The Role of Executive Function in the Semantic Comprehension Deficits of Stroke Aphasia and Semantic Dementia

Abstract

Event Abstract Back to Event The Role of Executive Function in the Semantic Comprehension Deficits of Stroke Aphasia and Semantic Dementia Curtiss Chapman1* and Randi Martin1 1 Rice University, United States Introduction Semantic memory is crucial for understanding and interacting with the world. Contrasting patterns of semantic deficits have been claimed for semantic dementia (SD) patients and comprehension-impaired stroke (SA) patients, leading to the proposal of a separation between semantic knowledge and processes that act on it. Specifically, SD patients have been argued to have a loss of amodal semantic representations, whereas SA patients have an impairment of executive control used to access and manipulate these representations (Jefferies & Lambon Ralph, 2006). In line with these claims, SD patients have shown consistent performance across semantic tasks, while SD patients show consistency only across tasks with similar executive demands. However, the distinction between patients groups is based on studies contrasting a relatively small number of SD and SA patients and limited testing of SD patients on measures of executive function. Methods The current study overcomes these shortcomings by testing SD and SA patients on several measures of executive function in addition to tasks of semantic comprehension. Comprehension tasks included: picture and word versions of the Camel and Cactus Test, where one must choose which item is most closely associated with a target item from four related items (e.g. camel is associated with cactus, not oak tree, sunflower, or rose); an environmental sounds–picture matching test; auditory word-picture matching with within-category distracters; and picture naming. Executive tasks included: digit and word span, N-back, cued task-set shifting, a modified trail-making task, verbal and non-verbal Stroop, picture-word interference, and the Wisconsin Card Sort Task. Results and Conclusions Results from 5 SD patients and 4 SA patients in our ongoing study suggest similar patterns of impairment on both semantic and executive function tasks for both patient groups. Both showed multi-modal semantic deficits via poor performance on at least 3 out of 5 semantic tasks tapping different modalities. Also, SA and SD patients showed no difference in consistency across semantic tasks (see Fig. 1a & b). Both groups also showed consistently poor performance on trail-making and verbal Stroop tasks compared to controls (see Figs. 1c & 1d). SD patients seem to be less impaired on both span measures (word span range: 2.17 – 4.43; digit span: 3.17 – 5.5) than SA patients (word span range: 1.63 – 3.75; digit span: 1.17 – 4.17), and performance was variable for both groups on non-verbal Stroop and picture-word interference. SD patients found many executive tasks too difficult to understand, which may be the reason for limited prior data for them on EF tasks.. These findings suggest that the use of syndrome categories like semantic dementia and comprehension-impaired stroke aphasia are not useful in distinguishing between storage and access deficits. Patients classified as having SD seem as likely as SA patients to have certain kinds of executive deficits and SA patients may be as likely as SD patients to show consistency across semantic tasks. The results imply that some other behavioral or neuroanatomical basis rather than syndrome classification should be used to address the hypothesized separation of storage vs. control aspects of semantic memory. Figure 1 References Jefferies, E., & Lambon Ralph, M. A. (2006). Semantic impairment in stroke aphasia vs. semantic dementia: A case-series comparison. Brain, 129, 2132-2147. Keywords: Semantic Dementia, Aphasia, semantic deficits, Executive Function, case series Conference: Academy of Aphasia 53rd Annual Meeting, Tucson, United States, 18 Oct - 20 Oct, 2015. Presentation Type: Poster Topic: Student first author Citation: Chapman C and Martin R (2015). The Role of Executive Function in the Semantic Comprehension Deficits of Stroke Aphasia and Semantic Dementia. Front. Psychol. Conference Abstract: Academy of Aphasia 53rd Annual Meeting. doi: 10.3389/conf.fpsyg.2015.65.00004 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 01 May 2015; Published Online: 24 Sep 2015. * Correspondence: Mr. Curtiss Chapman, Rice University, Houston, Texas, United States, curtiss.a.chapman@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Curtiss Chapman Randi Martin Google Curtiss Chapman Randi Martin Google Scholar Curtiss Chapman Randi Martin PubMed Curtiss Chapman Randi Martin Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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