The Development of the European Sleep Questionnaire A New Patient-Reported Outcome Measure.

Sleep medicine relies on patient-reported outcome measures (PROMs) to complement clinical interviews and objective sleep tests. Available sleep questionnaires focus on isolated symptoms or single disorders, limiting their ability to capture the complexity of sleep conditions. Also, many PROMs remain poorly validated. The European Sleep Questionnaire (ESQ) is being developed as a generic transdiagnostic sleep PROM designed to address these limitations. By integrating relevant interview components, it aims to streamline clinical assessment and better reflect real-world phenotypes across the full spectrum of sleep disorders. The ESQ has been initiated within the EU-funded Sleep Revolution project and is still being developed through an iterative process. Its design is informed by a comprehensive literature review as well as expert and patient input. The ESQ prototype contains 119 items organized into nine sections and uses Likert-type scales to assess symptom severity, frequency, and bothersomeness over the past month. It is equipped with an additional module for follow-up assessment. It is translated into 17 languages and is digitally implemented to support multicenter studies. Initial validation includes cognitive interviews and evaluation of psychometric properties in patients with various sleep disorders. Item refinement and scoring key creation will guide the further development of the ESQ, after which it will be made available for public use. The ESQ aims to support personalized clinical diagnosis and appraisal of treatment results. Future research will extend into other sleep disorders and specific populations, strengthening the ESQ as a comprehensive tool for clinical practice, research, and preventive strategies.