Lilla Zakariás

Positive effects of a computerised working memory and executive function training on sentence comprehension in aphasia

ABSTRACT Aphasia, the language disorder following brain damage, is frequently accompanied by deficits of working memory (WM) and executive functions (EFs). Recent studies suggest that WM, together with certain EFs, can play a role in sentence comprehension in individuals with aphasia (IWA), and that WM can be enhanced with intensive practice. Our aim was to investigate whether a combined WM and EF training improves the understanding of spoken sentences in IWA. We used a pre–post-test case control design. Three individuals with chronic aphasia practised an adaptive training task (a modified n-back task) three to four times a week for a month. Their performance was assessed before and after the training on outcome measures related to WM and spoken sentence comprehension. One participant showed significant improvement on the training task, another showed a tendency for improvement, and both of them improved significantly in spoken sentence comprehension. The third participant did not improve on the training task, however, she showed improvement on one measure of spoken sentence comprehension. Compared to controls, two individuals improved at least in one condition of the WM outcome measures. Thus, our results suggest that a combined WM and EF training can be beneficial for IWA.

A specific pattern of executive dysfunctions in transcortical motor aphasia

Background: Recent studies imply that executive functions (EF) are closely related to our ability to comprehend and produce language. A number of findings suggest that functional communication and language recovery in aphasia depend not only on intact language abilities but on EF as well. Some patients with transcortical motor aphasia (TMA) show language deficits only in tasks in which conflicting representations must be resolved by executive processes. In line with these results, others have proposed that TMA should be referred to as “dysexecutive aphasia”. EF in aphasia have mostly been studied using neuropsychological tests, therefore there is a need for systematic experimental investigations of these skills. Aims: 1. To investigate EF in TMA, and to test whether executive dysfunctions are specific to TMA. 2. To experimentally measure different components of EF: updating working memory representations and inhibition of prepotent responses. Methods & Procedures: Five individuals with TMA, five patients with conduction aphasia and ten healthy controls participated. We designed four nonverbal tasks: to measure updating of working memory representations, we used a visual and an auditory n-back task. To assess inhibition of prepotent responses, we designed a Stop-signal and a nonverbal Stroop task. All tasks involved within-subject baseline conditions. Outcomes & Results: We found certain EF deficits in both groups of individuals with aphasia as compared to healthy controls. Individuals with TMA showed impaired inhibition as indexed by the Stop-signal and the nonverbal Stroop tasks, as well as a deficit of updating of working memory representations as indexed by the auditory n-back task. Participants with conduction aphasia had difficulties in only one of the tasks measuring inhibition, but no clear evidence for impairment of updating of working memory representations was found. Conclusions: Although the results show different patterns of EF deficits in the groups with aphasia, the findings clearly demonstrate that EF deficits are not specific to participants with TMA. Based on these results, and on earlier data highlighting the role of executive processes in functional communication and language recovery, we suggest that tests of EF should be an inherent part of clinical aphasia assessment.

Working Memory and Interference Control in Children with Specific Language Impairment

Language and communication disorders are often associated with deficits in working memory (WM) and interference control. WM studies involving children with specific language impairment (SLI) have traditionally been framed using either resource theories or decay accounts, particularly Baddeleys model. Although significant interference problems in children with SLI are apparent in error analysis data from WM and language tasks, interference theories and paradigms have not been widely used in the SLI literature. A primary goal of the present paper is to provide an overview of interference deficits in children with SLI. Review of the extant literature on interference control shows deficits in this population; however, the source and the nature of the deficit remain unclear. Thus, a second key aim in our review is to demonstrate the need for theoretically driven experimental paradigms in order to better understand individual variations associated with interference weaknesses in children with SLI.

Transfer effects on spoken sentence comprehension and functional communication after working memory training in stroke aphasia

Abstract Recent treatment protocols have been successful in improving working memory (WM) in individuals with aphasia. However, the evidence to date is small and the extent to which improvements in trained tasks of WM transfer to untrained memory tasks, spoken sentence comprehension, and functional communication is yet poorly understood. To address these issues, we conducted a multiple baseline study with three German-speaking individuals with chronic post-stroke aphasia. Participants practised two computerised WM tasks (n-back with pictures and n-back with spoken words) four times a week for a month, targeting two WM processes: updating WM representations and resolving interference. All participants showed improvement on at least one measure of spoken sentence comprehension and everyday memory activities. Two of them showed improvement also on measures of WM and functional communication. Our results suggest that WM can be improved through computerised training in chronic aphasia and this can transfer to spoken sentence comprehension and functional communication in some individuals.

A végrehajtó funkciók zavara afáziában

Hatter es celok Ujabb eredmenyek szerint afaziaban a nyelvhasznalati kepesseg diszfunkciojahoz a vegrehajto funkciok zavara is tarsulhat. A vegrehajto funkciok a nyelvi feldolgozorendszer műkodeseben is szerepet jatszhatnak. Kutatasunkban afaziaval diagnosztizalt szemelyeknel vizsgaltuk a munkamemoria frissiteset es ket gatlofunkciot (a valaszalapu konfliktus es a reprezentacios konfliktus feloldasat), illetve ezek osszefuggeset a nyelvi teljesitmennyel. Modszer A vizsgalatban nyolc afaziaval diagnosztizalt, a frontalis lebeny seruleset mutato szemely, illetve a hozzajuk korban, nemben es iskolazottsagban illesztett egeszseges kontrollszemely vett reszt. A vegrehajto funkciok vizsgalatara harom feladatot hasznaltunk: a Stop Signal, a Nem-verbalis Stroop- es az N-back feladatokat. A nyelvi kepessegeket az afazia diagnosztikajaban altalanosan alkalmazott teszteken kivul a TROG Nyelvtani Szerkezetek Megertese teszttel mertuk. Eredmenyek Eredmenyeink a valaszalapu konfliktus gatlasanak es a munkamemoria friss...

Imageability ratings across languages

Imageability is a psycholinguistic variable that indicates how well a word gives rise to a mental image or sensory experience. Imageability ratings are used extensively in psycholinguistic, neuropsychological, and aphasiological studies. However, little formal knowledge exists about whether and how these ratings are associated between and within languages. Fifteen imageability databases were cross-correlated using nonparametric statistics. Some of these corresponded to unpublished data collected within a European research network—the Collaboration of Aphasia Trialists (COST IS1208). All but four of the correlations were significant. The average strength of the correlations (rho = .68) and the variance explained (R2 = 46%) were moderate. This implies that factors other than imageability may explain 54% of the results. Imageability ratings often correlate across languages. Different possibly interacting factors may explain the moderate strength and variance explained in the correlations: (1) linguistic and cultural factors; (2) intrinsic differences between the databases; (3) range effects; (4) small numbers of words in each database, equivalent words, and participants; and (5) mean age of the participants. The results suggest that imageability ratings may be used cross-linguistically. However, further understanding of the factors explaining the variance in the correlations will be needed before research and practical recommendations can be made.

The methodological quality of short-term/working memory treatments in post-stroke aphasia: a systematic review

Background: Individuals with aphasia after stroke often present with concomitant shortterm memory and working memory (STM/WM) impairments (Murray, Salis, Martin, & Dralle, 2018). These impairments can negatively influence language processing (e.g., Martin, Minkina, Kohen, & Kalinyak-Fliszar, 2018; Salis, Kelly, & Code, 2015; Zakariás, Salis, & Wartenburger, 2018). Research investigating the relationship between STM/WM and language processing has led to the promising hypothesis that treatments of STM/WM could lead to improvements in language functioning, a phenomenon known as generalization. However, despite the growing number of STM/WM treatments in aphasia, little is known about their methodological rigor and quality, and whether treatment-related improvements of STM/WM generalize beyond STM/WM treatment tasks and to aspects of language (e.g., spoken sentence comprehension). Aims: (1) To identify and describe STM/WM treatments in stroke aphasia through a systematic review of relevant literature; (2) to appraise the methodological quality (i.e., internal and external validity) of these treatments; (3) to investigate whether STM/WM, language (e.g., spoken sentence comprehension, functional communication), and other everyday functions can benefit from STM/WM treatments in stroke aphasia. Methods & procedures: A systematic search of 13 databases was conducted in 2014 (February) and then updated in 2016 (December). Reference lists of included studies, conference abstracts, and relevant reviews were also screened for potentially eligible studies. Inclusion criteria were studies that had been published in English and included: (1) adult participants presenting with non-progressive, acquired aphasia as a result of stroke; (2) STM/WM tasks in their treatments; (3) STM/WM outcome data. We used the Risk of Bias in N-of-1 Trials (RoBiNT; Tate et al., 2015) quantitative scale to rate the internal and external validity of the included studies. Outcomes & results: The selection and inclusion process is summarized in Figure 1. The systematic search and inclusion/exclusion procedure yielded 17 included studies (mainly single case and case-series designs) with 37 participants. Table 1 summarizes the included studies (not included in the reference list), methodological quality scores, treatment procedures, and main outcomes. Methodological quality scores indicated poor internal and external validity across studies. The majority of studies reported