Your search for: 'author:("Honea, Robyn A.")' has returned 10 results. (0.014s) Save search

Authors: Honea, Robyn A. | Vidoni, Eric | Harsha, Amith | Burns, Jeffrey M.

Article Type: Research Article

Abstract: Neuroimaging studies of apolipoprotein E (ApoE4) have implicated its association with brain atrophy in Alzheimer's disease. To date, few studies have used automated morphological analysis techniques to assess ApoE4-related brain structure change in both gray and white matter in nondemented older adults. Nondemented (CDR = 0, n = 53) subjects over 60 had MRI, diffusion tensor imaging, and neurocognitive assessments. We assessed differences in cognition and brain structure associated with ApoE4 genetic variation using voxel-based morphometry techniques, and tract-based spatial statistics of fractional anisotropy change. In nondemented older adults with the E4 allele, cognitive performance was reduced, and atrophy was …present in the hippocampus and amygdala compared to ApoE4 negative participants. We also report that E4 carriers have decreased fractional anisotropy in the left parahippocampal gyrus white matter. In conclusion, the presence of an ApoE4 allele in nondemented older adults is associated with decreases in cognition and gray and white matter changes in the medial temporal cortex. Overall we provide further evidence of the effects of genetic variance related to imaging and cognitive measures of risk for Alzheimer's disease. Show more

Keywords: Aging, Alzheimer's disease, apolipoprotein (APOE), cognition, dementia, diffusion tensor imaging (DTI), fractional anisotropy (FA), genetics, hippocampus, voxel-based morphometry (VBM)

DOI: 10.3233/JAD-2009-1163

Citation: Journal of Alzheimer's Disease, vol. 18, no. 3, pp. 553-564, 2009

Authors: Vidoni, Eric D. | Honea, Robyn A. | Burns, Jeffrey M.

Article Type: Research Article

Abstract: Cognitive and physical decline are important predictors of functional independence in Alzheimer's disease (AD). However, little is known about AD-related neural change leading to decreased independence. We hypothesized that regional gray matter atrophy, including the medial frontal cortex, would be related to cognition, physical function, and functional independence. Individuals without dementia (n = 56) and subjects with early-stage AD (n = 58) underwent MRI and a comprehensive cognitive and physical function evaluation. The relationship of cognitive and physical function measures and independence performing complex daily activities was explored using correlation and mediation analysis. These results suggest that cognition had both …a strong direct effect and mediated the influence of physical function on independence for those with AD. We followed this with a voxel-based morphometric global conjunction analysis of imaging data within each group to identify neural substrates common to our function measures. Imaging evidence supported our mediation analysis results. Imaging evidence revealed that in AD, regional gray matter atrophy measures in medial frontal and temporo-parietal areas were related to decreased cognition, physical function, and independence. Loss of independence in early AD is closely related to impaired cognition associated with performing complex behaviors. People with early AD may have decreased gray matter volume in the medial frontal and temporal-parietal cortices that is associated with loss of independence in activities of daily living. These results are the first to identify regionally specific brain volume changes that may be related to functional dependence seen in early AD. Show more

Keywords: Activities of daily living, cognition, physical function, voxel-based morphometry

DOI: 10.3233/JAD-2010-1245

Citation: Journal of Alzheimer's Disease, vol. 19, no. 2, pp. 517-527, 2010

Authors: Royall, Donald R. | Palmer, Raymond F. | Vidoni, Eric D. | Honea, Robyn A. | Burns, Jeffrey M.

Article Type: Research Article

Abstract: We have employed structural equation models to explicitly distinguish dementia-relevant variance in cognitive task performance (i.e., δ) from the variance that is unrelated to a dementing process (i.e., g'). Together g' and d comprise Spearman's “g”. Although d represents only a minor fraction of the total variance in cognitive task performance, it is more strongly associated with dementia severity than is g'. In this analysis, we replicate δ in a new dataspace, the University of Kansas Brain Aging Project, and associate it specifically with regional grey matter atrophy by voxel-based morphometry of magnetic resonance imaging data. The latent variable d …localizes to elements of the default mode network and related structures in the R hemisphere. Show more

Keywords: Aging, cognition, dementia, g, functional status

DOI: 10.3233/JAD-2012-120424

Citation: Journal of Alzheimer's Disease, vol. 32, no. 2, pp. 467-478, 2012

Authors: Loskutova, Natalia | Honea, Robyn A. | Brooks, William M. | Burns, Jeffrey M.

Article Type: Research Article

Abstract: Accelerated bone loss is associated with Alzheimer's disease (AD). Although the central nervous system plays a direct role in regulating bone mass, primarily through the actions of the hypothalamus, there is little work investigating the possible role of neurodegeneration in bone loss. In this cross-sectional study, we examined the association between bone mineral density (BMD) and neuroimaging markers of neurodegeneration (i.e., global and regional measures of brain volume) in early AD and non-demented aging. Fifty-five non-demented and 63 early AD participants underwent standard neurological and neuropsychological assessment, structural MRI scanning, and dual energy x-ray absorptiometry. In early AD, voxel-based morphometry …analyses demonstrated that low BMD was associated with low volume in limbic grey matter (GM) including the hypothalamus, cingulate, and parahippocampal gyri and in the left superior temporal gyrus and left inferior parietal cortex. No relationship between BMD and regional GM volume was found in non-demented controls. The hypothesis-driven region of interest analysis further isolating the hypothalamus demonstrated a positive relationship between BMD and hypothalamic volume after controlling for age and gender in the early AD group but not in non-demented controls. These results demonstrate that lower BMD is associated with lower hypothalamic volume in early AD, suggesting that central mechanisms of bone remodeling may be disrupted by neurodegeneration. Show more

Keywords: Alzheimer's disease, bone density, hypothalamus, voxel-based morphometry

DOI: 10.3233/JAD-2010-1364

Citation: Journal of Alzheimer's Disease, vol. 20, no. 1, pp. 313-322, 2010

Authors: Loskutova, Natalia | Honea, Robyn A. | Vidoni, Eric D. | Brooks, William M. | Burns, Jeffrey M.

Article Type: Research Article

Abstract: Studies suggest a link between bone loss and Alzheimer's disease. To examine bone mineral density (BMD) in early Alzheimer's disease (AD) and its relationship to brain structure and cognition, we evaluated 71 patients with early stage AD (Clinical Dementia Rating (CDR) 0.5 and 1) and 69 non-demented elderly control participants (CDR 0). Measures included whole body BMD by dual energy x-ray absorptiometry (DXA) and normalized whole brain volumes computed from structural MRI scans. Cognition was assessed with a standard neuropsychological test battery. Mean BMD was lower in the early AD group (1.11 ± 0.13) compared to the non-demented control group …(1.16 ± 0.12, p = 0.02), independent of age, gender, habitual physical activity, smoking, depression, estrogen replacement, and apolipoprotein E4 carrier status. In the early AD group, BMD was related to whole brain volume (b = 0.18, p = 0.03). BMD was also associated with cognitive performance, primarily in tests of memory (logical memory [b = 0.15, p = 0.04], delayed logical memory [b = 0.16, p = 0.02], and the selective reminding task – free recall [b = 0.18, p = 0.009]). BMD is reduced in the earliest clinical stages of AD and associated with brain atrophy and memory decline, suggesting that central mechanisms may contribute to bone loss in early AD. Show more

Keywords: Alzheimer's disease, bone mineral density, brain atrophy, hypothalamus, memory

DOI: 10.3233/JAD-2009-1185

Citation: Journal of Alzheimer's Disease, vol. 18, no. 4, pp. 777-785, 2009

Authors: Royall, Donald R. | Palmer, Raymond F. | Vidoni, Eric D. | Honea, Robyn A.

Article Type: Research Article

Abstract: Depressive symptoms are associated with an increased risk of Alzheimer's disease (AD) but the mechanism(s) involved has not been well established. In a convenience sample of participants in the University of Kansas' Brain Aging Project, we use structural equation modeling (SEM) to explicitly distinguish depressive symptom-related variance in cognitive task performance (i.e., DEPCOG) from that which is unrelated to a depressive symptoms. DEPCOG is strongly associated with the cognitive correlates of functional status (δ), which we previously associated with elements of the Default Mode Network (DMN). Both δ and DEPCOG map to a posterior cingulate seeded network that has recently …been associated with amyloid-β deposition and includes elements of the DMN. Both contribute significantly to clinical dementia status and dementia severity, as measured by the Clinical Dementia Rating Scale Sum of Boxes. These findings suggest that the cognitive correlates of depressive symptoms, even in the absence of a major depressive episode, may contribute to dementia in their own right, and could be responsible for some cases of incident clinical “AD”. This conclusion suggests new opportunities for the latter's diagnosis, prevention, and treatment. Show more

Keywords: Aging, cognition, dementia, depression, g, functional status

DOI: 10.3233/JAD-121639

Citation: Journal of Alzheimer's Disease, vol. 34, no. 2, pp. 547-560, 2013

Authors: Honea, Robyn A. | Vidoni, Eric D. | Swerdlow, Russell H. | Burns, Jeffrey M. | for the Alzheimer's Disease Neuroimaging Initiative

Article Type: Research Article

Abstract: A family history of Alzheimer's disease (AD) increases one's risk of developing late-onset AD (LOAD), and a maternal family history of LOAD influences risk more than a paternal family history. Accumulating evidence suggests that a family history of dementia associates with AD-typical biomarker changes. We analyzed cross-sectional data from non-demented, mild cognitive impairment (MCI), and LOAD participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) with PET imaging using Pittsburgh Compound B (PiB, n = 99) and cerebrospinal fluid (CSF) analysis (n = 403) for amyloid-β peptide (Aβ) and total tau. We assessed the relationship of CSF and PiB biomarkers and …family history of dementia, as well as parent gender effects. In the larger analysis of CSF biomarkers, we assessed diagnosis groups individually. In the overall sample, CSF Aβ, tau/Aβ ratio, and global PiB uptake were significantly different between family history positive and negative groups, with markers of increased AD burden associated with a positive maternal family history of dementia. Moreover, a maternal family history of dementia was associated with significantly greater PiB Aβ load in the brain in the parietal cortex, precuneus, and sensorimotor cortex. Individuals with MCI positive for a maternal family history of dementia had significantly more markers of AD pathophysiology than individuals with no family history of dementia. A family history of dementia is associated with AD-typical biomarker changes. These biomarker associations are most robust in individuals with a maternal family history, suggesting that a maternally inherited factor influences AD risk. Show more

Keywords: Alzheimer's disease, cerebrospinal fluid, genetics, PET

DOI: 10.3233/JAD-2012-120676

Citation: Journal of Alzheimer's Disease, vol. 31, no. 3, pp. 659-668, 2012

Authors: Watts, Amber | Honea, Robyn A. | Billinger, Sandra A. | Rhyner, Kathleen T. | Hutfles, Lewis | Vidoni, Eric D. | Burns, Jeffrey M.

Article Type: Research Article

Abstract: Background: Though hypertension is a commonly studied risk factor for white matter lesions (WMLs), measures of blood pressure may fluctuate depending on external conditions resulting in measurement error. Indicators of arterial stiffening and reduced elasticity may be more sensitive indicators of risk for WMLs in aging; however the interdependent nature of vascular indicators creates statistical complications. Objective: The purpose of the study was to determine whether a factor score comprised of multiple vascular indicators would be a stronger predictor of WMLs than traditional measures of blood pressure. Methods: In a sample of well-characterized nondemented older adults, we used a factor …analytic approach to account for variance common across multiple vascular measures while reducing measurement error. The result was a single factor score reflecting arterial stiffness and reduced elasticity. We used this factor score to predict white matter lesion volumes acquired via fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging. Results: The combined vascular factor score was a stronger predictor of deep WML (β = 0.42, p < 0.001) and periventricular WML volumes (β = 0.49, p < 0.001). After accounting for the vascular factor, systolic and diastolic blood pressure measurements were not significant predictors. Conclusions: This suggests that a combined measure of arterial elasticity and stiffening may be a stronger predictor of WMLs than systolic and diastolic blood pressure accounting for the multicollinearity associated with a variety of interrelated vascular measures. Show more

Keywords: Arterial stiffness, factor analysis, magnetic resonance imaging, vascular elasticity, white matter lesions

DOI: 10.3233/JAD-142085

Citation: Journal of Alzheimer's Disease, vol. 45, no. 1, pp. 187-193, 2015

Authors: Green, Zachary D. | Vidoni, Eric D. | Swerdlow, Russell H. | Burns, Jeffrey M. | Morris, Jill K. | Honea, Robyn A.

Article Type: Research Article

Abstract: Background: First-degree relatives of individuals with late-onset Alzheimer’s disease (AD) have increased risk for AD, with children of affected parents at an especially high risk. Objective: We aimed to investigate default mode network connectivity, medial temporal cortex volume, and cognition in cognitively healthy (CH) individuals with (FH+) and without (FH-) a family history of AD, alongside amnestic mild cognitive impairment (aMCI) and AD individuals, to determine the context and directionality of dysfunction in at-risk individuals. Our primary hypothesis was that there would be a linear decline (CH FH- > CH FH+ > aMCI > AD) within the risk groups on all measures of AD risk. Methods: …We used MRI and fMRI to study cognitively healthy individuals (n  = 28) with and without AD family history (FH+ and FH-, respectively), those with aMCI (n  = 31) and early-stage AD (n  = 25). We tested connectivity within the default mode network, as well as measures of volume and thickness within the medial temporal cortex and selected seed regions. Results: As expected, we identified decreased medial temporal cortex volumes in the aMCI and AD groups compared to cognitively healthy groups. We also observed patterns of connectivity across risk groups that suggest a nonlinear relationship of change, such that the FH+ group showed increased connectivity compared to the FH- and AD groups (CH FH+ > CH FH- > aMCI > AD). This pattern emerged primarily in connectivity between the precuneus and frontal regions. Conclusion: These results add to a growing literature that suggests compensatory brain function in otherwise cognitively healthy individuals with a family history of AD. Show more

Keywords: Alzheimer’s disease, default mode network, family history, hippocampus, maternal, mild cognitive impairment, precuneus, resting state

DOI: 10.3233/JAD-210326

Citation: Journal of Alzheimer's Disease, vol. 91, no. 2, pp. 559-571, 2023

Authors: Palmer, Jacqueline A. | Kaufman, Carolyn S. | Vidoni, Eric D. | Honea, Robyn A. | Burns, Jeffrey M. | Billinger, Sandra A.

Article Type: Short Communication

Abstract: Sex as a biological variable appears to contribute to the multifactorial etiology of Alzheimer’s disease. We tested sex-based interactions between cerebrovascular function and APOE4 genotype on resistance and resilience to brain pathology and cognitive executive dysfunction in cognitively-normal older adults. Female APOE4 carriers had higher amyloid-β deposition yet achieved similar cognitive performance to males and female noncarriers. Further, female APOE4 carriers with robust cerebrovascular responses to exercise possessed lower amyloid-β. These results suggest a unique cognitive resilience and identify cerebrovascular function as a key mechanism for resistance to age-related brain pathology in females with high genetic vulnerability to Alzheimer’s disease.

Keywords: Aging, Apolipoproteins E, amyloid, cardiovascular system, cerebrovascular circulation, cognition, female, hemodynamics, ultrasound

DOI: 10.3233/JAD-220359

Citation: Journal of Alzheimer's Disease, vol. 90, no. 2, pp. 535-542, 2022