Twenty-two healthy infants born at gestational ages of 28-32 weeks were randomly
assigned to experimental or control groups within the first 4 days following birth.
Experimental infants were placed in incubators equipped with oscillating waterbeds
and rhythmic sounds. Control infants were placed in traditional incubators.
All infants remained in their respective environment for 4 weeks. Measures
of treatment effects included weight gain, head measurement, weekly 2-hour observations
of state organization, and the Brazelton Neonatal Behavioral Assessment
Scale (BNBAS). No significant differences were obtained between the two
groups on any of the physical measures. A priori cluster scores on the BNBAS showed
significantly greater developmental progress in motoric and state organization processes
for the experimental group. A statistically significant interaction effect was
found between the two groups for the amount of time they spent in active sleep
during the treatment period and at the time of discharge. These results suggest
that general developmental progress was enhanced in the experimental group by
the stimulation procedure.