The Development of Circadian Rhythms in Human Infants

7.3.2 Non care giver dependent infant sleep parameters
Changes were seen in other sleep parameters. These measurements were not influenced or
affected by infant care practices dictated by main care giver such as time infant placed in
routine place of sleep; lights out. They are infant dependent and may more closely reflect
intrinsic developmental change in infant sleep.
Fragmentation index (SD), which relates to a measure of restlessness during night time
sleep, dropped significantly from 82.31 (39.78) to 68.24 (29.80); p = 0.021 (CI -26.006 to
-2.414), when comparison was made between pre and post temperature rhythm
development. A similar fall was seen in the number of minutes moving (SD) during night
time sleep (pre-temperature maturity no. minutes moving is 225.952 (130.372); whilst after
mature temperature maturity achieved no. minutes moving falls to 181.366 (92.119); p =
0.023; 95% CI -82.838 to -6.333.
The total number of minutes immobile during night time sleep period (SD) increased
from 334.81 (133.461) minutes to 381.80 (99.779) minutes; p=0.027 (95% CI 6.998
to 86.998). There was an obvious reduction in the number of immobile phases of 1
minute duration (SD.) It fell from 75.19 (35.74) to 69.90 (21.98) (p=0.027; 95% CI
-25.51 to -0.054). A trend was observed for the overall percentage (SD) of immobility
phases of 1 minute duration falling from 41.79 (20.74) to 36.24 (14.92) % (p = 0.706
95% CI -11.669 to 0.5825).
As the infants‟ age increased, the number of immobile phases of 1 minute duration
fell proportionally by an average 5.0% per week (P=0.005 95% CI: 1.5% to 8.3%).
Summary graphs for these parameters are shown below in figures 7.5 to 7.11.
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