Inter-observer and intra-observer reliability of a sleep questionnaire in Indian population

Sleep disorders are a cause of significant morbidity and mortality. These are however still not widely detected/treated. Though various questionnaires have been designed for screening purposes, none are available in India.

To construct a questionnaire for detection of sleep disorders and determine its reliability and validity.

The questionnaire was prepared from the Case Western Health Research Questionnaire, translated into Hindi and then back into English, prior to its use. This was administered to 20 subjects at an interval of 2 weeks by the same observer to determine the intra-observer reliability. For estimation of validity, 275 subjects were evaluated by a trained health worker and a specialist in sleep disorders. The specialist's opinion was taken as the 'gold standard' to calculate sensitivity and specificity.

The kappa statistic was 0.94 for intra-observer reliability. The sensitivity and specificity were calculated for the question, presence/absence of sleep disorders and for all the other questions also. The sensitivity ranged from 70-91% and specificity 80-100%.

This questionnaire is simple to use, reliable and has good sensitivity and specificity. It can be used in epidemiological community surveys.