Early polysomnographic characteristics associated with neurocognitive development at 36 months of age.

BACKGROUND: Few studies on the relationship between sleep quantity and/or quality and cognition have been conducted among preschoolers from the healthy general population. We aimed to identify, among 3-year-old children, early polysomnography (PSG) sleep factors associated with estimated intelligence quotient (IQ) using the Weschler Preschool and Primary Scale Intelligence-III test (WPPSI-III) and its indicators: full-scale (FISQ), verbal (VIQ), and performance (PIQ) intelligence quotients. METHODS: We included full-term children from the French birth-cohort AuBE with PSG recording at term (M0) and/or six months (M6), and available WPPSI-III scores at three years. Sleep and arousal characteristics of these infants were evaluated during day and night sleep periods. Relationships between IQ scores and sleep parameters were estimated using models with the child as a repeated effect adjusted for time (night/day), maturation (M0/M6), tobacco exposure (yes/no), anxiety-depressive scores during pregnancy, maternal age, duration of breastfeeding and child's gender. RESULTS: A total of 118 PSG recordings were obtained, representing a total of 78 unique children (38 with one PSG and 40 with two PSG). No correlations were found between night and day sleep durations at M0 or M6. Mean VIQ, PIQ, and FSIQ scores were within normal ranges. In multivariate models, longer sleep duration and higher sleep efficiency during the day were negatively associated with all IQ scores. More frequent arousals during the night were associated with lower VIQ scores. CONCLUSION: Early sleep characteristics such as night sleep fragmentation or longer naps could be associated with impaired cognitive function at three years of age.

Altered sleep architecture during the first months of life in infants born to depressed mothers.

OBJECTIVE: This study investigated sleep architecture in newborn and six-month-old infants who were born to depressed mothers. METHOD: Sixty-four healthy full-term infants (32 males and 32 females) participated in the study. Of these, 32 were high-risk infants who were born to mothers diagnosed with depression, and 32 were low-risk infants born to mothers without a personal history of depression. 24-hour polysomnography was recorded at zero and six months of age (M0 and M6). Sleep macro-structural parameters (total sleep time, TST; awake time; non-rapid eye movement, NREM sleep (%); rapid eye movement, REM sleep %; arousal index; and sleep efficiency) were analysed at M0 and M6. Micro-architectural sleep features (slow-wave activity, SWA; delta sleep ratio, DSR; spindle density; and rapid eye movement density) were calculated at M6. The data between high-risk and low-risk groups were compared using Student's t-tests. RESULTS: At M0 and M6, the high-risk infants showed more awake time and fewer arousals than the low-risk infants. However, the high-risk group had less NREM% at M0 and a shorter TST as well as less REM% at M6 than the low-risk group. At M6, the high-risk group showed higher SWA, higher DSR and lower spindle density in comparison with the low-risk group. CONCLUSIONS: Altered sleep structure was observed during their first months of life in infants born from depressed mothers, thereby suggesting that the prenatal environment could enhance the depression vulnerability of the child and potentially decrease their neuroplasticity.

Early features associated with the neurocognitive development at 36 months of age: the AuBE study.

BACKGROUND: Few studies on the relations between sleep quantity and/or quality and cognition have been conducted among preschoolers from healthy general population. We aimed at identifying, among 36 months old children, early factors associated with intelligence quotient (IQ) estimated through the Weschler Preschool and Primary Scale Intelligence-III test and its indicators: Full-Scale-, Verbal- and Performance-IQs and their subscale scores. METHODS: We included 194 children from the French birth cohort AuBE with both available Weschler Preschool and Primary Scale Intelligence-III scores at three years and sleep data. Information was collected through self-questionnaires at birth, 6, 12, 18 and 24 months. A day/night sleep ratio was calculated. RESULTS: Mean scores were in normal ranges for Verbal, Performance, and Full-Scale IQs ?. In multivariate models, being a third-born or more child and watching television ≥1 h/day at 24 months were negatively associated with all IQ scores, whereas collective care arrangement was positively associated. Night waking at six months and frequent snoring at 18 months were negatively associated with Performance IQ, some subscales, and Full Scale IQ contrary to day/night sleep ratio at 12 months. No association was observed between early sleep characteristics and Verbal IQ. CONCLUSION: We showed that early features including infant sleep characteristics influence IQ scores at 36 months old. Some of these may be accessible to prevention.