Obstructive sleep apnea syndrome and Alzheimer's disease pathology: may continuous positive airway pressure treatment delay cognitive deterioration?

PURPOSE The main aim of the present study was to identify the long-term effects of continuous positive airway pressure (CPAP) treatment in patients co-affected by obstructive sleep apnea syndrome (OSAS) and mild cognitive impairment (MCI) or dementia due to Alzheimer's disease (ADD). METHODS This retrospective multicentre study included patients affected by MCI or ADD, diagnosed according to the core clinical and biomarkers criteria, and presenting comorbid OSAS. Only patients performing at least a 1-year visit during their follow-up to monitor cognitive deterioration and adherence with CPAP treatment were included. Both Mini-Mental State Examination (MMSE) and clinical dementia rating scale (CDR) were conducted during the baseline and the follow-up visits. RESULTS Twenty-four patients were included in the study and were distributed according to the diagnosis in MCI (n = 8) or ADD (n = 16). There were no significant differences in the variables analysed at baseline between the CPAP non-adherent and CPAP adherent patients. In the whole group, a significant decrease was found in MMSE scores, and a significant increase was found in CDR scores between baseline and follow-up. No longitudinal changes in ESS scores were statistically significant from baseline to follow-up. A significant difference was found for the mean score change of the CDR since CPAP non-adherent patients showed a higher mean change of CDR compared to CPAP adherent patients. No significant differences were found for the mean change of MMSE. CONCLUSION These findings highlight the clinical potential of treating OSAS with CPAP to delay cognitive deterioration in patients with MCI or ADD.