Longitudinal links between maternal factors and infant cognition: Moderation by infant sleep.

The current study examined the moderating role of infant sleep in the link between maternal factors (i.e., maternal education, depressive symptoms, sleep disturbance) and infant cognition. Data come from 95 African American parent-child dyads. At 3 months of age, infant sleep was objectively measured using videosomnography and actigraphy, from which measures of sleep regulation and consolidation were calculated. Mothers also self-reported their level of education, depressive symptoms, and sleep quality. At 6 months of age, infants completed cognitive assessments, including a measure of general cognitive ability and observed attention behavior. Findings revealed that infant sleep quality interacted with maternal education and sleep disturbances to predict cognition. Specifically, the link between maternal education and infants' attention behavior was significant and positive for infants with better regulated sleep, but not for infants with poorly regulated sleep. Similarly, the link between maternal sleep disturbance and infant cognition depended on infant sleep quality. For infants with poorer sleep consolidation, increased maternal sleep disturbance predicted poorer infant general cognitive ability. For infants with better sleep consolidation, maternal sleep disturbance was positively related to both general cognitive ability and attention behavior. These findings suggest that infant sleep quality moderates the impact of environmental factors on cognitive functioning.

Neighborhood deprivation predicts infant sleep quality.

OBJECTIVES: The current study examined the relationship between neighborhood deprivation and infant sleep at 3 months of age. METHODS: Neighborhood and sleep data were collected from 80 African American infants and their caregivers. A composite neighborhood deprivation score was created using census data. Infant sleep was measured via 7 nights of actigraphy monitoring when infants were 3 months of age. Current analyses considered the average number of infant night wakings as an index of sleep quality. Multilevel models were used, in which children (level 1) were nested within census tracts (level 2). RESULTS: Controlling for level 1 covariates, greater neighborhood deprivation (b = 0.07, P < .01), was associated with poorer infant sleep, as characterized by a greater number of wakings during the nighttime sleep period. CONCLUSIONS: Findings suggest that infants who reside in communities marked by higher deprivation experience poorer quality sleep, even after controlling for family-level factors.

Assessment of infant sleep: how well do multiple methods compare?

The current study compares sleep variables obtained from videosomnography, actigraphy, and sleep diaries, three of the most common sleep assessment methods used in infant sleep studies. Using a sample of 90 African American 3-month olds, we compare correlations and discrepancies for seven sleep variables across each of the three pairs of assessment methods for one night of a week-long sleep study. These seven variables are indicative of sleep schedule (e.g. sleep onset time, rise time), duration (e.g. sleep period, sleep time, wake time), and fragmentation (e.g. night wakings, longest sleep period). We find that across all sleep assessment methods, correlations are highest for variables indicative of sleep schedule, and lowest for variables indicative of sleep fragmentation. Comparing the magnitude and significance of the discrepancies, we find that actigraphy and sleep diaries significantly overestimate sleep period duration and underestimate the number of night waking episodes, compared with videosomnography. Actigraphy and sleep diaries were more concordant with one another than with videosomnography. Epoch-by-epoch analyses indicated that actigraphy had low sensitivity to detect wakefulness, compared with videosomnography. Contrary to our hypothesis, the discrepancies between sleep assessment methods did not vary widely based on infant sleep location (own room vs. parent's room) or sleep surface (own bed vs. parent's bed). Limitations and implications of these findings for future research are discussed.