Objective: Pediatric obstructive sleep apnea syndrome (OSAS) is associated with neurocognitive and endothelial dysfunction. However, it is unclear whether these 2 frequent morbidities of OSAS in children represent similar or different underlying pathophysiological processes, because they have never been concurrently assessed in children.
Methods: Consecutive children (ages 5-8 years) with polysomnographically based OSAS underwent cognitive battery evaluation (Differential Ability Scales and the NeuroPsychological Assessment Battery) and cuff-occlusion hyperemic tests for assessment of endothelial function. The presence of neurocognitive deficits (NC(+)) was defined on the basis of the presence of ≥ 2 abnormal cognitive test results. Endothelial dysfunction (ED(+)) was defined as a time to maximal postocclusive hyperemic response of ≥ 45 seconds (T(max)).
Results: Twenty-one control children and 87 children with OSAS completed both cognitive and endothelial tests. Of these children, 48 were NC(+) and 50 had a T(max) of ≥ 45 seconds, and at least 80% of these children were in both groups. Conversely, among children in whom there was no presence of neurocognitive deficits (NC(-)), only 25.6% were ED(+), whereas among those without endothelial dysfunction (ED(-)) only 21.6% were NC(+). Furthermore, approximately one-third of the children with OSAS was NC(-) and ED(-). Thus, findings on hyperemic vascular responses were highly predictive of neurocognitive status.
Conclusions: Endothelial dysfunction and neurocognitive deficits are more likely to coexist than otherwise predicted from the frequency of each of these morbidities alone in pediatric OSAS. Thus, both of these morbid consequences may share similar pathogenetic mechanisms. Furthermore, a simple test such as the postocclusive hyperemic vascular response may help detect at-risk patients for neuropsychological deficits.