Neurocognitive Function in Snoring Children

BACKGROUND:

Obstructive sleep apnea syndrome (OSAS) is a relatively frequent condition which may affect up to 2-3 percent of school age children. The morbidity of untreated OSAS may include failure to thrive, pulmonary and systemic hypertension, and behavioral and neurocognitive deficiencies. However, it remains unclear to what extent OSAS impinges on aspects of neurocognitive and behavioral function, and whether sleep fragmentation, intermittent hypoxemia, and alveolar hypoventilation, which are the three major physiological alterations in OSAS, selectively affect particularly vulnerable components of neurocognitive function. Furthermore, certain similarities exist between the behavioral alterations occurring in OSAS and those seen in children with the Attention Deficit Hyperactivity Disorder (ADHD).

The study is in response to a Request for Applications (RFA) on Obstructive Sleep Apnea in Children. NHLBI issued the RFA in December, 1997, with co-sponsorship from the National Institute of Dental and Craniofacial Research and the National Institute of Child Health and Human Development.

DESIGN NARRATIVE:

The cross-sectional study tested the hypothesis that OSAS is detrimental to particular aspects of neurocognitive and behavioral functioning. Snoring 6 year-old children attending the public elementary school system in New Orleans Parish were prospectively identified by an appropriate questionnaire and enrolled in the study. Snoring children underwent overnight polysomnographic assessment to determine the presence and severity of OSAS, and their neurocognitive and behavioral functions were subsequently evaluated employing the Wechsler Intelligence Scale for Children-III, the Conners' Continuous Performance Test, and the Cambridge Neuropsychological Test Automated Battery test. Multivariate regression and analyses of variance allowed for determination of aspects of neurocognitive function and behavior that were vulnerable to OSAS in general, and to each of OSAS components in particular.

The study also tested the hypothesis that children with ADHD may have increased prevalence of snoring and OSAS. Children with this diagnosis were initially confirmed as having ADHD using the revised Diagnostic Interview for Children and Adolescents, the Conners' Parent Rating Scale, and the Child Behavior Checklist. ADHD children then underwent polysomnographic evaluation as well as extensive evaluation of neurocognitive function and behavior as above. The prevalence of snoring and OSAS were then calculated.

The study was extended through June 2007 to test the hypothesis that SDB will induce systemic inflammatory responses, and that the magnitude of such inflammatory response will be the major determinant of the severity of neurocognitive dysfunction associated with SDB.