The Impacts of Obstructive Sleep Apnea Severity on Brain White Matter Integrity and Cognitive Functions in Children: A Diffusion Tensor Imaging Study

Objective: To investigate the impacts of obstructive sleep apnea (OSA) on white matter (WM) integrity and cognitive functions of pediatric patients with different levels of OSA severity. Methods: Fifty-eight children with OSA and thirty-four healthy controls (HC) were recruited. All participants underwent diffusion tensor imaging (DTI) examination, polysomnography (PSG), and neurocognitive assessments. Patients were divided into mild OSA (MG) and moderate-severe OSA (SG) groups. WM integrity, PSG data, and neurocognitive assessment scores were compared among those groups. Results: For apnea hypopnea index (AHI), obstructive apnea hypopnea index (OAHI), arousal index, SpO(2) nadir, and attention, SG was worse than both MG and HC with MG worse than HC. For baseline SpO(2) and intelligence, SG was worse than both MG and HC with no significant difference between MG and HC. Impaired WM integrity was observed in bilateral anterior thalamic radiation, bilateral inferior fronto-occipital fasciculus, bilateral inferior longitudinal fasciculus, right superior longitudinal fasciculus, right hippocampus, left cingulate gyrus, right uncinate fasciculus, callosum forceps major, and callosum forceps minor only for SG than for HC. WM integrity was significantly correlated with OSA severity and neurocognitive assessment scores only for SG, but not for MG. Conclusion: Decreased baseline SpO(2), WM impairment, and intelligence decline were all observed only for SG, but not for MG, implying an associated relationship among decreased SpO(2), WM impairment and WM impairment. Thus, for SG, additional assessments of brain damage and cognitive function decline are needed for prognostic evaluation of OSA.