Acceptability, reliability, and validity of the Japanese version of the Stroke and Aphasia Quality of Life Scale-39 without illustrations

PURPOSE: This study aimed to address limitations in international equivalence and psychometric quality of the Japanese version of the Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39-J). We developed the SAQOL-39-J without illustrations (SAQOL-39-J-ni) to enhance international comparability and assessed its acceptability, reliability, and validity. METHOD: We recruited 100 participants (mean age = 61.64 years), including 92 individuals with post-stroke aphasia. Acceptability was examined through skewness, ceiling, and floor effects. Reliability was evaluated via internal consistency and test-retest reliability. Validity included assessments of internal and convergent validity. RESULT: Eight items (20.51%) did not meet skewness criteria, but the deviation was minor. No ceiling or floor effects were observed. Cronbach's α was 0.95, and test-retest reliability showed an ICC of 0.94 (95% CI: 0.86-0.97). Inter-item correlations ranged from rho = 0.21-0.79, and convergent validity showed total score correlations rho = -0.01-0.45. CONCLUSION: The SAQOL-39-J-ni demonstrated strong psychometric properties comparable to international versions. It is a reliable outcome measure for people with aphasia in Japan, supporting both clinical use and cross-cultural research.