%0 Journal Article %J J Alzheimers Dis %D 2021 %T White Matter Connectivity in Incident Mild Cognitive Impairment: A Diffusion Spectrum Imaging Study of World Trade Center Responders at Midlife. %A Huang, Chuan %A Kritikos, Minos %A Clouston, Sean A P %A Deri, Yael %A Serrano-Sosa, Mario %A Bangiyev, Lev %A Santiago-Michels, Stephanie %A Gandy, Sam %A Sano, Mary %A Bromet, Evelyn J %A Luft, Benjamin J %K Brain %K Cognitive Dysfunction %K Diffusion Tensor Imaging %K Emergency Responders %K Female %K Humans %K Incidence %K Male %K Middle Aged %K September 11 Terrorist Attacks %K White Matter %X

BACKGROUND: Individuals who participated in response efforts at the World Trade Center (WTC) following 9/11/2001 are experiencing elevated incidence of mild cognitive impairment (MCI) at midlife.

OBJECTIVE: We hypothesized that white matter connectivity measured using diffusion spectrum imaging (DSI) would be restructured in WTC responders with MCI versus cognitively unimpaired responders.

METHODS: Twenty responders (mean age 56; 10 MCI/10 unimpaired) recruited from an epidemiological study were characterized using NIA-AA criteria alongside controls matched on demographics (age/sex/occupation/race/education). Axial DSI was acquired on a 3T Siemen's Biograph mMR scanner (12-channel head coil) using a multi-band diffusion sequence. Connectometry examined whole-brain tract-level differences in white matter integrity. Fractional anisotropy (FA), mean diffusivity (MD), and quantified anisotropy were extracted for region of interest (ROI) analyses using the Desikan-Killiany atlas.

RESULTS: Connectometry identified both increased and decreased connectivity within regions of the brains of responders with MCI identified in the corticothalamic pathway and cortico-striatal pathway that survived adjustment for multiple comparisons. MCI was also associated with higher FA values in five ROIs including in the rostral anterior cingulate; lower MD values in four ROIs including the left rostral anterior cingulate; and higher MD values in the right inferior circular insula. Analyses by cognitive domain revealed nominal associations in domains of response speed, verbal learning, verbal retention, and visuospatial learning.

CONCLUSIONS: WTC responders with MCI at midlife showed early signs of neurodegeneration characterized by both increased and decreased white matter diffusivity in regions commonly affected by early-onset Alzheimer's disease.

%B J Alzheimers Dis %V 80 %P 1209-1219 %8 2021 %G eng %N 3 %1 https://www.ncbi.nlm.nih.gov/pubmed/33646156?dopt=Abstract %R 10.3233/JAD-201237 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Cardiorespiratory Fitness and White Matter Neuronal Fiber Integrity in Mild Cognitive Impairment. %A Ding, Kan %A Tarumi, Takashi %A Zhu, David C %A Tseng, Benjamin Y %A Thomas, Binu P %A Turner, Marcel %A Repshas, Justin %A Kerwin, Diana R %A Womack, Kyle B %A Lu, Hanzhang %A Cullum, C Munro %A Zhang, Rong %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Anisotropy %K Cardiorespiratory Fitness %K Case-Control Studies %K Cognition %K Cognitive Dysfunction %K Diffusion Tensor Imaging %K Executive Function %K Female %K Humans %K Linear Models %K Male %K Memory %K Middle Aged %K Nerve Fibers, Myelinated %K Neuropsychological Tests %K Texas %K White Matter %X

BACKGROUND: Mounting evidence showed the self-reported levels of physical activity are positively associated with white matter (WM) integrity and cognitive performance in normal adults and patients with mild cognitive impairment (MCI). However, the objective measure of cardiorespiratory fitness (CRF) was not used in these studies.

OBJECTIVE: To determine the associations of CRF measured by maximal oxygen uptake (VO2max) with WM fiber integrity and neurocognitive performance in older adults with MCI.

METHODS: Eighty-one participants (age = 65±7 years, 43 women), including 26 cognitively normal older adults and 55 amnestic MCI patients, underwent VO2max test to measure CRF, diffusion tensor imaging (DTI) to assess WM fiber integrity, and neurocognitive assessment focused on memory and executive function. DTI data were analyzed by the tract-based spatial statistics and region-of-interest approach.

RESULTS: Cognitively normal older adults and MCI patients were not different in global WM fiber integrity and VO2max. VO2max was associated positively with DTI metrics of fractional anisotropy in ∼54% WM fiber tracts, and negatively with mean and radial diffusivities in ∼46% and ∼56% of the WM fiber tracts. The associations of VO2max with DTI metrics remained statistically significant after adjustment of age, sex, body mass index, WM lesion burden, and MCI status. The DTI metrics obtained from the area that correlated to VO2max were associated with executive function performance in MCI patients.

CONCLUSIONS: Higher levels of CRF are associated with better WM fiber integrity, which in turn is correlated with better executive function performance in MCI patients.

%B J Alzheimers Dis %V 61 %P 729-739 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29226864?dopt=Abstract %R 10.3233/JAD-170415 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Cerebrospinal Fluid Markers of Alzheimer's Disease Pathology and Microglial Activation are Associated with Altered White Matter Microstructure in Asymptomatic Adults at Risk for Alzheimer's Disease. %A Melah, Kelsey E %A Lu, Sharon Yuan-Fu %A Hoscheidt, Siobhan M %A Alexander, Andrew L %A Adluru, Nagesh %A Destiche, Daniel J %A Carlsson, Cynthia M %A Zetterberg, Henrik %A Blennow, Kaj %A Okonkwo, Ozioma C %A Gleason, Carey E %A Dowling, N Maritza %A Bratzke, Lisa C %A Rowley, Howard A %A Sager, Mark A %A Asthana, Sanjay %A Johnson, Sterling C %A Bendlin, Barbara B %K Adipokines %K Aged %K Alzheimer Disease %K Amyloid beta-Peptides %K Biomarkers %K Chemokine CCL2 %K Chitinase-3-Like Protein 1 %K Diffusion Tensor Imaging %K Female %K Hippocampus %K Humans %K Image Processing, Computer-Assisted %K Lectins %K Male %K Microglia %K Middle Aged %K Peptide Fragments %K tau Proteins %K White Matter %X

BACKGROUND: The immune response in Alzheimer's disease (AD) involves activation of microglia which may remove amyloid-β (Aβ). However, overproduction of inflammatory compounds may exacerbate neural damage in AD. AD pathology accumulates years before diagnosis, yet the extent to which neuroinflammation is involved in the earliest disease stages is unknown.

OBJECTIVE: To determine whether neuroinflammation exacerbates neural damage in preclinical AD.

METHODS: We utilized cerebrospinal fluid (CSF) and magnetic resonance imaging collected in 192 asymptomatic late-middle-aged adults (mean age = 60.98 years). Neuroinflammatory markers chitinase-3-like protein 1 (YKL-40) and monocyte chemoattractant protein-1 (MCP-1) in CSF were utilized as markers of neuroinflammation. Neural cell damage was assessed using CSF neurofilament light chain protein (NFL), CSF total tau (T-Tau), and neural microstructure assessed with diffusion tensor imaging (DTI). With regard to AD pathology, CSF Aβ42 and tau phosphorylated at threonine 181 (P-Tau181) were used as markers of amyloid and tau pathology, respectively. We hypothesized that higher YKL-40 and MCP-1 in the presence of AD pathology would be associated with higher NFL, T-Tau, and altered microstructure on DTI.

RESULTS: Neuroinflammation was associated with markers of neural damage. Higher CSF YKL-40 was associated with both higher CSF NFL and T-Tau. Inflammation interacted with AD pathology, such that greater MCP-1 and lower Aβ42 was associated with altered microstructure in bilateral frontal and right temporal lobe and that greater MCP-1 and greater P-Tau181 was associated with altered microstructure in precuneus.

CONCLUSION: Inflammation may play a role in neural damage in preclinical AD.

%B J Alzheimers Dis %V 50 %P 873-86 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26836182?dopt=Abstract %R 10.3233/JAD-150897 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Characterizing White Matter Tract Degeneration in Syndromic Variants of Alzheimer's Disease: A Diffusion Tensor Imaging Study. %A Madhavan, Ajay %A Schwarz, Christopher G %A Duffy, Joseph R %A Strand, Edythe A %A Machulda, Mary M %A Drubach, Daniel A %A Kantarci, Kejal %A Przybelski, Scott A %A Reid, Robert I %A Senjem, Matthew L %A Gunter, Jeffrey L %A Apostolova, Liana G %A Lowe, Val J %A Petersen, Ronald C %A Jack, Clifford R %A Josephs, Keith A %A Whitwell, Jennifer L %K Aged %K Alzheimer Disease %K Aniline Compounds %K Anisotropy %K Aphasia, Primary Progressive %K Case-Control Studies %K Diffusion Tensor Imaging %K Female %K Humans %K Image Processing, Computer-Assisted %K Male %K Middle Aged %K Nerve Fibers, Myelinated %K Neurodegenerative Diseases %K Neuropsychological Tests %K Positron-Emission Tomography %K Psychiatric Status Rating Scales %K Retrospective Studies %K Thiazoles %K White Matter %X

BACKGROUND: Different clinical syndromes can arise from Alzheimer's disease (AD) neuropathology, including dementia of the Alzheimer's type (DAT), logopenic primary progressive aphasia (lvPPA), and posterior cortical atrophy (PCA).

OBJECTIVE: To assess similarities and differences in patterns of white matter tract degeneration across these syndromic variants of AD.

METHODS: Sixty-four subjects (22 DAT, 24 lvPPA, and 18 PCA) that had diffusion tensor imaging and showed amyloid-β deposition on PET were assessed in this case-control study. A whole-brain voxel-based analysis was performed to assess differences in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity across groups.

RESULTS: All three groups showed overlapping diffusion abnormalities in a network of tracts, including fornix, corpus callosum, posterior thalamic radiations, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus. Subtle regional differences were also observed across groups, with DAT particularly associated with degeneration of fornix and cingulum, lvPPA with left inferior fronto-occipital fasciculus and uncinate fasciculus, and PCA with posterior thalamic radiations, superior longitudinal fasciculus, posterior cingulate, and splenium of the corpus callosum.

CONCLUSION: These findings show that while each AD phenotype is associated with degeneration of a specific structural network of white matter tracts, striking spatial overlap exists among the three network patterns that may be related to AD pathology.

%B J Alzheimers Dis %V 49 %P 633-43 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26484918?dopt=Abstract %R 10.3233/JAD-150502 %0 Journal Article %J J Alzheimers Dis %D 2016 %T The Disconnection Hypothesis in Alzheimer's Disease Studied Through Multimodal Magnetic Resonance Imaging: Structural, Perfusion, and Diffusion Tensor Imaging. %A Lacalle-Aurioles, María %A Navas-Sánchez, Francisco Javier %A Alemán-Gómez, Yasser %A Olazarán, Javier %A Guzmán-De-Villoria, Juan Adán %A Cruz-Orduña, Isabel %A Mateos-Pérez, José María %A Desco, Manuel %K Aged %K Alzheimer Disease %K Brain %K Brain Mapping %K Cerebral Angiography %K Cerebrovascular Circulation %K Cognitive Dysfunction %K Diffusion Tensor Imaging %K Female %K Functional Laterality %K Humans %K Magnetic Resonance Imaging %K Male %K Mental Status Schedule %K Models, Neurological %K Multimodal Imaging %K Organ Size %K Prospective Studies %X

According to the so-called disconnection hypothesis, the loss of synaptic inputs from the medial temporal lobes (MTL) in Alzheimer's disease (AD) may lead to reduced activity of target neurons in cortical areas and, consequently, to decreased cerebral blood flow (CBF) in those areas. The aim of this study was to assess whether hypoperfusion in parietotemporal and frontal cortices of patients with mild cognitive impairment who converted to AD (MCI-c) and patients with mild AD is associated with atrophy in the MTL and/or microstructural changes in the white matter (WM) tracts connecting these areas. We assessed these relationships by investigating correlations between CBF in hypoperfused areas, mean cortical thickness in atrophied regions of the MTL, and fractional anisotropy (FA) in WM tracts. In the MCI-c group, a strong correlation was observed between CBF of the superior parietal gyri and FA in the parahippocampal tracts (left: r = 0.90, p <  0.0001; right: r = 0.597, p = 0.024), and between FA in the right parahippocampal tract and the right precuneus (r = 0.551, p = 0.041). No significant correlations between CBF in hypoperfused regions and FA in the WM tract were observed in the AD group. These results suggest an association between perfusion deficits and altered WM tracts in prodromal AD, while microvasculature impairments may have a greater influence in more advanced stages. We did not find correlations between cortical thinning in the medial temporal lobes and decreased FA in the WM tracts of the limbic system in either group.

%B J Alzheimers Dis %V 50 %P 1051-64 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26890735?dopt=Abstract %R 10.3233/JAD-150288 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Multimodal Magnetic Resonance Imaging in Alzheimer's Disease Patients at Prodromal Stage. %A Eustache, Pierre %A Nemmi, Federico %A Saint-Aubert, Laure %A Pariente, Jérémie %A Péran, Patrice %K Aged %K Alzheimer Disease %K Biomarkers %K Brain %K Cognitive Dysfunction %K Diffusion Tensor Imaging %K Female %K Fluorodeoxyglucose F18 %K Humans %K Magnetic Resonance Imaging %K Male %K Mental Status Schedule %K Multimodal Imaging %K Neuropsychological Tests %K Organ Size %K Positron-Emission Tomography %K Prodromal Symptoms %K Radiopharmaceuticals %X

One objective of modern neuroimaging is to identify markers that can aid in diagnosis, monitor disease progression, and impact long-term drug analysis. In this study, physiopathological modifications in seven subcortical structures of patients with mild cognitive impairment (MCI) due to Alzheimer's disease (AD) were characterized by simultaneously measuring quantitative magnetic resonance parameters that are sensitive to complementary tissue characteristics (e.g., volume atrophy, shape changes, microstructural damage, and iron deposition). Fourteen MCI patients and fourteen matched, healthy subjects underwent 3T-magnetic resonance imaging with whole-brain, T1-weighted, T2*-weighted, and diffusion-tensor imaging scans. Volume, shape, mean R2*, mean diffusivity (MD), and mean fractional anisotropy (FA) in the thalamus, hippocampus, putamen, amygdala, caudate nucleus, pallidum, and accumbens were compared between MCI patients and healthy subjects. Comparisons were then performed using voxel-based analyses of R2*, MD, FA maps, and voxel-based morphometry to determine which subregions showed the greatest difference for each parameter. With respect to the micro- and macro-structural patterns of damage, our results suggest that different and distinct physiopathological processes are present in the prodromal phase of AD. MCI patients had significant atrophy and microstructural changes within their hippocampi and amygdalae, which are known to be affected in the prodromal stage of AD. This suggests that the amygdala is affected in the same, direct physiopathological process as the hippocampus. Conversely, atrophy alone was observed within the thalamus and putamen, which are not directly involved in AD pathogenesis. This latter result may reflect another mechanism, whereby atrophy is linked to indirect physiopathological processes.

%B J Alzheimers Dis %V 50 %P 1035-50 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26836151?dopt=Abstract %R 10.3233/JAD-150353 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Tract-Specific Correlates of Neuropsychological Deficits in Patients with Subcortical Vascular Cognitive Impairment. %A Jung, Na-Yeon %A Han, Cheol E %A Kim, Hee Jin %A Yoo, Sang Wook %A Kim, Hee-Jong %A Kim, Eun-Joo %A Na, Duk L %A Lockhart, Samuel N %A Jagust, William J %A Seong, Joon-Kyung %A Seo, Sang Won %K Aged %K Brain %K Cerebrovascular Disorders %K Cognitive Dysfunction %K Diffusion Magnetic Resonance Imaging %K Diffusion Tensor Imaging %K Female %K Gray Matter %K Humans %K Male %K Neural Pathways %K Neuropsychological Tests %K White Matter %X

The white matter tract-specific correlates of neuropsychological deficits are not fully established in patients with subcortical vascular cognitive impairment (SVCI), where white matter tract damage may be a critical factor in cognitive impairment. The purpose of this study is to investigate the tract-specific correlates of neuropsychological deficits in SVCI patients using tract-specific statistical analysis (TSSA). We prospectively recruited 114 SVCI patients, and 55 age-, gender-, and education-matched individuals with normal cognition (NC). All participants underwent diffusion weighted imaging and neuropsychological testing. We classified tractography results into fourteen major fiber tracts and analyzed group comparison and correlation with cognitive impairments. Relative to NC subjects, SVCI patients showed decreased fractional anisotropy values in bilateral anterior-thalamic radiation, cingulum, superior-longitudinal fasciculus, uncinate fasciculus, corticospinal tract, and left inferior-longitudinal fasciculus. Focal disruptions in specific tracts were associated with specific cognitive impairments. Our findings suggest that disconnection of specific white matter tracts, especially those neighboring and providing connections between gray matter regions important to certain cognitive functions, may contribute to specific cognitive impairments in SVCI.

%B J Alzheimers Dis %V 50 %P 1125-35 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26836179?dopt=Abstract %R 10.3233/JAD-150841 %0 Journal Article %J J Alzheimers Dis %D 2016 %T White Matter Abnormalities Track Disease Progression in PSEN1 Autosomal Dominant Alzheimer's Disease. %A Sánchez-Valle, Raquel %A Monté, Gemma C %A Sala-Llonch, Roser %A Bosch, Beatriz %A Fortea, Juan %A Lladó, Albert %A Antonell, Anna %A Balasa, Mircea %A Bargalló, Nuria %A Molinuevo, José Luis %K Adult %K Aging %K Alzheimer Disease %K Brain %K Cohort Studies %K Diffusion Tensor Imaging %K Disease Progression %K Family %K Female %K Heterozygote %K Humans %K Image Processing, Computer-Assisted %K Magnetic Resonance Imaging %K Male %K Mental Status Schedule %K Middle Aged %K Mutation %K Neuropsychological Tests %K Organ Size %K Presenilin-1 %K White Matter %X

PSEN1 mutations are the most frequent cause of autosomal dominant Alzheimer's disease (ADAD), and show nearly full penetrance. There is presently increasing interest in the study of biomarkers that track disease progression in order to test therapeutic interventions in ADAD. We used white mater (WM) volumetric characteristics and diffusion tensor imaging (DTI) metrics to investigate correlations with the normalized time to expected symptoms onset (relative age ratio) and group differences in a cohort of 36 subjects from PSEN1 ADAD families: 22 mutation carriers, 10 symptomatic (SMC) and 12 asymptomatic (AMC), and 14 non-carriers (NC). Subjects underwent a 3T MRI. WM morphometric data and DTI metrics were analyzed. We found that PSEN1 MC showed significant negative correlation between fractional anisotropy (FA) and the relative age ratio in the genus and body of corpus callosum and corona radiate (p <  0.05 Family-wise error correction (FWE) at cluster level) and positive correlation with mean diffusivity (MD), axial diffusivity (AxD), and radial diffusivity (RD) in the splenium of corpus callosum. SMC presented WM volume loss, reduced FA and increased MD, AxD, and RD in the anterior and posterior corona radiate, corpus callosum (p <  0.05 FWE) compared with NC. No significant differences were observed between AMC and NC in WM volume or DTI measures. These findings suggest that the integrity of the WM deteriorates linearly in PSEN1 ADAD from the early phases of the disease; thus DTI metrics might be useful to monitor the disease progression. However, the lack of significant alterations at the preclinical stages suggests that these indexes might not be good candidates for early markers of the disease.

%B J Alzheimers Dis %V 51 %P 827-35 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26923015?dopt=Abstract %R 10.3233/JAD-150899 %0 Journal Article %J J Alzheimers Dis %D 2016 %T White Matter and Hippocampal Volume Predict the Risk of Dementia in Patients with Cerebral Small Vessel Disease: The RUN DMC Study. %A van Uden, Ingeborg W M %A van der Holst, Helena M %A Tuladhar, Anil M %A van Norden, Anouk G W %A de Laat, Karlijn F %A Rutten-Jacobs, Loes C A %A Norris, David G %A Claassen, Jurgen A H R %A van Dijk, Ewoud J %A Kessels, Roy P C %A de Leeuw, Frank-Erik %K Aged %K Cerebral Small Vessel Diseases %K Cohort Studies %K Dementia %K Diffusion Tensor Imaging %K Female %K Hippocampus %K Humans %K Image Processing, Computer-Assisted %K Magnetic Resonance Imaging %K Male %K Mental Status Schedule %K Middle Aged %K Statistics, Nonparametric %K White Matter %X

BACKGROUND: The relationship between cerebral small vessel disease (SVD) and dementia has been studied without considering white matter (WM) volume, the microstructural integrity of the WM surrounding the SVD, and grey matter (GM).

OBJECTIVE: We prospectively investigated the relationship between these structures and the risk of dementia, and formed a prediction model to investigate which characteristics (macro- or microstructural) explained most of the variance.

METHODS: The RUN DMC study is a prospective cohort study among 503 non-demented participants with an age between 50 and 85 years at baseline, with baseline assessment in 2006 and follow-up assessment in 2012. Two were lost to follow-up (yielding a 99.6% response-rate). Cox regression analysis was used, to calculate hazard ratios for dementia, of baseline MRI characteristics. Tract-Based Spatial Statistics (TBSS) analysis was used to assess the added value of microstructural integrity of the WM.

RESULTS: Mean age at baseline was 65.6 years (SD 8.8) and 56.8% was male. 43 participants developed dementia (8.6%), resulting in a 5.5-year cumulative risk of 11.1% (95% CI 7.7-14.6). Low WM and hippocampal volume are significant predictors for dementia. WM, WM hyperintensities, and hippocampal volume explained most of the variance. TBSS analyses showed no additional value of diffusion parameters.

CONCLUSIONS: WM and hippocampal volume were the main predictors for the development of incident dementia at 5-year follow-up in elderly with SVD. There was no additional diagnostic value of the diffusion tensor imaging parameters on top of the macrostructural characteristics.

%B J Alzheimers Dis %V 49 %P 863-73 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26529206?dopt=Abstract %R 10.3233/JAD-150573 %0 Journal Article %J J Alzheimers Dis %D 2016 %T White Matter Changes are Associated with Ventricular Expansion in Aging, Mild Cognitive Impairment, and Alzheimer's Disease. %A Coutu, Jean-Philippe %A Goldblatt, Alison %A Rosas, H Diana %A Salat, David H %K Aged %K Aging %K Alzheimer Disease %K Cognitive Dysfunction %K Diffusion Tensor Imaging %K Factor Analysis, Statistical %K Female %K Hippocampus %K Humans %K Imaging, Three-Dimensional %K Male %K Mental Status Schedule %K Neuropsychological Tests %K White Matter %X

White matter lesions are highly prevalent in individuals with Alzheimer's disease (AD). Although these lesions are presumed to be of vascular origin and linked to small vessel disease in older adults, little information exists about their relationship to markers of classical AD neurodegeneration. Thus, we examined the link between these white matter changes (WMC) segmented on T1-weighted MRI and imaging markers presumed to be altered due to primary AD neurodegenerative processes. Tissue microstructure of WMC was quantified using diffusion tensor imaging and the relationship of WMC properties and volume to neuroimaging markers was examined in 219 cognitively healthy older adults and individuals with mild cognitive impairment and AD using data from the Alzheimer's Disease Neuroimaging Initiative. No significant group differences in WMC properties were found. However, there were strong associations between diffusivity of WMC and ventricular volume, volume of WMC and total WM volume. In comparison, group differences in parahippocampal white matter microstructure were found for all diffusion metrics and were largely explained by hippocampal volume. Factor analysis on neuroimaging markers suggested two independent sets of covarying degenerative changes, with potentially age- and vascular-mediated tissue damage contributing to one factor and classical neurodegenerative changes associated with AD contributing to a second factor. These data demonstrate two potentially distinct classes of degenerative change in AD, with one factor strongly linked to aging, ventricular expansion, and both volume and tissue properties of white matter lesions, while the other factor related to classical patterns of cortical and hippocampal neurodegeneration in AD.

%B J Alzheimers Dis %V 49 %P 329-42 %8 2016 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/26444767?dopt=Abstract %R 10.3233/JAD-150306