On an overnight picture memory consolidation task, OSA patients being treated with CPAP therapy outperformed both untreated OSA patients and a control group of people who did not have OSA, suggesting that CPAP is effective at recouping memory abilities that are impaired by OSA. CPAP patients correctly identified more photographs after one night of sleep. The study involved a preliminary sample of 135 adults between the ages of 33 and 65 years.