COMPUTER-ANALYSIS OF ENVIRONMENTAL-TEMPERATURE, LIGHT AND NOISE IN INTENSIVE-CARE - CHAOS OR CHRONOME NURSERIES

Lighting, noise and temperature were monitored in two perinatal nurser ies. Rhythms of several frequencies were found, including prominent 24 -hour rhythms with acrophases around 13:00 (light intensity) and 16:00 (noise). For light and noise, the ratio formed by dividing the amplit ude of a 1-week (circaseptan) or half-week (circasemiseptan) fitted co sine curve by the amplitude of a 24-hour fitted cosine curve is smalle r than unity, since 24-hour rhythms are prominent for these variables. The amplitude ratios are larger than unity for temperature in the new borns' unit but not in the infants' unit. Earlier, the origin of the a bout-7-day rhythms of neonatal physiologic variables was demonstrated to have, in addition to a major endogenous, also a minor exogenous com ponent. Hence, the possibility of optimizing maturation by manipulatin g environmental changes can be considered, using, as gauges of develop ment, previously mapped chronomes (time structures of biologic multifr equency rhythms, trends and noise).