LAUSR

Sleepiness is a primary symptom among patients presenting at sleep clinics. Sleepiness is typically subjectively evaluated using the Epworth Sleepiness Scale (ESS), which has been associated with worse cardiovascular outcomes among sleep apnea patients. On the other hand, functional deficits due to sleepiness can be objectively quantified using a Psychomotor Vigilance Test (PVT). To better understand the presentation of “sleepiness”, we examined the relationship between subjective ESS and objective PVT among a clinical sample. We hypothesized that these two different measures of sleepiness would be correlated. A prospective sample of patients being evaluated for sleep disorders in the Sleep Center at the University of Pennsylvania completed the ESS and PVT at the same clinical visit. Demographic data were obtained at the visit or derived from the electronic health record. Pearson’s linear correlations were utilized to examine the association between the ESS and both the transformed lapses (sum of square root of number of lapses and square root of lapses+1) and mean reciprocal response time (RRT) on the PVT. In total, 167 patients (98 [58.7%] males) were studied, with a mean (±SD) age of 54.7±16.8 years and BMI of 34.5±9.9 kg/m2. There were a similar number of White (67 [42.1%]) and Black (71 [44.7%]) participants and 129 (77.3%) had diagnosed or suspected obstructive sleep apnea (OSA). Patients had an average ESS of 8.1±5.4, and 10.5±10.6 lapses, 5.9±2.9 transformed lapses, and mean RRT of 3.4±0.7 seconds-1 on PVT. Among all patients, there was no statistically significant correlation between ESS and either transformed lapses (rho = 0.10, p=0.200) or mean RRT (rho = -0.10, p=0.201). Results were similar when comparing the two sleepiness measures restricted to patients with OSA. Within patients being evaluated in a clinical sleep center, there was only a weak association between subjective sleepiness on the ESS and objective sleepiness on PVT. Thus, not all patients reporting daytime sleepiness have objective deficits, and vice versa. Results support using both assessments to fully characterize a patient’s sleepiness. Future studies should evaluate the relationship between adverse outcomes and subjective and objective sleepiness, alone and in combination.