LIGHT VARIABILITY IN THE MODERN NEONATAL NURSERY - CHRONOBIOLOGIC ISSUES

The role that nursery light variability may play in modulating infant biological rhythms is being studied in Stanford Medical Center's Neona tal intensive Care (NICU) and Intermediate Care (IN) Nurseries. In thi s investigation, spatial and temporal variability in illuminance was d etermined at 20 sites within each nursery over a 5-day period. The ana lysis of 240 measurements at 30 min intervals from each site revealed marked variability in illumination with respect to both time and posit ion in the nursery. These aperiodic lighting patterns differed greatly from the published characterization of NICUs as having 'constant' ill umination. Light pulses of variable frequency, intensity, and duration were common at each of the 40 bedsites studied. Given the powerful im pact of light on circadian rhythmicity and sleep in adults, the result s from this study suggest that modern NICU lighting, while implemented to facilitate intensive care, may have adverse effects on infant deve lopment. Future studies on the influence of light on biological rhythm icity and sleep are essential to provide a framework for clinical and environmental interventions, which may play a significant role in impr oving developmental outcome in hospitalized preterm or term infants.