Psychomotor Vigilance Test and Its Association With Daytime Sleepiness and Inflammation in Sleep Apnea: Clinical Implications

Abstract

Study Objectives: Excessive daytime sleepiness (EDS) is a key symptom of obstructive sleep apnea (OSA). The Psychomotor Vigilance Task (PVT) has been suggested as an objective easy-to-use, inexpensive alternative to the Multiple Sleep Latency Test (MSLT) to measure EDS. In patients with OSA, physiological sleepiness, but not subjective EDS (Epworth Sleepiness Scale [ESS]), has been associated with increased levels of the sleep-inducing proinflammatory cytokine interleukin-6 (IL-6). The goal of this study was to assess the association of PVT with objectively measured sleepiness (MSLT) and subjectively measured sleepiness (ESS) and IL-6 levels in patients with OSA. Methods: We studied 58 untreated patients with OSA who underwent an 8-hour in-laboratory polysomnography for 4 consecutive nights. MSLT, PVT, and 24-hour serial profiles of IL-6 were assessed on the fourth day. PVT variables included number of lapses, mean reciprocal of the fastest 10% and slowest 10% reaction times, and median of 1/reaction time. ESS was assessed on day 1 of the study. Results: Higher ESS scores were significantly associated with greater number of lapses (β = .34, P = .02) and lower values of 1/RT (β = −.36, P = .01) and slowest 10% RTs (β = −.30, P = .04). No significant association was observed between PVT and MSLT, nor PVT and IL-6 levels. Conclusions: Our findings suggest that PVT is associated with subjectively assessed daytime sleepiness, but not with physiological sleepiness nor IL-6 levels in patients with OSA. It appears that ESS and PVT may be useful in predicting risks associated with impaired performance, such as traffic accidents, in patients with OSA. Keywords: daytime sleepiness, objective daytime sleepiness, Psychomotor Vigilance Task, sleep apnea, subjective daytime sleepiness Citation: Li Y, Vgontzas A, Kritikou I, Fernandez-Mendoza J, Basta M, Pejovic S, Gaines J, Bixler EO. Psychomotor vigilance test and its association with daytime sleepiness and inflammation in sleep apnea: clinical implications.

<p>Psychomotor Performance in Patients with Obstructive Sleep Apnea Syndrome</p>

“…The results of our study are in accordance with prolonged reaction time in PVT 5, [14][15][16] and MDT 20 in OSA patients compared to controls. The impairments of OSA patients in visual discrimination task measuring the speed of perception to visual stimulus correspond to the similar findings of prolonged reaction time in MDT of the Vienna Test System.…”

“…11 Although it is well established that psychomotor speed assessed with the Stroop test 12,13 is impaired in OSA patients, more complex psychomotor performance measures are still not well established as being deteriorated in OSA. Psychomotor impairment in OSA patients has previously been assessed according to performance on reaction time tests such as the Psychomotor vigilance test (PVT), 6,9,[14][15][16] Multiple Unprepared Reaction Time Test (MURT), 17 Finger tapping test, 18 Trail Making Test, 19 and computerized Movement Detection Time Test (MDT). 20 Findings of decreased reaction time on PVT tests in OSA patients have been reported on community samples without control groups, 21 OSA patients compared to control patients being enrolled in sleep clinics, 15 or without control groups.…”

“…The novelty of the current study is employment of the ballast outcome measures, quite unique and precise indicators of psychomotor performance stability during the process of testing. Based on previous findings of prolonged reaction time in PVT, 5,[14][15][16] MDT, 20 Stroop test, 12,13 and executive function impairment of OSA patients, 6,28,29 we hypothesized that moderate and severe OSA have adverse effects on the reaction time of perception, reaction time of convergent thinking during solving simple arithmetic tasks, and operative thinking during complex psychomotor coordination task assessed by psychodiagnostic chronometric test battery. Additionally, we aimed to assess the contribution of BMI, age, EDS assessed with Epworth sleepiness scale (ESS), and severity of OSA assessed with apnea-hypopnea index (AHI) to the reaction time on chronometric tests in OSA patients and controls.…”

Characterizing Sleepiness: Are We Drawing the Right Line in the Sand?

“…The Psychomotor Vigilance Task, for example, long used as a measure of sleepiness resulting from sleep deprivation, 14 is not related to interleukin-6 levels, even when MSLT-SL values are. 12 So although it may not turn out, as ESS creator Dr. Johns has proposed, that "there are as many different kinds of sleepiness…as there are different situations in which to measure it,"…”

“…10 The Psychomotor Vigilance Task is a reliable, objective measure of impaired sustained attention and vigilance induced by sleep deprivation, 11 but does not correlate with MSLT-SL in patients with sleep apnea. 12 Driving simulator assessment, measuring an aspect of sleepiness with a high public health relevance, reveals that simulated motor vehicle crashes are predicted by MWT-SL but not MSLT-SL. 13 The work by Mehra et al takes an important next step toward investigating sleepiness in patients with systolic heart failure by probing biological mechanisms that may be involved in sleepiness in this population.…”