THE SPASTICITY-RELATED QUALITY OF LIFE 6-DIMENSIONS INSTRUMENT IN UPPER-LIMB SPASTICITY: PART II A FIRST PSYCHOMETRIC EVALUATION

Abstract

Objective: Psychometric evaluation of the Spasticityrelated Quality of Life 6-Dimensions instrument (SQoL-6D). Design: A clinimetric evaluation conducted in a multicentre, prospective, longitudinal cohort study at 8 UK sites. Patients: Adult patients (n = 104) undergoing focal treatment of upper-limb spasticity. Methods: The SQoL-6D was administered in the clinic at enrolment and at 8 weeks, then 1-4 days later at home to assess test-retest reliability. Results: The SQoL-6D demonstrated adequate construct validity and unidimensionality of the scale, allowing the calculation of a Total score. Cronbach's alpha (0.74) supported the internal consistency reliability, while the intraclass correlation coefficient supported test-retest reliability (0.82). Correlation coefficients with established instruments supported convergent validity, while significant differences between known-groups (of differing clinical severity) in SQoL-6D Total score confirmed its sensitivity to both cross-sectional and longitudinal differences. Conclusion: The SQoL-6D is a promising new measure to assess health status for patients with upper-limb spasticity of any aetiology. Further investigation and exploration of the allocation of weights to convert the SQoL-6D to a health-related quality of life utility index, are required.