Testing and validation of the German version of the Stroke Impact Scale (SIS)

Suitable and psychometrically tested instruments to assess health-related quality of life in stroke patients are still lacking in German speaking countries. The current paper describes the translation and psychometric testing of the German version of the Stroke Impact Scale, which was developed as a self- and proxy- report measure in the United States to assess the consequences of a stroke. The instrument contains 64 Likert-scaled items and assesses eight dimensions of health-related quality of life ("strength", "memory and thinking". "emotion", "communication", "ADL/IADC', "mobility", "hand function", and "participation"). The questionnaire was used in a cross-sectional study of 137 persons with stroke and was psychometrically tested. The results of this psychometric testing show a good acceptance on part of the interviewees. Convergent validity of the SIS dimensions was assessed with correlation of the SIS subscales and subscales of the short form SF-36 and Nottingham Health Profile and criteria-related validity was examined by comparison of mean scores across groups defined by Rankin scores. The reliability of the questionnaire was determined through internal consistency (Cronbach's). The German version of the SIS is a reliable and valid instrument to assess health-related quality of life, but more studies are needed to make statements about sensitivity of the instrument, psychometric quality of the proxy version and suitability of the questionnaire for specific stroke subgroups.