Obstructive sleep apnea and psychomotor vigilance task performance

Background: Obstructive sleep apnea (OSA) is a highly prevalent disorder with considerable morbidity and mortality. Vigilance and attentiveness are often impaired in OSA patients. In occupational medicine settings, subjective reports of sleepiness are notoriously inaccurate, making the identification of objective measures of vigilance potentially important for risk assessments of fitness for duty. In order to evaluate the effects of OSA on attentiveness and vigilance, we conducted a cross-sectional study to examine the association between OSA and psychomotor vigilance task (PVT) performance. Methods: Patients attending sleep clinics for evaluation of possible sleep apnea were recruited. The subjects underwent either a standard overnight laboratory polysomnography or home sleep study. Subjective daytime sleepiness was assessed by Epworth sleepiness scale, and vigilance was tested using a portable device. The participants were asked to respond to the PVT signals using their dominant hand. Each PVT administration lasted 10 minutes, with stimuli signals appearing randomly at variable intervals of 2-10 seconds. Results: Mean age of the participants was 46 +/- 15 years, and mean body mass index was 34.3 +/- 9.8 kg/m(2). Participants with higher Epworth scores had worse PVT performance (P<0.05). In multivariate analyses, age, body mass index, and poor sleep efficiency (measured by Pittsburgh sleep quality index score) were associated with worse PVT performance (P<0.05). In contrast, PVT performance did not differ significantly across categories of apnea hypopnea index severity. Subgroup analysis demonstrated that women had worse performance on all PVT measures (P<0.05). Conclusion: PVT performance can be utilized for risk assessments of sleepiness and may be particularly useful among populations where subjective reports are unreliable.