Psychometric properties of the German stroke and aphasia Quality of life scale 39 generic version

Abstract

a b s t r a c t bacKGrouNd: the international expert consensus core outcome set for post-stroke aphasia recommends the stroke and aphasia Quality of life scale - 39/generic (saQol-39g) for assessing patient-reported health-related quality of life. cultural adaptations of the saQol-39g are mandatory in stroke rehabilitation. aiM: We adapted the original English saQol-39g into German and evaluated its psychometric quality. dEsiGN: Evaluation of a self-report scale embedded in a prospective multicenter parallel group randomized waitlist-controlled trial on the effectiveness of intensive speech and language therapy. sEttiNG: Nineteen in- and outpatient aphasia rehabilitation centers in Germany. populatioN: people with chronic post-stroke aphasia (N.=156) of all types and severity levels. MEthods: We followed applicable guidelines for cross-cultural test adaptations and psychometric evaluations. psychometric analyses are based on the assessment before three weeks of intensive speech and language therapy (acceptability, internal consistency, validity; N.=156), on the assessments before and after three weeks of waiting in the control group (test-retest reliability; N.=78), and on the assessments before and after three weeks of intensive speech and language therapy (responsiveness; N.=156). RESULTS: The German SAQOL-39g was feasible across all aphasia severity grades (no missing data; no floor/ceiling effects). Internal consistency was excellent (Cronbach’s α=0.90); test-retest reliability was moderate-to-good (intraclass-correlations: ICC=0.73 for single/0.85 for average measures). both exploratory factor analyses and multidimensional scaling of proximity data/graphical network analysis supported the 3-dimensional structure (domains: physical, psychosocial, communication) of the English original version. convergent (|r|=0.29 to 0.48) and discriminative (|r|=0.03 to 0.07) validities were acceptable. responsiveness to intervention-induced change showed a small-to-medium treatment effect (group difference after intervention compared to waiting-list control: cohen’s d=0.34). coNclusioNs: the German saQol-39g is a reliable, valid and change-sensitive patient-reported outcome measure to assess the physical, communication and psychosocial quality of life in chronic post-stroke aphasia, with comparable psychometric properties and factorial structure to the original English version.