Objective: Patients with obstructive sleep apnea (OSA) commonly have cognitive complaints, particularly in attention, and report decreased quality of life. We examined how vigilance and sustained attention, as assessed by the Psychomotor Vigilance Task (PVT), were related to quality of life after controlling for apnea severity and depression in subjects with OSA.
Subjects and methods: Fifty-seven patients with newly diagnosed and untreated OSA had their sleep monitored with polysomnography. Quality of life was assessed by the Short Form-36 health survey questionnaire (SF-36). Mood was assessed by the Center for Epidemiologic Studies-Depression (CES-D) Scale. After sleep monitoring and psychological assessments were performed, the 10-minute PVT was administered. The main outcome variables were PVT lapse count and average response time (RT). Simple correlations and multiple linear regression were used to examine the association between PVT performance and age, body mass index, sleep variables, apnea hypopnea index, oxygen desaturation index, and CES-D.
Results and conclusion: Both the PVT lapse count and RT were significantly associated with the SF-36 physical component summary score (PCS). In multiple linear regression, PVT RT was an independent predictor of the SF-36 PCS (full model R(2) = 0.331, p = 0.003). PVT lapse was also an independent predictor of the SF-36 PCS (full model R(2) = 0.320, p = 0.004). However, neither PVT RT nor lapse was a significant independent predictor of the SF-36 mental component summary score (MCS). Only CES-D was an individual predictor of the SF-36 MCS (β = -0.676, p < 0.001). Impairments in sustained attention and vigilance may underlie the limitations in physical health-related quality of life reported by people with OSA, even after controlling for demographic variables, apnea severity, and depression.
Keywords: Obstructive sleep apnea; SF-36; psychomotor vigilance task; quality of life.