Symptom frequency and severity in vestibular disorders often do not correlate well with patients' restrictions of activities of daily living and limitations of participation. Due to the lack of appropriate patient reported outcome measures (PRO), the extent of limitations and restrictions is mostly unknown. The International Classification of Functioning, Disability and Health (ICF) is a conceptual framework and classification to evaluate all aspects of health and disability. An ICF-based measure, the Vestibular and Participation Measure (VAP), was recently proposed. Also, an ICF Core Set for vertigo, dizziness and balance disorders was developed to describe what aspects of functioning should be measured. This study protocol describes the development and cross-cultural validation of a new measure, the VAP-extended (VAP-e), based on VAP and ICF Core Set on three continents. To determine objectivity and cross-cultural validity of the VAP and to find potentially redundant items, Rasch models will be used. The VAP-e will be created by modifying or adding items from the Activities and Participation and Environmental Factors component of the ICF Core Set. Reliability, objectivity and responsiveness of the VAP-e will be tested.
Keywords: ICF; Vertigo; activities of daily living; dizziness; quality of life; social participation.