The spasticity-related quality of life 6-dimensions instrument in upper-limb spasticity: Part II A first psychometric evaluation.

Psychometric evaluation of the Spasticity-related Quality of Life 6-Dimensions instrument (SQoL-6D). A clinimetric evaluation conducted in a multicentre, prospective, longitudinal cohort study at 8 UK sites. Adult patients (n=104) undergoing focal treatment of upper-limb spasticity. 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. 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. 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.