Introduction:
Post-stroke aphasia often results in short-term memory/ working memory (STM/WM) impairments(1) which can negatively influence language processing(2-4). Research investigating the relationship between STM/WM and language processing suggests that treatments of STM/WM could generalize to improvements in language. Despite the increase in STM/WM treatments in aphasia, little is known about their methodological rigor, and whether treatment-related improvements of STM/WM generalize to aspects of language.
Research Aims:
- Identify STM/WM treatments in post-stroke aphasia through systematically reviewing relevant literature
- Appraise the methodological quality of these treatments
- Investigate whether STM/WM, language, and everyday functions can benefit from STM/WM treatments
Methods:
A systematic search of 13 databases was conducted in 2014 and 2016. Reference lists of included studies, conference abstracts and relevant reviews were screened for eligible studies.
Inclusion criteria were studies published in English and included:
- Adults presenting with non-progressive, acquired post-stroke aphasia;
- STM/WM tasks in their treatments;
- STM/WM outcome data.
The Risk of Bias in N-of-1 Trials5 was used to rate internal and external validity of included studies.
Results:
Seventeen studies with 37 participants were included. Improvements in STM/WM was reported by 12 studies. Treatment effects on language (16 studies), noted improvements in spoken sentence comprehension, spoken discourse production, everyday communication, and/or reading. Only four studies investigated outcomes on everyday STM/WM functioning; their results are inconclusive. Methodological evaluation indicated poor internal and external validity across studies.
Discussion:
Methodological limitations prevent drawing firm conclusions about the effectiveness of STM/WM treatments in post-stroke aphasia. Future studies should include outcome measures of communication, everyday memory and psychosocial functioning, to demonstrate clinically significant improvements after STM/WM treatments in aphasia.
Conclusion:
Results related to STM/WM, spoken sentence comprehension, and reading are promising, but require further methodologically robust investigation to determine the beneficial effects of this type of intervention.
References:
1 Murray, L., Salis, C., Martin, N., & Dralle, J. (2018). The use of standardised short-term and working memory tests in aphasia research: A systematic review. Neuropsychological Rehabilitation, 28(3), 309-351.
2Martin, N., Minkina, I., Kohen, F. P., & Kalinyak-Fliszar, M. (2018). Assessment of linguistic and verbal short-term memory components of language abilities in aphasia. Journal of Neurolinguistics, 1-27.
3Salis, C., Kelly, H., & Code, C. (2015). Assessment and treatment of short-term and working memory impairments in stroke aphasia: A practical tutorial. International Journal of Language & Communication Disorders, 50(6), 721-736.
4Zakariás, L., Salis, C., & Wartenburger, I. (2018). Transfer effects on spoken sentence comprehension and functional communication after working memory training in stroke aphasia. Journal of Neurolinguistics, 1-17
5 Tate, R. L., Rosenkoetter, U., Wakim, D., Sigmundsdottir, L., Doubleday, J., Togher, L., … Perdices, M. (2015). The risk-of-bias in N-of-1 trials (RoBiNT) scale: An expanded manual for the critical appraisal of single-case reports. Sydney, Australia: Author.