Publications by authors named "Chris Gregory"

Article Synopsis
  • High-dose testosterone replacement therapy (TRT) combined with finasteride offers benefits such as improved body composition, muscle strength, and bone density in older men, while mitigating the risk of prostate enlargement.
  • A pilot study involved 12 men with spinal cord injuries, demonstrating that TRT with finasteride significantly increased lean body mass and muscle size, alongside enhancing bone mineral density compared to a placebo.
  • Results suggest TRT + finasteride reduced fat mass and improved muscular strength, with measurable benefits observed as early as 6 months into the treatment, indicating its potential effectiveness for men with low testosterone post-injury.
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Stroke is a leading cause of disability in the US, often altering one's ability to access and consume food. The aim of the present study was to characterize and evaluate predictors of stroke survivors' diet quality (DQ). A cross-sectional evaluation of 2011-2018 National Health and Nutrition Examination Survey data is presented.

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Article Synopsis
  • The study investigates how aerobic exercise (AEx), especially high-intensity AEx (HI), may improve neuroplasticity, which is often reduced in individuals with depression.
  • Sixteen people with depression and 13 without underwent three different exercise conditions: low-intensity AEx, high-intensity AEx, and a control (sitting).
  • Results showed that HI AEx significantly increased neuroplasticity compared to the other conditions, suggesting it could enhance treatments that focus on improving brain adaptability in depression.
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Purpose: Stroke is a leading cause of long-term disability in the US, yet a feasible assessment measure with predictive value for components of the International Classification of Functioning, Disability, and Health (ICF) Core Set for Stroke is lacking. The purpose of the present study was to explore the predictive value of potential assessment measures on factors within each ICF component in stroke survivors.

Materials And Methods: Demographic, anthropometric, blood-based biomarker, physical functioning, and Global Physical Activity Questionnaire data were collected on stroke survivors in the 2011-2018 NHANES cycles.

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Background: Maximizing independence and function post-stroke are two common therapy goals. Rate of torque development in lower-extremity muscles was recently reported to be associated with walking speed; however, trainability and subsequent effect on gait is unknown. This study aimed to determine effect of power training on paretic and non-paretic limb torque parameters, spatiotemporal gait parameters, and walking speed in chronic stroke survivors.

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Background And Objectives: Functional outcomes after stroke are strongly related to focal injury measures. However, the role of global brain health is less clear. In this study, we examined the impact of brain age, a measure of neurobiological aging derived from whole-brain structural neuroimaging, on poststroke outcomes, with a focus on sensorimotor performance.

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Objectives: To (1) examine the feasibility of combining lower extremity aerobic exercise (AEx) with a virtual reality (VR) upper extremity (UE) rehabilitation intervention and (2) provide an estimate of effect size for the combined intervention on UE function, aerobic capacity, and health-related quality of life.

Design: Single-group feasibility trial.

Setting: Research laboratory.

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Purpose: Poststroke fatigue (PSF) contributes to increased mortality and reduces participation in rehabilitative therapy. Although PSF's negative influences are well known, there are currently no effective evidence-based treatments for PSF. The lack of treatments is in part because of a dearth of PSF pathophysiological knowledge.

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Background: Post-stroke depression (PSD) occurs in approximately one-third of chronic stroke survivors. Although pharmacotherapy reduces depressive symptoms, side effects are common and stroke survivors have increased likelihood of multimorbidity and subsequent polypharmacy. Thus, alternative non-pharmacological treatments are needed.

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Exercise training (EX) and weight loss (WL) improve lower extremity physical function (LEPF) in older overweight women; however, effects on rate of torque development (RTD) are unknown. This study aimed to determine the effects of WL + EX or WL alone on RTD, and relatedly LEPF, in overweight older women. Leg strength was assessed using isokinetic dynamometry, and RTD was calculated (RTD200 = RTD at 200 ms, RTDPeak = peak RTD, T2P = time to 1st peak).

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Background: Mass flexion-extension co-excitation patterns during walking are often seen as a consequence of stroke, but there is limited understanding of the specific contributions of different descending motor pathways toward their control. The corticospinal tract is a major descending motor pathway influencing the production of normal sequential muscle coactivation patterns for skilled movements. However, control of walking is also influenced by non-corticospinal pathways such as the corticoreticulospinal pathway that possibly contribute toward mass flexion-extension co-excitation patterns during walking.

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Globally, depression is a leading cause of disability and has remained so for decades. Antidepressant medications have suboptimal outcomes and are too frequently associated with side effects, highlighting the need for alternative treatment options. Although primarily known for its robust physical health benefits, exercise is increasingly recognized for its mental health and antidepressant benefits.

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Article Synopsis
  • Accurate lesion segmentation is essential for quantifying stroke-related damage and improving image processing, but current automated methods for T1-weighted MRIs remain unreliable.
  • Manual segmentation is the standard but is labor-intensive and requires specialized knowledge.
  • The newly released ATLAS v2.0 dataset, which includes 1,271 T1-weighted MRIs and segmented lesion masks, aims to enhance algorithm development and provide better evaluation through hidden datasets for more effective stroke research.
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Up to two-thirds of stroke survivors experience persistent sensorimotor impairments. Recovery relies on the integrity of spared brain areas to compensate for damaged tissue. Deep grey matter structures play a critical role in the control and regulation of sensorimotor circuits.

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Objective: Validate a conceptual framework and identify pathways between antecedent (life-course socioeconomic status (L-SES)), predisposing (age, sex, married, homeless as a child), enabling (health literacy, acculturation), and need (disability) social determinants of health (SDoH) and systolic blood pressure (SBP) in US immigrants.

Methods: 181 immigrants were enrolled in the study. Path analysis was used to identify paths by which SDoH influence SBP and to determine if antecedents, predisposing, enabling, and need factors have direct and indirect relationships with SBP.

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Identify the pathway by which social determinants of health (SDoH) variables impact systolic blood pressure (SBP) in immigrants. Latent variables were used to assess the relationship between SDoH and SBP. Latent variables were identified using confirmatory factor analysis (CFA) for (1) global socioeconomic status (SES) (education, income, number of hours worked per week), (2) stressors of immigration (life-course SES, immigration stress, immigration demand), (3) adaptation to immigration (perceived discrimination, perceived stress, health literacy), and (4) burden of disease (disability, comorbidities, chronic pain).

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Recent stroke studies have shown that the ipsi-lesional thalamus longitudinally and significantly decreases after stroke in the acute and subacute stages. However, additional considerations in the chronic stages of stroke require exploration including time since stroke, gender, intracortical volume, aging, and lesion volume to better characterize thalamic differences after cortical infarct. This cross-sectional retrospective study quantified the ipsilesional and contralesional thalamus volume from 69 chronic stroke subjects' anatomical MRI data (age 35-92) and related the thalamus volume to time since stroke, gender, intracortical volume, age, and lesion volume.

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The purpose of this study was to develop and evaluate a new, open-source MR-compatible device capable of assessing unipedal and bipedal lower extremity movement with minimal head motion and high test-retest reliability. To evaluate the prototype, 20 healthy adults participated in two magnetic resonance imaging (MRI) visits, separated by 2-6 months, in which they performed a visually guided dorsiflexion/plantar flexion task with their left foot, right foot, and alternating feet. Dependent measures included: evoked blood oxygen level-dependent (BOLD) signal in the motor network, head movement associated with dorsiflexion/plantar flexion, the test-retest reliability of these measurements.

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The goal of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well-powered meta- and mega-analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data.

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Background: Hypertension is responsible for about 12.8% of deaths around the world. Immigrants' risk of developing hypertension increases with length of residency.

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In neurologically healthy individuals, exercise positively impacts depressive symptoms, but there is limited knowledge regarding the association between exercise behaviors and depression after spinal cord injury (SCI). To examine associations between doing planned exercise and probable major depressive disorder (PMDD) after SCI. Community-dwelling adults, who were one or more years post traumatic SCI, completed self-report assessments at baseline (Time 1) and an average of 3.

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Context: Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function.

Objective: To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function.

Design: Cross-sectional study.

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Objective: Estimate (1) prevalence of major depressive disorder (MDD) diagnosis; (2) risk factors associated with MDD diagnosis; (3) time at which MDD is diagnosed post-spinal cord injury (SCI); and (4) interaction of inferred mobility status (IMS) in a commercially insured population over 3 years.

Design: Retrospective longitudinal cohort design.

Setting: A commercial insurance claims database from January 1, 2010 to December 31, 2013.

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Objective: The objective of this paper was to develop and test a novel control algorithm that enables stroke survivors to pedal a cycle in a desired cadence range despite varying levels of functional abilities after stroke.

Methods: A novel algorithm was developed which automatically adjusts 1) the intensity of functional electrical stimulation (FES) delivered to the leg muscles, and 2) the current delivered to an electric motor. The algorithm automatically switches between assistive, uncontrolled, and resistive modes to accommodate for differences in functional impairment, based on the mismatch between the desired and actual cadence.

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This study examined the relationship between immigrant specific social determinants of health (SDoH) and blood pressure control. Data on 181 adult immigrants from the Midwestern United States was analyzed. SDoH variables were categorized based on antecedents, predisposing, enabling, and need factors.

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