Reduced Regional Grey Matter Volumes in Pediatric Obstructive Sleep Apnea

Abstract

Pediatric OSA is associated with cognitive risk. Since adult OSA manifests MRI evidence of brain injury, and animal models lead to regional neuronal losses, pediatric OSA patients may also be affected. We assessed the presence of neuronal injury, measured as regional grey matter volume, in 16 OSA children (8 male, 8.1 ± 2.2 years, AHI:11.1 ± 5.9 events/hr), and 200 control subjects (84 male, 8.2 ± 2.0 years), 191 of whom were from the NIH-Pediatric MRI database. High resolution T1-weighted whole-brain images were assessed between groups with voxel-based morphometry, using ANCOVA (covariates, age and gender; family-wise error correction, P < 0.01). Significant grey matter volume reductions appeared in OSA throughout areas of the superior frontal and prefrontal, and superior and lateral parietal cortices. Other affected sites included the brainstem, ventral medial prefrontal cortex, and superior temporal lobe, mostly on the left side. Thus, pediatric OSA subjects show extensive regionally-demarcated grey matter volume reductions in areas that control cognition and mood functions, even if such losses are apparently independent of cognitive deficits. Since OSA disease duration in our subjects is unknown, these findings may result from either delayed neuronal development, neuronal damaging processes, or a combination thereof, and could either reflect neuronal atrophy or reductions in cellular volume (neurons and glia).

Figure 1. Brainstem regions of significantly lower regional grey matter volume in OSA (n = 16) over control (n = 200) subjects (P < 0.01), colored according to significance level.

Background is the average of the 216 subjects’ normalized T1-weighted brain scans. Slice locations are in MNI coordinates.

Figure 2. Cortical regions with significantly lower regional grey matter volume in 16 OSA compared to 200 control subjects (P < 0.01), colored according to significance level.

Background is the average anatomical of 216 subjects. Slice locations are in MNI coordinates. Key: L left, R right, FC frontal cortex, PFC prefrontal cortex, VMPFC ventral medial prefrontal cortex.

Figure 3. Cortical regions of significantly reduced regional grey matter volume in OSA over control subjects (P < 0.01) displayed in yellow on the cortical surface on a single subject in MNI space.