Investigating treatment fidelity in a conversation- based aphasia therapy

When conducting a speech and language therapy intervention study, one essential focus is the evaluation of outcomes. The therapy itself and its actual delivery, often discussed in the context of treatment fidelity (TF), are aspects which are mostly carried out in the background. According to Cherney et al. (2013), however, TF is an important component of any behavioural treatment study and should therefore be investigated. This article presents a study of TF embedded in a wider research project that evaluates a new conversation-based therapy for people with agrammatic aphasia and their conversation partners (Beckley et al., 2013; Beeke et al., 2011; Beeke et al., 2014). The therapy is called Better Conversations with Aphasia (BCA). Using the concept of TF, the degree to which BCA was delivered as planned can be measured. A pilot version of a BCA-specific observational fidelity tool was developed, based on a conceptual model of TF (Carroll et al., 2007), on practices reported in the TF literature and on the generic therapy session plans. The results indicate that, in terms of adherence to the therapy content, a high fidelity level (91.9 %) was reached for BCA. This article will also report on the degree to which the therapist showed desired behaviour associated with the delivery of BCA, and findings from an inter-rater reliability investigation of the fidelity tool. It concludes with reflections on the importance and value of TF investigations in speech and language therapy intervention.