Historically, definitions of post-stroke aphasia have acknowledged concomitant memory impairments, specifically, verbal short-term and working memory (STM/WM). While some aphasia treatments are effective, on the whole, the rehabilitation of aphasia remains a challenge. Evidence from diverse research paradigms reports associations between STM/WM and language functioning in aphasia, prompting a hypothesis that the treatment of STM/WM would improve language functioning. We carried out a systematic literature review in order to outline and appraise treatment methods of STM/WM impairments in aphasia.
Methods: We performed an extensive systematic literature search of 12 electronic databases, references were hand searched and relevant researchers contacted. Search terms included aphasia, short-term memory, working memory, rehabilitation and relevant synonyms. Studies that included STM and/or WM approaches in the treatment of adults with post-stroke aphasia were reviewed. We excluded studies where participants presented with acquired brain injuries other than stroke, and excluded mixed aetiology group studies where it was not possible to identify treatment outcomes for participants with aphasia. Finally, we excluded studies that involved related tasks and principles, e.g. attention, but did not report STM/WM abilities.
Results: The search strategy yielded 226 studies for screening, 11 of which fulfilled the inclusion criteria. In all studies, improvements were noted in terms of STM/WM functioning measures as well as other language functioning measures. Few studies included outcome measures of psychosocial functioning and no reported treatments have been replicated. All studies reported were single cases.
Discussion:
The supportive evidence for treatment of STM/WM is growing and suggests some benefits of treating STM/WM, not only in terms of improved STM/WM functioning but also other language functions.
Conclusion: While there were a number of indications of improvement following STM/WM treatment with some generalisation of improvement to language functions, there is a need for rehabilitation research in this area, and replications of existing treatment with higher quality research designs.