A Common Serial Order Mechanism for Verbal Working Memory and Language Production: Evidence from Aphasia

Field: Neuroscience (Life Sciences)

Event Abstract Back to Event A Common Serial Order Mechanism for Verbal Working Memory and Language Production: Evidence from Aphasia Yingxue Tian1*, Heather R. Dial2, Randi Martin1 and Simon Fischer-Baum1 1 Rice University, United States 2 University of Texas at Austin, United States Serial order information is critical in our daily life, from recalling a phone number, or producing phonemes when saying a word, or writing letters when spelling. In the domain of working memory (WM), there is clear evidence for a dissociation of item-identity and serial-order WM (Majerus, 2018). The current study tests two hypotheses about verbal serial order working memory (SOWM). First, that there is a single SOWM capacity that is involved in both verbal and nonverbal WM. Second, that there is a common order processing capacity shared between verbal WM and language production. Both hypotheses are addressed in a multiple-case study approach, looking at patterns of associations and dissociations in serial order performance in patients with memory and language impairments following stroke. Three chronic aphasic patients (M.B., E.V., and S.H.) were identified with impaired forward and backward digit span (span < 4). They were then tested on verbal WM, including item probe (IP), order probe (OP), and serial reconstruction (SRC). Evidence of SOWM impairments includes poor performance on SRC and impaired OP relative to IP (henceforth referred to as adjusted order span). Patient M.B. exhibited impaired verbal SOWM with both digits (SRC = 3.08) and letters (SRC = 2.45, p’s < .05) as well as with the probe tasks (verbal adjusted order span = 50%, p = .03) when compared to ten age- and education-matched control subjects, whereas the other two patients showed no evidence of a verbal SOWM impairment. To test the single SOWM hypothesis, patients were given the same WM battery with nonverbal materials (visuospatial locations). None of the patients showed nonverbal SOWM impairments. Most critically, M.B. exhibited SOWM deficit in the verbal domain but not the nonverbal domain (SRC = 5.33, nonverbal adjusted order span = 59%, p’s > .05). This dissociation between verbal and nonverbal SOWM systems provides clear evidence against the single SOWM hypothesis. To test the hypothesis that verbal SOWM and language production share a common order processing capacity, we next analyzed phoneme/grapheme errors in a corpus of repetition and spelling tasks. Errors in these tasks were categorized into item, order, and omission errors. M.B. produced significantly more phoneme and grapheme order errors than would be expected by chance (p’s < .001 in Monte Carlo simulation), whereas the other two patients did not have a tendency to make order errors in these tasks. The association between M.B.’s order impairment in verbal WM, spoken production and spelling, along with the fact that E.V. and S.H. do not show order impairments in any of those domains, suggests a common serial order mechanism. In sum, our multiple-case study suggests a common mechanism for serial order between verbal WM and the language production system that is distinct from the serial order mechanism used in nonverbal WM. References Majerus, S. (2018). Verbal working memory and the phonological buffer: The question of serial order. Cortex. Keywords: cognitive neuropsychology, Multiple-case, Language production, working memory, serial order Conference: Academy of Aphasia 57th Annual Meeting, Macau, Macao, SAR China, 27 Oct - 29 Oct, 2019. Presentation Type: Poster presentation Topic: Eligible for student award Citation: Tian Y, Dial HR, Martin R and Fischer-Baum S (2019). A Common Serial Order Mechanism for Verbal Working Memory and Language Production: Evidence from Aphasia. Front. Hum. Neurosci. Conference Abstract: Academy of Aphasia 57th Annual Meeting. doi: 10.3389/conf.fnhum.2019.01.00113 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: 06 May 2019; Published Online: 09 Oct 2019. * Correspondence: Mx. Yingxue Tian, Rice University, Houston, United States, yingxue.tian@rice.edu 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 Yingxue Tian Heather R Dial Randi Martin Simon Fischer-Baum Google Yingxue Tian Heather R Dial Randi Martin Simon Fischer-Baum Google Scholar Yingxue Tian Heather R Dial Randi Martin Simon Fischer-Baum PubMed Yingxue Tian Heather R Dial Randi Martin Simon Fischer-Baum Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.