Abstract
Background: This study explores the psychometric qualities of the Scenario Test, a new test to assess daily-life communication in severe aphasia. The test is innovative in that it: (1) examines the effectiveness of verbal and non-verbal communication; and (2) assesses patients' communication in an interactive setting, with a supportive communication partner.
Aims: To determine the reliability, validity, and sensitivity to change of the Scenario Test and discuss its clinical value.
Methods & Procedures: The Scenario Test was administered to 122 persons with aphasia after stroke and to 25 non-aphasic controls. Analyses were performed for the entire group of persons with aphasia, as well as for a subgroup of persons unable to communicate verbally (n = 43). Reliability (internal consistency, test–retest reliability, inter-judge, and intra-judge reliability) and validity (internal validity, convergent validity, known-groups validity) and sensitivity to change were examined using standard psychometric methods.
Outcomes & Results: The Scenario Test showed high levels of reliability. Internal consistency (Cronbach's α = 0.96; item-rest correlations = 0.58–0.82) and test–retest reliability (ICC = 0.98) were high. Agreement between judges in total scores was good, as indicated by the high inter- and intra-judge reliability (ICC = 0.86–1.00). Agreement in scores on the individual items was also good (square-weighted κ values 0.61–0.92). The test demonstrated good levels of validity. A principal component analysis for categorical data identified two dimensions, interpreted as general communication and communicative creativity. Correlations with three other instruments measuring communication in aphasia, that is, Spontaneous Speech interview from the Aachen Aphasia Test (AAT), Amsterdam–Nijmegen Everyday Language Test (ANELT), and Communicative Effectiveness Index (CETI), were moderate to strong (0.50–0.85) suggesting good convergent validity. Group differences were observed between persons with aphasia and non-aphasic controls, as well as between persons with aphasia unable to use speech to convey information and those able to communicate verbally; this indicates good known-groups validity. The test was sensitive to changes in performance, measured over a period of 6 months.
Conclusions & Implications: The data support the reliability and validity of the Scenario Test as an instrument for examining daily-life communication in aphasia. The test focuses on multimodal communication; its psychometric qualities enable future studies on the effect of Alternative and Augmentative Communication (AAC) training in aphasia.
Acknowledgements
This work was supported by the Stichting Rotterdams Kinderrevalidatie Fonds Adriaanstichting (KFA) and the Johanna Kinderfonds (JKF) (Grant Numbers 2004/0008-280 and 2004/0200-280). This support is hereby gratefully acknowledged. The authors also thank Jane van Gelder-Houthuizen (Rijndam Rehabilitation Centre) for her help in collecting the data. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.