Obstructive sleep apnea in elderly patients: Neuroimage and cognitive function before and after treatment

Background: Obstructive sleep apnea (OSA) in middle-aged patients leads to cognitive impairment and changes in brain morphology that could be improved by CPAP treatment. However, studies addressing the cognitive impairment in elderly OSA patients have given conflicting results and there is no data about brain alterations or the effect of CPAP treatment in these patients. Aim: To investigate whether elderly OSA patients present cognitive deficits and brain morphology/functional changes and to assess the efficacy of CPAP treatment. Methods: 27 elderly patients newly diagnosed of severe OSA and 15 age-matched healthy volunteers were included in the study. All participants underwent a neuropsychologic evaluation and magnetic resonance imaging (MRI) with structural and resting-state acquisitions at baseline. OSA patients were randomly assigned to CPAP or conservative treatment and both examinations were again assessed after 3 months of treatment. Results: At baseline, OSA patients showed lower volume of cerebellum and cerebellar tonsil when compared to healthy volunteers. Both OSA groups were similar on demographic measures, in terms of neurocognitive performance, grey matter volume and connectivity of the default mode network (DMN). After CPAP treatment, most cognitive domains showed significant improvements in parallel with increases in grey matter intensity within the cerebellum and higher connectivity in the right middle frontal gyrus in comparison with the conservative treatment group. Conclusions: Our study suggests that in elderly OSA patients both cognitive difficulties and structural and functional cerebral deficits could be improved by CPAP treatment.