Validity, reliability and responsiveness of a short version of the Stroke-Specific Quality of Life Scale in patients receiving rehabilitation

Abstract

Objective: To examine the measurement properties of a short version of the Stroke-Specific Quality of Life Scale (SS-QoL-12). Design: Self-report survey of patients with mild to moderate upper extremity dysfunction. Patients: A total of 126 patients provided 252 observations before and after treatment. Methods: The construct validity and reliability was examined using the Rasch model; the concurrent and predictive validity was estimated using Spearman?s rank correlation coefficients. Paired t-test and the standardized response mean (SRM) were performed to estimate the responsiveness of the SS-QoL-12. Results: The 2-factor model (psychosocial and physical domains) fit the data better with smaller deviances. All but 1 item showed acceptable fit, and no item biases were detected. The reliability of the subscales and the whole scale ranged from 0. 67 to 0. 99. The total score showed fair correlations with the criterion measures at pretreatment (ρ = 0. 28?0. 40) and fair to good correlations at post-treatment (ρ = 0. 39?0. 54). The subscales had low to fair correlations at pretreatment (ρ = 0. 19?0. 49) and fair to good correlations at post-treatment (ρ = 0. 31?0. 56). The total and the subscales had low to good predictions at baseline (ρ = 0. 22?0. 52). The whole scale and the psychosocial subscale were mildly responsive to change (SRM = 0. 22), but the physical subscale was not responsive to change (SRM = 0. 08). Conclusion: The SS-QoL-12 has acceptable to good measurement properties, with an advantage of requiring less time to administer than other scales. The use of the subscale and total scores depends on the purpose of research. Future studies should recruit stroke patients with a broad range of dysfunction and use a large sample size to validate the findings.