterm newborn infants: a polygraphic study.

Fifty-two preterm and fullterm infants requiring assisted ventilation were observed and examined polygraphically. In addition, 24 preterm infants without prenatal or perinatal complications and not needing assisted ventilation were examined polygraphically in order to validate a special method of differentiating sleep states and sleep cycles. State criteria were EEG records, eye movements and gross body movements. Using this evaluation method, all 14 low-risk preterm infants showed stable sleep states and cycles, as did 16 of 23 high-risk preterm and 10 of 15 high-risk fullterm infants. 11 high-risk preterm and fullterm infants were found to have extremely unstable sleep states, or were comatose. The EEG could not be evaluated in only one case. Infants requiring assisted ventilation showed the following changes in comparison with the infants who did not need ventilation: the percentage of quiet sleep increased significantly; the percentage of indeterminate sleep increased as a sign of more unstable behaviour; and the individual measurements of the recorded and observed variables showed wider variability. Bioelectric brain maturation decreased significantly with increasing risk among both preterm and fullterm infants given assisted ventilation.