Dose Considerations and Generalization Following Script Training for Poststroke Aphasia: A Randomized Factorial Clinical Trial

Purpose: Using script training as an intervention, this study modulated the dose parameters of stimulus repetition (i.e., long vs. short scripts) and session frequency (i.e., distributed vs. massed practice) and assessed their impact on maintenance and generalization in people with chronic poststroke aphasia. Method: The study was a single-site, factorial, single-blind randomized controlled trial. Participants were randomized in a 2 × 2 factorial design into one of four study arms, stratified by pretreatment aphasia severity: (a) distributed/short script, (b) distributed/long script, (c) massed/short script, and (d) massed/long script. Participants completed 10, 1-hr sessions of computer-based script training. Participants were assigned to one of four levels of script complexity with levels determined by aphasia severity. The primary generalization outcome measured performance on the trained script in a simulated conversation with a familiar speech-language pathologist posttreatment. Secondary outcomes included evaluating (a) maintenance of the primary outcome at 3 and 6 weeks posttreatment and (b) generalization of the trained script content to an unstructured conversation with an unfamiliar, naive partner at baseline, posttreatment, and 6 weeks posttreatment. Results: Eighty-five participants with aphasia enrolled in the study. There was no significant difference between groups from baseline to posttreatment and follow-up for stimulus repetition, but there was a significant difference for session frequency with massed performing better than distributed. Factor interactions over time indicated that long scripts showed greater improvements with distributed versus massed session frequency, whereas short scripts were better maintained than long scripts at 6-week follow-up. Within groups, there was significant improvement from baseline to posttreatment, which was generally maintained at 6 weeks posttreatment. Conclusions: Results provide further evidence supporting the efficacy of script training. Dose parameters such as session frequency and stimulus repetition may impact the maintenance and generalization of treatment and should be considered when delivering this and other aphasia treatments. Supplemental Material: https://doi.org/10.23641/asha.33990859