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- Member of: ASU Electronic Theses and Dissertations
Description
It is commonly known that the left hemisphere of the brain is more efficient in the processing of verbal information, compared to the right hemisphere. One proposal suggests that hemispheric asymmetries in verbal processing are due in part to the efficient use of top-down mechanisms by the left hemisphere. Most evidence for this comes from hemispheric semantic priming, though fewer studies have investigated verbal memory in the cerebral hemispheres. The goal of the current investigations is to examine how top-down mechanisms influence hemispheric asymmetries in verbal memory, and determine the specific nature of hypothesized top-down mechanisms. Five experiments were conducted to explore the influence of top-down mechanisms on hemispheric asymmetries in verbal memory. Experiments 1 and 2 used item-method directed forgetting to examine maintenance and inhibition mechanisms. In Experiment 1, participants were cued to remember or forget certain words, and cues were presented simultaneously or after the presentation of target words. In Experiment 2, participants were cued again to remember or forget words, but each word was repeated once or four times. Experiments 3 and 4 examined the influence of cognitive load on hemispheric asymmetries in true and false memory. In Experiment 3, cognitive load was imposed during memory encoding, while in Experiment 4, cognitive load was imposed during memory retrieval. Finally, Experiment 5 investigated the association between controlled processing in hemispheric semantic priming, and top-down mechanisms used for hemispheric verbal memory. Across all experiments, divided visual field presentation was used to probe verbal memory in the cerebral hemispheres. Results from all experiments revealed several important findings. First, top-down mechanisms used by the LH primarily used to facilitate verbal processing, but also operate in a domain general manner in the face of increasing processing demands. Second, evidence indicates that the RH uses top-down mechanisms minimally, and processes verbal information in a more bottom-up manner. These data help clarify the nature of top-down mechanisms used in hemispheric memory and language processing, and build upon current theories that attempt to explain hemispheric asymmetries in language processing.
ContributorsTat, Michael J (Author) / Azuma, Tamiko (Thesis advisor) / Goldinger, Stephen D (Committee member) / Liss, Julie M (Committee member) / Arizona State University (Publisher)
Created2013
Description
The benefits of exercise have been recommended in typical and other special populations. However, the evidence for persons with Down syndrome (DS) is still limited. This study was aimed at investigating the impact of an acute bout of aerobic exercise intervention on motor performance, executive function and intrinsic motivation in adolescents and young adults with DS. Ten participants with DS were assigned to an exercise group, who walked on a incremental treadmill protocol for 20 minutes. The exercise intensity was achieved at 66% of their predicted maximum heart rate. Another ten participants with DS were assigned to an attentional control group, who watched a video for 20 minutes. Measures of fine manual dexterity (e.g., Purdue Pegboard test), manual force production (e.g., grip strength test), processing speed (e.g., visual choice reaction time test), verbal processing (e.g., verbal fluency test), attention shifting ability (e.g., The Dimensional Card sorting test), and inhibitory control (e.g., Knock and Tap test) were tested pre and post intervention. An intrinsic motivation scale (e.g., enjoyment and effort) was conducted after the intervention. First, results showed participants significantly improved their performance in manual force production and Knock and Tap Test after the exercise intervention. While it has been proposed that exercise increases arousal status, neurotransmitters, or cerebral vasculature, the exact mechanisms in persons with DS are still unknown. However, our results showed that after treadmill walking, motor and cognitive improvements can be found in individuals with DS, even in a single exercise session. In addition, participants reported higher scores in enjoyment after video viewing than exercise, which may a result from musical effect or too much emphasis on external rewards in their early participation in exercise. These may imply that participants had low intrinsic motivation to an active lifestyle. Further, scores in effort were significantly higher after exercise than video viewing, which indicated their capabilities to perceive their physical exertion. However, other motivational regulations (e.g., introjected and identified regulations) have shown the relationship with exercise behavior in this population. Thus, further study should consider divergent motivational factors in order to implement an effective exercise program.
ContributorsChen, Chih-Chia (Author) / Ringenbach, Shannon D.R. (Thesis advisor) / Crews, Debra (Committee member) / Kulinna, Pamela (Committee member) / Amazeen, Eric (Committee member) / Arizona State University (Publisher)
Created2013
Description
This study examines the relations among three aspects of temperament (shyness, impulsivity, and effortful control), resting respiratory sinus arrhythmia (RSA) recorded during a calming film and RSA suppression during three behavioral measures of effortful control, and adjustment (anxiety and externalizing behavior) in a sample of 101 preschool-age children. Principal components analysis was used to create composites for effortful control, shyness, impulsivity, anxiety, and externalizing behavior, and hierarchical regression analysis was used to test the study hypotheses. As expected, baseline RSA was negatively related to effortful control in shy children, but was unrelated to effortful control in children who were not shy. It was hypothesized that high baseline RSA would reduce the relation between shyness and anxiety, and between impulsivity and externalizing behavior; this hypothesis was supported for externalizing behavior, but not for anxiety. The interaction between impulsivity and RSA as a predictor of externalizing was statistically independent of effortful control, indicating that these are unique effects. Finally, it was hypothesized that RSA suppression would be positively related to effortful control for children low, but not high, in shyness. There was a marginal interaction between shyness and RSA suppression, with RSA suppression marginally negatively related to EC for children low in shyness, but unrelated to effortful control for children high in shyness; the direction of this association was opposite predictions. These findings indicate that RSA is more strongly related to effortful control for children high in shyness, and that it consequently may not be appropriate to use RSA as an index of EC for all children. This study also draws attention to the need to consider the context in which baseline RSA is measured because a true baseline may not be obtained for shy children if RSA is measured in an unfamiliar laboratory context. The finding that high RSA moderated (but did not eliminate) the relation between impulsivity and externalizing behavior is consistent with the conceptualization of RSA as a measure of self-regulation, but further research is needed to clarify the mechanism underlying this effect.
ContributorsSulik, Michael John (Author) / Eisenberg, Nancy (Thesis advisor) / Spinrad, Tracy L. (Committee member) / Lemery-Chalfant, Kathryn (Committee member) / Arizona State University (Publisher)
Created2012
Description
Poor executive cognitive functioning (ECF) is associated with a variety of alcohol-related problems, however, it is not known whether poor ECF precedes the onset of heavy drinking. Establishing the temporal precedence of poor ECF may have implications for our understanding of the development of Alcohol Use Disorder (AUD). The present study tests associations between early-adolescent ECF and young-adult risky drinking and alcohol-related problems in a prospective study of youth followed to young adulthood. Participants completed three ECF tasks at ages 11-14 and reported on their risky drinking and alcohol-related problems at ages 18-24. A latent ECF factor was created to determine whether early-adolescent ECF was associated with drinking outcomes after controlling for relevant covariates (e.g., age, sex, family history of AUD). Early-adolescent ECF, as measured by a latent factor, was unrelated to young-adult alcohol misuse and alcohol-related problems. However, sensitivity analyses revealed that an individual ECF task tapping response inhibition predicted young-adult peak drinks in a day. Present findings suggest that ECF is not a robust predictor of risky drinking or alcohol-related problems, and that this relation may be specific to the ECF component of response inhibition.
ContributorsJones, Connor Brian (Author) / Meier, Madeline (Thesis advisor) / Chassin, Laurie (Committee member) / McClure, Samuel (Committee member) / Arizona State University (Publisher)
Created2017
Description
Military veterans have a significantly higher incidence of mild traumatic brain injury (mTBI), depression, and Post-traumatic stress disorder (PTSD) compared to civilians. Military veterans also represent a rapidly growing subgroup of college students, due in part to the robust and financially incentivizing educational benefits under the Post-9/11 GI Bill. The overlapping cognitively impacting symptoms of service-related conditions combined with the underreporting of mTBI and psychiatric-related conditions, make accurate assessment of cognitive performance in military veterans challenging. Recent research findings provide conflicting information on cognitive performance patterns in military veterans. The purpose of this study was to determine whether service-related conditions and self-assessments predict performance on complex working memory and executive function tasks for military veteran college students. Sixty-one military veteran college students attending classes at Arizona State University campuses completed clinical neuropsychological tasks and experimental working memory and executive function tasks. The results revealed that a history of mTBI significantly predicted poorer performance in the areas of verbal working memory and decision-making. Depression significantly predicted poorer performance in executive function related to serial updating. In contrast, the commonly used clinical neuropsychological tasks were not sensitive service-related conditions including mTBI, PTSD, and depression. The differing performance patterns observed between the clinical tasks and the more complex experimental tasks support that researchers and clinicians should use tests that sufficiently tax verbal working memory and executive function when evaluating the subtle, higher-order cognitive deficits associated with mTBI and depression.
ContributorsGallagher, Karen Louise (Author) / Azuma, Tamiko (Thesis advisor) / Liss, Julie (Committee member) / Lavoie, Michael (Committee member) / Arizona State University (Publisher)
Created2017
Description
A substantial amount of research demonstrates that preschoolers' phonological awareness skills are a robust predictor of children's later decoding ability. Several investigators examined performance of children with speech sound impairment (SSI), defined as inaccurate production of speech sounds in the absence of any etiology or communication impairment, on phonological awareness tasks. Investigators found that children with SSI scored below their typically developing peers (TD) on phonological awareness tasks. In contrast, others found no differences between groups. It seems likely that differences in findings regarding phonological awareness skills among children with SSI is the fact that there is considerable heterogeneity among children with SSI (i.e., speech errors can either be a phonological or articulation). Phonology is one component of a child's language system and a phonological impairment (SSI-PI) is evident when patterns of deviations of speech sounds are exhibited in a language system. Children with an articulation impairment (SSI-AI) produce speech sound errors that are affected by the movements of the articulators, not sound patterns. The purpose of the study was to examine whether or not children with SSI-PI are at greater risk for acquiring phonological awareness skills than children with SSI-AI. Furthermore, the phonological awareness skills of children with SSI-PI and SSI-AI were compared to those of their typical peers. In addition, the role of executive function as well as the influence of phonological working memory on phonological awareness task performance was examined.
Findings indicate that the SSI-PI group performed more poorly on an assessment of phonological awareness skills than the SSI-AI and TD groups. The SSI-PI group performed significantly more poorly on tasks of executive function and phonological working memory than the TD group. The results of this study support the hypothesis that children with SSI-PI may be more vulnerable to difficulties in reading than children with SSI-AI and children with TD.
Findings indicate that the SSI-PI group performed more poorly on an assessment of phonological awareness skills than the SSI-AI and TD groups. The SSI-PI group performed significantly more poorly on tasks of executive function and phonological working memory than the TD group. The results of this study support the hypothesis that children with SSI-PI may be more vulnerable to difficulties in reading than children with SSI-AI and children with TD.
ContributorsFox, Angela Marie (Author) / Wilcox, M. Jeanne (Thesis advisor) / Ingram, David (Committee member) / Gray, Shelley (Committee member) / Connor, Carol (Committee member) / Arizona State University (Publisher)
Created2015
Description
Alexithymia is a personality trait characterized by a diminished ability to identify and describe feelings, as well as an inability to distinguish physical symptoms associated with emotional arousal. Alexithymia is elevated in both patients with epilepsy (a neurologically-based seizure disorder) and psychogenic nonepileptic seizures (PNES; a psychological condition mimicking epilepsy); however, different neuropsychological processes may underlie this deficit in the two groups. To expand on previous research considering factors contributing to alexithymia in these populations, we examined the extent to which scores on the Toronto Alexithymia Scale (TAS-20) were predicted by performance on measures of executive and language functioning. We studied 138 PNES and 150 epilepsy patients with video-EEG confirmed diagnoses. Neuropsychological tests were administered to assess executive functioning (interference scores of the Stroop Color-Word Test and Part B of the Trail Making Test) and language functioning (Animals, Controlled Oral Word Association Test, and Boston Naming Test). Hierarchical linear regressions revealed that the relationships between disparate neuropsychological domains and alexithymia were not moderated by diagnosis of PNES or epilepsy. Multiple regression analyses within each group demonstrated that phonemic verbal fluency and response inhibition were significant predictors of alexithymia in epilepsy. Thus, alexithymia may reflect impairments in language and aspects of executive functioning in both PNES and epilepsy.
ContributorsReynolds, Christopher Martin (Author) / Roberts, Nicole A. (Thesis advisor) / Burleson, Mary H (Committee member) / Nanez, Jose (Committee member) / Arizona State University (Publisher)
Created2017
Description
Background: Stroke is a leading cause of long-term disability in the United States (US). Assisted Cycling Therapy (ACT) incorporates the use of an electric motor to enhance the rotations per minute (rpm). ACT of about 80 rpm, has been associated with improvements in motor, cognitive, and clinical function. The acute effects of ACT on motor and cognitive function of persons with stroke induced deficits have not been investigated.
Purpose: To compare the acute effects of ACT, voluntary cycling (VC), and no cycling (NC) on upper and lower extremity motor function and executive function in adults with chronic stroke (age: 60 ± 16 years; months since stroke: 96 ± 85).
Methods: Twenty-two participants (gender: female = 6, male = 16; types: ischemic = 12, hemorrhagic = 10; sides: left lesion = 15, right lesion = 7) completed one session of ACT, one session of VC and one session of NC on separate days using a 3 x 3 crossover design.
Results: ACT lead to greater improvements in lower and upper extremity function on the paretic and non-paretic side than VC or NC (all p < 0.05), except in the non-paretic lower extremity where ACT and VC produced similar improvement (both p < 0.05). ACT and VC, but not NC, were associated with improvements in inhibition (p < 0.05). A positive relationship between cadence and motor function (P < 0.05) was found. Ratings of perceived exertion shared an inverted-U shaped relationship with measures of processing speed (p < 0.05) and a negative linear relationship with measures of executive function (p < 0.05).
Conclusion: ACT appears to benefit paretic and non-paretic motor function globally whereas the benefits of VC are more task specific. Faster cycling cadence was associated with greater improvements in global motor function. ACT and VC seem to carry similar acute benefits in inhibition.
Purpose: To compare the acute effects of ACT, voluntary cycling (VC), and no cycling (NC) on upper and lower extremity motor function and executive function in adults with chronic stroke (age: 60 ± 16 years; months since stroke: 96 ± 85).
Methods: Twenty-two participants (gender: female = 6, male = 16; types: ischemic = 12, hemorrhagic = 10; sides: left lesion = 15, right lesion = 7) completed one session of ACT, one session of VC and one session of NC on separate days using a 3 x 3 crossover design.
Results: ACT lead to greater improvements in lower and upper extremity function on the paretic and non-paretic side than VC or NC (all p < 0.05), except in the non-paretic lower extremity where ACT and VC produced similar improvement (both p < 0.05). ACT and VC, but not NC, were associated with improvements in inhibition (p < 0.05). A positive relationship between cadence and motor function (P < 0.05) was found. Ratings of perceived exertion shared an inverted-U shaped relationship with measures of processing speed (p < 0.05) and a negative linear relationship with measures of executive function (p < 0.05).
Conclusion: ACT appears to benefit paretic and non-paretic motor function globally whereas the benefits of VC are more task specific. Faster cycling cadence was associated with greater improvements in global motor function. ACT and VC seem to carry similar acute benefits in inhibition.
ContributorsHolzapfel, Simon D (Author) / Ringenbach, Shannon D (Thesis advisor) / Bosch, Pamela R (Committee member) / Lee, Chong D (Committee member) / Der Ananian, Cheryl A (Committee member) / Hooker, Steven P (Committee member) / Arizona State University (Publisher)
Created2017
Description
The purpose of the present study is to explore a potential rehabilitation alternative/additive, when time, insurance, finances, or lack of knowledge are limitations for mild traumatic brain injury (mTBI) executive function (EF) rehabilitation. The experimental intervention involved two sets of participants an experimental group and a control group. Participants within the experimental and control groups partook in initial (week 1) and final (week 6) EF and TBI assessments. The experimental group additionally participated in four weeks (weeks 2 - 5) of an experimental intervention in beta stage of a web-based application. The aim of the intervention was to train EF skills planning, organization, and cognitive flexibility through serious gamification. At the conclusion of the study, it was observed that participants within the experimental group achieved higher scores on the experimental executive function assessment when compared to the control group. The difference in scores can be attributed to the weekly participation in executive function training.
ContributorsEzenyilimba, Akuadasuo (Author) / Cooke, Nancy (Thesis advisor) / McDaniel, Troy (Committee member) / Gray, Rob (Committee member) / Arizona State University (Publisher)
Created2023
Description
Falls are a public health concern for older adults with or without cognitive impairment, including clinical Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD) dementia. Executive function (EF) is linked to falls and is notably impaired in individuals with MCI and AD dementia. However, it is unclear which EF assessments are associated with falls in older adults with intact cognition, MCI, and AD dementia. Apolipoprotein E4 (ApoE4) increases the risk of MCI and AD dementia, with limited information suggesting decreased EF and gait impairment in ApoE4 carriers. The purpose of this study was to 1) investigate the relationships between EF assessments and falls (fall history and future fall) by cognitive status (intact cognition, MCI, AD dementia) and 2) determine if ApoE4 moderates the relationship between EF and falls across cognitive status. EF assessments included Digit Span (DS), Trail Making Test (ΔTMT), Stroop Interference Test, Controlled Oral Word Association assessments of phonemic and semantic fluency (COWAC), and Clock Drawing Test. Binary logistic regression was used with secondary data to analyze the EF and falls relationship. Results showed a significant association of the ΔTMT with fall history but may not be appropriate for use with people with AD dementia due to a floor effect. Significant interaction effects were shown between AD dementia and DS, ΔTMT, and EF as a latent variable, where individuals with a fall history had better EF performance. The interaction effects are influenced by the lower percentage of reported falls in people with severe AD dementia. In the second aim, a confounding effect exposed a potential four-way interaction where higher EF in ApoE4 non-carriers with AD dementia experienced a future fall without a fall history. Overall, more research is needed to determine which EF assessments are best suited for fall risk assessment and whether ApoE4 plays a role in the relationship between EF and falls. Since the low percentage of reported falls in people with severe AD dementia exposed a differing trend between EF and falls, more research is needed to develop valid and reliable tools for collecting fall data in individuals with severe AD dementia.
ContributorsDelgado, Ferdinand (Author) / Der Ananian, Cheryl (Thesis advisor) / Yu, Fang (Thesis advisor) / Mackinnon, David P (Committee member) / Peterson, Daniel S (Committee member) / Ofori, Edward (Committee member) / Arizona State University (Publisher)
Created2023