The purpose of this study is to evaluate the validity and reliability of the Turkish version of the Brompton Breathing Pattern Assessment Tool (BPAT) in individuals with asthma. This study aims to determine whether the BPAT is a valid and reliable tool for assessing breathing patterns in Turkish-speaking asthma patients. The research question being addressed is: "Is the Turkish version of the BPAT a valid and reliable tool for assessing breathing patterns in individuals with asthma?"

This study is designed to assess the validity and reliability of the Turkish version of the Brompton Breathing Pattern Assessment Tool (BPAT). BPAT is a well-established tool used to assess the breathing patterns of individuals with respiratory conditions. In this study, a group of asthma patients will be evaluated using the BPAT to determine its applicability and consistency in the Turkish-speaking population.

The reliability of the tool will be tested through repeated measurements, and its validity will be assessed by comparing BPAT results with other validated asthma assessment tools. The data will be analyzed to evaluate the internal consistency, test-retest reliability, and construct validity of the BPAT in a clinical asthma population.

The linguistic validation process will be conducted following the ISPOR Task Force guidelines, including forward translation, reconciliation, back-translation, and cognitive debriefing. The psychometric properties of the tool, including internal consistency, test-retest reliability, and construct validity, will be evaluated according to the COSMIN checklist standards.

Additionally, participant eligibility will be defined as individuals who are diagnosed with asthma and can understand and respond to questions in Turkish. The study will also explore any cultural adaptations necessary for the Turkish version of the BPAT to ensure its cultural relevance and accuracy in assessments.

Inclusion Criteria:

• Aged between 18 and 75 years
• Diagnosed with severe persistent asthma according to the Global Initiative for Asthma (GINA) criteria
• Turkish ethnicity
• Ability to read and write in Turkish
• Willingness to participate in the study

Exclusion Criteria:

• Having had a respiratory infection in the last 1 month
• Use of oral corticosteroids in the last 4 weeks
• Presence of malignancy, vasculitis, or pregnancy
• Body Mass Index (BMI) > 35 kg/m2
• Diagnosis of COPD or other primary respiratory diseases (excluding asthma)
• Any musculoskeletal, neurological, or cardiovascular condition that could interfere with breathing pattern assessment or impede potential respiratory physiotherapy applications

The participants for this study will be recruited from Health Sciences University, İstanbul Süreyyapaşa Chest Diseases and Chest Surgery Education and Research Hospital in Istanbul, Turkey. Participants will be selected based on the eligibility criteria outlined, including those diagnosed with severe persistent asthma as per the Global Initiative for Asthma (GINA) guidelines. Participants will be recruited from local clinics specializing in respiratory diseases and asthma management.

Individual participant data will not be publicly shared in order to protect patient confidentiality and comply with the local ethics committee regulations. However, completely anonymized data may be made available upon reasonable academic request to the Principal Investigator following the publication of the study results.