Veitch D.P.,Center for Imaging of Neurodegenerative Diseases |
Friedl K.E.,U.S. Army |
Weiner M.W.,University of California at San Francisco
Current Alzheimer Research | Year: 2013
Delayed neurological health consequences of environmental exposures during military service have been generally underappreciated. The rapidly expanding understanding of Alzheimer's disease (AD) pathogenesis now makes it possible to quantitate some of the likely long-term health risks associated with military service. Military risk factors for AD include both factors elevated in military personnel such as tobacco use, traumatic brain injury (TBI), depression, and post-traumatic stress disorder (PTSD) and other nonspecific risk factors for AD including, vascular risk factors such as obesity and obesity-related diseases (e.g., metabolic syndrome), education and physical fitness. The degree of combat exposure, Vietnam era Agent Orange exposure and Gulf War Illness may also influence risk for AD. Using available data on the association of AD and specific exposures and risk factors, the authors have conservatively estimated 423,000 new cases of AD in veterans by 2020, including 140,000 excess cases associated with specific military exposures. The cost associated with these excess cases is approximately $5.8 billion to $7.8 billion. Mitigation of the potential impact of military exposures on the cognitive function of veterans and management of modifiable risk factors through specifically designed programs will be instrumental in minimizing the impact of AD in veterans in the future decades. © 2013 Bentham Science Publishers.
Mueller S.G.,Center for Imaging of Neurodegenerative Diseases |
Bateman L.M.,Columbia University |
Laxer K.D.,California Pacific Medical Center
NeuroImage: Clinical | Year: 2014
The symptoms witnessed in unexplained death in epilepsy (SUDEP) suggest a breakdown of central autonomic control. Since the brainstem plays a crucial role in autonomic control, the objectives of this study were 1. To investigate if temporal lobe epilepsy (TLE) is associated with brainstem atrophy and to characterize it using graph Analysis 2. To compare the findings with those in two probable TLESUDEP. T1 images were obtained from 17 controls, 30 TLE (16 with mesial-temporal-sclerosis (TLE-MTS) and 14 without (TLE-no)) and from 2 patients who died of SUDEP. The brainstem was extracted, warped onto a brainstem atlas and Jacobian determinants maps (JDM) calculated. SPM8 was used to compare the JDMs at the group level, z-score maps were calculated for single subject analysis. Brainstem regions encompassing autonomic structures were identified based on macroscopic landmarks and mean z-scores from 5 × 5 × 5 voxel cubes extracted to calculate a new measure called atrophy-similarity index (ASI) for graph analysis. TLE-MTS had volume loss in the dorsal mesencephalon. The SUDEP cases had severe and more extensive volume loss in the same region. Nodal degrees and participation coefficients were decreased and local efficiency increased in SUDEP compared to controls. TLE is associated with volume loss in brainstem regions involved in autonomic control. Structural damage in these regions might increase the risk for a fatal dysregulation during situations with increased demand such as following severe seizures. © 2014 The Authors.
Mueller S.G.,Center for Imaging of Neurodegenerative Diseases |
Schuff N.,Center for Imaging of Neurodegenerative Diseases |
Yaffe K.,The Medical Memory |
Madison C.,The Medical Memory |
And 2 more authors.
Human Brain Mapping | Year: 2010
Background: Histopathological studies and animal models suggest that hippocampal subfields may be differently affected by aging, Alzheimer's disease (AD), and other diseases. High-resolution images at 4 Tesla depict details of the internal structure of the hippocampus allowing for in vivo volumetry of different subfields. The aims of this study were as follows: (1) to determine patterns of volume loss in hippocampal subfields in normal aging, AD, and amnestic mild cognitive impairment (MCI). (2) To determine if measurements of hippocampal subfields provide advantages over total hippocampal volume for differentiation between groups. Methods: Ninety-one subjects (53 controls (mean age: 69.3 ± 7.3), 20 MCI (mean age: 73.6 ± 7.1), and 18 AD (mean age: 69.1 ± 9.5) were studied with a high-resolution T2 weighted imaging sequence aimed at the hippocampus. Entorhinal cortex (ERC), subiculum, CA1, CA1-CA2 transition zone (CA1-2), CA3 & dentate gyrus (CA3&DG) were manually marked in the anterior third of the hippocampal body. Hippocampal volume was obtained from the Freesurfer and manually edited. Results: Compared to controls, AD had smaller volumes of ERC, subiculum, CA1, CA1-2, and total hippocampal volumes. MCI had smaller CA1-2 volumes. Discriminant analysis and power analysis showed that CA1-2 was superior to total hippocampal volume for distinction between controls and MCI. Conclusion: The patterns of subfield atrophy in AD and MCI were consistent with patterns of neuronal cell loss/reduced synaptic density described by histopathology. These preliminary findings suggest that hippocampal subfield volumetry might be a better measure for diagnosis of early AD and for detection of other disease effects than measurement of total hippocampus. © 2010 Wiley-Liss, Inc.
Durazzo T.C.,Center for Imaging of Neurodegenerative Diseases |
Durazzo T.C.,University of California at San Francisco |
Meyerhoff D.J.,Center for Imaging of Neurodegenerative Diseases |
Meyerhoff D.J.,University of California at San Francisco |
Nixon S.J.,University of Florida
Drug and Alcohol Dependence | Year: 2012
Background: The majority of studies investigating the neurocognitive consequences of chronic smoking have been conducted with adults 60 years and older. Therefore, the scope of neurocognitive dysfunction associated with chronic cigarette smoking in middle age (i.e., 30-60 age range) has not been fully delineated. Methods: Twenty-seven (44 ± 9 years of age; 4 females) non-smoking and 30 smoking (49 ± 8 years of age; 4 females) participants completed a comprehensive neurocognitive battery and measures of fine motor dexterity and postural stability. All participants were free of biomedical or psychiatric conditions that may have influenced neurocognitive and motor function. Results: Smokers performed significantly worse than non-smokers on the following domains: auditory-verbal and visuospatial learning, visuospatial memory, cognitive efficiency, executive skills, general intelligence, processing speed, fine motor dexterity and postural stability. The differences between smokers and non-smokers evidenced moderate to strong effect sizes and were not mediated by age, education, vocational level, estimated verbal intelligence or alcohol consumption. In smokers, a greater number of lifetime years of smoking was related to poorer performance on measures of cognitive efficiency, processing speed and visuospatial skills. Conclusions: Results from this middle-aged cohort replicated previous research and provides novel findings indicating that chronic smoking was associated with inferior performance on measures of general intelligence, visuospatial learning and memory and fine motor dexterity. Research that relates measures of neurobiological function/integrity to neurocognition is needed to better understand the mechanisms contributing to the poorer performance across multiple domains demonstrated by smokers. © 2011.
Chao L.,University of California at San Francisco |
Chao L.,Center for Imaging of Neurodegenerative Diseases |
Weiner M.,University of California at San Francisco |
Weiner M.,Center for Imaging of Neurodegenerative Diseases |
Neylan T.,University of California at San Francisco
Psychiatry Research - Neuroimaging | Year: 2013
We previously reported that hippocampal volume was associated with current, but not lifetime posttraumatic stress disorder (PTSD) symptom severity. In the present study, we test the hypothesis that like the hippocampus, the volumes of other brain regions previously implicated in PTSD, are also negatively related to current, but not lifetime PTSD symptom severity. One hundred ninety-one veterans underwent structural magnetic resonance imaging (MRI) on a 4. T scanner. Seventy-five veterans were trauma unexposed, 43 were trauma exposed without PTSD, 39 were trauma exposed with current PTSD, and 34 were trauma exposed veterans with remitted PTSD. Hippocampal, amygdala, rostral and caudal anterior cingulate, insula, and corpus callosum volumes, quantified with Freesurfer version 4.5, were analyzed by group using multivariate analysis of covariance. Veterans with PTSD had smaller hippocampal, caudal anterior cingulate, insula, and corpus callosum volumes than the unexposed controls (p≤0.009); smaller hippocampal, caudal anterior cingulate, insula (p≤0.009) and marginally smaller corpus callosum (p=0.06) than veterans with remitted PTSD; and smaller hippocampal and caudal anterior cingulate volumes than veterans without PTSD (p≤0.04). In contrast, there was no significant volume differences between veterans with remitted PTSD compared to those without PTSD or unexposed controls. The finding that current but not lifetime PTSD accounts for the volumes of multiple brain regions suggests that either smaller brain volume is a vulnerability factor that impedes recovery from PTSD or that recovery from PTSD is accompanied by a wide-spread restoration of brain tissue. © 2013 Elsevier Ireland Ltd.