Treatment of verbal short-term memory abilities to improve language function in aphasia: A case series treatment study

Recent approaches to interventions for aphasia have incorporated verbal short-term memory (STM) and working memory (WM) components. We investigated whether a treatment involving repetition of word sequences after a response delay would improve tolerance of increased verbal STM load in repetition and, consequently, improve performance on repetition and other language tasks. Eight individuals with aphasia participated. We used a single subject design with outcome measures on near-transfer tasks closely related to the treatment task and far-transfer tasks more distantly related to the treatment task. We minimized repeated presentation of stimuli in all phases of treatment to control for confounding effects of repeated exposure of treated items. Four participants demonstrated modest acquisition effects. On outcome measures, we observed improvements by some participants on near-transfer tasks, (repetition of concrete and abstract word strings and verbal spans) and far-transfer tasks (naming and discourse). Some participants demonstrated a significant decline in word repetition accuracy after a response delay before treatment, indicating difficulty in maintaining activation of linguistic representations. It was these participants who showed the most improvement on outcome measures. More studies are needed to determine who will respond to this treatment and what factors might influence the effectiveness of this treatment approach.