ACTBArizona Cognitive Test Battery AHI Apnea-hypopnea index IED Intra-extra dimensional set shift OSAS Obstructive sleep apnea syndrome PSG PolysomnographyAIM Good-quality sleep is essential for normal learning and memory. Sleep fragmentation and disrupted sleep architecture are commonly observed throughout the lifespan of individuals with Down syndrome, a condition marked by cognitive deficits emerging within the first few months of life. While obstructive sleep apnea syndrome (OSAS) is known to contribute to the loss of sleep quality in Down syndrome, its relation to cognitive and behavioral impairment remains poorly understood.METHOD Using ambulatory polysomnography, we measured sleep in an unreferred community-based sample of 38 individuals with Down syndrome (15 males, 23 females; mean age 9y 7mo (SD 1y 9mo), range 7-12y). Cognitive outcomes were assessed with the Arizona Cognitive Test Battery, a set of psychometric measures designed and validated for this population.RESULTS Among children with Down syndrome, mean Verbal IQ score (p=0.006) was 9 points lower in those with comorbid OSAS (apnea-hypopnea index >1.5) than in those without OSAS, and performance on measures of cognitive flexibility was poorer (p=0.03). In addition, those with OSAS showed increased light-stage sleep (p=0.009) at the expense of slow-wave sleep (p=0.04).INTERPRETATION These findings demonstrate a relation between OSAS and cognitive outcomes in Down syndrome. More work is required to fully understand the mechanisms underlying the links between poor sleep and impaired cognitive function. Overall, these findings highlight the importance of adequate sleep in typically and atypically developing populations.Down syndrome (trisomy 21) is the most common genetically defined cause of intellectual disability, with over 300 000 affected individuals residing in the United States alone. 1 The condition is characterized by decline of IQ during the infant and toddler years, well-documented deficits in the assimilation and expressive use of language, and impairments in cognitive flexibility and memory.2 As a result of alterations in craniofacial and oral musculature development and low muscle tone, individuals with Down syndrome are exceptionally vulnerable to obstructive sleep apnea syndrome (OSAS) from infancy, with estimates of the prevalence of the condition ranging from 30% to as high as 80%. [3][4][5] Ashworth et al. 6 have recently described the extent of sleep disruption in individuals with Down syndrome, noting that such individuals displayed more fragmented sleep than those with Williams syndrome, another intellectual disability. Because of the extent of their sleep disruption, individuals with Down syndrome could potentially suffer ill effects during critical periods of cognitive development.OSAS occurs when the upper airway becomes intermittently obstructed during sleep, resulting in incomplete ventilation, blood gas irregularities, and sleep fragmentation. It is best diagnosed with polysomnography (PSG), the criterion standard for sle...

Children with DS are at risk for developing symptoms of sleep disordered breathing, and may have additional sleep problems that are unrelated to sleep disordered breathing.

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