VALIDATION DATA

Internal consistency was adequate, with Cronbach’s α ranging from 0.74 to 0.88

Test-retest reliability was reported to be high in healthy participants who completed the questionnaire, separated in time by 5 months (Pearson’s r = 0.82; P < 0.001). However, in patients with suspected OSA, 23% of patients had an ESS score discrepancy greater than or equal to 5, separated by an average of 71 days, (Pearson’s r = 0.73; P < 0.001). In a similar study, an ESS score discrepancy greater than or equal to 5 was present in 21% of patients with OSA (Pearson’s r = 0.67; P < 0.01)

The focus of the ESS is to assess sleep propensity in different situations (face validity).

Although the initial examination of content validity does not reveal any inappropriate situations, the somnolent situations used in the ESS have been criticized because of missing or vague rationales (e.g. two of the scenarios were obtained from a study in abstract form that used a population-based survey asking respondents to rank defined daily situations based on their relative somnolence. The two scenarios that were ranked “most sleepy” (“sitting, inactive in a public place” and “as a passenger in a car”) were incorporated into the ESS).