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Statistical Analysis Of Two Arm Randomized Pre-Post Designs With One Post-Treatment Measurement, Fei Wan

2020-Current year OA Pubs

BACKGROUND: Randomized pre-post designs, with outcomes measured at baseline and after treatment, have been commonly used to compare the clinical effectiveness of two competing treatments. There are vast, but often conflicting, amount of information in current literature about the best analytic methods for pre-post designs. It is challenging for applied researchers to make an informed choice.

METHODS: We discuss six methods commonly used in literature: one way analysis of variance ("ANOVA"), analysis of covariance main effect and interaction models on the post-treatment score ("ANCOVAI" and "ANCOVAII"), ANOVA on the change score between the baseline and post-treatment scores ("ANOVA-Change"), repeated measures …

The Constances Job Exposure Matrix Based On Self-Reported Exposure To Physical Risk Factors: Development And Evaluation, Bradley A Evanoff, Marcus Yung, Skye Buckner-Petty, Johan Hviid Andersen, Yves Roquelaure, Alexis Descatha, Ann Marie Dale

Open Access Publications

OBJECTIVES: Job exposure matrices (JEMs) can be constructed from expert-rated assessments, direct measurement and self-reports. This paper describes the construction of a general population JEM based on self-reported physical exposures, its ability to create homogeneous exposure groups (HEG) and the use of different exposure metrics to express job-level estimates.

METHODS: The JEM was constructed from physical exposure data obtained from the Cohorte des consultants des Centres d'examens de santé (CONSTANCES). Using data from 35 526 eligible participants, the JEM consisted of 27 physical risk factors from 407 job codes. We determined whether the JEM created HEG by performing non-parametric multivariate …

Neuronal Activity Regulates Extracellular Tau In Vivo, Kaoru Yamada, Jerrah K. Holth, Fan Liao, Floy R. Stewart, Thomas E. Mahan, Hong Jiang, John R. Cirrito, Tirth K. Patel, Katja Hochgräfe, Eva-Maria Mandelkow, David M. Holtzman

Open Access Publications

Tau is primarily a cytoplasmic protein that stabilizes microtubules. However, it is also found in the extracellular space of the brain at appreciable concentrations. Although its presence there may be relevant to the intercellular spread of tau pathology, the cellular mechanisms regulating tau release into the extracellular space are not well understood. To test this in the context of neuronal networks in vivo, we used in vivo microdialysis. Increasing neuronal activity rapidly increased the steady-state levels of extracellular tau in vivo. Importantly, presynaptic glutamate release is sufficient to drive tau release. Although tau release occurred within hours in response to …

Ethanol Enhances Neurosteroidogenesis In Hippocampal Pyramidal Neurons By Paradoxical Nmda Receptor Activation, Kazuhiro Tokuda, Yukitoshi Izumi, Charles F. Zorumski

Open Access Publications

Using an antibody against 5α-reduced neurosteroids, predominantly allopregnanolone, we found that immunostaining in the CA1 region of rat hippocampal slices was confined to pyramidal neurons. This neurosteroid staining was increased following 15 min administration of 60 mm but not 20 mm ethanol, and the enhancement was blocked by finasteride and dutasteride, selective inhibitors of 5α-reductase, a key enzyme required for allopregnanolone synthesis. Consistent with a prior report indicating that N-methyl-D-aspartate (NMDA) receptor (NMDAR) activation can promote steroid production, we observed that D-2-amino-5-phosphonovalerate (APV), a competitive NMDAR antagonist, blocked the effects of 60 mm ethanol on staining. We previously reported that …

Controlled Cortical Impact Traumatic Brain Injury In 3xtg-Ad Mice Causes Acute Intra-Axonal Amyloid-Β Accumulation And Independently Accelerates The Development Of Tau Abnormalities, Hien T. Tran, Frank M. Laferla, David M. Holtzman, David L. Brody

Open Access Publications

Alzheimer's disease (AD) is a neurodegenerative disorder characterized pathologically by progressive neuronal loss, extracellular plaques containing the amyloid-β (Aβ) peptides, and neurofibrillary tangles composed of hyperphosphorylated tau proteins. Aβ is thought to act upstream of tau, affecting its phosphorylation and therefore aggregation state. One of the major risk factors for AD is traumatic brain injury (TBI). Acute intra-axonal Aβ and diffuse extracellular plaques occur in ∼30% of human subjects after severe TBI. Intra-axonal accumulations of tau but not tangle-like pathologies have also been found in these patients. Whether and how these acute accumulations contribute to subsequent AD development is not …

Nonuniform High-Gamma (60-500 Hz) Power Changes Dissociate Cognitive Task And Anatomy In Human Cortex, Charles M. Gaona, Mohit Sharma, Zachary V. Freudenburg, Jonathan D. Breshears, David T. Bundy, Jarod Roland, Dennis L. Barbour, Gerwin Schalk, Eric C. Leuthardt

Open Access Publications

High-gamma-band (>60 Hz) power changes in cortical electrophysiology are a reliable indicator of focal, event-related cortical activity. Despite discoveries of oscillatory subthreshold and synchronous suprathreshold activity at the cellular level, there is an increasingly popular view that high-gamma-band amplitude changes recorded from cellular ensembles are the result of asynchronous firing activity that yields wideband and uniform power increases. Others have demonstrated independence of power changes in the low- and high-gamma bands, but to date, no studies have shown evidence of any such independence above 60 Hz. Based on nonuniformities in time-frequency analyses of electrocorticographic (ECoG) signals, we hypothesized that …

Vestibular Heading Discrimination And Sensitivity To Linear Acceleration In Head And World Coordinates, Paul R. Macneilage, Martin S. Banks, Gregory C. Deangelis, Dora E. Angelaki

Open Access Publications

Effective navigation and locomotion depend critically on an observer's ability to judge direction of linear self-motion, i.e., heading. The vestibular cue to heading is the direction of inertial acceleration that accompanies transient linear movements. This cue is transduced by the otolith organs. The otoliths also respond to gravitational acceleration, so vestibular heading discrimination could depend on (1) the direction of movement in head coordinates (i.e., relative to the otoliths), (2) the direction of movement in world coordinates (i.e., relative to gravity), or (3) body orientation (i.e., the direction of gravity relative to the otoliths). To quantify these effects, we measured …

The Emotional Modulation Of Cognitive Processing: An Fmri Study, Joseph Simpson, Dost Ongür, Erbil Akbudak, Thomas Conturo, John Ollinger, Abraham Snyder, Debra Gusnard, Marcus Raichle

Open Access Publications

The functional neuroanatomy of visual processing of surface features of emotionally valenced pictorial stimuli was examined in normal human subjects using functional magnetic resonance imaging (fMRI). Pictorial stimuli were of two types: emotionally negative and neutral pictures. Task performance was slower for the negatively valenced than for the neutral pictures. Significant blood oxygen level dependent (BOLD) increases occurred in the medial and dorsolateral prefrontal cortex, midbrain, substantia innominata, and/or amygdala, and in the posterior cortical visual areas for both stimulus types. Increases were greater for the negatively valenced stimuli. While there was a small but significant BOLD decrease in the …