Outcomes from a pilot dose comparison study of naming therapy in aphasia

Abstract

ABSTRACT Background People with aphasia vary considerably in response to aphasia treatments. Treatment dose is likely to be an important factor in understanding treatment response variability and optimising aphasia recovery; however, there is limited empirical evidence to guide dose prescription in post-stroke aphasia rehabilitation. In the present study, we used a novel approach to personalise dose prescription and explored the effect of dose on treatment response in chronic post-stroke aphasia. Aims Examine the effect of providing personalised doses of a cued picture naming treatment (Kendall et al., 2014) on acquisition and maintenance of picture naming outcomes. Method This pilot study used a multiple-baselines design with follow-up at 4- and 12-weeks with replication across four people with chronic post-stroke anomia. Prior to treatment, a comprehensive battery of cognitive and language tests was completed. Participants then undertook a period of cued picture naming treatment (45-minute sessions, five days per week for three weeks) totalling 15 sessions (11.25 hours). Participants were allocated four picture sets – one each for three treated conditions (low dose, moderate dose, and high dose) and one for an untreated control set. The number of naming opportunities provided per dose condition was calibrated against individuals’ pre-treatment picture naming accuracy and speed. Generalised linear mixed effects models were used to evaluate learning effects during treatment, maintenance of these effects, and dose-response relationships. Outcomes Participants received 99% of prescribed treatment doses (i.e., number of naming opportunities provided over the course of treatment). As anticipated, individual treatment responses varied substantially. Three participants demonstrated significantly improved picture naming accuracy on probed items during treatment, with varying response profiles by participant and dose. All participants were able to name more pictures accurately on a bespoke 298-item object picture naming test following treatment. However, no participant demonstrated significant pre-post treatment gains relative to untreated items, although one person demonstrated improved naming four weeks after treatment for items treated under the high dose condition. Dose-response relationships amongst these participants exhibited a greater number of significant results on naming probes in the high dose condition, possibly suggesting superiority of the high dose condition over lower doses of cued picture naming treatment. Conclusion Modest treatment effects and variable dose-response relationships were observed. We explore the role of dose, cognitive factors such as self-monitoring abilities, and linguistic factors such as underlying lexical-semantic and phonological processing that may have influenced treatment response in these participants. Avenues for future research are identified.