Cerebral white matter diffusion properties and free-water with obstructive sleep apnea severity in older adults

TitleCerebral white matter diffusion properties and free-water with obstructive sleep apnea severity in older adults
Publication TypeJournal Article
Year of Publication2020
AuthorsBaril A-A, Gagnon K, Descoteaux M, Bedetti C, Chami S, Sanchez E, Montplaisir J, De Beaumont L, Gilbert D, Poirier J, Pelleieux S, Osorio RS, Carrier J, Gosselin N
JournalHuman brain mapping
Pagination2686 - 2701
Date Published2020/07/
ISBN Number1097-01931065-9471
KeywordsAging, Diffusion Tensor Imaging, hypoxia, Magnetic Resonance Imaging, sleep and neurodegenerative disorders, sleep-disordered breathing, White Matter

Characterizing the effects of obstructive sleep apnea (OSA) on the aging brain could be key in our understanding of neurodegeneration in this population. Our objective was to assess white matter properties in newly diagnosed and untreated adults with mild to severe OSA. Sixty-five adults aged 55 to 85 were recruited and divided into three groups: control (apnea-hypopnea index ≤5/hr; n = 18; 65.2 ± 7.2 years old), mild (>5 to ≤15 hr; n = 27; 64.2 ± 5.3 years old) and moderate to severe OSA (>15/hr; n = 20; 65.2 ± 5.5 years old). Diffusion tensor imaging metrics (fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity, and mean diffusivity) were compared between groups with Tract-Based Spatial Statistics within the white matter skeleton created by the technique. Groups were also compared for white matter hyperintensities volume and the free-water (FW) fraction. Compared with controls, mild OSA participants showed widespread areas of lower diffusivity (p < .05 corrected) and lower FW fraction (p < .05). Participants with moderate to severe OSA showed lower AD in the corpus callosum compared with controls (p < .05 corrected). No between-group differences were observed for FA or white matter hyperintensities. Lower white matter diffusivity metrics is especially marked in mild OSA, suggesting that even the milder form may lead to detrimental outcomes. In moderate to severe OSA, competing pathological responses might have led to partial normalization of diffusion metrics.

Short TitleHum Brain Mapp