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 Data-driven detection of latent atrophy factors related to phenotypical variants of posterior cortical atrophy

2019 ◽  
Author(s):  
Colin Groot ◽  
B.T. Thomas Yeo ◽  
Jacob W Vogel ◽  
Xiuming Zhang ◽  
Nanbo Sun ◽  
...  
Keyword(s):  
Gray Matter ◽  
Visual Processing ◽  
Amyloid Β ◽  
Space Perception ◽  
Object Perception ◽  
Data Driven ◽  
Cortical Atrophy ◽  
Intracranial Volume ◽  
Posterior Cortical Atrophy ◽  
The Right

AbstractPosterior cortical atrophy is a clinical-radiological syndrome characterized by visual processing deficits and atrophy in posterior parts of the brain, most often caused by Alzheimer’s disease pathology. Recent consensus criteria describe four distinct phenotypical variants of posterior cortical atrophy defined by clinical and radiological features; i) object perception/occipitotemporal (ventral), ii) space perception/temporoparietal (dorsal), iii) non-visual/dominant parietal and iv) primary visual (caudal). We employed a data-driven approach to identify atrophy factors related to these proposed variants in a multi-center cohort of 119 individuals with posterior cortical atrophy (age: 64 SD 7, 38% male, MMSE: 21 SD 5, 71% amyloid-β positive, 29% amyloid-β status unknown). A Bayesian modelling framework based on latent Dirichlet allocation was used to compute four latent atrophy factors in accordance with the four proposed variants. The model uses standardized gray matter density images as input (adjusted for age, sex, intracranial volume, field strength and whole-brain gray matter volume) and provides voxelwise probabilistic maps for all atrophy factors, allowing every individual to express each factor to a degree without a priori classification. The model revealed four distinct yet partially overlapping atrophy factors; right-dorsal, right-ventral, left-ventral, and limbic. Individual participant profiles revealed that the vast majority of participants expressed multiple factors, rather than predominantly expressing a single factor. To assess the relationship between atrophy factors and cognition, neuropsychological test scores covering four posterior cortical atrophy-specific cognitive domains were assessed (object perception, space perception, non-visual parietal functions and primary visual processing) and we used general linear models to examine the association between atrophy factor expression and cognition. 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-ventral and right-dorsal factors. Similar to the atrophy factors, most participants had mixed clinical profiles with impairments across multiple domains. However, when selecting four participants with an isolated impairment, we observed atrophy patterns and factor expressions that were largely in accordance with the hypothesized variants. Taken together, our results indicate that variants of posterior cortical atrophy exist but these constitute phenotypical extremes and most individuals fall along a broad clinical-radiological spectrum, indicating that classification into four mutually exclusive variants is unlikely to be clinically useful.

scholarly journals Brain structural and functional anomalies associated with simultanagnosia in patients with posterior cortical atrophy

2021 ◽  
Author(s):  
Yue Cui ◽  
Yang Liu ◽  
Caishui Yang ◽  
Chunlei Cui ◽  
Donglai Jing ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Gray Matter ◽  
Gray Matter Volume ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Matter Volume ◽  
Intrinsic Functional Connectivity ◽  
Middle Occipital Gyrus ◽  
The Right ◽  
Left Middle

AbstractSimultanagnosia is a common symptom of posterior cortical atrophy, and its association with brain structural and functional changes remains unclear. In our study, 18 posterior cortical atrophy patients with simultanagnosia, 29 patients with Alzheimer’s disease and 20 cognitively normal controls were recruited and subjected to full neuropsychological evaluation, including simultanagnosia tests, and structural and resting-state functional MRI. The gray matter volume was assessed by voxel-based morphometry, while the intrinsic functional connectivity was evaluated using the reduced gray matter volume regions of interest as the seed. In contrast to the patients with Alzheimer’s disease, those with posterior cortical atrophy showed the following: (1) markedly lower simultanagnosia test scores, (2) an altered regional gray matter volume of the left middle occipital gyrus and ventral occipital areas, and (3) lowered intrinsic functional connectivity with the left middle occipital gyrus, left lingual gyrus and right middle occipital gyrus separately. Additionally, the gray matter volume of the left middle occipital gyrus and left inferior occipital gyrus were each correlated with simultanagnosia in posterior cortical atrophy patients. The intrinsic functional connectivity of the left middle occipital gyrus with the right superior occipital gyrus and that of the right middle occipital gyrus with the left superior parietal gyrus were also correlated with simultanagnosia in posterior cortical atrophy patients. In summary, this study indicated that simultanagnosia is associated with gray matter reductions and decreased functional connectivity in the left middle occipital gyrus and the left inferior occipital gyrus in patients with posterior cortical atrophy.

scholarly journals Posterior Cortical Atrophy with Right Lower Egocentric Quadrantic Neglect and Lower Vertical Allocentric Neglect

2020 ◽  
Vol 35 (4) ◽  
pp. 448-457
Author(s):  
Usama Tariq ◽  
Alicia Parker ◽  
Leila Saadatpour ◽  
Leilani Doty ◽  
Kenneth M Heilman
Keyword(s):  
Parietal Lobe ◽  
Visual Space ◽  
Vertical Line ◽  
Cortical Atrophy ◽  
Horizontal Line ◽  
Posterior Cortical Atrophy ◽  
Lower Quadrant ◽  
Visuospatial Neglect ◽  
Parietal Lobes ◽  
The Right

Abstract Background/Objectives Whereas rare cases of hemispatial visual neglect have been reported in patients with a neurodegenerative disease, quadrantic visuospatial neglect has not been described. We report a patient with probable posterior cortical atrophy who demonstrated lower right-sided quadrantic visuospatial neglect, together with allocentric vertical neglect. Methods/Results A 68-year-old man initially noted deficits in reading and writing. Subsequently, he developed other cognitive deficits. On vertical line bisections, he deviated upward, and on horizontal line bisections, he deviated to the left. These deviations together suggest that this man’s neglect might be most severe in his right (head/body-centered) lower (below eye level) visual space. When attempting to perform vertical line bisections in all four egocentric quadrants, his upward deviations were largest in the right lower quadrant. On a cancelation test, he revealed bilateral lower (ventral) allocentric neglect but not egocentric neglect. This patient’s magnetic resonance imaging revealed cortical atrophy, most prominent in the left parietal lobe. Discussion Previous research in stroke patients has demonstrated that the parietal lobes are important in mediating attention to contralateral and inferior visual space. The presence of left parietal atrophy may have induced this right lower (ventral) egocentric inattention as well as bilateral ventral allocentric inattention. Although to our knowledge there have been no prior reports of a patient with right lower quadrantic and lower vertical allocentric visuospatial neglect, patients are rarely tested for these forms of neglect, and this patient illustrates the importance of evaluating patients for these and other forms of neglect.

scholarly journals Exploring Cortical Thickness Alteration in Parkinson Disease Patients with Freezing of Gaits

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
E. Li ◽  
Xiuhang Ruan ◽  
Yuting Li ◽  
Guoqin Zhang ◽  
Mengyan Li ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Gray Matter ◽  
Characteristic Curve ◽  
Freezing Of Gait ◽  
Middle Temporal Gyrus ◽  
Intracranial Volume ◽  
Significant Difference ◽  
Mri Protocol ◽  
Advanced Stages ◽  
The Right

Background: Freezing of gait (FoG) is a disabling gait disorder that commonly occurs in advanced stages of Parkinson’s disease (PD). The neuroanatomical mechanisms underlying FoG in PD are still unclear. The present study aims to explore alterations of structural gray matter (GM) in PD patients with FoG. Method: Twenty-four PD patients with FoG (FoG+), 37 PD patients without FoG (FoG-) and 24 healthy controls (HC) were included. All subjects underwent a standardized MRI protocol. The cortical thickness (CTh), segmentation volume without ventricles (BrainSegVolNotVent) and estimated total intracranial volume (eTIV) were analysed using the FreeSurfer pipeline. Results: CTh differences were found in the right middle temporal gyrus (rMTG) generally. Compared to that in HCs, the CTh of the rMTG in both the FoG+ and FoG- groups was smaller, while no significant difference between the FoG+ and FoG- groups. Correlation analyses demonstrated a negative correlation between the CTh of the rMTG and the UPDRS part II score in PD subjects, and a borderline significant correlation between the score of Freezing of Gait Questionnaire (FoGQ) and rMTG CTh. Additionally, receiver operating characteristic curve (ROC) analysis revealed a cut-off point of CTh =3.08 mm in the rMTG that could be used to differentiate PD patients and HCs (AUC =0.79, P <0.01). There were no differences in the BrainSegVolNotVent or eTIV among the 3 groups. Conclusions: Our findings currently suggest no significant difference between FoG+ and FoG- patients in terms of structural gray matter changes. However, decreased CTh in the rMTG related to semantic control may be used as a biomarker to differentiate PD patients and HCs.

Use of the Visual Object and Space Perception (VOSP) test battery in two cases of posterior cortical atrophy

Neurocase ◽  
2009 ◽  
Vol 15 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Hélène Videaud ◽  
Frederic Torny ◽  
Annie Prado-Jean ◽  
Philippe Couratier
Keyword(s):  
Space Perception ◽  
Test Battery ◽  
Cortical Atrophy ◽  
Visual Object ◽  
Posterior Cortical Atrophy

P1-473: Face, scene and object perception in posterior cortical atrophy

2011 ◽  
Vol 7 ◽  
pp. S265-S265
Author(s):  
Tim Shakespeare ◽  
Sebastian Crutch ◽  
Elizabeth Warrington
Keyword(s):  
Object Perception ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy

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 F2-01-03: “AM I THE RIGHT WAY UP?”: INVESTIGATING BALANCE PROBLEMS IN POSTERIOR CORTICAL ATROPHY

2019 ◽  
Vol 15 ◽  
pp. P516-P516
Author(s):  
Keir Yong ◽  
Amy Peters ◽  
Dilek Ocal ◽  
David M. Cash ◽  
Matthew Bancroft ◽  
...  
Keyword(s):  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
The Right ◽  
Balance Problems

scholarly journals AGR - 2 Diagnosis of Posterior Cortical Atrophy Through Inter-Departmental Collaboration

2019 ◽  
Vol 34 (6) ◽  
pp. 831-831
Author(s):  
S John ◽  
M Silva ◽  
N Newman ◽  
D Loring
Keyword(s):  
Neuropsychological Testing ◽  
Cortical Atrophy ◽  
White Female ◽  
Posterior Cortical Atrophy ◽  
Visual Spatial ◽  
Field Evidence ◽  
Confrontation Naming ◽  
Unsteady Gait ◽  
History Of ◽  
The Right

Abstract Objective We present a patient with rapidly progressive visual decline of 2-year duration that interfered with daily functioning. She was evaluated by neuro-ophthalmology and neurology prior to neuropsychological referral. A series of evaluations led to diagnosis of posterior cortical atrophy, demonstrating the importance of inter-departmental collaboration. Method A 66-year old white female presented with a 2-year history of progressive changes to vision and memory. Medical history included hypertension, dyslipidemia, and a strong family history of optic neuropathy causing blindness. She was diagnosed with a left homonymous hemianopia. MRI revealed "significant cortical atrophy more remarkable on the right temporal, parietal, and occipital regions." She reported dressing apraxia, unsteady gait, declines in reading and writing, and difficulty recalling well-learned information. Results She was a good historian, had fluent speech and no apparent comprehension difficulty. Neuropsychological evaluation revealed relatively preserved language and verbal abilities, including confrontation naming, in the presence of otherwise impaired performances across all domains of functioning. She demonstrated agraphia, acalculia, left-right confusion, and difficulties with motor programming. Perceptual and constructional tasks revealed prominent deficits in visual integration, map orientation, form discrimination, and construction of simple geometric designs. She was perseverative and susceptible to verbal and visual stimulus pull. Conclusions The pattern on neuropsychological testing, with prominent visual spatial and perceptual difficulties, was consistent with posterior cortical atrophy. The decline in visual ability is likely exacerbated but not entirely explained by left hemianopia. Neuropsychological, neuroimaging, and visual field evidence demonstrated posterior cortical atrophy in the absence of positive biomarker evidence, leading to initiation of anti-cholinesterase therapy.

scholarly journals 0080 Daytime Sleepiness Correlates with Increased Gray Matter Volume in the Right Middle Temporal Gyrus in Healthy Young Individuals

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A32-A32
Author(s):  
A I Burns ◽  
A Bullock ◽  
A C Raikes ◽  
N S Dailey ◽  
M A Grandner ◽  
...  
Keyword(s):  
Sleep Disorders ◽  
Gray Matter ◽  
Daytime Sleepiness ◽  
Gray Matter Volume ◽  
Middle Temporal Gyrus ◽  
Intracranial Volume ◽  
Middle Temporal ◽  
Matter Volume ◽  
History Of ◽  
The Right

Abstract Introduction Daytime sleepiness has been associated with some neuroimaging metrics, including altered functional connectivity within the default mode network and decreased gray matter volume (GMV) of the medial prefrontal cortex. Most prior studies, however, have focused on patients with sleep disorders or other pathologies. Here we examined the association between GMV and self-reported daytime sleepiness among a healthy group of young adults who reported no sleep-related problems. Methods Forty-five healthy adults (22 female; Mean Age=25.4, SD=5.6), who self-reported no history of sleep-related disorders or major medical conditions, completed the Epworth Sleepiness Scale (ESS), the Repeatable Battery for Neuropsychological Status (RBANS) and underwent high-resolution structural neuroimaging at 3T. Gray matter volumes were processed using standard procedures in SPM12. After controlling for age, sex, and intracranial volume, GMV was regressed against ESS scores. Results Greater ESS was associated with larger GMV within a cluster of voxels in the right middle temporal gyrus (MNI coordinates: 57, -9, -22; k=1344 voxels, p=.003, FWE cluster corrected). After controlling for ESS scores, larger GMV in this region was associated with poorer delayed memory performance (r=-.345, p=.022) and total neurocognitive performance on the RBANS (r=-.303, p=.046). Conclusion Greater daytime sleepiness in healthy normal sleepers was associated with greater GMV within a region of the right middle temporal gyrus. Greater volume of this region was also associated with poorer neuropsychological performance. Decreased GMV of this same region has previously been reported in patients with obstructive sleep apnea and insomnia, suggesting that it may be particularly sensitive to sleep disruption or may play a role in the etiology of sleep disorders, even among young individuals who deny any history of sleep-related dysfunction. Longitudinal work should focus on the potential of this region as a biomarker of vulnerability to sleep problems. Support  

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