The aim of this methodological study is to translate the Impact of Brachial Plexus Injury Questionnaire (IMBPIQ) into Turkish, culturally adapt it, and evaluate its validity and reliability for use in adults with brachial plexus birth palsy. The study will include 50 adult participants aged 18 years and older with a diagnosis of brachial plexus birth palsy. Participants will complete the Turkish version of the IMBPIQ, as well as the Disabilities of the Arm, Shoulder and Hand questionnaire and the Short Form-36. The psychometric properties of the Turkish IMBPIQ will be examined using reliability and validity analyses, including internal consistency, test-retest reliability, and construct validity.