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M.A. (Psychology) / Please refer to full text to view abstract

[Truncated thesis] This thesis is concerned with executive functioning in two different but related ways. The first is as an information processing construct in cognitive psychology. There are many different conceptualisations of the information processing basis of executive functioning but this thesis will pursue the notion that executive functioning is best thought of as adaptation to novelty. In the thesis, this will be operationalised using performance indices (principally reaction time) from a number of information processing tasks. These tasks have typically been used in the literature to index either executive functioning or speed of information processing. Both kinds of tasks are used to tackle the second concern of this thesis, namely, how executive functioning is measured. The data analytic techniques developed in this thesis are based on the hypothesis that executive functioning is the process or processes involved in resolving task novelty and consequently measurement will be enhanced through an analysis of performance changes within tasks as the task changes from novel to familiar. The analysis methods will be based largely on the computation of coefficient of variation of reaction time in successive performance windows across the information processing tasks. An elderly sample was chosen for this thesis because of a history of research that has attempted to determine whether cognitive deficits in the elderly are the consequence of the slowing of information processing speed or to impairment in executive functioning. ... The analysis was driven by the hypothesis that a significant shift in the coefficient of variation would mark a transition from novelty to familiarity in task performance and hence from executive to non-executive phases. Three methods were applied to individual performance curves to determine the point at which for each task this transition occurred. Using criterion measures of variability to separate the task data into two stages, analyses showed, contrary to the hypothesis, that later task performance was more highly associated with executive functioning than in initial task performance. The fourth stage of analysis (Chapter 7) applied confirmatory factor analysis to the newly-formed pre- and post transition data. Evidence was found that the magnitude of the contributions of EF across the pre- and post-criterion phases was stable, failing to support the hypothesis. Finally, structural equation modelling was used to examine how age and intelligence in this elderly sample exerts its influence on task performance and whether EF or IPS was the primary cause of age-related cognitive decline. The results showed that the age and intelligence effects on performance were mediated by the requirement to adapt to novelty. Although there was limited evidence to claim that EF is the primary cause of age-related cognitive decline, ageing effects were only apparent when the participants were adapting to novelty. The thesis concludes that there is some support for the hypothesis that executive functioning is best thought of as the processes underpinning adaptation to novelty. While not a panacea, the analytic techniques developed show promise for future research.

Graduation date: 2004

The present thesis describes the development and assessment of two computer-game-like tests designed to measure two cognitive abilities currently of considerable interest to many researchers: processing speed (Gs) and working memory (WM). It is hoped that such tests could provide a unique and important addition to the range of tests currently employed by researchers interested in these constructs. The results of five separate studies are presented across three published papers. In Paper 1-Study 1 (N = 49) a speeded computerized coding test (Symbol Digit) using the mouse as the response device was assessed. Because speeded tests are thought to be highly sensitive to response methods (Mead & Drasgow, 1994) it was deemed important to first assess how a mouse response method might affect the underlying construct validity of a speeded coding test independently of whether it was game-like. Factor analytic results indicated that the computerized coding test loaded strongly on the same factor as paper-andpencil measures of Gs. For Paper 2-Study 1 (N = 68) a more computer-game-like version of Symbol Digit was developed, Space Code. Development of Space Code involved the provision of a cover story, the replacing of code symbols with ‘spaceship’ graphics, the situating of the test within an overall ‘spaceship cockpit’, and numerous other graphical and aural embellishments to the task. Factor analytic results indicated that Space Code loaded strongly on a Gs factor but also on a factor comprised of visuo-spatial (Gv) ability tests. This finding was further investigated in the subsequent study. Paper 2-Study 2 (N = 74) involved a larger battery of ability marker tests and a range of additional computer-game-like elements were added to Space Code. Space Code included a scoring system, a timer with additional voice synthesized countdowns, aversive feedback for errors, and background music. Factor analysis indicated that after a general factor was extracted Space Code loaded on the same factor as paper-and-pencil measures of Gs and did not load on a factor comprised of non-speeded Gv tests. Paper 3-Study 1 (N = 74) was aimed at assessing a computer-game-like test of WM (Space Matrix) and further assessing Space Code within a broader network of tests. Space Matrix used a dual task format combining a simple version of Space Code with a visually presented memory task based on the Dot Matrix test (Miyake, Friedman, Rettinger, Shah, & Hegarty, 2001). The cover story and scoring system for Space Code was expanded to incorporate this additional memory element. Factor analysis indicated that Space Matrix was loaded on the same first order factor as standard WM tests and the Raven’s Advanced Progressive Matrices (Gf). Space Code was substantially loaded on the second order factor but was weakly loaded on each of two first order factors interpreted as Gs and WM/Gf. A final study is presented (Paper 3-Study2) in which Space Code and Space Matrix was administered to a school aged sample (N=94). Space Matrix exhibited construct validity as well as predictive validity (as a predictor of school grades), while results for Space Code were less encouraging. Space Matrix and Raven’s Progressive Matrices showed comparable relationships to school grades for Mathematics, English and Science subjects. It is concluded that the development of computer-game-like tests represents a promising new format for research and applied assessment of known cognitive abilities. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342350 / Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 2008

The present thesis describes the development and assessment of two computer-game-like tests designed to measure two cognitive abilities currently of considerable interest to many researchers: processing speed (Gs) and working memory (WM). It is hoped that such tests could provide a unique and important addition to the range of tests currently employed by researchers interested in these constructs. The results of five separate studies are presented across three published papers. In Paper 1-Study 1 (N = 49) a speeded computerized coding test (Symbol Digit) using the mouse as the response device was assessed. Because speeded tests are thought to be highly sensitive to response methods (Mead & Drasgow, 1994) it was deemed important to first assess how a mouse response method might affect the underlying construct validity of a speeded coding test independently of whether it was game-like. Factor analytic results indicated that the computerized coding test loaded strongly on the same factor as paper-andpencil measures of Gs. For Paper 2-Study 1 (N = 68) a more computer-game-like version of Symbol Digit was developed, Space Code. Development of Space Code involved the provision of a cover story, the replacing of code symbols with ‘spaceship’ graphics, the situating of the test within an overall ‘spaceship cockpit’, and numerous other graphical and aural embellishments to the task. Factor analytic results indicated that Space Code loaded strongly on a Gs factor but also on a factor comprised of visuo-spatial (Gv) ability tests. This finding was further investigated in the subsequent study. Paper 2-Study 2 (N = 74) involved a larger battery of ability marker tests and a range of additional computer-game-like elements were added to Space Code. Space Code included a scoring system, a timer with additional voice synthesized countdowns, aversive feedback for errors, and background music. Factor analysis indicated that after a general factor was extracted Space Code loaded on the same factor as paper-and-pencil measures of Gs and did not load on a factor comprised of non-speeded Gv tests. Paper 3-Study 1 (N = 74) was aimed at assessing a computer-game-like test of WM (Space Matrix) and further assessing Space Code within a broader network of tests. Space Matrix used a dual task format combining a simple version of Space Code with a visually presented memory task based on the Dot Matrix test (Miyake, Friedman, Rettinger, Shah, & Hegarty, 2001). The cover story and scoring system for Space Code was expanded to incorporate this additional memory element. Factor analysis indicated that Space Matrix was loaded on the same first order factor as standard WM tests and the Raven’s Advanced Progressive Matrices (Gf). Space Code was substantially loaded on the second order factor but was weakly loaded on each of two first order factors interpreted as Gs and WM/Gf. A final study is presented (Paper 3-Study2) in which Space Code and Space Matrix was administered to a school aged sample (N=94). Space Matrix exhibited construct validity as well as predictive validity (as a predictor of school grades), while results for Space Code were less encouraging. Space Matrix and Raven’s Progressive Matrices showed comparable relationships to school grades for Mathematics, English and Science subjects. It is concluded that the development of computer-game-like tests represents a promising new format for research and applied assessment of known cognitive abilities. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342350 / Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 2008

The present thesis describes the development and assessment of two computer-game-like tests designed to measure two cognitive abilities currently of considerable interest to many researchers: processing speed (Gs) and working memory (WM). It is hoped that such tests could provide a unique and important addition to the range of tests currently employed by researchers interested in these constructs. The results of five separate studies are presented across three published papers. In Paper 1-Study 1 (N = 49) a speeded computerized coding test (Symbol Digit) using the mouse as the response device was assessed. Because speeded tests are thought to be highly sensitive to response methods (Mead & Drasgow, 1994) it was deemed important to first assess how a mouse response method might affect the underlying construct validity of a speeded coding test independently of whether it was game-like. Factor analytic results indicated that the computerized coding test loaded strongly on the same factor as paper-andpencil measures of Gs. For Paper 2-Study 1 (N = 68) a more computer-game-like version of Symbol Digit was developed, Space Code. Development of Space Code involved the provision of a cover story, the replacing of code symbols with ‘spaceship’ graphics, the situating of the test within an overall ‘spaceship cockpit’, and numerous other graphical and aural embellishments to the task. Factor analytic results indicated that Space Code loaded strongly on a Gs factor but also on a factor comprised of visuo-spatial (Gv) ability tests. This finding was further investigated in the subsequent study. Paper 2-Study 2 (N = 74) involved a larger battery of ability marker tests and a range of additional computer-game-like elements were added to Space Code. Space Code included a scoring system, a timer with additional voice synthesized countdowns, aversive feedback for errors, and background music. Factor analysis indicated that after a general factor was extracted Space Code loaded on the same factor as paper-and-pencil measures of Gs and did not load on a factor comprised of non-speeded Gv tests. Paper 3-Study 1 (N = 74) was aimed at assessing a computer-game-like test of WM (Space Matrix) and further assessing Space Code within a broader network of tests. Space Matrix used a dual task format combining a simple version of Space Code with a visually presented memory task based on the Dot Matrix test (Miyake, Friedman, Rettinger, Shah, & Hegarty, 2001). The cover story and scoring system for Space Code was expanded to incorporate this additional memory element. Factor analysis indicated that Space Matrix was loaded on the same first order factor as standard WM tests and the Raven’s Advanced Progressive Matrices (Gf). Space Code was substantially loaded on the second order factor but was weakly loaded on each of two first order factors interpreted as Gs and WM/Gf. A final study is presented (Paper 3-Study2) in which Space Code and Space Matrix was administered to a school aged sample (N=94). Space Matrix exhibited construct validity as well as predictive validity (as a predictor of school grades), while results for Space Code were less encouraging. Space Matrix and Raven’s Progressive Matrices showed comparable relationships to school grades for Mathematics, English and Science subjects. It is concluded that the development of computer-game-like tests represents a promising new format for research and applied assessment of known cognitive abilities. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342350 / Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 2008

Until recently, there was no dementia screening tool for Indigenous Australians and a paucity of information on the extent of dementia in Indigenous Australians. This thesis describes the development and validation of a tool to assess cognitive impairment in remote Indigenous Australians with the primary purpose of determining the prevalence of dementia and other associated conditions in this population. The tool was reevaluated with the larger prevalence sample and a short version of the tool was developed and evaluated. The Kimberley Indigenous Cognitive Assessment (KICA) tool was validated with Indigenous Australians aged over 45 years from the Kimberley region of Western Australia (n=70). The results were later confirmed in a larger sample from the remote Kimberley (n=363), and an additional sample in rural and remote areas of the Northern Territory (n=47). The KICA results were compared to independent consensus diagnoses using DSM-IV and ICD-10. Interpreters were used whenever participants were not proficient in English. These data led to the determination of a cut-off score of 33/34 out of a possible total score of 39 for the cognitive component of the KICA (KICA-Cog), with a sensitivity of 0.93 and specificity of 0.95 and AUC of 0.98. The tool is now widely used within remote areas of Australia. A short version of the KICACog (sKICA-Cog) was developed and found to be a valid brief screening tool for dementia in the Kimberley population, and had a cut-off score of 20/21 out of a possible 25, with a sensitivity of 0.89, specificity of 0.95 and AUC of 0.98. The sKICA-Cog should be used in combination with the KICA cognitive informant questionnaire (KICA-IQ). The KICA-IQ cut-off score of 2/3 out of a possible 16 was determined, with a sensitivity of 0.76 and specificity of 0.84 and AUC of 0.91. Using the validated KICA, the prevalence of dementia and cognitive impairment not dementia (CIND) was determined in a semi-purposive sample consisting of 363 Indigenous Australians aged over 45 years from 6 Aboriginal communities and one town in the Kimberley region. Participants were screened with the full KICA and 165 participants had an independent specialist review with consensus diagnoses. The prevalence of dementia was 12.4%, 5.2 times greater than the Australian prevalence of 2.4%, after age adjustment. The prevalence of CIND was 8.0%. Characteristics associated with dementia included older age, male gender (OR 3.1, 95% CI 1.4, 6.8), no formal education (OR 2.7, 95% CI 1.1, 6.7), smoking (OR 4.5, 95% CI 1.1, 18.6), previous stroke (OR 17.9, 95% CI 5.9, 49.7), epilepsy (OR 33.5, 95% CI 4.8, 232.3) and head injury (OR 4.0, 95% CI 1.7, 9.4). Other factors associated with dementia included incontinence, falls and poor mobility. The KICA is a valid assessment tool for rural and remote Indigenous Australians. The prevalence of dementia amongst Indigenous Australians is substantially higher than generally found in non - Indigenous Australians and other populations in the developed and developing world.

Due to the fastest growing senior population, age-related cognitive impairments, including Alzheimer's disease, are becoming among the most common diseases in the United States. Currently, prevention through delay is considered the best way to tackle Alzheimer's disease and related dementia, as there is no known cure for those diseases. Early detection is crucial, in that screening individuals with Mild Cognitive Impairment may delay its onset and progression. For my dissertation work, I investigate how computing technologies can help medical practitioners detect and monitor cognitive impairment due to dementia, and I develop a computerized sketch-based screening tool. In this dissertation, I present the design, implementation, and evaluation of the ClockMe System, a computerized Clock Drawing Test. The traditional Clock Drawing Test (CDT) is a rapid and reliable instrument for the early detection of cognitive dysfunction. Neurologists often notice missing or extra numbers in the clock drawings of people with cognitive impairments and use scoring criteria to make a diagnosis and treatment plan. The ClockMe System includes two different applications - (1) the ClockReader for the patients who take the Clock Drawing Test and (2) the ClockAnalyzer for clinicians who use the CDT results to make a diagnosis or to monitor patients. The contributions of this research are (1) the creation of a computerized screening tool to help clinicians identify cognitive impairment through a more accessible and quick-and-easy screening process; (2) the delivery of computer-collected novel behavioral data, which may offer new insights and a new understanding of a patient's cognition; (3) an in-depth understanding of different stakeholders and the identification of their common user needs and desires within a complicated healthcare workflow system; and (4) the triangulation of multiple data collection methods such as ethnographical observations, interviews, focus group meetings, and quantitative data from a user survey in a real-world deployment study.

Indiana University-Purdue University Indianapolis (IUPUI) / The time course and biological mechanisms by which breast cancer (BC) and/or alterations in estrogen status lead to cognitive and brain changes remain unclear. The studies presented here use neuroimaging, cognitive testing, genetics, and biomarkers to investigate how post-chemotherapy interval (PCI), chemotherapy-induced amenorrhea (CIA), and genetic variation in the estrogen pathway affect the brain. Chapter 1 examines the association of post-chemotherapy interval (PCI) with gray matter density (GMD) and working memory-related brain activation in BC survivors (mean PCI 6.4, range 3-10 years). PCI was positively associated with GMD and activation in the right frontal lobe, and GMD in this region was correlated with global neuropsychological function. In regions where BC survivors showed decreased GMD compared to controls, this was inversely related to oxidative DNA damage and learning and memory scores. This is the first study to show neural effects of PCI and relate DNA damage to brain alterations in BC survivors. Chapter 2 demonstrates prospectively, in an independent cohort, decreased combined magnitudes of brain activation and deactivation from pre-to post-chemotherapy in patients undergoing CIA compared to both postmenopausal BC patients undergoing chemotherapy and healthy controls. CIA’s change in activity magnitude was strongly correlated with change in processing speed, suggesting this activity increase reflects effective cognitive compensation. These results demonstrate that the pattern of change in brain activity from pre- to post-chemotherapy varies according to pre-treatment menopausal status. Chapter 3 presents the effects of variation in ESR1, the gene that codes for estrogen receptor-α, on brain structure in healthy older adults. ESR1 variation was associated with hippocampus and amygdala volumes, particularly in females. Single nucleotide polymorphism (SNP) rs9340799 influenced cortical GMD and thickness differentially by gender. Apolipoprotein E (APOE)-ε4 carrier status modulated the effect of SNP rs2234693 on amygdala volumes in women. This study showed that genetic variation in estrogen relates to brain morphology in ways that differ by sex, brain region and APOE-ε4 carrier status. The three studies presented here explore the interplay of BC, estrogen, and cognition, showing that PCI, CIA, and ESR1 genotype influence brain phenotypes. Cognitive correlates of neuroimaging findings indicate potential clinical significance of these results.