Repository logo

Browsing by Author "Bielak, Allison, committee member"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Awareness of age-related change (AARC): measurement, conceptual status, and role for promoting successful aging
    (Colorado State University. Libraries, 2016) Brothers, Allyson F., author; Diehl, Manfred, advisor; Bielak, Allison, committee member; Fidler, Deborah, committee member; Henry, Kimberly, committee member
    Recent renewed interest has arisen regarding the ways in which individuals experience the process of growing older, an area of research known as subjective aging. A growing body of research shows a consistent pattern of results in which subjective aging exerts wide-reaching and consequential influence on both physical functioning as well as psychological well-being in later life. Historically, research has relied on simplistic, unidimensional measures, that while quite predictive of developmental outcomes, are somewhat of a 'black box' in that it is not understood exactly what information people rely on to make them. Therefore, the construct awareness of age-related change (AARC) was developed to yield insight into the specific behavioral domains in which aging experiences are noticed. Given the need for such a construct in the literature, the manuscript in Chapter 2 focuses on the development of a reliable and valid assessment tool to measure awareness of age-related change (AARC). Not only is such a construct more representative of leading theories in adult development and aging, it is also vital for understanding how people experience aging in different life domains. Therefore, the manuscript in Chapter 3 will explore how AARC is similar to and distinct from existing subjective aging constructs, and also how it is related to important physical and psychological outcome variables. Chapter 4 then extends the current state of research regarding subjective aging, which has largely been observational in nature, and attends to the issues of intervention design: Given the mounting evidence of the importance of attitudinal variables of aging, Chapter 4 explores the following questions: 1) Can more realistic and positive attitudes toward aging be promoted through intervention? and 2) Does modifying attitudes have tangible effects on health behavior promotion?
  • Thumbnail Image
    ItemOpen Access
    The relationship between cognitive functions and occupational performance in children, adults, and adults with attention deficit hyperactivity disorders (ADHD)
    (Colorado State University. Libraries, 2018) Lin, Mei-Heng, author; Davies, Patricia, advisor; Bielak, Allison, committee member; Gavin, William, committee member; Malcolm, Matthew, committee member
    The overarching goal of this dissertation is to explore the relationship between cognitive functions and occupational performance in neurotypical children, neurotypical adults, and adults with attention-deficit/hyperactivity disorder (ADHD). Electroencephalography (EEG)/event-related potential (ERP) techniques were used to measure the neural processes while participants performed a speeded computer-based task for the three studies conducted in this dissertation. The first study examined the test-retest reliability on the amplitudes of two ERP components associated with performance monitoring, the error-related negativity (ERN) and error-positivity (Pe), in 53 neurotypical adults and 118 neurotypical children aged 8-12-year-old. The findings indicated that the test-retest reliability of these measures was moderate for children (rERN = 0.55, rPe = 0.62), and was moderate to strong for adults (rERN = 0.69, rPe = 0.75). Moreover, the adaptive Woody filter was implemented to adjust for the trial-to-trial variation in latency (i.e., latency jitter) when measuring the ERN and Pe amplitudes. The findings showed that adjusting for the latency jitter did not improve the reliability of ERN and Pe amplitudes for both groups, suggesting that the latency variability may be a trait-like variable which systematically occurred across sessions. Furthermore, the test-retest reliability of stimulus-locked ERP components on correct trials was higher compared to the reliability of response-locked ERPs for children and adults, confirming that both children and adults generally attended to the task consistently across sessions. The second study demonstrated the feasibility of utilizing the structural equation modeling (SEM) approach to model the complicated inter-relationship between neural processes and simple task behaviors (e.g., response times) in 143 children with typical development aged 8-12 years. The findings from the latent models indicated that the brain-and-behavior relationships were significant on correct trials but were not significant on incorrect trials after controlling for trait and state factors. Moreover, both models demonstrated different patterns of relationship among latent variables to response time, yet both models yielded excellent model fit indices. This finding suggested that our conceptual models were valid in terms of detecting the distinct patterns of neural processes leading to opposite behavioral outcomes (e.g., correct and incorrect). The final model demonstrated that the post-error adjustment in the stream of neural processes provided an adaptive effect on the early neural processing of the stimulus on correct trials. To our knowledge, this is the first study demonstrating how the post-error adjustment occurs at the level of neural processing. The third study (1) compared the group differences (children, adults, and adults with ADHD) on neural and occupational performance measures, (2) examined the inter-relationship between these measures for each group, and (3) investigated which measures can best differentiate three groups. The findings suggested that adults with ADHD demonstrated significantly lower quality of occupational performance particularly on the motor aspect of the activities of daily living (ADL). Moreover, for neurotypical children, larger ERN amplitudes were associated with lower quality of social interaction. For adults with ADHD, larger N2 amplitude was associated with lower quality of social interaction. Lastly, discriminant analyses demonstrated that the combination of neural and occupational performance measures differentiated children, adults, and adults with ADHD with 93.2% classification accuracy. Taken together, this dissertation demonstrated significant brain-and-behavior relationships especially for neurotypical children and adults with ADHD by relating the neural measures (e.g., ERP components) to behaviors obtained from the computer-based task (e.g., response times), and to the quality of occupational performance (e.g., social interaction and ADL). Moreover, this dissertation demonstrated that having both neural and occupational performance measures is beneficial to obtain a comprehensive understanding of dimensions of maturation and disability.
  • Thumbnail Image
    ItemOpen Access
    Views of aging: their measurement, associations with the paradox of well-being, and malleability in the second half of life
    (Colorado State University. Libraries, 2024) Tseng, Han Yun, author; Diehl, Manfred, advisor; Bielak, Allison, committee member; Luong, Gloria, committee member; Henry, Kimberly, committee member
    As individuals age, they accumulate experiences that not only mark their position in the course of life, but also shape their feelings, beliefs, and attitudes towards aging, collectively known as subjective views of aging (VoA). Negative VoA, whether assessed explicitly through self-report questionnaires or implicitly via computer-administered subliminal priming tasks, consistently correlate with poorer self-rated health status, diminished functional outcomes, and reduced longevity in later life. Drawing upon the extensive VoA literature, this dissertation proposed three distinct yet related research themes of VoA, examining their measurement, their moderating role in buffering the impacts of declining health on subjective well-being (SWB), and their malleability via intervention. Specifically, the first manuscript in Chapter 2 validated a multidimensional VoA questionnaire, the Awareness of Age-Related Changes (AARC) scale, in a sample of Taiwanese older adults. This study also explored cross-cultural similarities and differences in AARC-gains and AARC-losses by examining measurement invariance with a comparable older adult sample in Germany. Chapter 3 investigated divergent trajectories of health and SWB from age 60s to 80s, known as the paradox of well-being in late life, using a 20-year longitudinal cohort study from Germany. To gain a more nuanced understanding of the well-being paradox, this manuscript explored the moderating role of VoA in the decoupled developmental trajectories of health and SWB. Chapter 4 focused on the malleability of adults' implicit and explicit VoA in the context of a randomized controlled trial (RCT). Whereas most interventions targeting older adults' negative VoA typically evaluated their efficacy based on explicit, self-reported VoA, this manuscript contrasted the intervention effects of the AgingPLUS program on explicit and implicit VoA. This study also examined the extent to which positive intervention-induced changes in explicit VoA were contingent upon varying levels of implicit VoA. Overall, the results derived from the three manuscripts aimed to (1) enhance the assessment and research of VoA in non-Western cultures and societies, (2) provide empirical support for VoA as positive age-related psychosocial processes contributing to high levels of well-being, and (3) inform the design of future interventions leveraging VoA for promoting successful and optimal aging among middle-aged and older adults. Overall, these findings underscored the importance of culturally sensitive approaches to measuring VoA across diverse aging populations. They also highlighted the potential of interventions promoting more positive VoA foster resilience and well-being in the second half of life.