Validation of a modified Hindi version of the Epworth Sleepiness Scale among a North Indian population

Since a majority of population in India does not drive automobiles, one item on the Epworth Sleepiness Scale (ESS) requires modification and validation. In addition, data collected by us indicated that a majority of rural and urban Indians regularly spend time in prayer/spiritual activity. The main purpose of this study was to develop a cross-cultural adaptation of the ESS for a North Indian population, in Hindi language (ESS-I). The study also provides evidence of reliability and validity of the modified version.

The subjects included were normal volunteers aged 18-75 years (Group 1) (n = 70), compared with patients with complaints of excessive daytime sleepiness, who had undergone polysomnography (Group 2) (n = 22) and patients who had undergone multiple sleep latency test (Group 3) (n = 10). The study was carried out in four phases: Translation and retranslation of the original scale with modification of item 8 (mainly addition of option of question on "while offering prayers or in spiritual activity"); reliability (test-retest) (n = 30); internal consistency (using Cronbach's alpha index) (n = 102); and sensitivity to change (n = 8).

Group 1 showed spiritual activity as a significantly more commonly practiced activity than driving. The Cronbach's alpha for the modified version was 0.892 (excellent), and this was not improved by removing the modified item. The alpha value for Group 1 versus Groups 2 and 3 was 0.667 and 0.892, respectively. The scale was reliable over time (test-retest), and it was sensitive to sleepiness change in patients with obstructive sleep apnea during treatment.

The ESS-I, is comparable to the original scale. It is reliable, valid, and change-sensitive. It is proposed that the modified version can be very useful for detecting sleepiness among Indian population, especially those who do not drive their own vehicles.