Remediation of language processing in aphasia: Improving activation and maintenance of linguistic representations in (verbal) short-term memory

Abstract

Background Verbal short-term memory (STM) impairments are invariably present in aphasia. Word processing involves a minimal form of verbal STM, i.e., the time course over which semantic and phonological representations are activated and maintained until they are comprehended, produced, or repeated. Thus it is reasonable that impairments of word processing and verbal STM may co-occur. The co-occurrence of language and STM impairments in aphasia has motivated an active area of research that has revealed much about the relationship of these two systems and the effect of their impairment on language function and verbal learning (Freedman & Martin, 2001; Martin & Saffran, 1999; Trojano & Grossi, 1995). In keeping with this view a number of researchers have developed treatment protocols to improve verbal STM in order to improve language function (e.g., Koenig-Bruhin & Studer-Eichenberger, 2007). This account of aphasia predicts that treatment of a fundamental ability, such as STM, which supports language function, should lead to improvements that generalise to content and tasks beyond those implemented in treatment. Aims We investigated the efficacy of a treatment for language impairment that targets two language support processes: verbal short-term memory (STM) and executive processing, in the context of a language task (repetition). We hypothesised that treatment of these abilities would improve repetition abilities and performance on other language tasks that require STM. Method A single-participant, multiple-baseline, multiple-probe design across behaviours was used with a participant with conduction aphasia. The treatment involved repetition of words and nonwords under three “interval” conditions, which varied the time between hearing and repeating the stimulus. Measures of treatment effects included acquisition, maintenance, and follow-up data, effect sizes, and pre- and post-treatment performance on a test battery that varies the STM and executive function demands of language tasks. Outcomes & Results Improvement of repetition was mostly specific to treated stimuli. Post-treatment measures of language ability indicated improvements in single and multiple word processing tasks, verbal working memory tasks, and verbal span. Conclusions Treatment of STM and executive processes in the context of a word repetition task resulted in improvements in other non-treated language tasks. The approach used in this study can be incorporated into other language-processing tasks typically used in treatment of language disorders (e.g., sentence processing).

Long-term maintenance of novel vocabulary in persons with chronic aphasia

“…They were also tested with selected language and verbal span measures to ascertain the normality of their language-processing abilities. The tests included the standardised Finnish version of the Boston Naming Test (BNT; Laine, Koivuselkä-Sallinen, Hänninen, & Niemi, 1997), phonological and semantic fluency tasks, narration, the semantic odd-one-out 1 The Temple Assessment of Language and Short-term Memory in Aphasia (TALSA) is a comprehensive test battery designed for evaluating language and verbal short-term memory abilities in aphasia (Martin et al, 2010;Kalinyak-Fliszar et al, 2011). In TALSA, short-term memory load (as number of alternatives to be compared or as different intervals between stimulus and response) are varied systematically across language tasks.…”

Short-term memory treatment: Patterns of learning and generalisation to sentence comprehension in a person with aphasia

“…The speakers reported in other STM studies (Koenig-Bruhin & Studer-Eichenberger, 2007;Majerus et al, 2005;Murray et al, 2006) showed smaller improvements in digit repetition after treatment. The speaker reported by Kalinyak-Fliszar et al (2011) did not improve in this task. Although the listening span does not require speech output but forward digit span does, they both involve either recognition or recall of the serial order of words, both of which are measures of STM (Jefferies et al, 2006).…”

Working memory treatment in aphasia: A theoretical and quantitative review

“…Currently, different authors have developed different verbal WM assessment instruments, inspired by different theoretical models (e.g., Harris et al, 2014;Kalinyak-Fliszar et al, 2011;Majerus et al, 2015;Vallat et al, 2014). A comprehensive WM test battery that would target the different WM components discussed here in a process-specific and integrated manner is still lacking.…”

“…A comprehensive WM test battery that would target the different WM components discussed here in a process-specific and integrated manner is still lacking. Although there have been some standardization efforts for a subset of the tasks and instruments presented here (e.g., Kalinyak-Fliszar et al, 2011;Majerus et al, 2015), standardized, psychometrically valid and theoretically-informed WM test batteries, particularly for use in severely impaired patients such as aphasic patients, remain scarce (Murray, Salis, Martin, & Dralle, 2016). By explicitly characterizing the storage versus processing requirements as well as the attentional and executive processes involved in all types of WM tasks, a theoretically-informed WM battery could also be a step toward the resolution of the debate around the distinction of 'working memory' versus 'short-term memory' tasks.…”