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.