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McIlvain G, Magoon EM, Clements RG, Merritt A, Hiscox LV, Schwarb H, Johnson CL. Acute effects of high-intensity exercise on brain mechanical properties and cognitive function. Brain Imaging Behav 2024:10.1007/s11682-024-00873-y. [PMID: 38538876 DOI: 10.1007/s11682-024-00873-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 04/26/2024]
Abstract
Previous studies have shown that engagement in even a single session of exercise can improve cognitive performance in the short term. However, the underlying physiological mechanisms contributing to this effect are still being studied. Recently, with improvements to advanced quantitative neuroimaging techniques, brain tissue mechanical properties can be sensitively and noninvasively measured with magnetic resonance elastography (MRE) and regional brain mechanical properties have been shown to reflect individual cognitive performance. Here we assess brain mechanical properties before and immediately after engagement in a high-intensity interval training (HIIT) regimen, as well as one-hour post-exercise. We find that immediately after exercise, subjects in the HIIT group had an average global brain stiffness decrease of 4.2% (p < 0.001), and an average brain damping ratio increase of 3.1% (p = 0.002). In contrast, control participants who did not engage in exercise showed no significant change over time in either stiffness or damping ratio. Changes in brain mechanical properties with exercise appeared to be regionally dependent, with the hippocampus decreasing in stiffness by 10.4%. We also found that one-hour after exercise, brain mechanical properties returned to initial baseline values. The magnitude of changes to brain mechanical properties also correlated with improvements in reaction time on executive control tasks (Eriksen Flanker and Stroop) with exercise. Understanding the neural changes that arise in response to exercise may inform potential mechanisms behind improvements to cognitive performance with acute exercise.
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Affiliation(s)
- Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Emily M Magoon
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Rebecca G Clements
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Alexis Merritt
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Lucy V Hiscox
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Hillary Schwarb
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA.
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Sanjana F, Delgorio PL, DeConne TM, Hiscox LV, Pohlig RT, Johnson CL, Martens CR. Vascular determinants of hippocampal viscoelastic properties in healthy adults across the lifespan. J Cereb Blood Flow Metab 2023; 43:1931-1941. [PMID: 37395479 PMCID: PMC10676145 DOI: 10.1177/0271678x231186571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/04/2023]
Abstract
Arterial stiffness and cerebrovascular pulsatility are non-traditional risk factors of Alzheimer's disease. However, there is a gap in understanding the earliest mechanisms that link these vascular determinants to brain aging. Changes to mechanical tissue properties of the hippocampus (HC), a brain structure essential for memory encoding, may reflect the impact of vascular dysfunction on brain aging. We tested the hypothesis that arterial stiffness and cerebrovascular pulsatility are related to HC tissue properties in healthy adults across the lifespan. Twenty-five adults underwent measurements of brachial blood pressure (BP), large elastic artery stiffness, middle cerebral artery pulsatility index (MCAv PI), and magnetic resonance elastography (MRE), a sensitive measure of HC viscoelasticity. Individuals with higher carotid pulse pressure (PP) exhibited lower HC stiffness (β = -0.39, r = -0.41, p = 0.05), independent of age and sex. Collectively, carotid PP and MCAv PI significantly explained a large portion of the total variance in HC stiffness (adjusted R2 = 0.41, p = 0.005) in the absence of associations with HC volumes. These cross-sectional findings suggest that the earliest reductions in HC tissue properties are associated with alterations in vascular function.
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Affiliation(s)
- Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Theodore M DeConne
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Lucy V Hiscox
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Ryan T Pohlig
- Department of Epidemiology, University of Delaware, Newark, DE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
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Tinney EM, Loui P, Raine LB, Hiscox LV, Delgorio PL, Kramer MK, Schwarb H, Martens CR, Kramer AF, Hillman CH, Johnson CL. Influence of mild cognitive impairment and body mass index on white matter integrity assessed by diffusion tensor imaging. Psychophysiology 2023; 60:e14306. [PMID: 37038273 PMCID: PMC10524314 DOI: 10.1111/psyp.14306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/16/2023] [Accepted: 03/27/2023] [Indexed: 04/12/2023]
Abstract
Mild cognitive impairment (MCI), a prodromal stage of Alzheimer's disease, is characterized by decreased memory and cognition, which are linked to degenerative changes in the brain. To assess whether white matter (WM) integrity is compromised in MCI, we collected diffusion-weighted images from 60 healthy older adults (OA) (69.16 ± 0.7) and 20 older adults with amnestic MCI (72.45 ± 1.9). WM integrity differences were examined using Tract-Based Spatial Statistics (TBSS). We hypothesized that those with MCI would have diminished WM integrity relative to OA. In a whole-brain comparison, those with MCI showed higher axial diffusivity in the splenium (SCC) and body of the corpus callosum (BCC), superior corona radiata (SCR), and the retrolenticular part of the internal capsule (RLIC) (p's < .05 TFCE-corrected). Additionally, significant between-group connectivity differences were observed using probabilistic tractography between the SCC, chosen from the TBSS results, and forceps major and minor (p-value's < .05). To further relate a physical health indicator to WM alterations, linear regression showed significant interactions between cognitive status and body mass index (BMI) on diffusivity outcome measures from probabilistic tractography (p-value-'s < .05). Additionally, we examined the association between relational memory, BMI, and WM integrity. WM integrity was positively associated with relational memory performance. These findings suggest that these regions may be more sensitive to early markers of neurodegenerative disease and health behaviors, suggesting that modifiable lifestyle factors may affect white matter integrity.
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Affiliation(s)
- Emma M. Tinney
- Northeastern University, Department of Psychology
- Northeastern University, Center for Cognitive and Brain Health
| | - Psyche Loui
- Northeastern University, Department of Psychology
- Northeastern University, Center for Cognitive and Brain Health
| | - Lauren B. Raine
- Northeastern University, Center for Cognitive and Brain Health
- Northeastern University, Department of Physical Therapy Movement Rehabilitation Sciences
- Northeastern University, Department of Medicinal Sciences
| | - Lucy V. Hiscox
- University of Delaware, Department of Biomedical Engineering
| | | | - Mary K. Kramer
- University of Delaware, Department of Biomedical Engineering
| | - Hillary Schwarb
- University of Illinois at Urbana-Champaign, Beckman Institute for Advanced Science and Technology
| | | | - Arthur F. Kramer
- Northeastern University, Department of Psychology
- University of Illinois at Urbana-Champaign, Beckman Institute for Advanced Science and Technology
| | - Charles H. Hillman
- Northeastern University, Department of Psychology
- Northeastern University, Center for Cognitive and Brain Health
- Northeastern University, Department of Physical Therapy Movement Rehabilitation Sciences
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Hiscox LV, Sharp TH, Olff M, Seedat S, Halligan SL. Sex-Based Contributors to and Consequences of Post-traumatic Stress Disorder. Curr Psychiatry Rep 2023; 25:233-245. [PMID: 37162661 DOI: 10.1007/s11920-023-01421-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/07/2023] [Indexed: 05/11/2023]
Abstract
PURPOSE OF REVIEW Women are twice as likely to develop post-traumatic stress disorder (PTSD) compared to men after a traumatic experience. The purpose of this mini review was to explore recent research on biological contributors to this sex difference. RECENT FINDINGS We identified 51 studies published since 2019. Studies found that beyond the influence of sex on the prevalence and symptoms of PTSD, there is evidence for and against sex-based differences in genetic and epigenetic factors (n = 8), brain structure and function (n = 11), neuroendocrine and inflammatory responses (n = 5), and in the role of sleep on emotional memory processing (n = 1). Sex differences were also observed in recovery and during PTSD treatment (n = 16). Finally, there is emerging evidence of sex-differentiated risk for medical and psychiatric comorbidities in PTSD (n = 10). Rapid advances are being made using integrated multidisciplinary approaches to understand why females are at a heightened risk for developing PTSD.
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Affiliation(s)
- Lucy V Hiscox
- Department of Psychology, University of Bath, Bath, UK
| | | | - Miranda Olff
- Department of Psychiatry, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- ARQ National Psychotrauma Centre, Diemen, the Netherlands
| | - Soraya Seedat
- Department of Psychiatry, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Sarah L Halligan
- Department of Psychology, University of Bath, Bath, UK.
- SAMRC Unit on Risk & Resilience in Mental Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa.
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Hiscox LV, Bray S, Fraser A, Meiser-Stedman R, Seedat S, Halligan SL. Sex differences in the severity and natural recovery of child PTSD symptoms: a longitudinal analysis of children exposed to acute trauma. Psychol Med 2023; 53:2682-2688. [PMID: 35000656 DOI: 10.1017/s0033291721004694] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Higher levels of PTSD symptoms are present among trauma-exposed females v. males in adulthood; however, much less is known about the emergence of this sex difference during development. METHODS In a multi-study sample of 7-18-year-olds (n = 3397), we examined the effect of sex and age on the severity of PTSD symptoms after a single incident trauma at 1 month (T1), and on symptom change after a natural recovery period of 3 (T2) and 6 months (T3). PTSD scores were harmonised across measurement types, and linear regressions were used to determine sex and age effects, adjusting for study level variance and trauma type. RESULTS A sex × age interaction was observed at T1 (p < 0.001) demonstrating that older age was associated with greater PTSD symptom severity in females (β = 0.008, p = 0.047), but less severe symptoms in males (β = -0.011, p = 0.014). The same pattern was observed at T2 and T3, with sex differences beginning to emerge by age 12 years. PTSD symptoms decreased naturally by ~25% at T2 with little further improvement by T3. Further, females showed a greater reduction in symptoms at T3 than males, although the same effect was not observed at T2. CONCLUSIONS Sex differences in PTSD symptoms become apparent during adolescence, due to opposing changes in susceptibility occurring in females and males with age. Understanding the factors contributing to these findings is likely to provide wider insight into sex-specific psychological vulnerability to trauma-related psychopathology.
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Affiliation(s)
- Lucy V Hiscox
- Department of Psychology, University of Bath, Bath, UK
| | - Sidney Bray
- Department of Psychology, University of Bath, Bath, UK
| | - Abigail Fraser
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Richard Meiser-Stedman
- Department of Clinical Psychology, Norwich Medical School, University of East Anglia, Norwich, UK
| | - Soraya Seedat
- Medical Research Council (MRC) Unit on Anxiety and Stress Disorders, Department of Psychiatry, Stellenbosch University, Tygerberg, Western Cape, South Africa
| | - Sarah L Halligan
- Department of Psychology, University of Bath, Bath, UK
- Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
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Hiscox LV, Fairchild G, Donald KA, Groenewold NA, Koen N, Roos A, Narr KL, Lawrence M, Hoffman N, Wedderburn CJ, Barnett W, Zar HJ, Stein DJ, Halligan SL. Antenatal maternal intimate partner violence exposure is associated with sex-specific alterations in brain structure among young infants: Evidence from a South African birth cohort. Dev Cogn Neurosci 2023; 60:101210. [PMID: 36764039 PMCID: PMC9929680 DOI: 10.1016/j.dcn.2023.101210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023] Open
Abstract
Maternal psychological distress during pregnancy has been linked to adverse outcomes in children with evidence of sex-specific effects on brain development. Here, we investigated whether in utero exposure to intimate partner violence (IPV), a particularly severe maternal stressor, is associated with brain structure in young infants from a South African birth cohort. Exposure to IPV during pregnancy was measured in 143 mothers at 28-32 weeks' gestation and infants underwent structural and diffusion magnetic resonance imaging (mean age 3 weeks). Subcortical volumetric estimates were compared between IPV-exposed (n = 63; 52% female) and unexposed infants (n = 80; 48% female), with white matter microstructure also examined in a subsample (IPV-exposed, n = 28, 54% female; unexposed infants, n = 42, 40% female). In confound adjusted analyses, maternal IPV exposure was associated with sexually dimorphic effects in brain volumes: IPV exposure predicted a larger caudate nucleus among males but not females, and smaller amygdala among females but not males. Diffusivity alterations within white matter tracts of interest were evident in males, but not females exposed to IPV. Results were robust to the removal of mother-infant pairs with pregnancy complications. Further research is required to understand how these early alterations are linked to the sex-bias in neuropsychiatric outcomes later observed in IPV-exposed children.
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Affiliation(s)
- Lucy V Hiscox
- Department of Psychology, University of Bath, Bath, UK.
| | | | - Kirsten A Donald
- Department of Pediatrics and Child Health, Red Cross War Memorial Children's Hospital and University of Cape Town, Cape Town, South Africa; The Neuroscience institute, University of Cape Town, Cape Town, South Africa
| | - Nynke A Groenewold
- Department of Pediatrics and Child Health, Red Cross War Memorial Children's Hospital and University of Cape Town, Cape Town, South Africa; The Neuroscience institute, University of Cape Town, Cape Town, South Africa; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Nastassja Koen
- The Neuroscience institute, University of Cape Town, Cape Town, South Africa; SA MRC Unit on Risk & Resilience in Mental Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Annerine Roos
- The Neuroscience institute, University of Cape Town, Cape Town, South Africa; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Katherine L Narr
- Departments of Neurology, Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | - Marina Lawrence
- Department of Pediatrics and Child Health, Red Cross War Memorial Children's Hospital and University of Cape Town, Cape Town, South Africa
| | - Nadia Hoffman
- Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Catherine J Wedderburn
- Department of Pediatrics and Child Health, Red Cross War Memorial Children's Hospital and University of Cape Town, Cape Town, South Africa; The Neuroscience institute, University of Cape Town, Cape Town, South Africa; Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Whitney Barnett
- Department of Psychology and Human Development, Vanderbilt University, USA
| | - Heather J Zar
- Department of Pediatrics and Child Health, Red Cross War Memorial Children's Hospital and University of Cape Town, Cape Town, South Africa; SA MRC Unit on Child & Adolescent Health, University of Cape Town, Cape Town, South Africa
| | - Dan J Stein
- The Neuroscience institute, University of Cape Town, Cape Town, South Africa; SA MRC Unit on Risk & Resilience in Mental Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Sarah L Halligan
- Department of Psychology, University of Bath, Bath, UK; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa; Department of Psychiatry, Stellenbosch University, Stellenbosch, South Africa
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Delgorio PL, Hiscox LV, McIlvain G, Kramer MK, Diano AM, Twohy KE, Merritt AA, McGarry MDJ, Schwarb H, Daugherty AM, Ellison JM, Lanzi AM, Cohen ML, Martens CR, Johnson CL. Hippocampal subfield viscoelasticity in amnestic mild cognitive impairment evaluated with MR elastography. Neuroimage Clin 2023; 37:103327. [PMID: 36682312 PMCID: PMC9871742 DOI: 10.1016/j.nicl.2023.103327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/06/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Hippocampal subfields (HCsf) are brain regions important for memory function that are vulnerable to decline with amnestic mild cognitive impairment (aMCI), which is often a preclinical stage of Alzheimer's disease. Studies in aMCI patients often assess HCsf tissue integrity using measures of volume, which has little specificity to microstructure and pathology. We use magnetic resonance elastography (MRE) to examine the viscoelastic mechanical properties of HCsf tissue, which is related to structural integrity, and sensitively detect differences in older adults with aMCI compared to an age-matched control group. Group comparisons revealed HCsf viscoelasticity is differentially affected in aMCI, with CA1-CA2 and DG-CA3 exhibiting lower stiffness and CA1-CA2 exhibiting higher damping ratio, both indicating poorer tissue integrity in aMCI. Including HCsf stiffness in a logistic regression improves classification of aMCI beyond measures of volume alone. Additionally, lower DG-CA3 stiffness predicted aMCI status regardless of DG-CA3 volume. These findings showcase the benefit of using MRE in detecting subtle pathological tissue changes in individuals with aMCI via the HCsf particularly affected in the disease.
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Affiliation(s)
- Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Mary K Kramer
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Alexa M Diano
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Kyra E Twohy
- Department of Mechanical Engineering, University of Delaware, Newark, DE, United States
| | - Alexis A Merritt
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | | | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Ana M Daugherty
- Department of Psychology and Institute of Gerontology, Wayne State University, Detroit, MI, United States
| | - James M Ellison
- Swank Memory Care and Geriatric Consultation, ChristianaCare, Wilmington, DE, United States; Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Alyssa M Lanzi
- Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Matthew L Cohen
- Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, United States
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States; Department of Mechanical Engineering, University of Delaware, Newark, DE, United States.
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Delgorio PL, Hiscox LV, Daugherty AM, Sanjana F, McIlvain G, Pohlig RT, McGarry MDJ, Martens CR, Schwarb H, Johnson CL. Structure-Function Dissociations of Human Hippocampal Subfield Stiffness and Memory Performance. J Neurosci 2022; 42:7957-7968. [PMID: 36261271 PMCID: PMC9617610 DOI: 10.1523/jneurosci.0592-22.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Aging and neurodegenerative diseases lead to decline in thinking and memory ability. The subfields of the hippocampus (HCsf) play important roles in memory formation and recall. Imaging techniques sensitive to the underlying HCsf tissue microstructure can reveal unique structure-function associations and their vulnerability in aging and disease. The goal of this study was to use magnetic resonance elastography (MRE), a noninvasive MR imaging-based technique that can quantitatively image the viscoelastic mechanical properties of tissue to determine the associations of HCsf stiffness with different cognitive domains across the lifespan. Eighty-eight adult participants completed the study (age 23-81 years, male/female 36/51), in which we aimed to determine which HCsf regions most strongly correlated with different memory performance outcomes and if viscoelasticity of specific HCsf regions mediated the relationship between age and performance. Our results revealed that both interference cost on a verbal memory task and relational memory task performance were significantly related to cornu ammonis 1-2 (CA1-CA2) stiffness (p = 0.018 and p = 0.011, respectively), with CA1-CA2 stiffness significantly mediating the relationship between age and interference cost performance (p = 0.031). There were also significant associations between delayed free verbal recall performance and stiffness of both the dentate gyrus-cornu ammonis 3 (DG-CA3; p = 0.016) and subiculum (SUB; p = 0.032) regions. This further exemplifies the functional specialization of HCsf in declarative memory and the potential use of MRE measures as clinical biomarkers in assessing brain health in aging and disease.SIGNIFICANCE STATEMENT Hippocampal subfields are cytoarchitecturally unique structures involved in distinct aspects of memory processing. Magnetic resonance elastography is a technique that can noninvasively image tissue viscoelastic mechanical properties, potentially serving as sensitive biomarkers of aging and neurodegeneration related to functional outcomes. High-resolution in vivo imaging has invigorated interest in determining subfield functional specialization and their differential vulnerability in aging and disease. Applying MRE to probe subfield-specific cognitive correlates will indicate that measures of subfield stiffness can determine the integrity of structures supporting specific domains of memory performance. These findings will further validate our high-resolution MRE method and support the potential use of subfield stiffness measures as clinical biomarkers in classifying aging and disease states.
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Affiliation(s)
- Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Ana M Daugherty
- Department of Psychology and Institute of Gerontology, Wayne State University, Detroit, Michigan 48202
| | - Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware 19713
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
| | - Ryan T Pohlig
- Biostatistics Core Facility, College of Health Sciences, University of Delaware, Newark, Delaware 19713
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware 19713
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716
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9
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Christie H, Hiscox LV, Halligan SL, Creswell C. Examining harmful impacts of the COVID‐19 pandemic and school closures on parents and carers in the United Kingdom: A rapid review. JCPP Advances 2022; 2:e12095. [PMID: 36247724 PMCID: PMC9537939 DOI: 10.1002/jcv2.12095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/23/2022] [Indexed: 11/07/2022] Open
Abstract
Background As a result of the COVID‐19 pandemic, school closures meant that for many households, home and school environments became intertwined. Parents and carers found themselves taking on the role as de‐facto educators, as well as balancing working from home and caring for additional members of the household. Understanding the full extent of the effects incurred by parents and carers during school closures is vital to identifying and supporting vulnerable families. This rapid review aimed to appraise the available evidence on the potential effects of the COVID‐19 pandemic on UK parents and carers. Methods Searches for academic literature were conducted using Proquest Central, Scopus, and Google Scholar between 21st and 28th April 2021 using search terms describing “parents and carers”, “COVID‐19” and the “UK”. Additional literature was identified on relevant parents and carers' organisations websites including charity reports. Results Thirty‐two articles were found relating to harms affecting parents and carers in the UK High levels of psychological distress, including anxiety and depression, were consistently identified in the general parent population, and especially in parents caring for a child with special educational needs and/or neurodevelopmental disorders (SEN/ND). Charity reports indicated that many parents, especially those from an ethnic minority background and kinship carers, were worse off financially and with food insecurities, whereas empirical evidence showed that mothers were more likely to initiate furlough for themselves compared with fathers or childless women. Domestic abuse support services also reported a sharp rise in demand during lockdown restrictions, and practitioners reported an increase in child and adolescent violence towards parents. Conclusions Given the known impacts of parental stress, mental health problems, domestic violence and financial hardship on children's development, it is critical that these findings are taken into account in case of future pandemics to minimise harms both to parents and their families.
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Affiliation(s)
- Hope Christie
- Department of Clinical Psychology University of Edinburgh Edinburgh UK
| | | | | | - Cathy Creswell
- Department of Experimental Psychology & Department of Psychiatry Oxford University Oxford UK
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10
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Hiscox LV, McGarry MDJ, Johnson CL. Evaluation of cerebral cortex viscoelastic property estimation with nonlinear inversion magnetic resonance elastography. Phys Med Biol 2022; 67. [PMID: 35316794 PMCID: PMC9208651 DOI: 10.1088/1361-6560/ac5fde] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/22/2022] [Indexed: 12/25/2022]
Abstract
Objective. Magnetic resonance elastography (MRE) of the brain has shown promise as a sensitive neuroimaging biomarker for neurodegenerative disorders; however, the accuracy of performing MRE of the cerebral cortex warrants investigation due to the unique challenges of studying thinner and more complex geometries.Approach. A series of realistic, whole-brain simulation experiments are performed to examine the accuracy of MRE to measure the viscoelasticity (shear stiffness,μ, and damping ratio, ξ) of cortical structures predominantly effected in aging and neurodegeneration. Variations to MRE spatial resolution and the regularization of a nonlinear inversion (NLI) approach are examined.Main results. Higher-resolution MRE displacement data (1.25 mm isotropic resolution) and NLI with a low soft prior regularization weighting provided minimal measurement error compared to other studied protocols. With the optimized protocol, an average error inμand ξ was 3% and 11%, respectively, when compared with the known ground truth. Mid-line structures, as opposed to those on the cortical surface, generally display greater error. Varying model boundary conditions and reducing the thickness of the cortex by up to 0.67 mm (which is a realistic portrayal of neurodegenerative pathology) results in no loss in reconstruction accuracy.Significance. These experiments establish quantitative guidelines for the accuracy expected ofin vivoMRE of the cortex, with the proposed method providing valid MRE measures for future investigations into cortical viscoelasticity and relationships with health, cognition, and behavior.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States of America.,Department of Psychology, University of Bath, Bath, United Kingdom
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States of America
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11
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Diamond PR, Airdrie JN, Hiller R, Fraser A, Hiscox LV, Hamilton-Giachritsis C, Halligan SL. Change in prevalence of post-traumatic stress disorder in the two years following trauma: a meta-analytic study. Eur J Psychotraumatol 2022; 13:2066456. [PMID: 35646293 PMCID: PMC9132436 DOI: 10.1080/20008198.2022.2066456] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Understanding the course of post-traumatic stress disorder (PTSD) and the factors that impact this is essential to inform decisions about when and for whom screening and intervention are likely to be beneficial. OBJECTIVE To provide meta-analytic evidence of the course of recovery from PTSD in the first year following trauma, and the factors that influence that recovery. METHOD We conducted a meta-analysis of observational studies of adult PTSD prevalence which included at least two assessments within the first 12 months following trauma exposure, examining prevalence statistics through to 2 years post-trauma. We examined trauma intentionality (intentional or non-intentional), PTSD assessment method (clinician or self-report), sample sex distribution, and age as moderators of PTSD prevalence over time. RESULTS We identified 78 eligible studies including 16,484 participants. Pooled prevalence statistics indicated that over a quarter of individuals presented with PTSD at 1 month post-trauma, with this proportion reducing by a third between 1 and 3 months. Beyond 3 months, any prevalence changes were detected over longer intervals and were small in magnitude. Intentional trauma, younger age, and female sex were associated with higher PTSD prevalence at 1 month. In addition, higher proportions of females, intentional trauma exposure, and higher baseline PTSD prevalence were each associated with larger reductions in prevalence over time. CONCLUSIONS Recovery from PTSD following acute trauma exposure primarily occurs in the first 3 months post-trauma. Screening measures and intervention approaches offered at 3 months may better target persistent symptoms than those conducted prior to this point. HIGHLIGHTS PTSD rates in the immediate aftermath of trauma exposure decline from 27% at 1 month to 18% at 3 months post-trauma, showing significant spontaneous recovery.Problems appear to stabilize after 3 months.Screening/intervention for PTSD at 3 months post-trauma is indicated.
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Affiliation(s)
- P R Diamond
- Department of Psychology, University of Bath, Bath, UK
| | - J N Airdrie
- Department of Psychology, University of Bath, Bath, UK
| | - R Hiller
- Department of Psychology, University of Bath, Bath, UK
| | - A Fraser
- Bristol Population Health Science Institute, Bristol Medical School, University of Bristol, Bristol, UK
| | - L V Hiscox
- Department of Psychology, University of Bath, Bath, UK
| | | | - S L Halligan
- Department of Psychology, University of Bath, Bath, UK.,Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
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12
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Sanjana F, Delgorio PL, Hiscox LV, DeConne TM, Hobson JC, Cohen ML, Johnson CL, Martens CR. Blood lipid markers are associated with hippocampal viscoelastic properties and memory in humans. J Cereb Blood Flow Metab 2021; 41:1417-1427. [PMID: 33103936 PMCID: PMC8142125 DOI: 10.1177/0271678x20968032] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/18/2020] [Accepted: 09/29/2020] [Indexed: 12/13/2022]
Abstract
Age-related memory loss shares similar risk factors as cardiometabolic diseases including elevated serum triglycerides (TGs) and low-density lipoprotein cholesterol (LDL-C) and reduced high-density lipoprotein cholesterol (HDL-C). The mechanisms linking these aberrant blood lipids to memory loss are not completely understood but may be partially mediated by reduced integrity of the hippocampus (HC), the primary brain structure for encoding and recalling memories. In this study, we tested the hypothesis that blood lipid markers are independently associated with memory performance and HC viscoelasticity-a noninvasive measure of brain tissue microstructural integrity assessed by high-resolution magnetic resonance elastography (MRE). Twenty-six individuals across the adult lifespan were recruited (14 M/12 F; mean age: 42 ± 15 y; age range: 22-78 y) and serum lipid profiles were related to episodic memory and HC viscoelasticity. All subjects were generally healthy without clinically abnormal blood lipids or memory loss. Episodic memory was negatively associated with the TG/HDL-C ratio. HC viscoelasticity was negatively associated with serum TGs and the TG/HDL-C ratio, independent of age and in the absence of associations with HC volume. These data, although cross-sectional, suggest that subtle differences in blood lipid profiles in healthy adults may contribute to a reduction in memory function and HC tissue integrity.
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Affiliation(s)
- Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Theodore M DeConne
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Joshua C Hobson
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Matthew L Cohen
- Department of Communication Sciences and Disorders, University of Delaware, Newark, DE, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
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13
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Hiscox LV, Schwarb H, McGarry MDJ, Johnson CL. Aging brain mechanics: Progress and promise of magnetic resonance elastography. Neuroimage 2021; 232:117889. [PMID: 33617995 PMCID: PMC8251510 DOI: 10.1016/j.neuroimage.2021.117889] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/12/2021] [Accepted: 02/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroimaging techniques that can sensitivity characterize healthy brain aging and detect subtle neuropathologies have enormous potential to assist in the early detection of neurodegenerative conditions such as Alzheimer's disease. Magnetic resonance elastography (MRE) has recently emerged as a reliable, high-resolution, and especially sensitive technique that can noninvasively characterize tissue biomechanical properties (i.e., viscoelasticity) in vivo in the living human brain. Brain tissue viscoelasticity provides a unique biophysical signature of neuroanatomy that are representative of the composition and organization of the complex tissue microstructure. In this article, we detail how progress in brain MRE technology has provided unique insights into healthy brain aging, neurodegeneration, and structure-function relationships. We further discuss additional promising technical innovations that will enhance the specificity and sensitivity for brain MRE to reveal considerably more about brain aging as well as its potentially valuable role as an imaging biomarker of neurodegeneration. MRE sensitivity may be particularly useful for assessing the efficacy of rehabilitation strategies, assisting in differentiating between dementia subtypes, and in understanding the causal mechanisms of disease which may lead to eventual pharmacotherapeutic development.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | | | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
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14
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Giudice JS, Alshareef A, Wu T, Knutsen AK, Hiscox LV, Johnson CL, Panzer MB. Calibration of a Heterogeneous Brain Model Using a Subject-Specific Inverse Finite Element Approach. Front Bioeng Biotechnol 2021; 9:664268. [PMID: 34017826 PMCID: PMC8129184 DOI: 10.3389/fbioe.2021.664268] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/12/2021] [Indexed: 12/02/2022] Open
Abstract
Central to the investigation of the biomechanics of traumatic brain injury (TBI) and the assessment of injury risk from head impact are finite element (FE) models of the human brain. However, many existing FE human brain models have been developed with simplified representations of the parenchyma, which may limit their applicability as an injury prediction tool. Recent advances in neuroimaging techniques and brain biomechanics provide new and necessary experimental data that can improve the biofidelity of FE brain models. In this study, the CAB-20MSym template model was developed, calibrated, and extensively verified. To implement material heterogeneity, a magnetic resonance elastography (MRE) template image was leveraged to define the relative stiffness gradient of the brain model. A multi-stage inverse FE (iFE) approach was used to calibrate the material parameters that defined the underlying non-linear deviatoric response by minimizing the error between model-predicted brain displacements and experimental displacement data. This process involved calibrating the infinitesimal shear modulus of the material using low-severity, low-deformation impact cases and the material non-linearity using high-severity, high-deformation cases from a dataset of in situ brain displacements obtained from cadaveric specimens. To minimize the geometric discrepancy between the FE models used in the iFE calibration and the cadaveric specimens from which the experimental data were obtained, subject-specific models of these cadaveric brain specimens were developed and used in the calibration process. Finally, the calibrated material parameters were extensively verified using independent brain displacement data from 33 rotational head impacts, spanning multiple loading directions (sagittal, coronal, axial), magnitudes (20–40 rad/s), durations (30–60 ms), and severity. Overall, the heterogeneous CAB-20MSym template model demonstrated good biofidelity with a mean overall CORA score of 0.63 ± 0.06 when compared to in situ brain displacement data. Strains predicted by the calibrated model under non-injurious rotational impacts in human volunteers (N = 6) also demonstrated similar biofidelity compared to in vivo measurements obtained from tagged magnetic resonance imaging studies. In addition to serving as an anatomically accurate model for further investigations of TBI biomechanics, the MRE-based framework for implementing material heterogeneity could serve as a foundation for incorporating subject-specific material properties in future models.
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Affiliation(s)
- J Sebastian Giudice
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, United States
| | - Ahmed Alshareef
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Taotao Wu
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, United States
| | - Andrew K Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Matthew B Panzer
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, United States
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15
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Delgorio PL, Hiscox LV, Daugherty AM, Sanjana F, Pohlig RT, Ellison JM, Martens CR, Schwarb H, McGarry MDJ, Johnson CL. Effect of Aging on the Viscoelastic Properties of Hippocampal Subfields Assessed with High-Resolution MR Elastography. Cereb Cortex 2021; 31:2799-2811. [PMID: 33454745 DOI: 10.1093/cercor/bhaa388] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 11/06/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related memory impairments have been linked to differences in structural brain parameters, including the integrity of the hippocampus (HC) and its distinct hippocampal subfields (HCsf). Imaging methods sensitive to the underlying tissue microstructure are valuable in characterizing age-related HCsf structural changes that may relate to cognitive function. Magnetic resonance elastography (MRE) is a noninvasive MRI technique that can quantify tissue viscoelasticity and may provide additional information about aging effects on HCsf health. Here, we report a high-resolution MRE protocol to quantify HCsf viscoelasticity through shear stiffness, μ, and damping ratio, ξ, which reflect the integrity of tissue composition and organization. HCsf exhibit distinct mechanical properties-the subiculum had the lowest μ and both subiculum and entorhinal cortex had the lowest ξ. Both measures correlated with age: HCsf μ was lower with age (P < 0.001) whereas ξ was higher (P = 0.002). The magnitude of age-related differences in ξ varied across HCsf (P = 0.011), suggesting differential patterns of brain aging. This study demonstrates the feasibility of using MRE to assess HCsf microstructural integrity and suggests incorporation of these metrics to evaluate HC health in neurocognitive disorders.
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Affiliation(s)
- Peyton L Delgorio
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
| | - Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
| | - Ana M Daugherty
- Department of Psychology, Institute of Gerontology, Wayne State University, Detroit, MI 48202, USA.,Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI 48202, USA.,Institute of Gerontology, Wayne State University, Detroit, MI 48202, USA
| | - Faria Sanjana
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA
| | - Ryan T Pohlig
- Biostatistics Core Facility, College of Health Sciences, University of Delaware, Newark, DE 19713, USA
| | - James M Ellison
- Swank Center for Memory Care and Geriatric Consultation, ChristianaCare, Wilmington, DE 19801, USA
| | - Christopher R Martens
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, USA
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
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16
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Hiscox LV, Hiller R, Fraser A, Rabie S, Stewart J, Seedat S, Tomlinson M, Halligan SL. Sex differences in post-traumatic stress disorder in a high adversity cohort of South African adolescents: an examination of depressive symptoms, age, and trauma type as explanatory factors. Eur J Psychotraumatol 2021; 12:1978669. [PMID: 34691370 PMCID: PMC8530480 DOI: 10.1080/20008198.2021.1978669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Evidence from high-income countries (HICs) has documented a higher rate of post-traumatic stress disorder (PTSD) in females than males. However, data are limited on sex differences in PTSD from low- and middle-income countries (LMICs), despite particularly high levels of trauma experienced by LMIC youth. OBJECTIVES In a sample of adolescents from an impoverished South African community, we examined sex differences in PTSD, as well as co-occurring depression, adolescent age, and the type and extent of trauma exposure as potential contributors to female vulnerability. METHODS Participants were recruited from high schools in the Khayelitsha area of Cape Town. Self-reported trauma exposure, PTSD and depressive symptoms were measured in 797 adolescents (62% female) aged 13-17 years. Poisson regressions were used to examine Risk Ratios (RR) based on probable PTSD diagnoses, and linear regressions were applied to assess posttraumatic stress symptom (PTSS) severity. RESULTS 92% of adolescents reported trauma exposure, of whom 28% had probable PTSD. Prevalence of PTSD was higher for females than for males, even when controlling for total trauma exposure (RR = 1.71, p < .001) and co-occurring depressive symptoms (RR = 1.45, p = .005). By contrast, sex differences in depression were eliminated after controlling for co-occurring PTSS. There was little evidence of age effects on the emergence of sex differences. At lower thresholds of interpersonal trauma, females showed higher levels of PTSS compared to males, but no sex differences were found at high levels of exposure. CONCLUSION Higher PTSD rates are observed in adolescent females in a high adversity-LMIC sample suggesting sex differences are robust across international contexts. Sex differences in PTSD are unlikely to be explained by co-occurring depression and in this context sex differences in depression may be secondary to trauma and PTSD. However, exposure to significant interpersonal trauma appears to overrule any specific female vulnerability.
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Affiliation(s)
- Lucy V Hiscox
- Department of Psychology, University of Bath, Bath, UK
| | - Rachel Hiller
- Department of Psychology, University of Bath, Bath, UK
| | - Abigail Fraser
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Stephan Rabie
- Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Jackie Stewart
- Institute for Life Course Health Research, Department of Global Health, Stellenbosch University, Stellenbosch, South Africa
| | - Soraya Seedat
- Medical Research Council (MRC) Unit on Anxiety and Stress Disorders, Department of Psychiatry, Stellenbosch University, Tygerberg, Western Cape, South Africa
| | - Mark Tomlinson
- Institute for Life Course Health Research, Department of Global Health, Stellenbosch University, Stellenbosch, South Africa
| | - Sarah L Halligan
- Department of Psychology, University of Bath, Bath, UK.,Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
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17
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Hiscox LV, McGarry MDJ, Schwarb H, Van Houten EEW, Pohlig RT, Roberts N, Huesmann GR, Burzynska AZ, Sutton BP, Hillman CH, Kramer AF, Cohen NJ, Barbey AK, Paulsen KD, Johnson CL. Standard-space atlas of the viscoelastic properties of the human brain. Hum Brain Mapp 2020; 41:5282-5300. [PMID: 32931076 PMCID: PMC7670638 DOI: 10.1002/hbm.25192] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/28/2020] [Accepted: 08/16/2020] [Indexed: 12/16/2022] Open
Abstract
Standard anatomical atlases are common in neuroimaging because they facilitate data analyses and comparisons across subjects and studies. The purpose of this study was to develop a standardized human brain atlas based on the physical mechanical properties (i.e., tissue viscoelasticity) of brain tissue using magnetic resonance elastography (MRE). MRE is a phase contrast‐based MRI method that quantifies tissue viscoelasticity noninvasively and in vivo thus providing a macroscopic representation of the microstructural constituents of soft biological tissue. The development of standardized brain MRE atlases are therefore beneficial for comparing neural tissue integrity across populations. Data from a large number of healthy, young adults from multiple studies collected using common MRE acquisition and analysis protocols were assembled (N = 134; 78F/ 56 M; 18–35 years). Nonlinear image registration methods were applied to normalize viscoelastic property maps (shear stiffness, μ, and damping ratio, ξ) to the MNI152 standard structural template within the spatial coordinates of the ICBM‐152. We find that average MRE brain templates contain emerging and symmetrized anatomical detail. Leveraging the substantial amount of data assembled, we illustrate that subcortical gray matter structures, white matter tracts, and regions of the cerebral cortex exhibit differing mechanical characteristics. Moreover, we report sex differences in viscoelasticity for specific neuroanatomical structures, which has implications for understanding patterns of individual differences in health and disease. These atlases provide reference values for clinical investigations as well as novel biophysical signatures of neuroanatomy. The templates are made openly available (github.com/mechneurolab/mre134) to foster collaboration across research institutions and to support robust cross‐center comparisons.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Elijah E W Van Houten
- Département de génie mécanique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Ryan T Pohlig
- College of Health Sciences, University of Delaware, Newark, Delaware, USA
| | - Neil Roberts
- School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
| | - Graham R Huesmann
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carle Neuroscience Institute, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Agnieszka Z Burzynska
- Department of Human Development and Family Studies and Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, Colorado, USA
| | - Bradley P Sutton
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Charles H Hillman
- Department of Psychology, Northeastern University, Boston, Massachusetts, USA.,Department of Physical Therapy, Movement, & Rehabilitation Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Arthur F Kramer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Aron K Barbey
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Keith D Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
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18
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Sanjana F, Delgorio PL, Hiscox LV, DeConne TM, Hobson JC, Johnson CL, Martens CR. Association between serum triglycerides and brain mechanical properties in humans. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.06112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Hiscox LV, Johnson CL, McGarry MDJ, Marshall H, Ritchie CW, van Beek EJR, Roberts N, Starr JM. Mechanical property alterations across the cerebral cortex due to Alzheimer's disease. Brain Commun 2019; 2:fcz049. [PMID: 31998866 PMCID: PMC6976617 DOI: 10.1093/braincomms/fcz049] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 11/25/2019] [Accepted: 12/06/2019] [Indexed: 11/12/2022] Open
Abstract
Alzheimer's disease is a personally devastating neurodegenerative disorder and a major public health concern. There is an urgent need for medical imaging techniques that better characterize the early stages and monitor the progression of the disease. Magnetic resonance elastography (MRE) is a relatively new and highly sensitive MRI technique that can non-invasively assess tissue microstructural integrity via measurement of brain viscoelastic mechanical properties. For the first time, we use high-resolution MRE methods to conduct a voxel-wise MRE investigation and state-of-the-art post hoc region of interest analysis of the viscoelastic properties of the cerebral cortex in patients with Alzheimer's disease (N = 11) compared with cognitively healthy older adults (N = 12). We replicated previous findings that have reported significant volume and stiffness reductions at the whole-brain level. Significant reductions in volume were also observed in Alzheimer's disease when white matter, cortical grey matter and subcortical grey matter compartments were considered separately; lower stiffness was also observed in white matter and cortical grey matter, but not in subcortical grey matter. Voxel-based morphometry of both cortical and subcortical grey matter revealed localized reductions in volume due to Alzheimer's disease in the hippocampus, fusiform, middle, superior temporal gyri and precuneus. Similarly, voxel-based MRE identified lower stiffness in the middle and superior temporal gyri and precuneus, although the spatial distribution of these effects was not identical to the pattern of volume reduction. Notably, MRE additionally identified stiffness deficits in the operculum and precentral gyrus located within the frontal lobe; regions that did not undergo volume loss identified through voxel-based morphometry. Voxel-based-morphometry and voxel-based MRE results were confirmed by a complementary post hoc region-of-interest approach in native space where the viscoelastic changes remained significant even after statistically controlling for regional volumes. The pattern of reduction in cortical stiffness observed in Alzheimer's disease patients raises the possibility that MRE may provide unique insights regarding the neural mechanisms which underlie the development and progression of the disease. The measured mechanical property changes that we have observed warrant further exploration to investigate the diagnostic usefulness of MRE in cases of Alzheimer's disease and other dementias.
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Affiliation(s)
- Lucy V Hiscox
- Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh EH8 9JZ, UK
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19713, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19713, USA
| | | | - Helen Marshall
- Edinburgh Imaging Facility, School of Clinical Sciences, The Queen’s Medical Research Institute (QMRI), University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Craig W Ritchie
- Centre for Dementia Prevention at Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4UX, UK
| | - Edwin J R van Beek
- Edinburgh Imaging Facility, School of Clinical Sciences, The Queen’s Medical Research Institute (QMRI), University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Neil Roberts
- Edinburgh Imaging Facility, School of Clinical Sciences, The Queen’s Medical Research Institute (QMRI), University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - John M Starr
- Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh EH8 9JZ, UK
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20
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Hiscox LV, Johnson CL, Barnhill E, McGarry MDJ, Huston J, van Beek EJR, Starr JM, Roberts N. Magnetic resonance elastography (MRE) of the human brain: technique, findings and clinical applications. Phys Med Biol 2016; 61:R401-R437. [DOI: 10.1088/0031-9155/61/24/r401] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Walsh ND, Dalgleish T, Dunn VJ, Abbott R, St Clair MC, Owens M, Fairchild G, Kerslake WS, Hiscox LV, Passamonti L, Ewbank M, Ban M, Calder AJ, Goodyer IM. 5-HTTLPR-environment interplay and its effects on neural reactivity in adolescents. Neuroimage 2012; 63:1670-80. [PMID: 23034517 PMCID: PMC3480648 DOI: 10.1016/j.neuroimage.2012.07.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 07/16/2012] [Accepted: 07/24/2012] [Indexed: 01/07/2023] Open
Abstract
It is not known how 5-HTTLPR genotype × childhood adversity (CA) interactions that are associated with an increased risk for affective disorders in population studies operate at the neural systems level. We hypothesized that healthy adolescents at increased genetic and environmental risk for developing mood disorders (depression and anxiety) would demonstrate increased amygdala reactivity to emotional stimuli compared to those with only one such risk factor or those with none. Participants (n = 67) were classified into one of 4 groups dependent on being homozygous for the long or short alleles within the serotonin-transporter-linked polymorphic region (5-HTTLPR) of the SLC6A4 gene and exposure to CA in the first 11 years of life (present or absent). A functional magnetic resonance imaging investigation was undertaken which involved viewing emotionally-salient face stimuli. In addition, we assessed the role of other variables hypothesized to influence amygdala reactivity, namely recent negative life-events (RNLE) assessed at ages 14 and 17, current anxiety symptoms and psychiatric history. We replicated prior findings demonstrating moderation by gene variants in 5-HTTLPR, but found no support for an effect of CA on amygdala reactivity. We also found a significant effect of RNLE aged 17 with amygdala reactivity demonstrating additive, but not interactive effects with 5-HTTLPR. A whole-brain analysis found a 5-HTTLPR × CA interaction in the lingual gyrus whereby CA appears to differentially modify neural reactivity depending on genotype. These results demonstrate that two different forms of environmental adversities interplay with 5-HTTLPR and thereby differentially impact amygdala and cortical reactivity.
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Affiliation(s)
- Nicholas D Walsh
- Developmental and Life-course Research Group, Department of Psychiatry, University of Cambridge, Cambridge, CB2 8AD, UK.
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