Study Objectives: Excessive daytime sleepiness (EDS) is common in participants with sleep disorders, particularly obstructive sleep apnea (OSA), and can be assessed using the Epworth Sleepiness Scale (ESS) and the Psychomotor Vigilance Test (PVT). However, the relationship between these measures of sleepiness/attention, and their relationships to OSA severity and treatment, remains understudied. This study examined these associations in a sleep center population. Methods: A total of 167 participants, primarily diagnosed or suspected of OSA (n=128 [76.6%]), completed the ESS and PVT during their clinical visit. Associations among ESS, PVT, OSA severity and CPAP adherence were examined using Pearsons correlations, unadjusted and controlling for age, sex and body mass index. Results: Results showed no significant correlations between ESS and PVT measures of attention/vigilance. While higher ESS scores correlated with more severe apnea-hypopnea index (AHI) in participants with OSA, no association was found with PVT measures. Among participants using continuous positive airway pressure (CPAP), greater hours/night of usage was associated with lower ESS scores, but not with better PVT performance. Conclusions: Our data indicate that ESS scores track more closely than PVT to OSA severity and treatment. The findings suggest that the tendency to fall asleep as measured by the ESS and attention deficits on PVT may capture different aspects of sleepiness. While the ESS is commonly used in sleep clinics, further research is needed to determine if PVT should also be used routinely in clinical practice.

The authors have declared no competing interest.

This study did not receive any funding.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This project was reviewed and determined to qualify as Quality Improvement by the University of Pennsylvania Institutional Review Board. An IRB number was not assigned as a result.

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All data produced in the present work are contained in the manuscript.