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Purpose: This study investigated whether sentence repetition-based working-memory (SR-WM) treatment increased sentence-repetition abilities and the treatment effects generalized to sentence-comprehension abilities, WM-span tasks, and general language-assessment tasks.
Method: Six individuals with aphasia participated in the study. The treatment consisted of 12 sessions of approximately 1 hr per day, 3 times per week. The SR-WM treatment protocol followed components including maintenance and computation of linguistic units by facilitating a chunking strategy. We manipulated the length and syntactic structures of the sentence-repetition stimuli using a limited set of vocabulary.
Results: Participants demonstrated significant increased repetition ability in treated and untreated sentences after treatment. Furthermore, they showed generalization effects on the sentence-comprehension task, WM measures, and general language tasks, but with some differential patterns, depending on task demands.
Conclusions: The SR-WM treatment approach, by manipulating syntactic structures and minimizing top-down semantic processing, elicited increased performance on sentence repetition as well as other linguistic domains. Results indicated that it is clinically and theoretically important to examine whether WM treatment serves as a potentially underlying treatment approach that facilitates the distributed network associated with language processing.
Working-memory (WM) deficits in aphasia have received considerable attention, given that WM is regarded as an underlying cognitive mechanism involved in maintaining and manipulating linguistic information (Baddeley & Hitch, 1974). Baddeley and Hitch's (1974) WM model consists of three systems: a central executive and its two slave subsystems of phonological loops concerned with verbal information and the visuospatial sketchpad involved in visual and spatial information. Many studies on WM use several terminologies to reference WM. Some researchers used short-term memory (STM) and WM interchangeably (e.g., Friedmann & Gvion, 2003; Murray, 2004), and a group of researchers added an adjective ("phonological") ahead of WM (e.g., Gvion & Friedmann, 2012; Montgomery, 1995), emphasizing the subsystem of the phonological loop among WM components. Just and Carpenter (1992) proposed a concept of WM capacity by incorporating the "capacity" or "resource" concept from attention to WM. They suggested their capacity model is similar to Baddeley and Hitch's WM model in that both models emphasize processing and storage components in conceptualizing WM. However, Just and Carpenter's WM model did not include modality-specific buffers, whereas Baddeley and Hitch's WM conception contained modality-specific components such as phonological loops and a visuospatial...