Internal consistency and validity of the Stroke Impact Scale 2.0 (SIS 2.0) and SIS-16 in an Australian sample

Abstract

Background and purpose: The impact of stroke is multidimensional however standard stroke measures do not discriminate well when stroke patients are less physically impaired. The Stroke Impact Scale 2.0 (SIS 2.0) is a multidimensional measure of the impact of stroke but its' psychometric properties require further testing. The SIS-16 is a measure of physical functioning designed to be more sensitive to differences in physical functioning than current stroke outcome measures but there is only preliminary information detailing its' reliability and validity. The current study examined the internal consistency and validity of the SIS 2.0 and SIS-16 in an Australian sample of stroke patients.

Methods: The SIS 2.0, SIS-16, World Health Organization Bref-Scale (WHOQOL-BREF) and Zung's Self-Rating Depression Scale (SDS) were completed by 74 stroke patients in rural Victoria, Australia.

Results: The item convergent validity index indicated good item convergence of the SIS-16 and SIS 2.0 domains. The item discriminant validity index had only adequate divergence for most SIS 2.0 domains. Internal consistencies of the SIS-16 and SIS 2.0 domains were acceptable (alpha = 0.87-0.95). Correlations between the SIS-16 and SIS 2.0 and the WHOQOL-BREF and SDS supported the convergent and discriminant validity of the SIS-16 and all the dimensions of the SIS 2.0 except 'Participation' which lacked discriminant validity.

Conclusions: The SIS 2.0 and SIS-16 had good psychometric properties with support for the internal consistency and validity of both measures.