Background: Although the treatment of obstructive sleep apnea (OSA) with positive airway pressure (PAP) has been shown to be effective, nightly adherence to treatment remains poor. The objective of this study was to examine the degree to which various levels of PAP therapy adherence normalized verbal memory function after 3 months of therapy in patients with OSA who were memory-impaired prior to the initiation of PAP therapy.
Methods: Participants were administered neuropsychological testing prior to the initiation of PAP treatment and at a 3-month follow-up visit. Fifty-eight memory-impaired participants were categorized into the following three groups based on 3 months of adherence to PAP therapy: (1) poor users (n = 14), participants who averaged < 2 h of PAP use per night; (2) moderate users (n = 25), participants who averaged 2 to 6 h of PAP use per night; and (3) optimal users (n = 19), participants who averaged > 6 h of PAP use per night.
Results: Logistic regression analyses revealed that the odds of optimal users exhibiting normalization of memory function following 3 months of PAP therapy were 7.9 times (p = 0.01) the odds of poor users exhibiting normalization of memory abilities. Overall, 21% of poor users, 44% of moderate users, and 68% of optimal users exhibited memory performance in the clinically normal range following 3 months of PAP use (chi(2) = 7.27; p = 0.03).
Conclusions: These preliminary findings indicate that impaired verbal memory performance in patients with OSA may be reversible with optimal levels of PAP treatment. OSA patients exhibiting verbal memory impairments may experience a clinically meaningful benefit in their memory abilities when they use PAP for at least 6 h per night.