Sarah Villard

Between-session intra-individual variability in sustained, selective, and integrational non-linguistic attention in aphasia

A number of studies have identified impairments in one or more types/aspects of attention processing in patients with aphasia (PWA) relative to healthy controls; person-to-person variability in performance on attention tasks within the PWA group has also been noted. Studies using non-linguistic stimuli have found evidence that attention is impaired in this population even in the absence of language processing demands. An underlying impairment in non-linguistic, or domain-general, attention processing could have implications for the ability of PWA to attend during therapy sessions, which in turn could impact long-term treatment outcomes. With this in mind, this study aimed to systematically examine the effect of task complexity on reaction time (RT) during a non-linguistic attention task, in both PWA and controls. Additional goals were to assess the effect of task complexity on between-session intra-individual variability (BS-IIV) in RT and to examine inter-individual differences in BS-IIV. Eighteen PWA and five age-matched neurologically healthy controls each completed a novel computerized non-linguistic attention task measuring five types of attention on each of four different non-consecutive days. A significant effect of task complexity on both RT and BS-IIV in RT was found for the PWA group, whereas the control group showed a significant effect of task complexity on RT but not on BS-IIV in RT. Finally, in addition to these group-level findings, it was noted that different patients exhibited different patterns of BS-IIV, indicating the existence of inter-individual variability in BS-IIV within the PWA group. Results may have implications for session-to-session fluctuations in attention during language testing and therapy for PWA.

To what extent does attention underlie language in aphasia

ABSTRACT Background: It is well established that persons with aphasia (PWA) exhibit impaired performance on assessments not only of language function but also of cognitive skills, including attention processing. Attention is a particularly important cognitive skill to examine in aphasia because of its fundamental, domain-general nature, as well as the fact that a link between attention deficits and language deficits in this population has been proposed in previous work. Aims: We review and discuss the current understanding of attention in aphasia and offer a literature-based schema for understanding how attention may influence language in PWA. Main Contribution: We first identify two common features of current models of attention in healthy populations, specifically, the domain-generality of attention and the existence of multiple types of attention. We then review the literature on attention in aphasia in light of these two features and discuss what the evidence in this area thus far indicates about the nature of the connection between attention and language in aphasia. Importantly, we discuss a dimension of task performance—intra-individual variability (IIV) over time—which, though relatively little studied in the context of attention in aphasia to date, may be crucial to gain a more complete understanding of PWAs’ ability to maintain consistent attention over time. Conclusions: IIV in attention may have important implications for understanding not only attention in aphasia but also language performance and even language treatment outcomes in this population, and is therefore worthy of closer examination.

The effect of a sentence comprehension treatment on discourse comprehension in aphasia

Background: While it is well understood that individuals with aphasia have difficulty with discourse comprehension, very few studies have examined the nature of discourse comprehension deficits in aphasia and the potential for improvement in discourse comprehension after rehabilitation. To address the first goal, we previously developed the Test of Syntactic Effects on Discourse Comprehension (TSEDC), which provides a measure of the extent to which a participant’s sentence comprehension ability aids in comprehending passages. Aims: The goal of this study was to examine the effect of a sentence comprehension treatment on the TSEDC to assess whether training participants to understand sentences of different syntactic complexity would improve their ability to understand passages that vary by their level of syntactic complexity. Methods & Procedures: Forty participants with aphasia received sentence comprehension treatment using one of two syntactic comprehension tasks: object manipulation (OM) or sentence to picture matching (SPM). The dependent measure was improved sentence comprehension of one sentence type in one task-related protocol, with the order of task and structure counterbalanced across participants. Before and after treatment, participants also completed a self-paced auditory story comprehension task that involved nine passages that contained either semantically reversible canonical sentences (simple passages) or semantically reversible non-canonical sentences (complex passages). At the end of each passage, participants were asked explicit or implicit questions about the story. Accuracy and reaction times were measured for each patient for each story before and after treatment. Outcomes & Results: Analysis of the treatment data revealed that participants improved in their ability to understand trained sentences (both in terms of effect size and per cent change on trained structure), irrespective of whether the trained task was SPM or OM. There was no significant relationship between treatment improvements on the SPM/OM treatment (even when the task targeted in treatment was controlled for) and changes in performance on the TSEDC. Also, there was no significant improvement in TSEDC accuracy after treatment, even when various aspects of the narrative passages, including passage complexity (simple/complex), the nature of sentence type (semantically constrained/semantically reversible) and the nature of questions asked (explicit or implicit), were accounted for. Conclusions: Inherent differences between the sentence comprehension treatment and the TSEDC may have precluded generalisation.

Does Naming Therapy Make Ordering in a Restaurant Easier? Dynamics of Co-Occurring Change in Cognitive-Linguistic and Functional Communication Skills in Aphasia

Purpose This study was conducted to investigate the static and dynamic relationships between impairment-level cognitive-linguistic abilities and activity-level functional communication skills in persons with aphasia (PWA). Method In Experiment 1, a battery of standardized assessments was administered to a group of PWA (N = 72) to examine associations between cognitive-linguistic ability and functional communication at a single time point. In Experiment 2, impairment-based treatment was administered to a subset of PWA from Experiment 1 (n = 39) in order to examine associations between change in cognitive-linguistic ability and change in function and associations at a single time point. Results In both experiments, numerous significant associations were found between scores on tests of cognitive-linguistic ability and a test of functional communication at a single time point. In Experiment 2, significant treatment-induced gains were seen on both types of measures in participants with more severe aphasia, yet cognitive-linguistic change scores were not significantly correlated with functional communication change scores. Conclusions At a single time point, cognitive-linguistic and functional communication abilities are associated in PWA. However, although changes on standardized assessments reflecting improvements in both types of skills can occur following an impairment-based therapy, these changes may not be significantly associated with each other.

Between-session and within-session intra-individual variability in attention in aphasia

&NA; Persons with aphasia (PWA) have been found in many previous studies to exhibit impaired performance on attention processing tasks, even when these tasks do not contain linguistic stimuli. There is also some evidence that as individuals, PWA may show more intra‐individual variability (i.e. time‐based fluctuations) in attention than healthy controls. The current study systematically examines two types of intra‐individual variability in attention in aphasia, between‐session intra‐individual variability (BS‐IIV) and within‐session intra‐individual variability (WS‐IIV), looking in particular at how task demands impact these dimensions of performance. We administered five novel attention tasks with varying processing demands, three non‐linguistic and two linguistic, to 20 PWA and 20 similar‐aged healthy controls. Results showed that PWA exhibited higher levels of WS‐IIV than controls but that levels of BS‐IIV were similar between the two groups. Increased task demands were found to result in increased BS‐IIV and WS‐IIV for both groups, and there was some evidence suggesting that the addition of language demands may further increase both WS‐IIV and BS‐IIV in the PWA group. In addition to these group differences, substantial inter‐individual variability in WS‐IIV and BS‐IIV was observed within the PWA group. These findings have implications for better understanding attentional fluctuations in aphasia, as well as how it relates to language deficits in this population, and potentially for better understanding language treatment outcomes. HighlightsPersons with aphasia exhibit greater fluctuations in attention than controls.Language demands may cause additional increases in attentional fluctuations.Not all persons with aphasia show similar patterns of attentional fluctuations.

Evaluating Treatment and Generalization Patterns of Two Theoretically Motivated Sentence Comprehension Therapies

Purpose The current study examined treatment outcomes and generalization patterns following 2 sentence comprehension therapies: object manipulation (OM) and sentence-to-picture matching (SPM). Findings were interpreted within the framework of specific deficit and resource reduction accounts, which were extended in order to examine the nature of generalization following treatment of sentence comprehension deficits in aphasia. Method Forty-eight individuals with aphasia were enrolled in 1 of 8 potential treatment assignments that varied by task (OM, SPM), complexity of trained sentences (complex, simple), and syntactic movement (noun phrase, wh-movement). Comprehension of trained and untrained sentences was probed before and after treatment using stimuli that differed from the treatment stimuli. Results Linear mixed-model analyses demonstrated that, although both OM and SPM treatments were effective, OM resulted in greater improvement than SPM. Analyses of covariance revealed main effects of complexity in generalization; generalization from complex to simple linguistically related sentences was observed both across task and across movement. Conclusions Results are consistent with the complexity account of treatment efficacy, as generalization effects were consistently observed from complex to simpler structures. Furthermore, results provide support for resource reduction accounts that suggest that generalization can extend across linguistic boundaries, such as across movement type.