Recent evidence has suggested that sleep may facilitate language learning. The current study examined variation in language ability in 29 toddlers with Down syndrome (DS) in relation to levels of sleep disruption. Toddlers with DS and poor sleep (66%, n = 19) showed greater deficits on parent-reported and objective measures of language, including vocabulary and syntax. Correlations between sleep and language were found in groups with equivalent medical and social backgrounds and after control for relevant behavioral co-morbidities, including autism symptoms. These results emphasize the important role of quality sleep in all children’s expressive language development, and may help increase our understanding of the etiology of language deficits in developmental disorders, potentially leading to new treatment approaches.

ObjectivesTo evaluate sleep consolidation and circadian activity rhythms in infants and toddlers with Down syndrome (DS) under light and socially entrained conditions within a familiar setting. Given previous human and animal data suggesting intact circadian regulation of melatonin across the day and night, it was hypothesized that behavioral indices of circadian rhythmicity would likewise be intact in the sample with DS.MethodsA cross-sectional study of 66 infants and young children with DS, aged 5–67 months, and 43 typically developing age-matched controls. Sleep and measures of circadian robustness or timing were quantified using continuous in-home actigraphy recordings performed over seven days. Circadian robustness was quantified via time series analysis of rest-activity patterns. Phase markers of circadian timing were calculated alongside these values. Sleep efficiency was also estimated based on the actigraphy recordings.ResultsThis study provided further evidence that general sleep quality is poor in infants and toddlers with DS, a population that has sleep apnea prevalence as high as 50% during the preschool years. Despite poor sleep quality, circadian rhythm and phase were preserved in children with DS and displayed similar developmental trajectories in cross-sectional comparisons with a typically developing (TD) cohort. In line with past work, lower sleep efficiency scores were quantified in the group with DS relative to TD children. Infants born with DS exhibited the worst sleep fragmentation; however, in both groups, sleep efficiency and consolidation increased across age. Three circadian phase markers showed that 35% of the recruitment sample with DS was phase-advanced to an earlier morning schedule, suggesting significant within-group variability in the timing of their daily activity rhythms.ConclusionsCircadian rhythms of wake and sleep are robust in children born with DS. The present results suggest that sleep fragmentation and any resultant cognitive deficits are likely not confounded by corresponding deficits in circadian rhythms.

Sleep is recognized as a physiological state associated with learning, with studies showing that knowledge acquisition improves with naps. Little work has examined sleep-dependent learning in people with developmental disorders, for whom sleep quality is often impaired. We examined the effect of natural, in-home naps on word learning in typical young children and children with Down syndrome (DS). Despite similar immediate memory retention, naps benefitted memory performance in typical children but hindered performance in children with DS, who retained less when tested after a nap, but were more accurate after a wake interval. These effects of napping persisted 24 h later in both groups, even after an intervening overnight period of sleep. During naps in typical children, memory retention for object-label associations correlated positively with percent of time in rapid eye movement (REM) sleep. However, in children with DS, a population with reduced REM, learning was impaired, but only after the nap. This finding shows that a nap can increase memory loss in a subpopulation, highlighting that naps are not universally beneficial. Further, in healthy preschooler’s naps, processes in REM sleep may benefit learning.

Low sleep efficiency and sleep disruptions 1 have been associatedwith various cognitive deficits in typical and atypical populations

Introduction: Emotional information undergoes preferential memory processing. Psychostimulants facilitate processing of emotional and neutral memories in rodents, though this effect is less clear in humans. Sleep is important for emotional memory consolidation, yet psychostimulants disrupt sleep. Here, we tested the hypothesis that daytime administration of psychostimulants (compared with placebo) would enhance emotional and neutral memory over wake, but would impair sleep consolidation of these memories. We further tested this hypothesis by combining stimulants with a hypnotic to examine whether boosting sleep would counteract sleep disruption and enhance memory. Methods: In a double-blind, placebo(PBO)-controlled, crossover design, 25(13F) healthy subjects were tested in four conditions (dextroamphetamine(DEX)/PBO, DEX/zolpidem(ZOL), PBO/ZOL, PBO/ PBO), one week apart. At 9:00AM, 20mg of DEX/PBO was administered. 75 minutes later subjects encoded 20 negative and 20 neutral IAPS pictures. At 9:00PM, a memory test was given including 20 pictures from encoding and 20 foils (TEST1). At 11:00PM, subjects received 10mg of ZOL/PBO, and slept in the lab with polysomnography. At 10:30AM, the remaining 20 images from encoding and 20 foils were tested (TEST2). Results: We replicated the emotional enhancement effect, negative>-neutral(p=.01). Unlike prior results, compared to PBO, DEX boosted memory for neutral images(p=.023), but not for emotional images(p=.78) at TEST1. After sleep, TEST2 maintained a marginal main effect for emotion, negative>neutral(p=.08). Furthermore, we found a main effect of drug, with the DEX/ZOL condition outperforming DEX/PBO(p=.02) and PBO/PBO(p=.013). Conclusion:Here, we show a preference for emotional memory processing over wake and sleep. However, we found no benefit of psychostimulants for emotional processing across wake, yet stimulants did boost memory for neutral pictures, suggesting stimulants may augment saliency of neutral information. Furthermore, stimulant disruption of sleep may impair long-term memory consolidation, as the combined stimulant/hypnotic condition showed greatest long-term memory. Support (If Any): Support: ONR N00014-14-1-0513. TO NAP OR NOT TO NAP? SLEEP-DEPENDENT MEMORY CONSOLIDATION IN TYPICALLY AND ATYPICALLY DEVELOPING PRESCHOOLERSSpanò G, Gómez R, Demara B, Cowen S, Edgin J University of Arizona, Tucson, AZ Introduction: Little work has examined the processes of sleep-dependent memory consolidation in children with sleep disorders. Down syndrome (DS) -characterized by sleep disturbances and memory impairments -constitutes a good model to examine these links. Methods: We assessed word learning in preschoolers with and without DS (25 DS and 24 typically developing (TD) controls) across delays including mid-day naps and wake. Sleep physiology was collected with home-based polysomnography. Results: Our results show that, despite equivalent levels of baseline retention, children with DS retained less over sleep, but not after the