Sleep cyclic alternating pattern analysis in infants with apparent life-threatening events: a daytime polysomnographic study.

OBJECTIVE: Non-REM sleep is characterized by a physiologic oscillating pattern that exhibits different levels of arousal, coded as cyclic alternating pattern. The aim of this study was to analyze the development of cyclic alternating pattern parameters in a group of infants with apparent life-threatening events.

METHODS: A total of 26 infants with apparent life-threatening events (14 females, mean age 3.4 months, 2.37 S.D., age range 0.5-9 months) were studied while they slept in the morning between feedings, by means of a 3-h video-electroencephalographic-polygraphic recording. Sleep was visually scored using standard criteria. The control group was composed of 36 healthy infants (16 females, mean age 3.2 months, 2.17 S.D., age range 0.5-9 months).

RESULTS: Children with apparent life-threatening events showed an increased frequency of periodic breathing, gastroesofageal reflux and of other risk conditions. They presented also an increased obstructive apnoea/hypopnea index. A full NREM sleep development was found in a significantly smaller percentage of patients, and they showed a significant reduction of the percentage of REM sleep, of cyclic alternating pattern A1 subtypes, an increased percentage of A2 and A3 subtypes and increased index of A2, A3 subtypes and arousal, compared to normal controls. Cyclic alternating pattern rate showed a significant positive correlation with age, only in controls.

CONCLUSIONS: Our results show a higher level of arousal and an increased non-REM sleep discontinuity in babies with apparent life-threatening events, compared to controls.

SIGNIFICANCE: The enhanced mechanism of arousal might counteract life-threatening events and represent an important neurophysiologic distinction from future victims of sudden infant death syndrome who also experience similar events.