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Posterior cortical atrophy

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https://www.readbyqxmd.com/read/28192686/the-down-syndrome-brain-in-the-presence-and-absence-of-fibrillar-%C3%AE-amyloidosis
#1
Tiina Annus, Liam R Wilson, Julio Acosta-Cabronero, Arturo Cardenas-Blanco, Young T Hong, Tim D Fryer, Jonathan P Coles, David K Menon, Shahid H Zaman, Anthony J Holland, Peter J Nestor
People with Down syndrome (DS) have a neurodevelopmentally distinct brain and invariably developed amyloid neuropathology by age 50. This cross-sectional study aimed to provide a detailed account of DS brain morphology and the changes occuring with amyloid neuropathology. Forty-six adults with DS underwent structural and amyloid imaging-the latter using Pittsburgh compound B (PIB) to stratify the cohort into PIB-positive (n = 19) and PIB-negative (n = 27). Age-matched controls (n = 30) underwent structural imaging...
January 17, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28183367/selective-functional-disconnection-of-the-orbitofrontal-subregions-in-schizophrenia
#2
Y Xu, W Qin, C Zhuo, L Xu, J Zhu, X Liu, C Yu
BACKGROUND: As a disconnection syndrome, schizophrenia has shown impaired resting-state functional connectivity (rsFC) in the orbitofrontal cortex (OFC); however, the OFC is a rather heterogeneous region and the rsFC changes in the OFC subregions remain unknown. METHOD: A total of 98 schizophrenia patients and 102 healthy controls underwent resting-state functional MRI using a sensitivity-encoded spiral-in imaging sequence (SENSE-SPIRAL) to reduce susceptibility-induced signal loss and distortion...
February 10, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28180083/lateralized-occipital-degeneration-in-posterior-cortical-atrophy-predicts-visual-field-deficits
#3
Rebecca S Millington, Merle James-Galton, Mari N Maia Da Silva, Gordon T Plant, Holly Bridge
BACKGROUND: Posterior cortical atrophy (PCA), the visual variant of Alzheimer's disease, leads to high-level visual deficits such as alexia or agnosia. Visual field deficits have also been identified, but often inconsistently reported. Little is known about the pattern of visual field deficits or the underlying cortical changes leading to this visual loss. METHODS: Multi-modal magnetic resonance imaging was used to investigate differences in gray matter volume, cortical thickness, white matter microstructure and functional activity in patients with PCA compared to age-matched controls...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28130700/higher-fasting-plasma-glucose-is-associated-with-increased-cortical-thinning-over-12-years-the-path-through-life-study
#4
Marnie E Shaw, Julia Nettersheim, Perminder S Sachdev, Kaarin J Anstey, Nicolas Cherbuin
Recent evidence suggests that type 2 diabetes (T2D) is associated with accelerated brain ageing, consistent with the observation of increased risk of cognitive impairment and dementia in affected individuals. Even non-diabetic individuals with impaired fasting plasma glucose (IFG) levels have shown increased cerebral atrophy, compared to individuals with normal glucose levels. We tested whether longitudinal rates of age-related cortical thinning were associated with fasting plasma glucose levels in a large sample (n = 322) of early-old age individuals (60-66 years) who were scanned with magnetic resonance imaging (1...
January 27, 2017: Brain Topography
https://www.readbyqxmd.com/read/28072384/impact-of-cerebellar-atrophy-on-cortical-gray-matter-and-cerebellar-peduncles-as-assessed-by-voxel-based-morphometry-and-high-angular-resolution-diffusion-imaging
#5
Michael Dayan, G Olivito, M Molinari, Mara Cercignani, Marco Bozzali, M Leggio
In recent years the cerebellum has been attributed amore important role in higher-level functions than previously believed. We examined a cohort of patients suffering from cerebellar atrophy resulting in ataxia, with two main objectives: first to investigate which regions of the cerebrum were affected by the cerebellar degeneration, and second to assess whether diffusion magnetic resonance imaging (dMRI) metrics within the medial (MCP) and superior cerebellar peduncle (SCP) - namely fractional anisotropy (FA) and radial diffusivity (RD) - could be used as a biomarker in patients with this condition...
October 2016: Functional Neurology
https://www.readbyqxmd.com/read/28068564/distinct-patterns-of-increased-translocator-protein-in-posterior-cortical-atrophy-and-amnestic-alzheimer-s-disease
#6
William C Kreisl, Chul Hyoung Lyoo, Jeih-San Liow, Joseph Snow, Emily Page, Kimberly J Jenko, Cheryl L Morse, Sami S Zoghbi, Victor W Pike, R Scott Turner, Robert B Innis
We sought to determine whether patients with posterior cortical atrophy (PCA) demonstrate a pattern of binding to translocator protein 18 kDa, a marker of microglial activation, that is distinct from that in patients with amnestic presentation of Alzheimer's disease (AD). Eleven PCA patients, 11 amnestic AD patients, and 15 age-matched controls underwent positron emission tomography with (11)C-PBR28 to measure translocator protein 18 kDa. PCA patients showed greater (11)C-PBR28 binding than controls in occipital, posterior parietal, and temporal regions...
March 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28052060/structural-variation-in-amyloid-%C3%AE-fibrils-from-alzheimer-s-disease-clinical-subtypes
#7
Wei Qiang, Wai-Ming Yau, Jun-Xia Lu, John Collinge, Robert Tycko
Aggregation of amyloid-β peptides into fibrils or other self-assembled states is central to the pathogenesis of Alzheimer's disease. Fibrils formed in vitro by 40- and 42-residue amyloid-β peptides (Aβ40 and Aβ42) are polymorphic, with variations in molecular structure that depend on fibril growth conditions. Recent experiments suggest that variations in amyloid-β fibril structure in vivo may correlate with variations in Alzheimer's disease phenotype, in analogy to distinct prion strains that are associated with different clinical and pathological phenotypes...
January 12, 2017: Nature
https://www.readbyqxmd.com/read/28047588/su-f-i-20-volumetric-reduction-of-the-corpus-callosum-in-alzheimer-s-disease-and-mild-cognitive-impairment
#8
R Juh, T Suh, J Han, C Kim, C Oh
PURPOSE: This study investigated correlations between regional corpus callosum (CC) atrophy and cognitive measurements in AD subjects at mild disease stages with volumetry. Our aims were to replicate ROI-based findings of reduced volumes of the CC in mild cognitive impairment (MCI) patients relative to AD and to investigate, on a voxel-by-voxel basis, the presence of significant correlations between CC atrophy and cognitive test scores in AD subjects. METHODS: We used the VBM and cross-sectional ROI-based volumetry approach to conduct a detailed assessment of CC volumetric reductions in a probable AD patient (n=40) in comparison to MCI (n=40) and Subjective memory impairment (SMI) (n=12) matched for age...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28031997/cortical-asymmetry-in-parkinson-s-disease-early-susceptibility-of-the-left-hemisphere
#9
Daniel O Claassen, Katherine E McDonell, Manus Donahue, Shiv Rawal, Scott A Wylie, Joseph S Neimat, Hakmook Kang, Peter Hedera, David Zald, Bennett Landman, Benoit Dawant, Swati Rane
BACKGROUND AND PURPOSE: Clinically, Parkinson's disease (PD) presents with asymmetric motor symptoms. The left nigrostriatal system appears more susceptible to early degeneration than the right, and a left-lateralized pattern of early neuropathological changes is also described in several neurodegenerative conditions, including Alzheimer's disease, frontotemporal dementia, and Huntington's disease. In this study, we evaluated hemispheric differences in estimated rates of atrophy in a large, well-characterized cohort of PD patients...
December 2016: Brain and Behavior
https://www.readbyqxmd.com/read/27918935/depressive-symptoms-in-parkinson-s-disease-correlate-with-cortical-atrophy-over-time
#10
Alexandru Hanganu, Marie-Andrée Bruneau, Clotilde Degroot, Christophe Bedetti, Béatriz Mejia-Constain, Anne-Louise Lafontaine, Sylvain Chouinard, Oury Monchi
INTRODUCTION: Depressive symptoms are very common in patients with Parkinson's disease (PD) and have a significant impact on the quality of life. METHODS: The present study analyzed the correlations between over-time changes in depressive symptoms and gray matter parameters of cortical thickness and subcortical volumes in non-demented PD patients. RESULTS: A significant correlation was observed, between increased scores for depression over time and lower cortical thickness over time in the right temporo-parietal junction, right occipital medial region, right dorsolateral prefrontal cortex, right posterior cingulate region, left middle temporal as well as left supplementary motor area...
February 2017: Brain and Cognition
https://www.readbyqxmd.com/read/27913156/the-oral-spelling-profile-of-posterior-cortical-atrophy-and-the-nature-of-the-graphemic-representation
#11
Silvia Primativo, Keir X X Yong, Timothy J Shakespeare, Sebastian J Crutch
Spelling is a complex cognitive task where central and peripheral components are involved in engaging resources from many different cognitive processes. The present paper aims to both characterize the oral spelling deficit in a population of patients affected by a neurodegenerative condition and to clarify the nature of the graphemic representation within the currently available spelling models. Indeed, the nature of graphemic representation as a linear or multi-componential structure is still debated. Different hypotheses have been raised about its nature in the orthographic lexicon, with one positing that graphemes are complex objects whereby quantity and identity are separately represented in orthographic representations and can thus be selectively impaired...
January 8, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/27896492/hemianopic-line-bisection-error-in-a-patient-with-alzheimer-s-disease
#12
Heeyoung Kang, Soo-Kyoung Kim, Ki-Jong Park, Nack-Cheon Choi, Oh-Young Kwon, Byeong Hoon Lim
Visual symptoms are frequently observed in posterior cortical atrophy compared to typical amnestic Alzheimer's disease (AD). We report the case of a patient with amnestic AD with long-lasting homonymous hemianopia. A 62-year-old woman, who was diagnosed in amnestic AD, complained of visual disturbance. She had left homonymous hemianopia in the perimetry test and left tactile extinction. Regardless of posture, retinotopically leftward error was observed on 21 cm line bisection test. Brain single photon emission computerized tomography (SPECT) showed bilateral temporoparietal hypoperfusion, which was more severe to the right than left side...
November 28, 2016: Neurological Sciences
https://www.readbyqxmd.com/read/27834777/the-road-less-traveled-alternative-pathways-for-action-verb-processing-in-parkinson-s-disease
#13
Sofía Abrevaya, Lucas Sedeño, Sol Fitipaldi, David Pineda, Francisco Lopera, Omar Buritica, Andrés Villegas, Catalina Bustamante, Diana Gomez, Natalia Trujillo, Ricardo Pautassi, Agustín Ibáñez, Adolfo M García
Action verbs are critically embodied in motor brain networks. In Parkinson's disease (PD), damage to the latter compromises access to such words. However, patients are not fully incapable of processing them, as their performance is far from floor level. Here we tested the hypothesis that action-verb processing in PD may rely on alternative disembodied semantic circuits. Seventeen PD patients and 15 healthy controls listened to action verbs and nouns during functional MRI scanning. Using cluster-mass analysis with a permutation test, we assessed task-related functional connectivity considering seeds differentially engaged by action and non-action words (namely, putamen and M1 versus posterior superior temporal lobe, respectively)...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27781971/impact-of-cerebellar-atrophy-on-cortical-gray-matter-and-cerebellar-peduncles-as-assessed-by-voxel-based-morphometry-and-high-angular-resolution-diffusion-imaging
#14
Michael Dayan, G Olivito, M Molinari, Mara Cercignani, Marco Bozzali, M Leggio
In recent years the cerebellum has been attributed amore important role in higher-level functions than previously believed. We examined a cohort of patients suffering from cerebellar atrophy resulting in ataxia, with two main objectives: first to investigate which regions of the cerebrum were affected by the cerebellar degeneration, and second to assess whether diffusion magnetic resonance imaging (dMRI) metrics within the medial (MCP) and superior cerebellar peduncle (SCP) - namely fractional anisotropy (FA) and radial diffusivity (RD) - could be used as a biomarker in patients with this condition...
October 26, 2016: Functional Neurology
https://www.readbyqxmd.com/read/27771044/the-self-reference-effect-in-dementia-differential-involvement-of-cortical-midline-structures-in-alzheimer-s-disease-and-behavioural-variant-frontotemporal-dementia
#15
Stephanie Wong, Muireann Irish, Eric D Leshikar, Audrey Duarte, Maxime Bertoux, Greg Savage, John R Hodges, Olivier Piguet, Michael Hornberger
Encoding information in reference to the self enhances subsequent memory for the source of this information. In healthy adults, self-referential processing has been proposed to be mediated by the cortical midline structures (CMS), with functional differentiation between anterior-ventral, anterior-dorsal and posterior regions. While both Alzheimer's disease (AD) and behavioural-variant frontotemporal dementia (bvFTD) patients show source memory impairment, it remains unclear whether they show a typical memory advantage for self-referenced materials...
October 3, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/27771043/tracking-the-development-of-agrammatic-aphasia-a-tensor-based-morphometry-study
#16
Jennifer L Whitwell, Joseph R Duffy, Mary M Machulda, Heather M Clark, Edythe A Strand, Matthew L Senjem, Jeffrey L Gunter, Anthony J Spychalla, Ronald C Petersen, Clifford R Jack, Keith A Josephs
Agrammatic aphasia can be observed in neurodegenerative disorders and has been traditionally linked with damage to Broca's area, although there have been disagreements concerning whether damage to Broca's area is necessary or sufficient for the development of agrammatism. We aimed to investigate the neuroanatomical correlates of the emergence of agrammatic aphasia utilizing a unique cohort of patients with primary progressive apraxia of speech (PPAOS) that did not have agrammatism at baseline but developed agrammatic aphasia over time...
September 30, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/27757821/distinct-effects-of-late-adulthood-cognitive-and-physical-activities-on-gray-matter-volume
#17
Eider M Arenaza-Urquijo, Robin de Flores, Julie Gonneaud, Miranka Wirth, Valentin Ourry, William Callewaert, Brigitte Landeau, Stéphanie Egret, Florence Mézenge, Béatrice Desgranges, Gaël Chételat
Engagement in cognitive activity (CA) and physical activity (PA) during the lifespan may counteract brain atrophy later in life. Here, we investigated engagement in CA and PA during late adulthood in association with gray matter volume (GM) in normal older adults, with special focus on the hippocampus. Forty-five cognitively normal older individuals (mean age: 72) underwent T1-weighted MRI and self-reported CA and PA assessment. Whole brain voxel-wise multiple regression models were carried out to assess the relationships between CA, PA and GM volume adjusted by age and sex...
October 18, 2016: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/27702740/neuro-cognitive-mechanisms-of-simultanagnosia-in-patients-with-posterior-cortical-atrophy
#18
Julia Neitzel, Marion Ortner, Marleen Haupt, Petra Redel, Timo Grimmer, Igor Yakushev, Alexander Drzezga, Peter Bublak, Christoph Preul, Christian Sorg, Kathrin Finke
Posterior cortical atrophy is dominated by progressive degradation of parieto-occipital grey and white matter, and represents in most cases a variant of Alzheimer's disease. Patients with posterior cortical atrophy are characterized by increasing higher visual and visuo-spatial impairments. In particular, a key symptom of posterior cortical atrophy is simultanagnosia i.e. the inability to perceive multiple visual objects at the same time. Two neuro-cognitive mechanisms have been suggested to underlie simultanagnosia, either reduced visual short-term memory capacity or decreased visual processing speed possibly resulting from white matter impairments over and above damage to cortical brain areas...
December 2016: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/27688479/18f-fdg-pet-in-posterior-cortical-atrophy-and-dementia-with-lewy-bodies
#19
Jennifer Whitwell, Jonathan Graff-Radford, Tarun Singh, Daniel Drubach, Matthew Senjem, Anthony Spychalla, Nirubol Tosakulwong, Val J Lowe, Keith Josephs
: Posterior cortical atrophy (PCA) and Dementia with Lewy bodies (DLB) have both been associated with occipital lobe hypometabolism on (18)F fluorodeoxyglucose (FDG) positron emission tomography (PET), while relative sparing of posterior cingulate metabolism compared to precuneus/cuneus (i.e. cingulate island sign) is a feature of DLB. We aimed to determine whether patterns of hypometabolism or the cingulate island sign differed between PCA and DLB. METHODS: Sixteen clinically diagnosed PCA and 13 probable DLB subjects underwent (18)F-FDG PET...
September 29, 2016: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/27687870/neuro-visual-rehabilitation
#20
REVIEW
Noa Raz, Netta Levin
Despite the fact that almost one-third of patients suffer from visual deficits following brain damage; neuro-visual rehabilitation to compensate for visual field deficits is relatively neglected in the clinical setting. This is in contrast to physio and speech therapies, which are the bread and butter of rehabilitative programs. Likewise, programs that address coping with dementia usually concentrate on language, memory and cognitive skills, but often fail to address the deficits experienced by the subset of patients suffering from progressive cortico-visual dysfunction...
September 29, 2016: Journal of Neurology
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