Background and purpose: The Epworth sleepiness scale (ESS) is a simple and widely used system of quantifying sleepiness, but it may be inaccurate if the patient is not fully aware of the problem or the partner gives an inaccurately positive estimate of the patient's sleep. We investigated the agreement between patient and partner perceptions of the patient's sleepiness.
Patients and methods: Eighty-two patients and their partners rated patient sleepiness by separately answering the ESS. We measured agreement between their ESS scores, and each of the eight items, using the Bland & Altman method.
Results: Patients rated their sleepiness lower (11.1+/-5.4) than their partners did (12.3+/-5.1) (P = 0.025) with 40 patients (49%) scoring 4 or more points different from their partners. The mean difference between scores was -1.2 (SD: 4.5), with patient scores ranging between 10 points lower and eight points higher than those of their partners. Items exploring high (item 5) or low (6 and 8) soporific situations had the least disagreement.
Conclusions: Disagreement between patient and partner perceptions of the patient's sleepiness is frequent, and greater for ESS items exploring intermediate soporific situations.