Characterization of sleep habits of children with Sotos syndrome.

Sotos syndrome (SS) is a genetic disorder characterized by accelerated growth in childhood, developmental deficits, and characteristic craniofacial features. While clinicians and parents have reported unusual sleep habits, only one study by Rutter and Cole in 1991 mentioned sleep complaints (Rutter and Cole, Developmental Medicine and Child Neurology, 1991, 33, 898-902). This study aimed to characterize the sleep habits of individuals with SS. We performed a cross-sectional study of individuals with a definite, probable, or possible diagnosis of Sotos syndrome. Participants were asked to complete the Children's Sleep Habits Questionnaire (CHSQ). We compared our data to historical data available from the literature. Subjects with SS showed more sleep disturbance than typically developing individuals (TD), although their sleep onset was less likely to be delayed and their sleep duration was longer. Participants with SS also showed different sleep patterns compared to children with other forms of intellectual and developmental disabilities (IDD). Individuals with SS exhibited early bed and rise times, frequently used transitional objects, displayed repetitive motion at sleep onset, and did not show a decrease in sleep duration with age. The majority of participants fell asleep at the same time each night, in their own bed, and within 20 min, and rarely showed signs of sleepwalking or night terrors. These results improve our understanding of sleep habits of individuals with SS and may be used to guide treatment and provide normalization for children with SS.

Model-based assessment of cardiovascular autonomic control in children with obstructive sleep apnea.

STUDY OBJECTIVES: To quantitatively assess daytime autonomic cardiovascular control in pediatric subjects with and without obstructive sleep apnea syndrome (OSAS). DESIGN: Respiration, R-R intervals, and noninvasive continuous blood pressure were monitored in awake subjects in the supine and standing postures, as well as during cold face stimulation. SETTING: Sleep disorders laboratory in a hospital setting. PARTICIPANTS: Ten pediatric patients (age 11.4 +/- 3.6 years) with moderate to severe OSAS (obstructive apnea-hypopnea index = 21.0 +/- 6.6/1 h) before treatment and 10 age-matched normal control subjects (age 11.5 +/- 3.7 years). MEASUREMENTS AND RESULTS: Spectral analysis of heart rate variability revealed that high-frequency power was similar and the ratio of low- to high-frequency power was lower in subjects with OSAS vs control subjects. The closed-loop minimal model allowed heart rate variability to be partitioned into a component mediated by respiratory-cardiac coupling and a baroreflex component, whereas blood pressure variability was assumed to result from the direct effects of respiration and fluctuations in cardiac output. Baroreflex gain was lower in subjects with OSAS vs control subjects. Under orthostatic stress, respiratory-cardiac coupling gain decreased in both subject groups, but baroreflex gain decreased only in controls. The model was extended to incorporate time-varying parameter changes for analysis of the data collected during cold face stimulation: cardiac output gain increased in controls but remained unchanged in OSAS. CONCLUSIONS: Our findings suggest that vagal modulation of the heart remains relatively normal in pediatric subjects with OSAS. However, baseline cardiovascular sympathetic activity is elevated, and reactivity to autonomic challenges is impaired.