Event Abstract Back to Event Separate Serial Order Short-term Memory Systems: A Case Series Approach Yingxue Tian1* and Simon Fischer-Baum1 1 Rice University, Psychology, United States Remembering a sequence of items requires memory for both the items in the sequence and their order. Neuropsychological case series support dissociations between item-identity and serial order short-term memory (STM) for both verbal and nonverbal sequences. The current research focuses on serial order STM. Using a case series approach, we contrast two hypotheses: serial order STM is a domain-general capacity vs. separate serial order STM systems for verbal and nonverbal materials. Group-average neuropsychological data support separate serial order STM systems. For example, Kesner et al. (1994) reported a group of prefrontal-damaged patients who have greater serial order STM deficits in the verbal domain than in the nonverbal domain. However, averaging across a heterogeneous group of patients may blur important associations that would support the domain-general serial order STM hypothesis. Therefore, we take a case series approach, investigating the patterns of dissociations and associations in serial order STM capacities and item-identity capacities in the verbal and nonverbal domains. Specifically, we tested the prediction that individuals with serial order STM impairments in one domain will also have serial order STM impairments in the other domain. We identified four chronic aphasic patients from the Rice Aphasia Patient Database with impaired forward and backward digit span (span < 4) and seven age and education-matched control subjects. Subjects were given a series of tasks tapping into item-identity and order STM with both verbal and nonverbal stimuli. Digits and consonants were used as verbal stimuli, and spatial locations were used as nonverbal stimuli. A series of STM measures were collected: item probe (IP), order probe (OP) and serial reconstruction (SRC). All tasks started with sequences at length 2, and the lengths of sequences increased until the accuracy of performance dropped below 75%. The STM spans were interpolated to the sequence length corresponding to 75% accuracy. Two patients showed no clear pattern of item or order STM impairment. However, we observed a double dissociation between serial order STM capacities in verbal and nonverbal domains from the other two patients (see Figure 1). One (M.B.) had a more severe deficit in serial order STM than item-identity STM in the verbal domain. Specifically, his span for SRC and OP with letters and digits are 3.08 or less, while his IP is 4.67 for both letters and digits. However, his serial order STM capacity is normal in the nonverbal domain (SRC = 5.33, OP = 5.33). Another (T.Q.) was also less impaired in item-identity than serial order in the verbal domain (digits: SRC = 2.8, OP = 2.25, IP = 3.67; letters: SRC = 2.1, OP = 2.4, IP = 4.25), but showed the opposite pattern in the nonverbal domain (SRC = 2.71, OP = 2.83, IP = 1.83). We replicate previous studies reporting dissociations between item-identity and serial order STM in both verbal and nonverbal STM. However, our results are inconsistent with the prediction of the domain-general serial order STM hypothesis. Therefore, our results suggest that there are separate serial order STM systems for verbal and nonverbal materials. Figure 1 References Kesner, R. P., Hopkins, R. O., & Fineman, B. (1994). Item and order dissociation in humans with prefrontal cortex damage. Neuropsychologia, 32(8), 881-891. Keywords: serial order, short-term memory, domain-specificity, case series, cognitive neuropsychology Conference: Academy of Aphasia 55th Annual Meeting , Baltimore, United States, 5 Nov - 7 Nov, 2017. Presentation Type: poster or oral Topic: Consider for student award Citation: Tian Y and Fischer-Baum S (2019). Separate Serial Order Short-term Memory Systems: A Case Series Approach. Conference Abstract: Academy of Aphasia 55th Annual Meeting . doi: 10.3389/conf.fnhum.2017.223.00012 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: 27 Apr 2017; Published Online: 25 Jan 2019. * Correspondence: Miss. Yingxue Tian, Rice University, Psychology, Houston, 77251, TX, 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. 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