The challenge of achieving greater generalization in phonological treatment of Aphasia

ABSTRACT

Background

Stimulus selection is important to anomia treatment because similarity between trained and untrained words in the mental lexicon may influence treatment generalization. We focused on phonological similarity between trained and untrained words from a clinical trial of Phonomotor Treatment (PMT) that showed gains in confrontation naming accuracy of untrained words post-treatment. One way to capture the amount of similarity between the trained and untrained words is to consider the phonological network path distance between words. We posited that the distance between trained and untrained words in a phonological network could account for the improvement in confrontation naming accuracy post-treatment.

Aim

To define the phonological network distance between trained and untrained words that influences change in confrontation naming accuracy post-treatment.

Methods and procedures

We retrospectively analyzed data from 28 people with aphasia who received PMT as part of a clinical trial. Participants completed confrontation naming (baseline, post-treatment, and 3-months post-treatment) of words varying in phonological distance to the treatment stimuli. We used a phonological network to calculate the average shortest path length (ASPL), defined by the number of phoneme differences, between an untrained word and all trained words. We used mixed effects regression models to predict change in confrontation naming accuracy of untrained words post-treatment from ASPL. Several post-hoc analyses were also conducted.

Outcomes and results

We found no effect of ASPL on change in confrontation naming accuracy of untrained words immediately post- and 3-months post-treatment. However, post-hoc analyses indicated significant subject heterogeneity and limitations in observable path distance between trained and untrained words.

Conclusion

Despite the clinical trial report that confrontation naming of untrained words improved after PMT, we found no overall effect of ASPL on the amount of improvement. We discuss further investigation of the entire domain of phonological sequence knowledge (the phonological sequence knowledge landscape) and its influence on treatment generalization, and the potential importance of identifying predictors of treatment response to enhance the effects of treatment generalization.

KEYWORDS:

• Phonomotor treatment
• anomia
• phonological network
• path distance
• predictors of response

Acknowledgments

We thank Samantha Gibbs for assistance in data analysis and our research participants for their time and effort.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by the Department of Veterans Affairs, Rehabilitation Research and Development Service under a RR&D Merit Review Grant #C6572R and by the National Institutes of Health/National Institute on Deafness and Other Communication Disorders under a Ruth L. Kirschstein NRSA #5F32DC017074.