The Epworth Sleepiness Scale (ESS) is a tool widely used to assess excessive daytime sleepiness. Unfortunately, it is not reliable in low-income countries where situations such as reading a book, watching TV or driving a car are not common. The aim of this study was thus to assess the performance of a modified version of the Epworth scale in a low-income country.
We used data from the Benin Society and Sleep (BeSAS) study where the ESS and a modified ESS (mESS) were administered to participants. In the mESS, questions four questions over eight were redesigned to reflect common living situations in Benin. The internal coherence of the mESS was assessed using the Cronbach alpha coefficient (CAC). The discriminatory ability of the scale was assessed by comparing the mean scores according to reported sleep quality, insomnia complaints and apnea-hypopnea index (AHI).
A total of 2909 participants were recruited, 1129 were male (38.9%) with a mean age (SD) of 44.7 (14.5) y. Overall, 52.4% (1526) completed all the mESS questions while 453 (15.6%) completed the standard ESS. The CAC of the mES was 0.86 showing good internal coherence. Concerning the discriminatory ability, mean scores for mESS were 7.8 for participants with ISI < 8 vs 9.2 for participants with ISI≥8 (p<0.001), 7.8 for participants withPSQI<5 vs 8.3 for participants with PSQI≥5 (p=0.03). No difference was found when comparing the participants participants using different cut-offs of AHI (15 and 30).
The mES is more reliable than ES in the Beninese population. mESS shows good internal coherence and differentiates between insomniacs vs non-insomniacs and between good and poor sleepers. Although the mES is not a perfect score, it appears more relevant in the Benin population than the original Epworth scale but needs further validation/improvement in other low-income countries.