Effects of 3-month CPAP therapy on brain structure in obstructive sleep apnea: A diffusion tensor imaging study

Abstract

White matter (WM) fiber alterations in patients with obstructive sleep apnea (OSA) is associated with cognitive impairment, which can be alleviated by continuous positive airway pressure (CPAP). In this study, we aimed to investigate the changes in WM in patients with OSA at baseline (pre-CPAP) and 3 months after CPAP adherence treatment (post-CPAP), and to provide a basis for understanding the reversible changes after WM alteration in this disease. Magnetic resonance imaging (MRI) was performed on 20 severely untreated patients with OSA and 20 good sleepers. Tract-based spatial statistics was used to evaluate the fractional anisotropy (FA), mean diffusion coefficient, axial diffusion coefficient, and radial diffusion coefficient (RD) of WM. To assess the efficacy of treatment, 20 patients with pre-CPAP OSA underwent MRI again 3 months later. A correlation analysis was conducted to evaluate the relationship between WM injury and clinical evaluation. Compared with good sleepers, patients with OSA had decreased FA and increased RD in the anterior thalamic radiation, forceps major, inferior fronto-occipital tract, inferior longitudinal tract, and superior longitudinal tract, and decreased FA in the uncinate fasciculus, corticospinal tract, and cingulate gyrus (P < 0.05). No significant change in WM in patients with post-CPAP OSA compared with those with pre-CPAP OSA. Abnormal changes in WM in untreated patients with OSA were associated with oxygen saturation, Montreal cognitive score, and the apnea hypoventilation index. WM fiber was extensively alteration in patients with severe OSA, which is associated with cognitive impairment. Meanwhile, cognitive recovery was not accompanied by reversible changes in WM microstructure after short-term CPAP therapy.

Obstruktive Schlafapnoe – Einfluss auf kardiovaskuläres System und Kognition

“…The morphologically detectable changes are partially reversible by successful PAP therapy 66 121 122 123 . The irreversible morphologic brain changes are associated with residual daytime sleepiness despite adequate therapy 64 78 124 .…”

“…Die morphologisch nachweisbaren Veränderungen sind teilweise durch eine erfolgreiche PAP-Therapie reversibel 66 121 122 123 . Die irreversiblen morphologischen Hirnveränderungen werden mit einer residuellen Tagesschläfrigkeit trotz ausreichender Therapie in Verbindung gebracht 64 78 124 .…”

Microstructural Changes in the Cerebral White Matter After 12 Months of CPAP Treatment for Moderate to Severe Obstructive Sleep Apnoea: A TBSS Study

“…30 However, we did not observe similar results in our previous study, including no reversible restoration of WM fiber bundle integrity in patients with OSA after short-term (three months) CPAP treatment. 31 Moreover, few studies have investigated whether the structure of WM fiber tracts is reversed after long-term CPAP treatment.…”

Functional Connectivity Changes in the Insular Subregions of Patients with Obstructive Sleep Apnea after 6 Months of Continuous Positive Airway Pressure Treatment

“…A diffusion tensor imaging study found almost complete recovery from white matter abnormalities in OSA patients after 12 months of CPAP treatment [ 29 ]. Our previous resting-state functional magnetic resonance imaging (rs-fMRI) study found that after 1 month of CPAP treatment, spontaneous brain activity in the bilateral cerebellum posterior lobe, right superior frontal gyrus (SFG), and left precentral gyrus could reverse, and these changes were associated with improvements in cognition and sleepiness, but no structural brain changes were found, suggesting that functional changes may be asynchronous with structural changes [ 30 , 31 ]. However, no study on the FC of insular subregions after CPAP treatment in OSA patients has been reported.…”