Browsing by Subject "Longitudinal"

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Adult Cognitive Functioning In Adolescent-Onset And Persistent Alcohol Use Disorders In Men
(2013-05) Sparks, Jordan
Alcohol use disorders ("AUDs") have a high prevalence rate, are heterogeneous, and are associated with deficits in executive abilities, learning, and memory. The literature on adolescent AUD and adult cognitive functioning is limited, and no prospective study has simultaneously examined how an AUD-onset during a neurologically-vulnerable period, persistence of use in adulthood, and an interaction of these processes may attenuate or exacerbate cognitive issues. This study used two AUD subtypes commonly employed to characterize the heterogeneity in AUD presentation - the adolescent-onset and persistent subtype - to address these questions, and also relied on measures of behavioral disinhibition and intellectual functioning ascertained during childhood to address the concern that the relationship between AUDs and later-cognitive functioning may be subject to confounding. It was hypothesized that premorbid childhood risk factors would relate to both AUD subtype and adult cognition, that both an adolescent-onset and a persistent course of AUD would relate to cognitive deficits in adulthood, and that accounting for premorbid risk factors would attenuate this relationship. A community sample of 650 men born in Minnesota was assessed at six visits occurring between age 11 and age 29 and divided into AUD groups of adolescent-onset persisters and desisters, adult-onset persisters and desisters, and controls. Both AUD-membership and age 29 cognitive performance were associated with risk factors that preceded AUD-onset; when accounting for premorbid risk, there was scant evidence that AUDs were associated with cognitive deficits. Future research of AUDs and cognition should account for premorbid risk factors.
Antibiotic resistance in the lower intestinal microbiota of dairy cattle: longitudinal analysis of phenotypic and genotypic resistance.
(2012-02) Boyer, Timothy Charles
This research focused on methods of measuring antibiotic resistance and analysis of antibiotic resistance data in dairy cattle that were sampled repeatedly over time. Specific objectives included: characterization and longitudinal analysis of phenotypic antibiotic resistance of commensal Escherichia coli, development of a statistical model for the analysis of low quantity resistance genes measured by quantitative real-time polymerase chain reaction (qPCR), measurement of antibiotic resistance genes in the lower intestinal bacterial communities of dairy cattle that received a short-term therapeutic dose of antibiotic and untreated cattle, and measurement and longitudinal analysis of the quantities of six antibiotic resistance genes in the lower intestinal bacterial communities of dairy cattle. Enteric E. coli collected from dairy cattle over 1.5 years were tested for phenotypic resistance to 17 antimicrobials. A total of 93 phenotypic patterns were observed among 3,402 isolates tested, with a majority (67%) susceptible to all 17 antimicrobials. The most prevalent resistances were to tetracycline, sulfamethoxazole, and streptomycin. Latent class and latent transition analyses were carried out to group the animals into classes according to their resistance phenotypes and to estimate the probabilities of transitioning into and out of classes over time. Probabilities of transitioning to a pan-susceptible class were high, as were the probabilities of remaining in the pan-susceptible class. Probabilities of transitioning form a pan-susceptible class to a resistant class were very low. Measurement of antibiotic resistance genes by qPCR presents challenges for genes that are present in very low quantities. A statistical model was developed to analyze qPCR data made up of a significant proportion of observations that fall below the limit of quantification of a qPCR assay. Computer simulations showed that the statistical model produced less biased estimates of regression parameters than common methods of handling low quantity qPCR data. qPCR was applied to a cohort of dairy cattle that received a five day course of ceftiofur and matched untreated cattle. Quantities of a gene (blaCMY-2) that confers resistance to ceftiofur were measured and analyzed using the statistical model developed for low quantity genes. Treated animals had significantly higher quantities of blaCMY-2 during treatment than untreated animals. By the first day post-treatment, gene quantities had returned to pre-treatment levels. The quantities of six different antibiotic resistance genes were measured by qPCR in the fecal community bacterial DNA of a cattle population that was sampled repeatedly over 2.5 years. Significantly increasing trends over time were observed for three of the six genes conferring resistance to tetracyclines, macrolides, and cephalosporins. Comparison of phenotypic resistance and qPCR data showed that qPCR performed on community DNA is a more sensitive method of detection that phenotypic testing of cultured isolates.
Comparing crossing hazard rate functions by joint modeling survival and longitudinal data
(2013-06) Park, Ka Young
Comparison of two hazard rate functions is important for evaluating treatment effect in studies concerning times to some important events. In practice, it is quite common that the two hazard rate functions cross each other at one or more unknown time points, representing temporal changes of the treatment effect. In certain applications, besides survival data, we also have related longitudinal data available regarding some time-dependent covariates. In such cases, a joint model that accommodates both types of data can allow us to infer the association between the survival and longitudinal data and to better assess the treatment effect. In our research, we propose a modeling approach for comparing two crossing hazard rate functions by joint modeling survival and longitudinal data. Maximum likelihood estimation is used in estimating the parameters of the proposed joint model using the EM algorithm. Asymptotic properties of the maximum likelihood estimators are studied. To illustrate the virtues of the proposed method, we compare the performance of the proposed method with several existing methods in a simulation study. Our proposed method is also demonstrated using a real dataset obtained from a HIV clinical trial. Furthermore, when jointly modeling the survival and longitudinal data in such cases, model selection and model diagnostics are especially important to provide reliable statistical analysis of the data. Therefore, we discuss several criteria for assessing model fit that have been used for model selection, and apply them to a joint modeling approach for comparing two crossing hazard rate functions when both survival and longitudinal data are available. Also, we propose both formal and informal methods for model assessment of the joint modeling approach. Our proposed methods are validated by a simulation study, and they are demonstrated by a real-data example concerning early breast cancer treatments.
The Convergence of Retrospective and Prospective Assessments of Childhood Abuse: Prospective Longitudinal Evidence from an At-risk sample
(2023) Nivison, Marissa
Scholars across multiple disciplines, both within and beyond developmental psychology, have been long interested in the effects of childhood abuse. Many studies have investigated the legacy of experiences of childhood abuse. However, most of these studies take a retrospective approach to studying early life experiences. Recent meta-analytic evidence (Baldwin et al., 2019) has demonstrated that retrospective measures of child abuse are not a valid proxy for prospective longitudinal data. The present report builds on these meta-analytic findings by investigating the convergence of prospectively documented child abuse from birth to age 17.5 in the Minnesota Longitudinal Study of Risk and Adaptation (MLSRA) and retrospective assessments of physical and sexual abuse newly coded in the context of the Adult Attachment Interview (AAI). Surprisingly, the convergence between prospective and retrospective assessments of childhood abuse was notably higher (k = .71) than previously seen in meta-analytic findings (k = .19). Convergence between retrospective and prospective measures were similar across dichotomous and continuous measures of abuse as well as type of abuse (physical and sexual). Convergence was lowest for abuse perpetrated by non-caregivers and for abuse perpetrated in infancy. The implications for future research investigating childhood experiences of physical and sexual abuse are discussed.
Dual language development among Vietnamese-English bilingual children:modeling trajectories and cross-linguistic associations within a dynamic systems framework.
(2011-06) Pham, Giang Thuy
The purpose of this longitudinal study was to mathematically model first and second language trajectories and interactions among developing sequential bilingual school-age children. Language data were collected in four waves, with a one-year interval between each wave. Participants (N = 34, mean age of 7.3 at Wave 1) lived in the US, spoke Vietnamese as a first and home language (L1) and began learning the majority community language, English (L2), in early childhood. Children completed measures in the L1 and L2 at lexical, grammatical, and discourse subsystems each year for four consecutive years. Multivariate hierarchical linear models were calculated to examine the shape and rates of change for the two languages nested within individual children. Associations within and between languages were examined across different language subsystems at each wave and over time in a series of correlational and longitudinal analyses. Results showed (a) positive growth across all language subsystems for the L1 and L2 with relatively more rapid gains in the L2, (b) moderate to strong positive associations between languages at each wave and over time, (c) bidirectional cross-linguistic transfer, and (d) changes in the nature of L1-L2 relationships with age. Findings are interpreted within a Dynamic Systems framework in which a child's language system emerges from multiple interactions across cognitive, social and language systems as well as interactions within and between languages (de Bot, Lowie, & Verspoor, 2007; Kohnert, 2007).
Factors accounting for change in effective parenting following homelessness.
(2012-08) Plowman, Elizabeth Jeanne
When homeless, families experience disruptions that may compromise parents’ abilities to demonstrate effective caregiving behaviors with their children. Consistently supportive parenting practices, however, are critical for children’s adaptive development within highly stressful environments. Although supportive housing sites provide families with affordable, private housing, it is unknown if parenting practices change or remain stable as families navigate from homeless to housed status. The purpose of this study was to describe change in observed effective parenting practices of 229 formerly homeless parent-child dyads over three years, and to examine the role of individual and contextual factors in contributing to change processes. Mothers and children, enrolled in a randomized control trial, participated annually in 26-min of videotaped interaction tasks on four measurement occasions. Using second-order latent growth curve modeling, we examined growth in a latent factor of effective parenting. The effective parenting factor met assumptions of strong factorial invariance, providing evidence that change in the construct was attributed to true growth rather than measurement error. Results indicated that group-level effective parenting improved over time, although individuals demonstrated variability in change. A quadratic fixed factor model provided the best fit to the data; effective parenting increased, but improvements tapered off as time passed. Parents who reported lower levels of parenting self-efficacy at baseline experienced greater improvements in parenting. Perceived social support, participation in a prevention program, and history of residential instability did not predict growth. Results are discussed in the context of intervention and parenting in transition.
Fatigue and disease trajectories in chronic liver disease patients: the role of gender and coexistent symptoms.
(2010-08) Jorgensen, Roberta Ann
BACKGROUND: Fatigue is a common symptom in chronic liver disease, significantly impacting multiple aspects of quality of life. Although fatigue severity correlates poorly with traditional markers of liver disease activity, greater fatigue has been associated with an increased risk for early death, providing evidence of its prognostic significance (Jones, 2006). Gender differences exist in fatigue reporting yet little is know about gender differences in liver disease. Fatigue in liver disease has been associated with symptoms of sleep disturbance and daytime somnolence yet the relationship of these other symptoms with underlying disease is not well studied. The purpose of this study was to investigate the interrelatedness of fatigue and disease trajectories in patients with chronic liver disease. The intent of this analysis was to explore whether the general level and rate of change over time differs by gender and the presence at baseline of other symptoms. METHOD: A secondary analysis was done of data collected on 150 primary sclerosing cholangitis (PSC) patients who participated in a treatment trial over a 5-year period. Patients completed yearly fatigue questionnaires and quality of life assessments, which included symptom questions, and were assessed on severity of their liver disease by calculation of risk scores. Linear mixed-effect models were used to examine patterns of fatigue and disease, their covariation over time, and the predictive effect of gender and coexistent symptoms. RESULTS: Fatigue increases only slightly over time; yet liver disease severity exhibits an accelerated rate of progression. Female gender, insomnia, concentration difficulty, and itching predict significantly greater fatigue levels. Itching and disease duration were related to disease severity. Although women suffer great fatigue morbidity they do not suffer worse disease. Levels and patterns of fatigue and disease severity do not covary over time, indicating that they are separate processes. CONCLUSIONS: Fatigue levels in liver disease patients remain stable with little increase over time; however disease progresses at an increasing rate of change. Women and those with insomnia, concentration difficulty and itching are more likely to have greater fatigue but not worse disease. No evidence was found of an association between fatigue and disease levels or related patterns of change over time.
Identity Integration in Emerging Adulthood: A Longitudinal Investigation of Well-Being and Psychological Outcomes
(2019-06) Nelson, Sarah C.
This study applies the theoretical framework for identity integration presented by Syed and McLean (2016) to a longitudinal and mixed methods investigation of the process and content of contextual identity integration in emerging adults at four time points over the first three years of college (N = 189, Mage at wave one = 18.70). A unique application of Little’s (2015) Personal Projects Analysis was used to address five weaknesses of past investigations of contextual identity integration by exploring identity integration at the second tier of personality: characteristic adaptations. Results suggested two unique processes: contextual identity integration and contextual identity disintegration. For the majority of participants contextual identity integration decreased across the first three years of college. Concurrent associations suggested complex associations between psychological health, contextual identity integration and disintegration. Taken together with coding of the content of these integrative processes, findings suggest the significance of interpersonal connection to contextual identity integration, as well as the importance of novel approaches to the measurement of identity integration.
Incorporation of Covariates in Bayesian Piecewise Growth Mixture Models
(2022-12) Lamm, Rik
The Bayesian Covariate Influenced Piecewise Growth Mixture Model (CI-PGMM) is an extension of the Piecewise Growth Mixture Model (PGMM, Lock et al., 2018) with the incorporation of covariates. This was done by using a piecewise nonlinear trajectory over time, meaning that the slope has a point where the trajectory changes, called a knot. Additionally, the outcome data belong to two or more latent classes with their own mean trajectories, referred to as a mixture model. Covariates were incorporated into the model in two ways. The first was influencing the outcome variable directly, explaining additional random error variance. The second is the influence of the covariates on the class membership directly with the use of multinomial logistic regression. Both uses of covariates can potentially influence the class memberships and along with that, the trajectories and locations of the knot(s). This additional explanation of class memberships and trajectories can provide information on how individuals change, who is likely to belong in certain unknown classes, and how these class memberships can affect when the rapid change of a knot will happen. The model is shown to be appropriate and effective using two steps. First, a real data application using the National Longitudinal Survey of Youth is used to show the motivation for the model. This dataset measures income over time each year for individuals following high school. Covariates of sex and dropout status were used in the class predictive logistic regression model. This resulted in a two-class solution showing effective use of the covariates with the logistic regression coefficients drastically affecting the class memberships. The second step is using a simulation after the motivating real data application. Pilot studies were used to show if the model was suitable for a full simulation using the coefficients from the real data example as a basis for the data generation. Four pilot studies were performed, and reasonable estimates were found for the full simulation. The conditions were set up with a two class model. One class containing one knot, and the second class as a linear slope. Two class predictive covariates and one outcome predictive covariate were used. A full simulation with 200 generated datasets was performed with manipulated conditions being error variance, sample size, model type, and class probability for a 3x3x3x2 model with 54 total conditions. Outcome measures of convergence, average relative bias, RMSE, and coverage rate were used to show suitability of the model. The simulation showed the use for the CI-PGMM was stable and accurate for multiple conditions. Sample size and model type were the most impactful predictors of appropriate model use. All outcome measures were worse for the small sample sizes and became more accurate when the sample sizes were larger. Also, the simpler models showed less bias and better convergence. However, these differences are smaller when the sample size is sufficiently large. These findings were supported with multi-factor ANOVA comparing simulation conditions. Use of the CI-PGMM in the real data example and the full simulation allowed for incorporation of covariates when appropriate. I show that model complexity can lead to issues of lower convergence, thus the model should only be used when appropriate and the sample size is sufficiently large. When used, however, the model can shed light on associations between covariates, class memberships, and locations of knots that were previously unavailable.
P3-related brain components and the externalizing spectrum disorders.
(2009-11) Yoon, Henry Hyunkoo
Objective: This dissertation explored the neurophysiological correlates of lifetime externalizing (EXT) spectrum disorders in two studies using a community-based sample of 29-year-old adult men assessed longitudinally. The first study used high-density EEG brain data to test the hypothesis that reductions in time-domain and time-frequency component measures previously identified in 17-year-old youth with EXT continue to be present in adults at age 29 when participants have largely passed through the age of heaviest substance misuse, and when brain development is further complete. The second study tested the notion that reductions on these brain measures could serve as endophenotypes (or inherited biomarkers) for EXT risk by investigating the developmental stability of these associations across a 12-year span. We further uniquely tested whether significant reduction in time-domain P3 amplitude could be used to predict the eventual diagnosis of an externalizing disorder over a decade later. Method: In both studies, EEG data were obtained using a visual oddball task. Participants were assessed from age-17 through age-29 for the lifetime presence of EXT disorders. The first study used data from 378 male twin participants from the original 17-year-old cohort of the Minnesota Twin Family Study (MTFS) who had high-density EEG data that allowed for regional scalp analyses, including data from the frontal region that was not available before. The second study included the same 29-year-old males who had EEG data collected from a midline parietal site (site-Pz) at both their age-17 and age-29 assessments (n = 325). All comparisons were made against controls free of any EXT diagnosis by age 29. Results: The hypothesis tested in the first study was supported with both time-domain and time-frequency components coinciding with P3 activity significantly reduced across all EXT groups, particularly at the posterior regions. Furthermore, a theta time-frequency component yielded frontal discriminations that were not apparent in the time-domain. Hypotheses from the second study were also confirmed with group results demonstrating reductions in these brain measures across all EXT groups with comparable effects observed at both age-17 and age-29. Finally, P3 amplitude at age-17 was predictive of EXT status by age-29 with every one-microvolt decrease in P3 amplitude associated with an approximately 5% increase in risk for an age-29 EXT diagnosis. In both studies, the effects of acute and cumulative substance exposure on the various brain measures were insignificant. Conclusions: Despite brain changes associated with normative development and potential substance exposure related to EXT symptomatology, both time-domain and time-frequency measures associated with P3 activity continue to provide effective, stable and predictive brain markers related to a wide spectrum of EXT psychopathology. These findings offer further support for the notion that P3-related measures constitute endophenotypes that tap into a neural substrate underlying behavioral disinhibition.
The prestige treadmill: connections between prestige and revenue in higher education.
(2011-08) Sanford, Thomas
This study examines the relationship between prestige and institutional funding profiles. Specifically, it analyses the relationship between increases in institutional prestige and an institution's dependency on traditional revenue sources, defined as tuition, fees, and state appropriations. Research and theory suggest that increases in prestige can reduce an institution's dependence on traditional revenue streams and therefore increase its revenue diversification. This analysis uses linear mixed models to examine cross-sectional, time-structured and balanced data over a period of 21 years. The findings suggest that prestige has no statistically significant relationship to an institution's ability to increase the proportion of its revenue coming from non-traditional sources, compared to its peer institutions.
Sensory Features in Autism Spectrum Disorder: A Systematic Review of Measurement Quality and Empirical Investigation of Sensory Responsivity in Children at High and Low Familial Risk for Autism
(2021-12) Gunderson, Jaclyn
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with heterogenous presentation and varying outcomes for children impacted by the condition. The etiology and bio-mechanisms of autism are not well understood. For decades research has focused on the social, communication, and cognitive symptoms associated with ASD. However, sensory symptoms were added to the diagnostic criteria for ASD in 2013 and continue to gain research attention. Historically, sensory symptoms were thought to emerge as secondary consequences of social-cognitive deficits. However, recent empirical work suggests that sensory symptoms manifest early in development and may contribute to the heterogeneity of ASD. For this dissertation, I systematically reviewed the literature to appraise the quality of proxy report sensory measurement tools used to assess sensory features in ASD. Furthermore, in a sample of children with a high and low familial likelihood for developing ASD, I characterized sensory responsivity in social and non-social contexts early in life and investigated the development of sensory responsivity throughout childhood with considerations for variables that may relate to developmental changes and their association with later adaptive behavior. Results from the current studies indicate that proxy report sensory questionnaires attempt to quantify sensory features in ASD via vastly different dimensions with little attention given to either construct or structural validity. Moreover, results show that sensory responsivity behaviors emerged across social and non-social contextual domains early in life and relate to restricted and repetitive behavior and adaptive behavior later in toddlerhood. Compared to children without ASD, children with ASD tend to demonstrate more early sensory responsivity behaviors that increase in a curvilinear relation to chronological age with specific trajectory differences across responsivity behavior patterns (hyperresponsivity, hyporesponsivity, sensory seeking). Additionally, heightened hyporesponsivity in the first year of life predicts lower adaptive behavior later in childhood. Specifically, results suggest that sensory features emerge prior to the consolidation of broad ASD symptoms and relate to adaptive outcomes. However, construct dimensions including the un-agreed upon multidimensionality of sensory features has important implications for future understanding and clinical practice.
Social support mediates the relation between attachment and responses to potentially traumatic events
(2013-09) Shallcross, Sandra Lynn
Insecure adult attachment is consistently related to posttrauma functioning, but this relation has rarely been examined prospectively across a wide range of potentially traumatic events (PTEs). In addition, the mediating mechanisms for this relation are not yet fully understood. Therefore, the first aim of this study was to assess whether pretrauma attachment orientation would predict changes in functioning following a PTE. The second aim was to determine whether social support would mediate this relation. Undergraduate students (N = 1,084) completed pre-PTE measures of psychological and social well-being at Time 1 (T1); 73% (N = 789) completed a follow up survey 2 months later (Time 2; T2). Those who reported experiencing PTE between T1 and T2 completed a final follow-up survey 4 months after T1 (Time 3; T3). Insecure attachment orientation predicted increases in PTSD, psychological distress and aggression, and decreases in social functioning from T1 to T3. These relations were mediated by perceptions of social support reported at T2. These findings have important implications for research and practice with populations exposed to potentially traumatic events.

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