Dating sites for sleep apnea
These grey matter maps were “modulated” by the volume change at each voxel, an approach originally termed “optimized” VBM, and smoothed with a Gaussian filter (full width at half maximum = 10 mm).The VBM procedure relies on differentiating grey and white matter and other materials present in the head (cerebral spinal fluid [CSF], skull) based on intensity and location.Scans must have distinct intensities for grey and white matter, as well as CSF.The intensity values, or the relative difference between intensities of each tissue type, do not influence the analysis so long as they are distinct.The manual procedure was also used to check the quality of each T1-weighted scan, and exclude those images with motion artifacts.Scans were corrected for intensity bias due to field inhomogeneities using the SPM “unified” procedure with standard parameter settings was then used to normalize the T1-weighted scans to the VBM8 template in MNI space, and create regional grey matter maps for each subject.We used a large control cohort, since increasing cohort size is one approach to improve reliability of VBM analyses in OSA.
All methods were performed in accordance with the relevant guidelines and regulations.
Recently, we reported functional MRI findings in a subgroup of children with mild OSA who did not manifest an evidence of cognitive deficits on the enhanced regional recruitment of specific brain regions during an attention-executive task, but this study did not explicitly explore evidence for regional grey matter losses.
Earlier animal studies from our laboratory clearly showed that intermittent hypoxia and sleep fragmentation, primary characteristics of OSA, induce discernible neuronal cell losses in several brain regions.
Additional control subjects were originally scanned, but were excluded from analysis due to motion artifacts in the images.
We downloaded high-resolution T1-weighted images of remaining control subjects from the NIH Pediatric MRI database ( with permission.