Altered cerebral white matter network topology and cognition in children with obstructive sleep apnea.

OBJECTIVES: The study aimed to explore the underlying mechanisms of OSA-related cognitive impairment by investigating the altered topology of brain white matter networks in children with OSA. METHODS: Graph theory was used to examine white matter networks' network topological properties in 46 OSA and 31 non-OSA children. All participants underwent MRI, polysomnography, and cognitive testing. The effects of the obstructive apnea-hypopnea index (OAHI) on topological properties of white matter networks and network properties on cognition were studied using hierarchical linear regression. Mediation analyses were used to explore whether white matter network properties mediated the effects of OAHI on cognition. RESULTS: Children with OSA had significantly higher assortativity than non-OSA children. Furthermore, OAHI was associated with the nodal properties of several brain regions, primarily in the frontal and temporal lobes. The relationship between OAHI and verbal comprehension index was mediated through clustering coefficients in the right temporal pole of the superior temporal gyrus. CONCLUSIONS: OSA affects the development of white matter networks in children's brains. Besides, the mediating role of white matter network properties between the OAHI and the verbal comprehension index provided neuroimaging evidence of impaired cognitive function in children with OSA.

Alterations of brain gray matter volume in children with obstructive sleep apnea.

Objective: Obstructive sleep apnea (OSA) seriously affects the children's cognitive functions, but the neuroimaging mechanism of cognitive impairment is still unclear. The purpose of our study was to explore the difference in brain local gray matter volume (GMV) between children with OSA and non-OSA, and the correlation between the difference regions of brain gray matter volume and cognitive, the severity of OSA. Method: Eighty-three children aged 8-13 years were recruited in our study, 52 children were diagnosed as OSA by polysomnography, and 31 as the non-OSA. All the subjects were underwent high-resolution 3-dimensional T1-weighted magnetic resonance images. The voxel-based morphometry (VBM) was be used to analyse the local GMV. The Das-Naglieri cognitive assessment system (DN: CAS) was used to assess the subjects' cognitive. The difference of local GMV between the two groups was analyzed by two-sample T-test. The PSG variables and the scores of DN: CAS between the OSA group and non-OSA group were compared by independent samples t-tests. Pearson correlation was used to calculate the association between the difference areas of gray matter volumes in brain and DN: CAS scores, obstructive apnea/hypopnea index (OAHI, an index of the severity of OSA). Results: The gray matter volume of the right Middle Frontal Gyrus (MFG_R) in OSA children were larger than the non-OSA children, and the OSA children had lower scores of the Word Series in DN: CAS. There was negative correlation between the scores of Expressive Attention in DN: CAS and the gray matter volume of the right middle frontal gyrus, and it was no significantly correlation between OAHI and the gray matter volume of the right middle frontal gyrus. Conclusion: Our results suggest that the development of gray matter volume in frontal cortex, which associated with attention, were sensitive to the effects of OSA, provides neuroimaging evidence for cognitive impairment in children with OSA.

Cochlear implantation surgery in patients with narrow facial recess.

CONCLUSION: The new method of facial recess enlargement through suspending, antedisplacing, and adhering the chorda tympani nerve to the posterior wall of the auditory canal can expose the round window, make electrode insertion easier, and preserve the function of the facial nerve and chorda tympani nerve. OBJECTIVE: To describe and report cochlear implantation surgery in patients with narrow facial recess, including surgical technique and postoperative outcomes. METHODS: Cochlear implantation surgery was performed in our hospital in 39 cases with narrow facial recess by enlarging the facial recess. To enlarge the distance between the facial nerve and chorda tympani nerve, the chorda tympani nerve was suspended. The chorda tympani was anteplaced and adhered to the posterior wall of the auditory canal. RESULTS: Among the 39 cases, the narrowest distance between the facial nerve and the chorda tympani nerve was less than 1.0 mm. All patients successfully underwent cochlear implantation surgery. No injuries of the facial nerve, chorda tympani nerve, or the posterior wall of the auditory canal were reported in any of the patients. There were significant differences in the injuries of the facial nerve, chorda tympani nerve, and posterior wall of the auditory canal in these cases compared with previous approaches to this operation.