EC Neurology

Background: The challenges associated with diagnosing narcolepsy and its impact on patient's quality of life have led to the use of screening questionnaires as an initial diagnostic step. The Swiss Narcolepsy Scale (SNS), known for its higher specificity than others, had not been translated and validated in Persian. In this study, we aimed to assess the validity and reliability of the Persian version of the SNS questionnaire.

Methods: The translation process involved a rigorous backward and forward translation approach followed by an expert panel review comprising ten sleep specialists to evaluate the questionnaire's validity. A cross-sectional sampling method was employed to recruit 79 participants, including patients with hypersomnolence complaints who underwent polysomnography (PSG) and multiple sleep latency tests (MSLT), as well as healthy non-shift workers without any history or complaints of sleep-related disorders. The questionnaire's value for diagnosing narcolepsy was assessed using measures such as Cronbach's alpha, content validity ratio (CVR), content validity index (CVI), accuracy, sensitivity, and specificity.

Results: The Persian version of the SNS questionnaire demonstrated acceptable validity and reliability, with notably higher specificity and accuracy than the Epworth Sleepiness Scale (ESS) for narcolepsy screening. The CVR, CVI, and Cronbach's alpha values were 0.926, 0.880, and 0.603, respectively, while the accuracy, specificity, and sensitivity were 69.6%, 84.0%, and 44.8%, respectively.

Conclusion: The Persian version of the SNS questionnaire exhibits acceptable validity and reliability, and it outperforms the ESS in terms of specificity and accuracy for narcolepsy screening.

Keywords: Narcolepsy; Epworth Sleepiness Scale; SNS; Swiss Narcolepsy Scale; Persian Version