Age Affects White Matter Integrity and Episodic Memory Across the Older Adult Lifespan

2020 ◽  
Author(s):  
Jenna Merenstein ◽  
María M. Corrada ◽  
Claudia H. Kawas ◽  
Ilana J. Bennett
Keyword(s):  
Cognitive Impairment ◽  
White Matter ◽  
Episodic Memory ◽  
Older Adult ◽  
Diffusion Tensor ◽  
Oldest Old ◽  
White Matter Integrity ◽  
Adult Lifespan ◽  
Increased Risk ◽  
Effect Of Age

Aging is accompanied by declines in white matter integrity (e.g., demyelination, decreased fiber density) that contribute to cognitive deficits. Diffusion tensor imaging (DTI) studies have observed these integrity declines in vivo separately in younger-old (ages 65-89) and oldest-old (ages 90+) adults. But it remains unclear whether the effect of age on integrity is magnified in advanced age groups and whether this may result from normal aging or dementia-related pathology. Here, we tested whether age-related differences in white matter integrity followed linear or nonlinear patterns when considering the entire older adult lifespan (n = 108; 65-98 years) and whether these patterns were influenced by oldest-old adults at increased risk of dementia (cognitive impairment no dementia, CIND). To assess the functional impact of white matter aging, we then examined the extent to which it explained age effects on episodic memory performance (delayed recall, recognition). Results revealed significant nonlinear declines in the integrity of medial temporal, callosal, and association fiber classes, with linear declines observed for the projection/thalamic fiber class. These patterns remained after excluding the oldest-old participants with CIND, indicating that larger differences in white matter integrity with increased age cannot solely be explained by pathology associated with early cognitive impairment. We also found that the effect of age on episodic memory was partially mediated by integrity of medial temporal fibers, suggesting that they are essential for facilitating memory-related neural signals across the older adult lifespan.

Olfactory Function and Diffusion Tensor Imaging as Markers of Mild Cognitive Impairment in Early Stages of Parkinson's Disease

2021 ◽  
pp. 155005942110582
Author(s):  
Sophie A. Stewart ◽  
Laura Pimer ◽  
John D. Fisk ◽  
Benjamin Rusak ◽  
Ron A. Leslie ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Impairment ◽  
Diffusion Tensor Imaging ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Neurodegenerative Disorder ◽  
Diffusion Tensor ◽  
Early Stage ◽  
White Matter Integrity

Parkinson's disease (PD) is a neurodegenerative disorder that is typified by motor signs and symptoms but can also lead to significant cognitive impairment and dementia Parkinson's Disease Dementia (PDD). While dementia is considered a nonmotor feature of PD that typically occurs later, individuals with PD may experience mild cognitive impairment (PD-MCI) earlier in the disease course. Olfactory deficit (OD) is considered another nonmotor symptom of PD and often presents even before the motor signs and diagnosis of PD. We examined potential links among cognitive impairment, olfactory functioning, and white matter integrity of olfactory brain regions in persons with early-stage PD. Cognitive tests were used to established groups with PD-MCI and with normal cognition (PD-NC). Olfactory functioning was examined using the University of Pennsylvania Smell Identification Test (UPSIT) while the white matter integrity of the anterior olfactory structures (AOS) was examined using magnetic resonance imaging (MRI) diffusion tensor imaging (DTI) analysis. Those with PD-MCI demonstrated poorer olfactory functioning and abnormalities based on all DTI parameters in the AOS, relative to PD-NC individuals. OD and microstructural changes in the AOS of individuals with PD may serve as additional biological markers of PD-MCI.

scholarly journals Changes in Cerebral Volume and White Matter Integrity in Adults on Hemodialysis and Relationship to Cognitive Function

Nephron ◽  
2020 ◽  
Vol 145 (1) ◽  
pp. 35-43
Author(s):  
Wesley T. Richerson ◽  
Laura G. Umfleet ◽  
Brian D. Schmit ◽  
Dawn F. Wolfgram
Keyword(s):  
Cognitive Impairment ◽  
White Matter ◽  
Cognitive Performance ◽  
Gray Matter ◽  
Structural Changes ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
White Matter Integrity ◽  
Healthy Controls ◽  
Matter Volume

<b><i>Introduction:</i></b> Patients on hemodialysis (HD) have a significant burden of cognitive impairment. Characterizing the cerebral structural changes in HD patients compared to healthy controls and evaluating the relationship of cerebral structural integrity with cognitive performance in HD patients can help clarify the pathophysiology of the cognitive impairment in HD patients. <b><i>Methods:</i></b> In this cross-sectional study, in-center HD patients ≥50 years of age underwent brain structural and diffusion MRIs and cognitive assessment using the NIH Toolbox cognition battery. The cerebral imaging measures of the HD participants were compared to imaging from age-matched controls. Gray matter volume, white matter volume, and white matter integrity determined by diffusion tensor imaging parameters (including fractional anisotropy [FA]) were measured in both cohorts to determine differences in the cerebral structure between HD participants and healthy controls. The association between cognitive performance on the NIH Toolbox cognition battery and cerebral structural integrity was evaluated using multiple linear regression models. <b><i>Results:</i></b> We compared imaging measures form 23 HD participants and 15 age-matched controls. The HD participants had decreased gray matter volumes (526.8 vs. 589.5 cm<sup>3</sup>, <i>p</i> &#x3c; 0.01) and worsened white matter integrity overall (FA values of 0.2864 vs. 0.3441, <i>p</i> &#x3c; 0.01) within major white matter tracts compared to healthy controls. Decreases in white matter integrity in the left superior longitudinal fasciculus was associated with lower executive function scores (<i>r</i><sup><i>2</i></sup> = 0.24, <i>p</i> = 0.02) and inferior longitudinal fasciculus with lower memory scores (<i>r</i> = 0.25 and <i>p</i> = 0.03 for left and <i>r</i><sup>2</sup> = 0.21 and <i>p</i> = 0.03 for right). <b><i>Conclusions:</i></b> HD patients have a pattern of decreased white matter integrity and gray matter atrophy compared to controls. Decreases in white matter integrity were associated with decreased cognitive performance in the HD population.

Abstract P020: Atrial Fibrillation and White Matter Microstructural Integrity: The Atherosclerosis Risk in Communities Neurocognitive Study

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Iris Yuefan Shao ◽  
Melinda Power ◽  
Thomas Mosley ◽  
Rebecca Gottesman ◽  
Lin Chen ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Cerebral Infarct ◽  
Cross Sectional ◽  
Increased Risk ◽  
History Of ◽  
The Cross ◽  
Microstructural Integrity

Background: Evidence suggests atrial fibrillation (AF) is associated with increased risk of cognitive decline and dementia, even in the absence of stroke. Pathways such as AF-induced brain hypoperfusion and small vessel disease resulting in white matter abnormalities may also compromise cerebrovasculature and brain tissue, which would lead to cognitive impairment and dementia. However, mechanisms responsible for the association between AF and cognitive impairment independent of stroke and cerebral infarcts remain relatively unexplored. The study aims to assess the cross-sectional association between prevalent AF and white matter microstructural integrity (WMMI) as a marker for cerebrovascular disease. Methods: We performed a cross-sectional analysis of 1937 participants attending the ARIC-Neurocognitive Study (ARIC-NCS) in 2011-2013 that were either black or white and with brain magnetic resonance imaging (MRI). Prevalent AF was defined by a history of AF based on study ECG and hospitalization record. WMMI was defined using regional average fractional anisotropy and mean diffusivity from Diffusion Tensor Imaging measurements in the MRI. We excluded participants with a prior history of stroke or cerebral infarct. A multivariable regression model was used to assess the association between AF and WMMI measures. Results: Among 1943 participants (mean age = 76 years, 28% black, 60% female), 7% (N= 133) had prevalent AF. After multivariable adjustment, prevalence of AF was not associated with WMMI measurements (Table). Conclusion: In a community-based study, prevalent AF was not independently associated with WMMI in the absence of stroke or cerebral infarct. However, the reduced sample size of the AF population as well as the cross-sectional study design are important limitations. Further longitudinal studies are needed to investigate prospectively the association of AF with early markers of white matter disease.

scholarly journals Decreased White Matter Integrity in Neuropsychologically Defined Mild Cognitive Impairment Is Independent of Cortical Thinning

2013 ◽  
Vol 19 (8) ◽  
pp. 925-937 ◽  
Author(s):  
Nikki H. Stricker ◽  
David H. Salat ◽  
Jessica M. Foley ◽  
Tyler A. Zink ◽  
Ida L. Kellison ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Cortical Thickness ◽  
Gray Matter ◽  
Diffusion Tensor ◽  
A Priori ◽  
Hippocampal Volume ◽  
White Matter Integrity ◽  
White Matter Changes

AbstractImproved understanding of the pattern of white matter changes in early and prodromal Alzheimer's disease (AD) states such as mild cognitive impairment (MCI) is necessary to support earlier preclinical detection of AD, and debate remains whether white matter changes in MCI are secondary to gray matter changes. We applied neuropsychologically based MCI criteria to a sample of normally aging older adults; 32 participants met criteria for MCI and 81 participants were classified as normal control (NC) subjects. Whole-head high resolution T1 and diffusion tensor imaging scans were completed. Tract-Based Spatial Statistics was applied and a priori selected regions of interest were extracted. Hippocampal volume and cortical thickness averaged across regions with known vulnerability to AD were derived. Controlling for cortical thickness, the MCI group showed decreased average fractional anisotropy (FA) and decreased FA in parietal white matter and in white matter underlying the entorhinal and posterior cingulate cortices relative to the NC group. Statistically controlling for cortical thickness, medial temporal FA was related to memory and parietal FA was related to executive functioning. These results provide further support for the potential role of white matter integrity as an early biomarker for individuals at risk for AD and highlight that changes in white matter may be independent of gray matter changes. (JINS, 2013, 19, 1–13)

scholarly journals Acupuncture improves white matter perfusion and white matter integrity in vascular dementia rats: an MRI-based imaging study

2020 ◽  
Author(s):  
Siming Ma ◽  
Lu Wang ◽  
Xin-Tong Su ◽  
Jin Huang ◽  
Lu-Lu Lin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Impairment ◽  
White Matter ◽  
Vascular Dementia ◽  
Acupuncture Treatment ◽  
Diffusion Tensor ◽  
White Matter Lesions ◽  
Microglia Activation ◽  
White Matter Integrity

Abstract Background: White matter lesions induced by chronic cerebral hypoperfusion (CCH) are common pathological changes, and are associated with cognitive impairment in vascular dementia (VaD). It has been reported that acupuncture can improve cognitive deficits of VaD rats through increasing cortical cerebral blood flow and attenuating neuroinflammation. However, the effects of acupuncture on white matter perfusion and white matter structural integrity have been not investigated. Methods: VaD was induced by bilateral common carotid arteries occlusion (BCCAO) in Wistar rats. Morris water maze (MWM) was used to evaluated the spatial learning and memory of rats. Arterial spin labeling imaging (ASL) and diffusion tensor imaging (DTI) were performed to measure the cerebral blood flow and white matter integrity in corpus callosum, external capsule, internal capsule, optic nerve and optic tract. Pathological staining was also applied to detect the myelin loss and neuroinflammation. Results: BCCAO rats with declined cerebral blood flow exhibited significant worse MWM performance, and altered DTI parameters including decreased fractional anisotropy, elevated radial diffusivity and axial diffusivity in white matter regions. After acupuncture treatment at GV20 and ST36, cognitive dysfunction, disruption of white matter perfusion and integrity were reversed. Pathological results supported that acupuncture could attenuate the loss of myelin sheath and microglia activation. Conclusions: Our findings suggest that acupuncture treatment protects cognitive impairment of BCCAO rats through increasing subcortical white matter perfusion and improving white matter lesions. Keywords: Acupuncture; ASL; DTI; cerebral blood flow; white matter; microglia activation

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