scholarly journals The Evolution of Alexia in Two Cases of Posterior Cortical Atrophy

2011 ◽  
Vol 24 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Eleonora Catricalà ◽  
Pasquale A. Della Rosa ◽  
Paola Ortelli ◽  
Valeria Ginex ◽  
Alessandra Marcone ◽  
...  
Keyword(s):  
Clinical Features ◽  
Visual Processing ◽  
Single Photon ◽  
Photon Emission ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Disease Evolution ◽  
Neuropsychological Dysfunction ◽  
Reading Impairment ◽  
Uncommon Presentation

Posterior cortical atrophy (PCA) is an uncommon presentation of Alzheimer's disease (AD), characterised by prevalent anatomo-functional involvement of posterior cortical areas. Accordingly, the main clinical features at onset are disorders of high-order visual processing, such as alexia and impairments of visuo-spatial and visuo-constructional abilities. The clinical features in the early stages of disease are variable, and they have been suggested to stem from prevalent ventral or dorsal brain pathology, and/or asymmetric hemispheric involvement. With disease progression, these differences tend to blur with the increasing severity of neuropsychological dysfunction. We report two PCA patients showing different patterns of reading impairment (respectively, letter-by-letter reading and neglect dyslexia). A follow-up study suggested that the qualitative features of alexia remain distinctive with disease evolution. In addition, single photon emission tomography (SPECT) studies revealed different patterns of hypoperfusion, consistent with the alexia types. A careful reading assessment can provide important insights to the pattern of progression of the disease in patients with PCA up to the late stages of the pathology.

scholarly journals Latent atrophy factors related to phenotypical variants of posterior cortical atrophy

Neurology ◽  
2020 ◽  
Vol 95 (12) ◽  
pp. e1672-e1685 ◽  
Author(s):  
Colin Groot ◽  
B.T. Thomas Yeo ◽  
Jacob W. Vogel ◽  
Xiuming Zhang ◽  
Nanbo Sun ◽  
...  
Keyword(s):  
Gray Matter ◽  
Visual Processing ◽  
Space Perception ◽  
Object Perception ◽  
Cortical Atrophy ◽  
Intracranial Volume ◽  
Posterior Cortical Atrophy ◽  
Modeling Framework ◽  
Β Amyloid ◽  
The Right

ObjectiveTo determine whether atrophy relates to phenotypical variants of posterior cortical atrophy (PCA) recently proposed in clinical criteria (i.e., dorsal, ventral, dominant-parietal, and caudal) we assessed associations between latent atrophy factors and cognition.MethodsWe employed a data-driven Bayesian modeling framework based on latent Dirichlet allocation to identify latent atrophy factors in a multicenter cohort of 119 individuals with PCA (age 64 ± 7 years, 38% male, Mini-Mental State Examination 21 ± 5, 71% β-amyloid positive, 29% β-amyloid status unknown). The model uses standardized gray matter density images as input (adjusted for age, sex, intracranial volume, MRI scanner field strength, and whole-brain gray matter volume) and provides voxelwise probabilistic maps for a predetermined number of atrophy factors, allowing every individual to express each factor to a degree without a priori classification. Individual factor expressions were correlated to 4 PCA-specific cognitive domains (object perception, space perception, nonvisual/parietal functions, and primary visual processing) using general linear models.ResultsThe model revealed 4 distinct yet partially overlapping atrophy factors: right-dorsal, right-ventral, left-ventral, and limbic. We found that object perception and primary visual processing were associated with atrophy that predominantly reflects the right-ventral factor. Furthermore, space perception was associated with atrophy that predominantly represents the right-dorsal and right-ventral factors. However, individual participant profiles revealed that the large majority expressed multiple atrophy factors and had mixed clinical profiles with impairments across multiple domains, rather than displaying a discrete clinical–radiologic phenotype.ConclusionOur results indicate that specific brain behavior networks are vulnerable in PCA, but most individuals display a constellation of affected brain regions and symptoms, indicating that classification into 4 mutually exclusive variants is unlikely to be clinically useful.

scholarly journals Posterior cortical atrophy: A rare variant of Alzheimer’s disease

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Michael A. Meyer ◽  
Stephen A. Hudock
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Photon Emission ◽  
Occipital Cortex ◽  
Cortical Atrophy ◽  
Emission Computed Tomography ◽  
Posterior Cortical Atrophy ◽  
Homonymous Hemianopsia

Posterior cortical atrophy is a rare condition first described in 1988 involving progressive degeneration and atrophy of the occipital cortex, often recognized after an unexplained homonymous hemianopsia may be discovered. We report a case in association with Alzheimer’s disease in a 77-year-old female, who underwent brain single-photon emission computed tomography as well brain positron emission tomography using Florbetapir to further evaluate progressive cognitive decline. The patient had also been followed in Ophthalmology for glaucoma, where a progressive unexplained change in her visual field maps were noted over one year consistent with a progressive right homonymous hemianopsia. This rare combination of findings in association with her dementia led to a detailed review of all her imaging studies, concluding with the surprising recognition for a clear hemi-atrophy of the primary left occipital cortex was occurring, consistent with Alzheimer’s disease affecting the primary visual cortex. Further awareness of this disease pattern is needed, as Alzheimer’s disease typically does not affect the primary visual cortex; other conditions to consider in general include Lewy Body dementia, cortico-basal degeneration and prion disease.

scholarly journals Frontoparietal cortical atrophy with gliosis in the gray matter of cerebral cortex: case report

2002 ◽  
Vol 60 (2B) ◽  
pp. 462-468 ◽  
Author(s):  
Paulo Roberto de Brito-Marques ◽  
Roberto Vieira de Mello ◽  
Luciano Montenegro
Keyword(s):  
Parietal Lobe ◽  
Single Photon ◽  
Senile Plaques ◽  
Photon Emission ◽  
Neuronal Loss ◽  
Cortical Layer ◽  
Cortical Atrophy ◽  
Status Spongiosus ◽  
External Capsule ◽  
Neuronal Swelling

The case of a patient who suffered from progressive amnesia, depressive humor, language and visuospatial disturbances, and hallucination episodies with interference at the daily living activities is reported. She had moderate neuropsichological diffuse deficits at the first examination, especially at the executive and visuo-constructive functions. Her cerebrospinal fluid test presented high total protein. Magnetic resonance image showed slight white matter increase in periventricular, semi-oval center bilateral and left external capsule regions, besides light frontal and parietal lobe atrophy, bilaterally. Brain single photon emission computerized tomography revealed both a bilateral moderate frontal and a severe parietal lobe hypoperfusion, especially on the left side. Macroscopic examination showed cortical atrophy, severe on the frontal, moderate on the parietal and mild on the posterior third temporal lobes, bilaterally. There was a slight atrophy on the neostriatum in the basal ganglia. The histopathological findings of the autopsy showed severe neuronal loss with intensive gemioscytic gliosis and variable degrees of status spongiosus in cortical layer. Hematoxylin-eosin and Bielschowsky staining did not show neuronal swelling (balooned cell), argyrophilic inclusion (Pick's bodies), neurofibrillary tangles nor senile plaques. Immunohistochemical staining for anti-ubiquitin, anti-tau, anti-beta-amyloide, and anti-prion protein were tested negative.

scholarly journals Increased Cerebral Blood Flow in Anemic Patients on Long-Term Hemodialytic Treatment

1992 ◽  
Vol 12 (5) ◽  
pp. 745-749 ◽  
Author(s):  
Sissel Vorstrup ◽  
Piotr Lass ◽  
Gunhild Waldemar ◽  
Lisbet Brandi ◽  
Jes F. Schmidt ◽  
...  
Keyword(s):  
Neurological Examination ◽  
Single Photon ◽  
Photon Emission ◽  
Significant Negative Correlation ◽  
Cortical Atrophy ◽  
Control Group ◽  
Metabolic Demand ◽  
Moderate Dementia ◽  
Oxygen Carrying Capacity

CBF was measured in 15 patients on chronic hemodialytic treatment. CBF was measured with xenon-133 inhalation using single photon emission tomography. In addition, computerized tomography (CT) and a neurological examination were done prior to hemodialysis. Mean CBF was 66.2 ± 17.3 (SD) ml 100 g−1 min−1, which was significantly higher ( t-test, p < 0.05) than for an age-matched control group (54.7 ± 10.2 ml 100 g−1 min−1). However, the hematocrit for the patients was considerably lower, 0.30 ± 0.07, as compared to 0.43 ± 0.03 in the controls. A significant negative correlation was observed between CBF and the hematocrit ( y = –1.79x + 120.7, r = −0.71, p < 0.01). Calculating CBF from this equation in the dialyzed patients using a hematocrit of 0.43 yielded a mean CBF value of 43.7 ml 100 g−1 min−1, i.e., 20% below the expected. Two patients showed a focal CBF decrease. CT showed central or cortical atrophy in five patients, and two had small hypodense lesions. The neurological examination revealed slight to moderate dementia in seven cases. Although mean CBF was found to be increased by 21% as compared to the control group, an even higher CBF level would have been expected to outweigh the decreased oxygen carrying capacity of the blood. The findings suggest a lowered metabolic demand of the brain tissue, probably due to subtle brain damage.

scholarly journals Understanding early dementia: EEG, MRI, SPECT and memory evaluation

2015 ◽  
Vol 6 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Davide Vito Moretti
Keyword(s):  
Cortical Thickness ◽  
Memory Impairment ◽  
Single Photon ◽  
Photon Emission ◽  
Brain Perfusion ◽  
Cortical Atrophy ◽  
Emission Computed Tomography ◽  
Power Ratio ◽  
The Difference ◽  
Frequency Power

AbstractBackground: An increase in the EEG upper/low a power ratio has been associated with mild cognitive impairment (MCI) due to Alzheimer’s disease (AD) and to the atrophy of temporoparietal brain areas. Subjects with a higher α3/α2 frequency power ratio showed lower brain perfusion than in the low α3/α2 group. The two groups show significantly different hippocampal volumes and correlation with q frequency activity. Methods: Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording, and high resolution 3D magnetic resonance imaging (MRI). Twenty-seven of them underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The α3/α2 power ratio and cortical thickness were computed for each subject. The difference in cortical thickness between the groups was estimated. Results: In the higher upper/low a group, memory impairment was more pronounced in both the MRI group and the SPECT MCI groups. An increase in the production of q oscillations was associated with greater interhemisperic coupling between temporal areas. It also correlated with greater cortical atrophy and lower perfusional rate in the temporoparietal cortex. Conclusion: High EEG upper/low α power ratio was associated with cortical thinning and lower perfusion in temporoparietal areas. Moreover, both atrophy and lower perfusion rate significantly correlated with memory impairment in MCI subjects. Therefore, the increase in the EEG upper/low α frequency power ratio could be useful in identifying individuals at risk for progression to AD dementia in a clinical context.

scholarly journals Unusual Pattern of Reading Errors in a Patient with Posterior Cortical Atrophy

2019 ◽  
Vol 11 (2) ◽  
pp. 157-166
Author(s):  
Ivanna M. Pavisic ◽  
Keir X.X. Yong ◽  
Silvia Primativo ◽  
Sebastian J. Crutch ◽  
Aida Suarez Gonzalez
Keyword(s):  
Phonological Processing ◽  
Visual Processing ◽  
Word Reading ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Stimulus Interval ◽  
Reading Errors ◽  
Response Stimulus ◽  
In Series ◽  
The Rich

Posterior cortical atrophy (PCA) is a degenerative condition characterized by a progressive deterioration of visual processing. Dyslexia constitutes an early and frequent visual symptom of the disease and previous comprehensive investigations in series of individuals have extensively documented a characteristic abundance of visual errors as the most prevalent error category in this population. Here we describe the profile of a patient with PCA, C.P., who presents an unusual prevalence of phonological, instead of purely visual, errors in his reading, in the context of an otherwise classic PCA phenotype. In keeping with the well-known PCA profile, C.P. exhibited deficits at the pre-lexical level with elements of crowding and defective early visual processing impairments but additionally showed an unusually prominent disruption of phonological processing. We also argue that our patient may have a refractory access type deficit in reading given that accuracy doubled with the introduction of a five-second response-stimulus interval. To our knowledge, no previous case of a refractory deficit affecting word reading has been reported in PCA. Our examination builds on previous knowledge about reading behaviour in PCA and describes a singular example of the rich phenotypic heterogeneity within the syndrome.

scholarly journals Longitudinal neuroanatomical and cognitive progression of posterior cortical atrophy

Brain ◽  
2019 ◽  
Vol 142 (7) ◽  
pp. 2082-2095 ◽  
Author(s):  
Nicholas C Firth ◽  
Silvia Primativo ◽  
Razvan-Valentin Marinescu ◽  
Timothy J Shakespeare ◽  
Aida Suarez-Gonzalez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Visual Processing ◽  
Phenotypic Diversity ◽  
Rate Of Change ◽  
Tissue Loss ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Brain Volumes ◽  
Regional Brain

Abstract Posterior cortical atrophy is a clinico-radiological syndrome characterized by progressive decline in visual processing and atrophy of posterior brain regions. With the majority of cases attributable to Alzheimer’s disease and recent evidence for genetic risk factors specifically related to posterior cortical atrophy, the syndrome can provide important insights into selective vulnerability and phenotypic diversity. The present study describes the first major longitudinal investigation of posterior cortical atrophy disease progression. Three hundred and sixty-one individuals (117 posterior cortical atrophy, 106 typical Alzheimer’s disease, 138 controls) fulfilling consensus criteria for posterior cortical atrophy-pure and typical Alzheimer’s disease were recruited from three centres in the UK, Spain and USA. Participants underwent up to six annual assessments involving MRI scans and neuropsychological testing. We constructed longitudinal trajectories of regional brain volumes within posterior cortical atrophy and typical Alzheimer’s disease using differential equation models. We compared and contrasted the order in which regional brain volumes become abnormal within posterior cortical atrophy and typical Alzheimer’s disease using event-based models. We also examined trajectories of cognitive decline and the order in which different cognitive tests show abnormality using the same models. Temporally aligned trajectories for eight regions of interest revealed distinct (P < 0.002) patterns of progression in posterior cortical atrophy and typical Alzheimer’s disease. Patients with posterior cortical atrophy showed early occipital and parietal atrophy, with subsequent higher rates of temporal atrophy and ventricular expansion leading to tissue loss of comparable extent later. Hippocampal, entorhinal and frontal regions underwent a lower rate of change and never approached the extent of posterior cortical involvement. Patients with typical Alzheimer’s disease showed early hippocampal atrophy, with subsequent higher rates of temporal atrophy and ventricular expansion. Cognitive models showed tests sensitive to visuospatial dysfunction declined earlier in posterior cortical atrophy than typical Alzheimer’s disease whilst tests sensitive to working memory impairment declined earlier in typical Alzheimer’s disease than posterior cortical atrophy. These findings indicate that posterior cortical atrophy and typical Alzheimer’s disease have distinct sites of onset and different profiles of spatial and temporal progression. The ordering of disease events both motivates investigation of biological factors underpinning phenotypic heterogeneity, and informs the selection of measures for clinical trials in posterior cortical atrophy.

scholarly journals 99mTc-d,l-HMPAO and SPECT of the Brain in Normal Aging

1991 ◽  
Vol 11 (3) ◽  
pp. 508-521 ◽  
Author(s):  
Gunhild Waldemar ◽  
Steen G. Hasselbalch ◽  
Allan R. Andersen ◽  
Florence Delecluse ◽  
Palle Petersen ◽  
...  
Keyword(s):  
Single Photon ◽  
Photon Emission ◽  
Flow Region ◽  
Significant Negative Correlation ◽  
Low Flow ◽  
Cortical Atrophy ◽  
Stepwise Multiple Regression ◽  
Inhalation Technique ◽  
Emission Computed Tomography ◽  
Photon Emission Computed Tomography

Single photon emission computed tomography (SPECT) with 99mTc- d,l-hexamethylpropyleneamine oxime (99mTc- d,l-HMPAO) was used to determine global and regional CBF in 53 healthy subjects aged 21–83 years. For the whole group, global CBF normalized to the cerebellum was 86.4% ± 8.4 (SD). The contribution of age, sex, and atrophy to variations in global CBF was studied using stepwise multiple regression analysis. There was a significant negative correlation of global CBF with subjective ratings of cortical atrophy, but not with ratings of ventricular size, Evans ratio, sex, or age. In a subgroup of 33 subjects, in whom volumetric measurements of atrophy were performed, cortical atrophy was the only significant determinant for global CBF, accounting for 27% of its variance. Mean global CBF as measured with the 133Xe inhalation technique and SPECT was 54 ± 9 ml/100 g/min and did not correlate significantly with age. There was a preferential decline of CBF in the frontal cortex with advancing age. The side-to-side asymmetry of several regions of interest increased with age. A method was described for estimation of subcortical CBF, which decreased with advancing cortical atrophy. The relative area of the subcortical low-flow region increased with age. These results are useful in distinguishing the effects of age and simple atrophy from disease effects, when the 99mTc- d,l-HMPAO method is used.

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