scholarly journals Non-Parametric Mixture Modelling and its Application to Disease Progression Modelling

2018 ◽  
Author(s):  
Nicholas C. Firth ◽  
Neil P. Oxtoby ◽  
Silvia Primativo ◽  
Emilie Brotherhood ◽  
Alexandra L. Young ◽  
...  
Keyword(s):  
Disease Progression ◽  
Test Data ◽  
Cognitive Test ◽  
Cognitive Changes ◽  
Cross Sectional ◽  
Mixture Modelling ◽  
Changes Over Time ◽  
Over Time ◽  
Cognitive Data ◽  
Non Parametric

AbstractDementia is characterised by its progressive degeneration of cognitive abilities. In research cohorts, detailed neuropsychological test batteries are often administered to better understand how cognition changes over time. Understanding cognitive changes in dementia is of great importance, particularly in determining how structural changes in the brain may affect cognition and in facilitating earlier detection of symptomatic changes. Disease progression models are often applied to these data to understand how a disease changes over time from cross-sectional data or to disease trajectories from large numbers of individuals. Previous disease progression models used to build longitudinal models from cross-sectional data have focused on brain imaging data; however, these models are not directly applicable to cognitive data. Here we use the novel, non-parametric, Kernel Density Estimation Mixture Modelling (KDEMM) approach and demonstrate accurate modelling of the progression of cognitive test data. We found that using KDEMM resulted in more accurate models of disease progression in simulated data compared to Gaussian Mixture Models (GMMs) for the majority of parameters used to simulate the data. When comparing KDEMM and GMM to cognitive data collected in different Alzheimers Disease subtypes, we found the KDEMM resulted in a model much more in line with clinical phenotype. We anticipate that the KDEMM will be used to integrate cognitive test data, and other non-normally distributed datasets into complex disease progression models.

Temporal Trends in the Severity and Mortality of Neonatal Hypoxic-Ischemic Encephalopathy in the Era of Hypothermia

Neonatology ◽  
2021 ◽  
pp. 1-8
Author(s):  
Cristina Vega-Del-Val ◽  
Juan Arnaez ◽  
Sonia Caserío ◽  
Elena Pilar Gutiérrez ◽  
Marta Benito ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Cross Sectional Study ◽  
Annual Incidence ◽  
Hypoxic Ischemic Encephalopathy ◽  
Cross Sectional ◽  
Incidence And Mortality ◽  
Changes Over Time ◽  
Ischemic Encephalopathy ◽  
Annual Decline ◽  
Over Time

<b><i>Introduction:</i></b> There is a paucity of studies examining temporal trends in the incidence and mortality of moderate-to-severe hypoxic-ischemic encephalopathy (HIE) during the last decade of therapeutic hypothermia (TH). <b><i>Methods:</i></b> Multicenter cross-sectional study of all infants ≥35 weeks gestational age diagnosed with moderate-to-severe HIE within 6 h of birth in an extensive region of Spain between 2011 and 2019, in order to detect trend changes over time in the (1) annual incidence, (2) severity of neurological and systemic organ involvement, and (3) neonatal death from HIE. <b><i>Results:</i></b> Annual incidence rate of moderate-to-severe HIE was 0.84 (95% confidence interval [CI] 0.7–0.97) per 1,000 births, without trend changes over time (<i>p</i> = 0.8), although the proportion of severe HIE infants showed an average annual decline of 0.86 points (95% CI 0.75–0.98). There were 102 (70%) infants diagnosed with moderate HIE and 44 (30%) with severe HIE. TH was offered to 139/146 (95%) infants. Infants with clinical and/or electrical seizures showed a decreasing trend from 56 to 28% (<i>p</i> = 0.006). Mortality showed a nonstatistically significant decline (<i>p</i> = 0.4), and the severity of systemic damage showed no changes (<i>p</i> = 0.3). Obstetric characteristics remained unchanged, while higher perinatal pH values (<i>p</i> = 0.03) and Apgar scores (<i>p</i> = 0.05), and less need for resuscitation (<i>p</i> = 0.07), were found over time. <b><i>Conclusion:</i></b> The annual incidence of moderate-to-severe HIE has stabilized at around 1 per 1,000 births, with a temporal trend toward a decrease in severe HIE infants and a slight decline of mortality. No association was found between temporal trends and changes in perinatal/obstetric characteristics over time.

scholarly journals Evolution of impulsive–compulsive behaviors and cognition in Parkinson’s disease

2019 ◽  
Vol 267 (1) ◽  
pp. 259-266
Author(s):  
Aleksander H. Erga ◽  
Guido Alves ◽  
Ole Bjørn Tysnes ◽  
Kenn Freddy Pedersen
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Short Form ◽  
Population Based ◽  
Self Report ◽  
Cognitive Changes ◽  
Compulsive Behaviors ◽  
Changes Over Time ◽  
Over Time

Abstract The longitudinal course of ICBs in patients with Parkinson’s disease (PwP) relative to controls has not been explored as of yet. The aim of this study is to determine the frequency, evolution and associated cognitive and clinical features of impulsive and compulsive behaviors (ICBs) over 4 years of prospective follow-up in a population-based cohort with early Parkinson’s disease (PD). We recruited 124 cognitively intact participants with early PD and 156 matched controls from the Norwegian ParkWest study. ICBs were assessed using the self-report short form version of the Questionnaire for Impulsive–Compulsive Disorders in PD. Cognitive changes were examined in PwP with and without ICBs who completed the 4-year follow-up. Generalized linear mixed modelling and mixed linear regression were used to analyze clinical factors and cognitive changes associated with ICBs in PwP over time. ICBs were more common in PwP than controls at all visits, with an age-adjusted odds ratio (OR) varying between 2.5 (95% CI 1.1–5.6; p = 0.022) and 5.1 (95% CI 2.4–11.0; p < 0.001). The 4-year cumulative frequency of ICBs in PwP was 46.8% and 23.3% developed incident ICBs during the study period, but the presence of ICBs was non-persistent in nearly 30%. ICBs were independently associated with younger age (OR 0.95, 95% CI 0.91–0.99: p = 0.008) and use of dopamine agonist (OR 4.1, 95% CI 1.56–10.69). Cognitive changes over time did not differ between patients with and without ICBs. In conclusion, ICBs are common in PwP, but are often non-persistent and not associated with greater cognitive impairment over time.

scholarly journals Cross-sectional and prospective associations between sleep regularity and metabolic health in the Hispanic Community Health Study/Study of Latinos

SLEEP ◽  
2020 ◽  
Author(s):  
Josef Fritz ◽  
Andrew J K Phillips ◽  
Larissa C Hunt ◽  
Akram Imam ◽  
Kathryn J Reid ◽  
...  
Keyword(s):  
Community Health ◽  
Cell Function ◽  
Diabetes Risk ◽  
Health Study ◽  
Diabetes Incidence ◽  
Antidiabetic Medication ◽  
Cross Sectional ◽  
Hispanic Community ◽  
Changes Over Time ◽  
Over Time

Abstract Study Objectives Sleep is an emergent, multi-dimensional risk factor for diabetes. Sleep duration, timing, quality, and insomnia have been associated with diabetes risk and glycemic biomarkers, but the role of sleep regularity in the development of metabolic disorders is less clear. Methods We analyzed data from 2107 adults, aged 19–64 years, from the Sueño ancillary study of the Hispanic Community Health Study/Study of Latinos, followed over a mean of 5.7 years. Multivariable-adjusted complex survey regression methods were used to model cross-sectional and prospective associations between the sleep regularity index (SRI) in quartiles (Q1-least regular, Q4-most regular) and diabetes (either laboratory-confirmed or self-reported antidiabetic medication use), baseline levels of insulin resistance (HOMA-IR), beta-cell function (HOMA-β), hemoglobin A1c (HbA1c), and their changes over time. Results Cross-sectionally, lower SRI was associated with higher odds of diabetes (odds ratio [OR]Q1 vs. Q4 = 1.64, 95% CI: 0.98–2.74, ORQ2 vs. Q4 = 1.12, 95% CI: 0.70–1.81, ORQ3 vs. Q4 = 1.00, 95% CI: 0.62–1.62, ptrend = 0.023). The SRI effect was more pronounced in older (aged ≥ 45 years) adults (ORQ1 vs. Q4 = 1.88, 95% CI: 1.14–3.12, pinteraction = 0.060) compared to younger ones. No statistically significant associations were found between SRI and diabetes incidence, as well as baseline HOMA-IR, HOMA-β, and HbA1c values, or their changes over time among adults not taking antidiabetic medication. Conclusions Our results suggest that sleep regularity represents another sleep dimension relevant for diabetes risk. Further research is needed to elucidate the relative contribution of sleep regularity to metabolic dysregulation and pathophysiology.

Trajectories of major depression disorders: A systematic review of longitudinal neuroimaging findings

2016 ◽  
Vol 51 (5) ◽  
pp. 441-454 ◽  
Author(s):  
Katharina Dohm ◽  
Ronny Redlich ◽  
Pienie Zwitserlood ◽  
Udo Dannlowski
Keyword(s):  
Systematic Review ◽  
Major Depression ◽  
Longitudinal Studies ◽  
Time Window ◽  
Mood State ◽  
Sample Sizes ◽  
Cross Sectional ◽  
Changes Over Time ◽  
Over Time ◽  
Course Of Depression

Objective: Structural and functional brain alterations in major depression disorder (MDD) are well studied in cross-sectional designs, but little is known about the causality between onset and course of depression on the one hand, and neurobiological changes over time on the other. To explore the direction of causality, longitudinal studies with a long time window (preferably years) are needed, but only few have been undertaken so far. This article reviews all prospective neuroimaging studies in MDD patients currently available and provides a critical discussion of methodological challenges involved in the investigation of the causal relationship between brain alterations and the course of MDD. Method: We conducted a systematic review of studies published before September 2015, to identify structural magnetic resonance imaging (MRI) studies that assess the relation between neuronal alterations and MDD in longitudinal (⩾1 year) designs. Results: Only 15 studies meeting minimal standards were identified. An analysis of these longitudinal data showed a large heterogeneity between studies regarding design, samples, imaging methods, spatial restrictions and, consequently, results. There was a strong relationship between brain-volume outcomes and the current mood state, whereas longitudinal studies failed to clarify the influence of pre-existing brain changes on depressive outcome. Conclusion: So far, available longitudinal studies cannot resolve the causality between the course of depression and neurobiological changes over time. Future studies should combine high methodological standards with large sample sizes. Cooperation in multi-center studies is indispensable to attain sufficient sample sizes, and should allow careful assessment of possible confounders.

scholarly journals T189. FREE THYROXIN CONCENTRATIONS MODERATE THE RESPONSE TO A COGNITIVE REMEDIATION THERAPY IN PEOPLE WITH EARLY PSYCHOSIS: PRELIMINARY FINDINGS

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S303-S304
Author(s):  
Francesc Estrada ◽  
Josep Maria Crosas ◽  
Maribel Ahuir ◽  
Sara Pérez ◽  
Wanda Zabala ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Cognitive Remediation ◽  
Early Psychosis ◽  
Cognitive Tasks ◽  
First Episode ◽  
Cognitive Changes ◽  
Cognitive Domains ◽  
Episode Psychosis ◽  
Changes Over Time ◽  
Over Time

Abstract Background Cognitive deficits are a common cause of functional disability in people with psychotic disorders. Cognitive remediation produces moderate improvements in cognitive performance in people with schizophrenia, although there is variability in the responses between patients. As previous longitudinal studies suggest that free thyroxin (FT4) levels influence attention cognitive tasks in patients with early psychosis, we aimed to conduct a pilot study to explore whether thyroid hormones might predict the response to cognitive remediation therapy (CRT) in patients with first-episode psychosis. Methods 27 patients (8 women; 19 men) with first-episode psychosis aged between 18 and 35 years old were randomized to receive a computerized CRT for three months (2 sessions/week) (N=14) or treatment as usual (TAU) (N=13). A full cognitive battery (CANTAB Schizophrenia) was administered at baseline and follow-up (3 months later, after the CRT/TAU period). Plasma levels of thyroid-stimulating hormone (TSH) and FT4 were measured. Data were analyzed on an intention-to-treat basis. Correlation analyses were conducted to explore the association between TSH and FT4 levels and cognitive changes over time. An ANOVA for repeated measures was used to compare longitudinal changes over time by the experimental group while adjusting for TSH and FT4 levels. Significance was defined as p&lt;0.05. Results TSH concentrations were not associated with cognitive changes over time. FT4 concentrations were associated with cognitive worsening over time in cognitive tasks dealing with reaction time (simple median movement time [r= 0.60, p= 0.003]; simple median reaction time [r= 0.44, p= 0.039]), sustained attention (signal detection for the rapid visual processing task [r= -0.46, p= 0.028]) and verbal memory (immediate recognition [r= -0.54, p= 0.008]; delayed recognition [r= -0.48, p= 0.019]). The ANOVA for repeated measures did not show time by group effects although a time by FT4 significant effect was found for cognitive tasks dealing with these cognitive domains (p&lt;0.05 for all). Discussion Although a direct effect of the CRT on cognitive improvement was not found, baseline FT4 concentrations appeared to predict the response to CRT in people with early psychosis. Significant associations were found for cognitive domains dealing with attention processes, which are in accordance with previous studies exploring the association between thyroid function and cognitive functioning in early psychotic patients. Our preliminary findings suggest that the determination of thyroid function status might be important for establishing which patients could show cognitive improvements over time. If these results are replicated in larger studies, the determination of thyroid status might help identify those individuals more prone for showing cognitive improvements, and allowing the implementation of a personalized medicine approach in the field of cognitive rehabilitation in psychosis.

scholarly journals Institutional logic and scholars' reactions to performance measurement in universities

2021 ◽  
Vol 34 (9) ◽  
pp. 104-130
Author(s):  
Kirsi-Mari Kallio ◽  
Tomi J. Kallio ◽  
Giuseppe Grossi ◽  
Janne Engblom
Keyword(s):  
Performance Measurement ◽  
Organizational Level ◽  
Institutional Logic ◽  
Institutional Work ◽  
Cross Sectional ◽  
Content Type ◽  
Measurement Systems ◽  
Performance Measurement Systems ◽  
Changes Over Time ◽  
Over Time

PurposeEmploying institutional logic and institutional work as its theoretical framework, this study analyzes scholars' reactions to performance measurement systems in academia.Design/methodology/approachLarge datasets were collected over time, combining both quantitative and qualitative elements. The data were gathered from a two-wave survey in 2010 (966 respondents) and 2015 (672 respondents), conducted among scholars performing teaching- and research-oriented tasks in three Finnish universities.FindingsThe analysis showed statistically significant changes over time in the ways that the respondents were positioned in three major groups influenced by different institutional logics. This study contributes to the international debate on institutional change in universities by showing that in Finnish universities, emerging business logics and existing professional logics can co-exist and be blended among a growing group of academics. The analysis of qualitative open-ended answers suggests that performance measurement systems have led to changes in institutional logic, which have influenced the scholars participating in institutional work at the microlevel in academia.Social implicationsWhile most scholars remain critical of performance measurement systems in universities, the fact that many academics are adapting to performance measurement systems highlights significant changes that are generally occurring in academia.Originality/valueWhile most extant studies have focused on field- and organizational-level analyses, this study focuses on understanding how the adoption of performance measurement systems affects institutional logic and institutional work at the microlevel. Moreover, the study's cross-sectional research setting increases society's understanding of institutional evolution in academia.

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