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

The current report describes the journey from the sharing of a single, extraordinary experience during a support group conversation to the development of a novel scientific investigation of balance problems in a rarer form of dementia. The story centres around the involvement of people living with or caring for someone with posterior cortical atrophy (often referred to as the visual variant of Alzheimer’s disease) in highlighting hitherto under-appreciated consequences of their condition upon their ability to know ‘Am I the right way up?’. We describe how comments and descriptions of these balance symptoms were collated and communicated, and the involvement of people with posterior cortical atrophy in shaping a series of scientific hypotheses and developing and adapting appropriate experimental materials and procedures. We also reflect more broadly on how we might better recognise, acknowledge and encourage different forms of involvement, and describe several engagement-inspired extensions to the research involving people living with dementia, scientists and artists.

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Latent atrophy factors related to phenotypical variants of posterior cortical atrophy

Neurology ◽

10.1212/wnl.0000000000010362 ◽

2020 ◽

Vol 95 (12) ◽

pp. e1672-e1685 ◽

Cited By ~ 1

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.

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

Brain Imaging and Behavior ◽

10.1007/s11682-021-00568-8 ◽

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.

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

Archives of Clinical Neuropsychology ◽

10.1093/arclin/acz078 ◽

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.

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

Archives of Clinical Neuropsychology ◽

10.1093/arclin/acz037.02 ◽

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.

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

10.1101/679225 ◽

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.

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Statokinetic Dissociation (Riddoch Phenomenon) in a Patient with Homonymous Hemianopsia as the First Sign of Posterior Cortical Atrophy

Case Reports in Neurology ◽

10.1159/000481304 ◽

2017 ◽

Vol 9 (3) ◽

pp. 256-260 ◽

Cited By ~ 2

Author(s):

Ryuichiro Hayashi ◽

Shigeki Yamaguchi ◽

Toshio Narimatsu ◽

Hiroshi Miyata ◽

Yasushi Katsumata ◽

...

Keyword(s):

Visual Cortex ◽

Visual Field ◽

Cortical Atrophy ◽

Visual Field Defects ◽

Posterior Cortical Atrophy ◽

Unilateral Neglect ◽

Homonymous Hemianopsia ◽

Kinetic Perimetry ◽

The Right ◽

Field Defects

We report a 60-year-old woman with posterior cortical atrophy (PCA) who presented with left homonymous hemianopsia persisting for 5 years; the patient’s condition was observed using static, but not kinetic, perimetry. This statokinetic dissociation of hemianopsia, which is often called Riddoch syndrome, might have been caused by a dysfunction of the right primary visual and visual association cortices, representing a functional imbalance within a disturbed visual cortex. In patients with PCA and visual field defects, both static and kinetic perimetry may be useful for understanding the extent of degeneration in the visual cortex, in addition to examinations of unilateral neglect.

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Very early-onset posterior cortical atrophy

Aktuelle Neurologie ◽

10.1055/s-2006-953087 ◽

2006 ◽

Vol 33 (S 1) ◽

Author(s):

W.G. Janzarik ◽

S. Rauer ◽

C. Weiller ◽

K. Schmidtke

Keyword(s):

Early Onset ◽

Cortical Atrophy ◽

Posterior Cortical Atrophy

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An autopsy-proven case of Corticobasal degeneration heralded by Pontine infarction

BMC Neurology ◽

10.1186/s12883-021-02178-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Dallah Yoo ◽

Sung-Hye Park ◽

Sungwook Yu ◽

Tae-Beom Ahn

Keyword(s):

Neurodegenerative Disorders ◽

Clinical Manifestations ◽

Neuronal Loss ◽

Corticobasal Degeneration ◽

Executive Dysfunction ◽

Lacunar Infarction ◽

Cortical Atrophy ◽

Dystonic Posturing ◽

Proven Case ◽

The Right

Abstract Background Neurodegenerative disorders are characterized by insidious progression with poorly-delineated long latent period. Antecedent clinical insult could rarely unmask latent neurodegenerative disorders. Here, we report an autopsy-proven case of corticobasal degeneration which was preceded by a lacunar infarction. Case presentation A 58-year-old man presented with acute ataxia associated with a lacunar infarction in the right paramedian pons. His ataxia persisted with additional progressive gait difficulty and left arm clumsiness. Six months later, a follow-up neurological examination showed asymmetrical bradykinesia, apraxia, dystonic posturing, postural instability, and mild ataxia of the left limbs. Cognitive examination revealed frontal executive dysfunction and visuospatial difficulties. Dopamine transporter imaging scan demonstrated bilateral reduced uptakes in mid-to-posterior putamen, more prominent on the right side. Levodopa-unresponsive parkinsonism, asymmetric limb dystonia, and ideomotor apraxia became more conspicuous, while limb ataxia gradually vanished. The patient became unable to walk without assistance after 1 year, and died 4 years after the symptom onset. Autopsy findings showed frontoparietal cortical atrophy, ballooned neurons, and phosphorylated tau-positive astrocytic plaques and neuropil threads with gliosis and neuronal loss, confirming the corticobasal degeneration. Conclusions The case illustrates that precedent clinical events such as stroke might tip a patient with subclinical CBS into overt clinical manifestations.

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