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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

OXIDATIVE STRESS AND REDOX PROTEOMICS STUDIES IN MODELS OF NEURODEGENERATIVE DISORDERS: I. THE CANINE MODEL OF HUMAN AGING; II. INSIGHTS INTO SUCCESSFUL AGING; AND III. TRAUMATIC BRAIN INJURY

Opii, Wycliffe Omondi 01 January 2006 (has links)
The studies presented in this dissertation were conducted with the objective ofgaining greater understanding into the mechanisms of successful aging, the role ofmitochondria dysfunction in traumatic brain injury, and also on the mechanisms ofimproved learning and cognitive function in the aging.Aging is usually characterized by impairments in physiological functionsincreasing its susceptibility to dementia and neurodegenerative disorders. In thisdissertation, the mechanisms of dementia-free aging were investigated. The use of anantioxidant fortified diet and a program of behavioral enrichment in the canine model ofhuman aging was shown to result in a significant decrease in the levels of oxidativestress. A proteomic analysis of these brains also demonstrated a significant decrease inthe oxidative modification of key brain proteins and an increase in the expression levelsof other key brain proteins associated with energy metabolism and antioxidant systemswhich correlated with improved learning and memory.We show that following TBI key mitochondrial-related proteins undergoextensive oxidative modification, possibly contributing to the severe loss ofmitochondrial energetics and neuronal cell death previously observed in experimentalTBI.Taken together, these findings support the role of oxidative stress in thepathophysiology of aging and age-related neurodegenerative disorders and in CNS injury.These studies also show that antioxidants and a program of behavioral enrichmentprovide protection against oxidative stress-mediated cognitive impairments.
382

Rehabilitative Input and Support Received by Older Adults following a Mild Traumatic Brain Injury event.

Taylor, Olivia January 2014 (has links)
Introduction: Older adults have been shown to be particularly vulnerable to the effects of mild traumatic brain injury (mTBI). However, limited research exists that examines the information and support received by older adults after a TBI, despite suggestions that input may be insufficient. We therefore aimed to evaluate the information and rehabilitative support received by individuals after mTBI, and to determine whether there were any age-related differences. Method: Adults (n = 250) who presented at the Christchurch Hospital Emergency Department over a 12 month period, with a diagnosis of mTBI were invited to participate in the study. Of these, 106 consented and 80 were able to be contacted for follow up. Participants were aged 18-85 years (M = 48) and evenly distributed into four age groups (18-30, 31-50, 51-65 and 66-85 years). Participants were interviewed over the phone using a questionnaire developed in a pilot study. Questions focussed on information and treatment received after the participants’ injury, as well as questions about cognitive and mood problems following the injury. Data was analysed both quantitatively and qualitatively. Results: There were no significant differences between age groups for the number of post-TBI symptoms reported by participants. However, as predicted, the post-injury information and assistance received were inconsistent and differed across groups: 25% of all participants did not receive any information after their TBI, and older adults were the least satisfied with the information received. Post-injury assistance was most commonly offered by friends, family and significant others, but this may not have been sufficient to encourage complete recovery. Participants made suggestions for assistance and support that they would have liked following their injury. Conclusions: The current study has significant implications for the treatment of mTBI as ill-informed and neglected patients are unlikely to return to pre-injury functioning and mental state. Furthermore, a rapidly increasing older population makes immediate attention to mTBI in older adults imperative.
383

The Mindfully Attached Therapist: Factors that Predict and Prevent the Development of Compassion Fatigue

Armes, Stephanie E 01 January 2014 (has links)
Characterized as a loss of empathy, compassion fatigue is experienced by many in the helping professions. Also known as secondary traumatic stress, compassion fatigue occurs when those in the helping professions experience trauma through interacting with the traumatic experiences of the people they are helping. Previous literature has found the development of compassion fatigue to be inevitable due to the amount of empathy those professionals must utilize on a daily basis. Mindfulness practices, such as Mindfulness Based Cognitive Therapy (MBCT) and Mindfulness Based Stress Reduction (MBSR) have been found to be a helpful learning tool for those in the helping professions to reduce their levels of stress. Using a convenience sample of 74 therapists, the present study utilized attachment as a framework for exploring factors of predicting and preventing compassion fatigue. Attachment styles in romantic relationships was predicted to be associated with the development of compassion fatigue, while mindfulness levels were predicted to be preventative in the development of compassion fatigue. Findings indicated that levels of compassion fatigue were higher for females, and that higher levels of mindfulness was associated with lower levels of compassion fatigue for both males and females. Implications for therapists, supervisors, and therapists-in-training are addressed.
384

Adaptive Functioning following Pediatric Traumatic Injury: The Relationship between Parental Stress, Parenting Styles, and Child Functional Outcomes

Micklewright, Jackie Lyn 18 June 2009 (has links)
Moderate and severe pediatric traumatic brain injuries (TBI) are associated with significant familial stress and child cognitive and adaptive sequelae (Taylor et al., 1999). Research has demonstrated a relationship between familial stress and resources and child recovery of functioning following TBI (Taylor et al., 1999). We built on these findings by examining authoritarian parenting values and styles as a mediator of the relationship between parental stress and child adaptive outcomes 12-36 months following TBI or orthopedic injury (ORTHO). Participants were 21 children/adolescents with traumatic brain injuries and 23 with orthopedic injuries and one of their parents/guardians. Parents completed measures of demographics, parental stress, parenting values and styles, and child adaptive functioning. Child participants completed brief demographic questionnaires and intelligence screeners. Moderation was examined using hierarchical multiple regression. Mediation and moderated mediation were examined using bootstrapping tests of the indirect effect of parental stress on child adaptive functioning. After controlling for family insurance status, higher levels of parental stress were associated with reduced child adaptive functioning in the TBI group but not the ORTHO group. An examination of the mediational analyses revealed that higher levels of parental stress were associated with a greater reliance on authoritarian parenting styles, which was associated with reduced overall adaptive functioning and daily living skills across the two injury groups. Therefore, across groups, the relationship between parental stress and child overall adaptive functioning and daily living skills was found to be partially mediated by an authoritarian parenting style. Moderated mediation results revealed the presence of a significant interaction and 95% confidence interval on the socialization domain and indicated that the relationship between authoritarian parenting styles and child adaptive social skills differed significantly between the two groups. Our findings suggest a relationship between parental stress, authoritarian parenting styles, and child adaptive functioning in the 12-36 months following pediatric traumatic injury. Future research should explore the association among these, as well as other potentially mediating variables, both within and between the two groups with the goal of further elucidating the relationship between familial/environmental variables and child adaptive functioning following traumatic brain and orthopedic injury.
385

Central need schemas and response to trauma : is sexual identity a variable?

Courtney, Patrick E. January 1996 (has links)
This study explored the relationship between life events and central need schemas(i.e. basic assumptions about oneself and the world). The hypotheses tested were 1) people who have experienced traumatic stress will have more negative or disrupted schemas in areas of central need than those who haven't experienced traumatic stress, 2) the schemas of lesbian women, gay men, and bisexual men and women who have not experienced significant traumatic stress differ from those of heterosexual men and women who have not experienced significant traumatic stress, and 3) one's sexual identity is a variable in how one responds to traumatic stress. Results did not support the first or third hypotheses. However, support was found for the second hypothesis. Lack of support for two of the hypotheses is believed to be due to the specific data analysis used for the study A discussion of the results and suggestions for future research are then presented. / Department of Counseling Psychology and Guidance Services
386

Post-traumatic stress disorder and comorbid depression in a West African population

Terranova, Margaret R. 25 January 2012 (has links)
Despite the established relationship between Post-Traumatic Stress Disorder (PTSD) and depression in Western cultures, research concerning the prevalence rates and relationship between the comorbid disorders in Non-Western communities remains sparse. The present study explored the relationship between PTSD and comorbid depression in citizens currently living in Ghana, West Africa. Ghanaian Nationals (n=140) completed the PTSD and demographic sections of the Structured Clinical Interview for the DSM-IV (SCID-I), as well as the Center for Epidemiological Studies Depression Scale (CES-D). Both measures were administered through interview format. Results revealed a lower prevalence rate of PTSD than expected. Further analysis demonstrated that meeting the diagnostic criteria for PTSD increased the chance of meeting the diagnostic criteria for depression, as well as increased depression scores. To confirm that the prevalence rates found in this study were reflective of actual cases of depression (not measurement error) a scale reliability analysis was conducted on the CES-D. The results of this analysis confirmed internal consistency. Results suggest that although the prevalence rate of PTSD was low, a relationship is present between the disorders in a non-Western sample. The reliability of the measures means that PTSD and depression were assessed for, but what is not certain is whether the actual construct of the disorders could occur differently in a non-Western sample, causing a different presentation of symptoms. Future research is needed to examine the Western construct of PTSD and depression to determine if there is a different presentation of symptoms not accounted for by Western measures. / Department of Psychological Science
387

Secondary traumatic stress and vicarious traumatization : protective factors and their utilization

Bischoff, Scott Eric 03 May 2014 (has links)
This study examined the impact on psychotherapists who are repeatedly empathically exposed to their client’s traumatic content. Psychotherapists were asked to complete survey packets which included quantitative measures of Secondary Traumatic Stress (STS) and Vicarious Traumatization (VT), which are both theorized to be negative conditions which may develop after being exposed to other’s traumatic content. Some respondents were then interviewed, and the transcribed interviews were analyzed utilizing the qualitative technique of grounded theory. The results of this study suggested psychotherapists mediate the impact of traumatic exposure through a variety of factors, including personal characteristics, external support systems, and the use of a variety of self-care skills. These factors, along with psychotherapist’s responses to barriers interfering with accessing these factors, appear to change over time as therapists gain experience. Additionally, rather than developing negative symptoms as a result of their work, many therapists appear to develop positive outlooks, a deep respect for their client’s and human resiliency, and a sense of confidence that they can help their clients. / Department of Counseling Psychology and Guidance Services
388

The role of dissociation in the development and maintenance of post-traumatic stress disorder

Murray, James Lee January 1997 (has links)
The aim of this thesis was to investigate psychological factors influencing the development and maintenance of post-traumatic symptoms, with particular attention to the role of dissociation. The concept of dissociation is at present not well understood, and a secondary aim of this thesis was to clarify its meaning and structure and enable its assessment. Chapter 2 reports the development and testing of a questionnaire measuring trait dissociation, and the factor analysis of this questionnaire into seven sub-factors with low to medium intercorrelations, along with an analysis of the reliability and validity of this questionnaire, which was used in the subsequent studies. Chapters 3 and 4 consist of experimental studies investigating the relationship between dissociation and later intrusive memories using a videotape of scenes from road traffic accidents as a stimulus. The first study attempted to manipulate dissociation, while the second used extreme scorers on the trait dissociation questionnaire. The manipulation of dissociation proved difficult, but both studies showed a relationship between dissociation and later intrusions. Chapters 6 and 7 report on two prospective clinical studies following road traffic accident victims over the first six months following their accident, and investigates the role of dissociation and other psychological factors in the development of post-traumatic symptoms. Both state and trait dissociation, and the emotional numbing subfactor of dissociation in particular, predict the later development and maintenance of other post-traumatic symptoms. Persistent dissociation was more predictive of later symptoms than dissociation in the first few days after the accident. These results are discussed in relation to current thinking about the concept of dissociation and the DSM diagnoses of post-traumatic stress disorder and acute stress disorder. In particular it seems useful to distinguish between components of dissociation in terms of their relationship to PTSD. Possible future research and clinical implications are also addressed.
389

The Investigation of Long-term Cognitive Changes after Mild Traumatic Brain Injury using Novel and Sensitive Measures

Ozen, Lana January 2012 (has links)
Memory and concentration problems are frequently reported long after experiencing a mild traumatic brain injury (mild TBI), though conflict with null findings of deficits on standard neuropsychological tests. Experimental research shows that these inconsistencies are, in part, due to the simplicity of neuropsychological tests. As well, past research suggests that when neuropsychological deficits are occasionally detected within this population, they could be influenced by diagnosis threat: an expectation bias for impaired performance when individuals are merely informed that cognitive problems may be experienced following a mild TBI. The main goal of this thesis was to specify the long-term cognitive effects of mild TBI, with the prediction that, while cognitive complaints may be over-reported due to diagnosis threat, significant deficits can be detected using sensitive measures in experimental paradigms. Experiment 1 sought to document whether diagnosis threat influenced self-report of everyday attention and memory problems and neuropsychological task performance in individuals with a remote history of mild TBI. We found that undergraduate students with a mild TBI were significantly more likely to report having attention and memory failures in their daily lives when exposed to diagnosis threat, compared to undergraduate students not exposed to diagnosis threat. These findings call into question the efficacy of using of self-report measures to identify long-term cognitive deficits following a mild TBI. In an attempt to further specify persistent significant cognitive deficits, we designed two different experimental paradigms that uniquely manipulated the demand place on executive processes, as past research suggested deficits emerge only when tasks require considerable cognitive resources. In Experiment 2a, we manipulated processing load on a visual working memory task, across two conditions, while also limiting the potential effect of diagnosis threat. While self-report and neuropsychological measures of attention and memory did not differentiate the groups, the mild TBI group took significantly longer to accurately detect repeated targets on our working memory task. Accuracy was comparable in the low-load condition and, unexpectedly, mild TBI performance surpassed that of controls in the high-load condition. Temporal analysis of target identification suggested a strategy difference between groups: mild TBI participants made a significantly greater number of accurate responses following the target’s offset, and significantly fewer erroneous distracter responses prior to target onset, compared to controls. In Experiment 2b we also examined whether manipulating executive processing demands would differentiate mild TBI from controls, this time on a routine action task that required participants to learn a sequence of hand movements to targets. While not significant, we found a trend such that mild TBI participants were slower to respond on trials with a large executive demand compared controls, while no differences were found on trials with relatively low executive requirements. Results from Experiments 2a and 2b provide stronger evidence for mild TBI-related slowing during a working memory task with an executive component compared to a skilled action task that also had an executive component, but placed minimal demand on memory. To more precisely identify the brain basis of this cognitive slowing, in Experiment 3 we administered a visual n-back task in which we systematically increased working memory demands from 0- to 3-item loads. We found that, compared to controls, mild TBI participants showed a reduction in P300 amplitude, conceptualized as an index of available cognitive resources for stimulus classification. While no late stage response differences were found between groups, P300 amplitude was negatively correlated with response times at higher loads in both control and mild TBI participants. Findings suggest that high functioning young adults who sustained a mild TBI in their remote past, have a reduced amount, or inefficient recruitment of, cognitive resources for target detection; a potential mechanism underlying mild TBI-related response slowing on tasks that place a heavy demand on processing resources. Similar to the effects of mild TBI, aging is also known to negatively impact cognition. In Experiment 4, we examined whether TBI-related deficits persist into older adulthood, and compound the negative effect of aging on cognition. We administered the same working memory task as in Experiment 2a, along with a variety of neuropsychological tests in order to investigate the effect of a TBI sustained an average of 50 years in the past. While no group differences emerged on our experimental working memory task, older adults with a history of 1 or 2 TBIs performed significantly worse than non head-injured older adults only on neuropsychological measures of attention that had an executive component. Such results suggest that a remote TBI sustained early in life further compounds normal age-related cognitive decline. Together, these experiments help specify the measures that best detect long lasting cognitive changes following TBI. Particularly, our findings provide a potential explanation for why long-term cognitive deficits are difficult to identify in the young mild TBI population: the majority of neuropsychological tests are insensitive to minor changes in information processing speed and, as a result, the execution of slowing strategies to maintain accuracy may go undetected. Our findings also demonstrate the importance of investigating longer-term effects of TBI, as they may be chronic and impact cognitive task performance in old age, amplifying normal age-related cognitive deficits.
390

Development and Validation of a Music-based Attention Assessment for Patients with Traumatic Brain Injury

Jeong, Eunju 09 December 2011 (has links)
Impairments in attention are commonly seen in individuals with traumatic brain injury (TBI). While attention assessment measurements have been developed rigorously and utilized frequently in cognitive neurorehabilitation, there is a paucity of auditory attention assessment instruments that are ecologically valid and that assess different subtypes of attention. Yet, deficits in auditory attention can severely limit everyday functioning, negatively impact work and personal relationships and compromise personal safety. The purpose of this study was to develop and to investigate the psychometric properties of a Music-based Attention Assessment (MAA) instrument. The MAA is a multiple choice, melodic contour identification test, designed to assess three different types of auditory attention, including sustained attention, selective attention, and divided attention. The MAA was piloted with patients with TBI (n = 15) and healthy adults (n = 30) separately to evaluate preliminary psychometric properties. Both pilot studies reported that the MAA possessed a very high reliability and appropriate item properties. However, the MAA was revised due to a ceiling effect on mean test scores in the healthy adult group. The revised version of the MAA was administered to healthy adults (n = 165) as well as TBI patients (n= 22) to investigate construct validity, item properties, test reliability, and difference in MAA performance between groups. Here, psychometric validation of the revised version of the MAA is described, and the obtained results reported. Exploratory factor analysis identified five-factor constructs, supporting the different types of attention that underlie the test items of the revised version of the MAA. The factors identified were Sustained-Short, Sustained-Med to Long, Selective-Noise, Selective & Divided, and Divided-Long. After item elimination, the finalized 45-item MAA in relation to the identified five-factor constructs provided evidence of high internal consistencies as computed by split-half reliability coefficients (r = .836) and Cronbach’s alpha (α = .940), indicating homogeneity of test items within each of the five subtest as well as for the total test. As predicted, significant differences were found between the healthy adult and TBI patient samples across the exploratively obtained five-factor constructs of the revised version of the MAA. The MAA performance was significantly better in the healthy adult group than in the TBI patient group, except on the Sustained Attention–Short Subtest, indicating pervasive attention impairments in patients with TBI. The finding also suggests that a basic level of sustained attention to deal with a small amount of auditory information during a limited time might be intact for the patients with TBI who have a moderate to severe level of brain injury. The aggregate findings suggest that the MAA is a valid and reliable measure that provides diagnostic information in regards to the three types of auditory attention deficits frequently observed in patients with TBI. The use of melodic contours in attention assessment is discussed along with limitations of the study and suggestions for future research. The MAA, when used in conjunction with attention assessment instruments in different sensory modalities, would provide a greater level of precision in the attention assessment of patients with TBI, resulting in more symptom specific and individualized rehabilitation and treatment.

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