Assessing sleep problems and daytime functioning: a translation, adaption, and validation of the Athens Insomnia Scale for non-clinical application (AIS-NCA).

Sleep problems are common and have been linked to health problems, diminished well-being, and impaired performance. Many scales to diagnose clinically relevant sleep problems are time-consuming, complex, and difficult to administer in non-clinical and multi-thematic studies. Through a multi-stage translation (from English to German) and scale testing process, we developed a parsimonious measure of sleep problems and daytime functioning for non-clinical applications based on the Athens Insomnia Scale. Results: Exploratory (NStudy 1 = 25,140) and confirmatory (NStudy 2 = 14,797) factor analyses suggest a two-dimensional structure with the subscales "sleep problems" and "daytime functioning". Internal scale consistency was acceptable. Measurement invariance was found across time, gender, age, and diagnosed sleep disorders. The scale discriminates between people with and without sleep disorders and predicts emerging sleep disorders. Short-term retest reliability was acceptable (NStudy 3 = 78). Convergent validity with other sleep measures and discriminant validity with indicators of well-being were observed (NStudy 4 = 341). After a multi-stage translation to English, we confirmed the factor structure and found measurement invariance across languages (NStudy 5 = 623). Conclusion: Our short 7-item scale has good psychometric properties and is suitable for self-administration, making it useful in measuring sleep problems and daytime functioning efficiently and reliably, especially for large population studies.