%0 Journal Article %J J Alzheimers Dis %D 2016 %T Depressive Symptoms and Small Hippocampal Volume Accelerate the Progression to Dementia from Mild Cognitive Impairment. %A Chung, Jun Ku %A Plitman, Eric %A Nakajima, Shinichiro %A Chakravarty, M Mallar %A Caravaggio, Fernando %A Takeuchi, Hiroyoshi %A Gerretsen, Philip %A Iwata, Yusuke %A Patel, Raihaan %A Mulsant, Benoit H %A Graff-Guerrero, Ariel %K Aged %K Aged, 80 and over %K Cognitive Dysfunction %K Dementia %K Depression %K Disease Progression %K Female %K Hippocampus %K Humans %K Image Processing, Computer-Assisted %K Longitudinal Studies %K Magnetic Resonance Imaging %K Male %K Middle Aged %K Psychiatric Status Rating Scales %X

Previous studies have highlighted that decreased hippocampal volume, an early neural correlate of dementia, is commonly observed in patients with mild cognitive impairment (MCI). However, it is unclear whether neurodegenerative and resultant clinical trajectories are accelerated in MCI patients with concomitant depressive symptoms, leading to a faster conversion to dementia stages than those who are not depressed. No longitudinal study has investigated whether depressed amnestic MCI (DEP+aMCI) patients show an earlier onset of progression to dementia than non-depressed amnestic MCI (DEP-aMCI) patients and whether progressive hippocampal volume reductions are related in the conversion process. Using data from Alzheimer's Disease Neuroimaging Initiative, we examined 2-year follow-up data from 38 DEP+aMCI patients and 38 matched DEP-aMCI patients and compared their ages of conversion from aMCI to AD and trajectories of progressive hippocampal volume changes. DEP+ and DEP- patients were defined as having baseline Geriatric Depression Scale scores of 5 or above and 0, respectively. DEP+ converters showed earlier ages of conversion to dementia (p = 0.009) and greater left hippocampal volume loss than both DEP- converters and DEP+ non-converters over the 2-year period (p = 0.003, p = 0.001, respectively). These findings could not be explained by changes in total brain volume, differences in their clinical symptoms of dementia, daily functioning, or apolipoprotein E4 genotypes. No difference in conversion rate to dementia or progressive hippocampal volume change was found between DEP+ patients and DEP-patients, which suggested depressive symptoms themselves may not lead to progression of dementia from MCI. In conclusion, there is a synergistic effect of depressive symptoms and smaller left hippocampal volume in MCI patients that accelerates conversion to dementia.

%B J Alzheimers Dis %V 49 %P 743-54 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26519442?dopt=Abstract %R 10.3233/JAD-150679 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Volumetric and shape analysis of the thalamus and striatum in amnestic mild cognitive impairment. %A Leh, Sandra E %A Kälin, Andrea M %A Schroeder, Clemens %A Park, Min Tae M %A Chakravarty, M Mallar %A Freund, Patrick %A Gietl, Anton F %A Riese, Florian %A Kollias, Spyros %A Hock, Christoph %A Michels, Lars %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Amyloid %K Biomarkers %K Case-Control Studies %K Cognitive Dysfunction %K Corpus Striatum %K Female %K Hippocampus %K Humans %K Magnetic Resonance Imaging %K Male %K Middle Aged %K Neuropsychological Tests %K Positron-Emission Tomography %K Thalamus %X

Alterations in brain structures, including progressive neurodegeneration, are a hallmark in patients with Alzheimer's disease (AD). However, pathological mechanisms, such as the accumulation of amyloid and the proliferation of tau, are thought to begin years, even decades, before the initial clinical manifestations of AD. In this study, we compare the brain anatomy of amnestic mild cognitive impairment patients (aMCI, n = 16) to healthy subjects (CS, n = 22) using cortical thickness, subcortical volume, and shape analysis, which we believe to be complimentary to volumetric measures. We were able to replicate "classical" cortical thickness alterations in aMCI in the hippocampus, amygdala, putamen, insula, and inferior temporal regions. Additionally, aMCI showed significant thalamic and striatal shape differences. We observed higher global amyloid deposition in aMCI, a significant correlation between striatal displacement and global amyloid, and an inverse correlation between executive function and right-hemispheric thalamic displacement. In contrast, no volumetric differences were detected in thalamic, striatal, and hippocampal regions. Our results provide new evidence for early subcortical neuroanatomical changes in patients with aMCI, which are linked to cognitive abilities and amyloid deposition. Hence, shape analysis may aid in the identification of structural biomarkers for identifying individuals at highest risk of conversion to AD.

%B J Alzheimers Dis %V 49 %P 237-49 %8 2016 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26444755?dopt=Abstract %R 10.3233/JAD-150080