There was no predictive relationship between subjective improvements in daytime sleepiness, fatigue, depression, and objective vigilance with continuous positive airway pressure (CPAP) use in patients with obstructive sleep apnea (OSA), a recent study found. A total of 182 patients underwent psychomotor vigilance task (PVT) testing and measurements of subjective daytime sleepiness, fatigue, and depression at baseline and after a minimum of 1 month of adherent CPAP use at an adequate pressure. Researchers found:

• Patients with both mild-to-moderate (n=92) and severe (n=90) OSA experienced improvements in subjective daytime sleepiness, fatigue, and depression, but objective improvement in vigilance was only seen in patients with severe OSA.
• While a correlation was found between improvements in daytime sleepiness and some PVT parameters in patients with severe OSA, changes in subjective daytime sleepiness, fatigue, and depression scores were not predictive of objective improvement in vigilance while controlling for all these subjective symptoms and for age, gender, body mass index, apnea-hypopnea index/respiratory event index and total sleep time/total recording time with pulse oximetry below 90%.