%0 Journal Article %J J Alzheimers Dis %D 2016 %T Distinctive Resting State Network Disruptions Among Alzheimer's Disease, Subcortical Vascular Dementia, and Mixed Dementia Patients. %A Kim, Hee Jin %A Cha, Jungho %A Lee, Jong-Min %A Shin, Ji Soo %A Jung, Na-Yeon %A Kim, Yeo Jin %A Choe, Yearn Seong %A Lee, Kyung Han %A Kim, Sung Tae %A Kim, Jae Seung %A Lee, Jae Hong %A Na, Duk L %A Seo, Sang Won %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Aniline Compounds %K Cerebral Cortex %K Cross-Sectional Studies %K Dementia %K Dementia, Vascular %K Female %K Humans %K Image Processing, Computer-Assisted %K Male %K Middle Aged %K Models, Neurological %K Neural Pathways %K Neuropsychological Tests %K Oxygen %K Psychiatric Status Rating Scales %K Radionuclide Imaging %K Rest %K Thiazoles %X

BACKGROUND: Recent advances in resting-state functional MRI have revealed altered functional networks in Alzheimer's disease (AD), especially those of the default mode network (DMN) and central executive network (CEN). However, few studies have evaluated whether small vessel disease (SVD) or combined amyloid and SVD burdens affect the DMN or CEN.

OBJECTIVE: The aim of this study was to evaluate whether SVD or combined amyloid and SVD burdens affect the DMN or CEN.

METHODS: In this cross-sectional study, we investigated the resting-state functional connectivity within DMN and CEN in 37 Pittsburgh compound-B (PiB)(+) AD, 37 PiB(-) subcortical vascular dementia (SVaD), 13 mixed dementia patients, and 65 normal controls.

RESULTS: When the resting-state DMN of PiB(+) AD and PiB(-) SVaD patients were compared, the PiB(+) AD patients displayed lower functional connectivity in the inferior parietal lobule while the PiB(-) SVaD patients displayed lower functional connectivity in the medial frontal and superior frontal gyri. Compared to the PiB(-) SVaD or PiB(+) AD, the mixed dementia patients displayed lower functional connectivity within the DMN in the posterior cingulate gyrus. When the resting-state CEN connectivity of PiB(+) AD and PiB(-) SVaD patients were compared, the PiB(-) SVaD patients displayed lower functional connectivity in the anterior insular region. Compared to the PiB(-) SVaD or PiB(+) AD, the mixed dementia patients displayed lower functional connectivity within the CEN in the inferior frontal gyrus.

CONCLUSIONS: Our findings suggest that in PiB(+) AD and PiB(-) SVaD, there is divergent disruptions in resting-state DMN and CEN. Furthermore, patients with combined amyloid and SVD burdens exhibited more disrupted resting-state DMN and CEN than patients with only amyloid or SVD burden.

%B J Alzheimers Dis %V 50 %P 709-18 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26757039?dopt=Abstract %R 10.3233/JAD-150637 %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