Validity and Reliability of the Thai Version of the Barthel Index Self-Report (BI-SR-TH) for People with Spinal Cord Injury

OBJECTIVE This study aimed to cross-culturally translate and evaluate the psychometric properties of the Thai version of the Barthel Index Self-Report (BI-SR-TH) for Thai people with spinal cord injury (SCI). METHODS A descriptive cross-sectional validation and reliability study was conducted at the Maharaj Nakorn Chiang Mai Hospital, involving 109 Thai people aged 18 or older with either traumatic or non-traumatic SCI. The English postal version of the Barthel Index was translated into Thai following standard cross-cultural procedures, including forward and backward translation. Participants completed both the BI-SR-TH and the Thai EuroQoL (EQ-5D-5L) questionnaires via self-report and clinician assessment using the Barthel Index. The BI-SR-TH was re-administered to the participants one week later. Psychometric evaluation included assessments of internal consistency (Cronbach’s alpha), concurrent validity (Spearman’s correlation with clinician-rated BI), construct validity (convergent and discriminant validity assessed by correlations with relevant and distinct EQ-5D-5L domains), and test-retest reliability (intraclass correlation coefficient, ICC). The agreement between the BI-