Time filter

Source Type

Los Angeles, CA, United States

Daianu M.,University of Southern California | Daianu M.,University of California at Los Angeles | Mendez M.F.,Behavioral Neurology Program | Baboyan V.G.,University of Southern California | And 6 more authors.
Brain Imaging and Behavior | Year: 2015

Cortical and subcortical nuclei degenerate in the dementias, but less is known about changes in the white matter tracts that connect them. To better understand white matter changes in behavioral variant frontotemporal dementia (bvFTD) and early-onset Alzheimer’s disease (EOAD), we used a novel approach to extract full 3D profiles of fiber bundles from diffusion-weighted MRI (DWI) and map white matter abnormalities onto detailed models of each pathway. The result is a spatially complex picture of tract-by-tract microstructural changes. Our atlas of tracts for each disease consists of 21 anatomically clustered and recognizable white matter tracts generated from whole-brain tractography in 20 patients with bvFTD, 23 with age-matched EOAD, and 33 healthy elderly controls. To analyze the landscape of white matter abnormalities, we used a point-wise tract correspondence method along the 3D profiles of the tracts and quantified the pathway disruptions using common diffusion metrics – fractional anisotropy, mean, radial, and axial diffusivity. We tested the hypothesis that bvFTD and EOAD are associated with preferential degeneration in specific neural networks. We mapped axonal tract damage that was best detected with mean and radial diffusivity metrics, supporting our network hypothesis, highly statistically significant and more sensitive than widely studied fractional anisotropy reductions. From white matter diffusivity, we identified abnormalities in bvFTD in all 21 tracts of interest but especially in the bilateral uncinate fasciculus, frontal callosum, anterior thalamic radiations, cingulum bundles and left superior longitudinal fasciculus. This network of white matter alterations extends beyond the most commonly studied tracts, showing greater white matter abnormalities in bvFTD versus controls and EOAD patients. In EOAD, network alterations involved more posterior white matter – the parietal sector of the corpus callosum and parahipoccampal cingulum bilaterally. Widespread but distinctive white matter alterations are a key feature of the pathophysiology of these two forms of dementia. © 2015 The Author(s) Source

Koek R.J.,Psychiatry service | Koek R.J.,University of California at Los Angeles | Langevin J.-P.,University of California at Los Angeles | Krahl S.E.,University of California at Los Angeles | And 12 more authors.
Trials | Year: 2014

Background: Combat post-traumatic stress disorder (PTSD) involves significant suffering, impairments in social and occupational functioning, substance use and medical comorbidity, and increased mortality from suicide and other causes. Many veterans continue to suffer despite current treatments. Deep brain stimulation (DBS) has shown promise in refractory movement disorders, depression and obsessive-compulsive disorder, with deep brain targets chosen by integration of clinical and neuroimaging literature. The basolateral amygdala (BLn) is an optimal target for high-frequency DBS in PTSD based on neurocircuitry findings from a variety of perspectives. DBS of the BLn was validated in a rat model of PTSD by our group, and limited data from humans support the potential safety and effectiveness of BLn DBS.Methods/Design: We describe the protocol design for a first-ever Phase I pilot study of bilateral BLn high-frequency DBS for six severely ill, functionally impaired combat veterans with PTSD refractory to conventional treatments. After implantation, patients are monitored for a month with stimulators off. An electroencephalographic (EEG) telemetry session will test safety of stimulation before randomization to staggered-onset, double-blind sham versus active stimulation for two months. Thereafter, patients will undergo an open-label stimulation for a total of 24 months. Primary efficacy outcome is a 30% decrease in the Clinician Administered PTSD Scale (CAPS) total score. Safety outcomes include extensive assessments of psychiatric and neurologic symptoms, psychosocial function, amygdala-specific and general neuropsychological functions, and EEG changes. The protocol requires the veteran to have a cohabiting significant other who is willing to assist in monitoring safety and effect on social functioning. At baseline and after approximately one year of stimulation, trauma script-provoked 18FDG PET metabolic changes in limbic circuitry will also be evaluated.Discussion: While the rationale for studying DBS for PTSD is ethically and scientifically justified, the importance of the amygdaloid complex and its connections for a myriad of emotional, perceptual, behavioral, and vegetative functions requires a complex trial design in terms of outcome measures. Knowledge generated from this pilot trial can be used to design future studies to determine the potential of DBS to benefit both veterans and nonveterans suffering from treatment-refractory PTSD. © 2014 Koek et al.; licensee BioMed Central Ltd. Source

Horning S.M.,Behavior and Aging Research Center | Melrose R.,Behavior and Aging Research Center | Melrose R.,University of California at Los Angeles | Sultzer D.,Behavior and Aging Research Center | Sultzer D.,University of California at Los Angeles
International Journal of Geriatric Psychiatry | Year: 2014

Objective Individuals suffering from Alzheimer's disease (AD) often have impaired awareness or a lack of insight into their cognitive deficits and functional abilities, especially in the later stages of the disease. Previous research has documented a relationship between depression and insight in AD, such that greater awareness of one's disease has been associated with a higher degree of depression. However, little is known about the relationship between insight, cognitive decline, and other psychiatric or behavioral problems associated with AD. Methods This study included 107 outpatients who met criteria for probable AD. Instruments included the Neurobehavioral Rating Scale, the Apathy Evaluation Scale, and the mini mental state exam. A series of hierarchical regression analyses were conducted to determine the relationship between insight and depressed mood, anxiety, psychosis, apathy, agitation, and behavioral retardation in AD patients after controlling for cognitive skills. Results Insight was found to significantly predict depressed mood, anxiety, and apathy even after controlling for global cognition. Greater insight was found to be associated with depressed mood and anxiety. However, impaired insight was associated with higher levels of apathy. Conclusion Insight may be differentially related to mood symptoms and apathy within AD, such that patients with intact insight are more depressed, whereas patients with impaired insight are more apathetic. This suggests that assessment of insight in AD may complement the clinical evaluation of depression and apathy in AD and help guide the most appropriate interventions. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. © Published 2013. This article is a U.S. Government work and is in the public domain in the USA. Source

Melrose R.J.,Behavior and Aging Research Center | Melrose R.J.,University of California at Los Angeles | Ettenhofer M.L.,Uniformed Services University of the Health Sciences | Harwood D.,Behavior and Aging Research Center | And 7 more authors.
Journal of Geriatric Psychiatry and Neurology | Year: 2011

Patients with Alzheimer disease (AD) exhibit profound difficulties in completing instrumental activities of daily living (IADLs), such as managing finances, organizing medications, and food preparation. It is unclear which brain areas underlie IADL deficits in AD. To address this question, we used voxel-based analysis to correlate the performance of IADLs with resting cerebral metabolism as measured during [18F] fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging in 44 patients with AD. Poorer ability to complete IADLs was associated with hypometabolism in right-sided cortical regions, including the parietal lobe, posterior temporal cortex, dorsolateral prefrontal cortex, and frontal pole. Follow-up path analyses examining anatomically defined regions of interest (ROI) demonstrated that the association between metabolism and IADLs was mediated by global cognition in frontal ROIs, and partially mediated by global cognition in the parietal ROI. Findings suggest that hypometabolism of right sided brain regions involved in executive functioning, visuospatial processing, attention, and working memory underlie functional impairments in patients with AD. © The Author(s) 2011. Source

Melrose R.J.,Behavior and Aging Research Center | Melrose R.J.,University of California at Los Angeles | Harwood D.,Behavior and Aging Research Center | Harwood D.,University of California at Los Angeles | And 5 more authors.
Journal of Clinical and Experimental Neuropsychology | Year: 2013

The copy condition of the Rey-Osterrieth Complex Figure (ROCF) is sensitive to Alzheimer's disease (AD) pathology, but its neural correlates remain unclear. We used fluorodeoxyglucose positron emission tomography (FDG-PET) to elucidate this association in 77 patients with probable AD. We observed a correlation between ROCF and metabolic rate of bilateral temporal-parietal cortex and occipital lobe, and right frontal lobe. Global and local elements of the ROCF correlated with metabolic rate of these same regions. The copy approach correlated with right lateral temporal cortex. The ROCF appears reflective of posterior temporal-parietal cortex functioning, highlighting the role of visuospatial processing in constructional abilities in AD. © 2013 Taylor and Francis. Source

Discover hidden collaborations