Abstract
Introduction
Obstructive sleep apnea (OSA) is a breathing disorder characterized by episodes of nocturnal hypoxia and chronic systemic inflammation, affecting more than 50% of obese youths. Both obesity and OSA independently have a negative impact on brain structure and function, but their combined effect on the developing brain is unknown. The purpose of this study was to assess MRI measurements of cortical thickness (CT) in obese youths with various degrees of OSA severity. We hypothesized that CT is abnormal in obese adolescents with OSA.
Methods
55 obese subjects (26 females, 29 males, mean 14.3 ± 2.4 years) were included in the analysis. All subjects were assessed with polysomnography (PSG) to evaluate presence and severity of OSA. T1-weighted MPRAGE images were acquired using a 3T MRI scanner following PSG. CT was extracted using the CIVET 2.1.1 pipeline, and statistical analysis was performed on SurfStat to examine global and regional CT in relation to age using a general linear model.
Results
Based on PSG outcome, subjects were divided into 3 groups, no OSA (OAHI < 1.5 events/hr., n = 15), mild OSA (OAHI < 5, n = 14), and moderate/severe OSA (OAHI ≥ 5, n = 26). Cortical thickness analysis revealed a negative-trending correlation between global CT and age in no OSA (T = -0.49, P > 0.6), as seen in typical development. This correlation weakened in the presence of mild OSA (T = -0.20, P > 0.8) and became significantly positive in moderate/severe OSA (T = 3.87, P = 0.001), affecting several cortical areas.
Conclusion
These results indicate that brain development in obese adolescents with moderate/severe OSA significantly deviates from the typical trajectory of cortical thinning. This thickening could be due to exacerbated inflammation from the combined effect of both diseases, or a neurotrophic effect of leptin. More data is needed to validate these findings.
Support
None
The diffusion tensor imaging (DTI) component of the NIH MRI study of normal brain development (PedsDTI)
