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Behavioral and Brain Functions : BBF Apr 2024One important role of the TPJ is the contribution to perception of the global gist in hierarchically organized stimuli where individual elements create a global visual...
One important role of the TPJ is the contribution to perception of the global gist in hierarchically organized stimuli where individual elements create a global visual percept. However, the link between clinical findings in simultanagnosia and neuroimaging in healthy subjects is missing for real-world global stimuli, like visual scenes. It is well-known that hierarchical, global stimuli activate TPJ regions and that simultanagnosia patients show deficits during the recognition of hierarchical stimuli and real-world visual scenes. However, the role of the TPJ in real-world scene processing is entirely unexplored. In the present study, we first localized TPJ regions significantly responding to the global gist of hierarchical stimuli and then investigated the responses to visual scenes, as well as single objects and faces as control stimuli. All three stimulus classes evoked significantly positive univariate responses in the previously localized TPJ regions. In a multivariate analysis, we were able to demonstrate that voxel patterns of the TPJ were classified significantly above chance level for all three stimulus classes. These results demonstrate a significant involvement of the TPJ in processing of complex visual stimuli that is not restricted to visual scenes and that the TPJ is sensitive to different classes of visual stimuli with a specific signature of neuronal activations.
Topics: Humans; Parietal Lobe; Magnetic Resonance Imaging; Recognition, Psychology; Neuroimaging; Multivariate Analysis; Photic Stimulation; Pattern Recognition, Visual; Visual Perception; Brain Mapping
PubMed: 38637870
DOI: 10.1186/s12993-024-00233-2 -
Journal of Clinical Neurology (Seoul,... May 2024
PubMed: 38627231
DOI: 10.3988/jcn.2023.0468 -
Frontiers in Neuroscience 2024Posterior Cortical Atrophy (PCA) is a syndrome characterized by a progressive decline in higher-order visuospatial processing, leading to symptoms such as space...
INTRODUCTION
Posterior Cortical Atrophy (PCA) is a syndrome characterized by a progressive decline in higher-order visuospatial processing, leading to symptoms such as space perception deficit, simultanagnosia, and object perception impairment. While PCA is primarily known for its impact on visuospatial abilities, recent studies have documented language abnormalities in PCA patients. This study aims to delineate the nature and origin of language impairments in PCA, hypothesizing that language deficits reflect the visuospatial processing impairments of the disease.
METHODS
We compared the language samples of 25 patients with PCA with age-matched cognitively normal (CN) individuals across two distinct tasks: a visually-dependent picture description and a visually-independent job description task. We extracted word frequency, word utterance latency, and spatial relational words for this comparison. We then conducted an in-depth analysis of the language used in the picture description task to identify specific linguistic indicators that reflect the visuospatial processing deficits of PCA.
RESULTS
Patients with PCA showed significant language deficits in the visually-dependent task, characterized by higher word frequency, prolonged utterance latency, and fewer spatial relational words, but not in the visually-independent task. An in-depth analysis of the picture description task further showed that PCA patients struggled to identify certain visual elements as well as the overall theme of the picture. A predictive model based on these language features distinguished PCA patients from CN individuals with high classification accuracy.
DISCUSSION
The findings indicate that language is a sensitive behavioral construct to detect visuospatial processing abnormalities of PCA. These insights offer theoretical and clinical avenues for understanding and managing PCA, underscoring language as a crucial marker for the visuospatial deficits of this atypical variant of Alzheimer's disease.
PubMed: 38379764
DOI: 10.3389/fnins.2024.1342909 -
Internal Medicine (Tokyo, Japan) Feb 2024A 73-year-old woman with posterior cortical atrophy (PCA) presented with progressive apperceptive visual agnosia, alexia, agraphia, ventral simultanagnosia,...
A 73-year-old woman with posterior cortical atrophy (PCA) presented with progressive apperceptive visual agnosia, alexia, agraphia, ventral simultanagnosia, prosopagnosia, and allocentric (stimulus-centered) left-sided hemispatial neglect. All of these symptoms were attributed to damage to the bilateral occipito-temporal cortices, consistent with ventral variant PCA. While the Pittsburgh compound B uptake was extensively distributed throughout the occipito-parietal (dorsal) and occipito-temporal (ventral) areas, the THK5351 (ligand binding to tau aggregates/astrocyte gliosis) accumulation was limited to the ventral area. These findings suggest that local accumulation of tau proteins and/or astrocyte gliosis over the occipito-temporal cortices can result in ventral variant PCA.
PubMed: 38369357
DOI: 10.2169/internalmedicine.2844-23 -
Neuro-ophthalmology (Aeolus Press) 2024Vision specialists will benefit from increased awareness of posterior cortical atrophy (PCA) syndrome. Failure to adequately identify the chief complaint as a visual...
Vision specialists will benefit from increased awareness of posterior cortical atrophy (PCA) syndrome. Failure to adequately identify the chief complaint as a visual symptom may lead to incorrect diagnosis or diagnostic delay. A previously healthy, 59-year-old woman presented with a 5-year history of 'losing her stuff'. Upon psychiatric and neuro-ophthalmological evaluation, this symptom was better recognised as a feature of visual agnosia and simultanagnosia. She also presented with multiple previously unrecognised symptoms indicative of higher visual processing dysfunction, such as alexia without agraphia, ocular motor apraxia, optic ataxia, prosopagnosia, akinetopsia and topographagnosia, so further assessment to investigate for PCA was carried out. After a work-up including cognitive assessment, brain structural/functional imaging, and laboratory tests she was diagnosed with visual-variant Alzheimer's disease. Patients with PCA merit a detailed review of their symptoms, as well as the use of office tests such as cognitive evaluation tools, different types of perimetry, colour vision tests, and non-delayed psychiatric consultation for correct management and assessment. This report will emphasise five key aspects to be considered when evaluating patients with PCA.
PubMed: 38357623
DOI: 10.1080/01658107.2023.2257311 -
Perceptual and Motor Skills Feb 2024Typical visual perception includes an attention bias toward right hemisphere mediated global, holistic cortical processing. An atypically local, detail-oriented focus of...
Typical visual perception includes an attention bias toward right hemisphere mediated global, holistic cortical processing. An atypically local, detail-oriented focus of attention is characteristic of left hemisphere processing and is often observed in patients whose field of attention is restricted by certain types of neurocognitive impairment. We designed the present pair of studies to induce a local attentional focus to observe its consequences on neurocognitive measures of visuospatial processing. In Experiment I, participants wore glasses mimicking simultanagnosia, a disorder of visual attention, to induce a narrowed, atypical attentional style while they completed visual neuropsychological tasks. This simulation impaired participants' capacities to visually synthesize and efficiently reproduce Complex Figure stimuli as measured with the Boston Qualitative Scoring System (BQSS), and it induced an atypical attentional style on Rorschach Performance Assessment System (R-PAS) responses. In Experiment II, participants wore glasses designed to provoke differential hemispheric activation, also hypothesized to influence style of visual attention; but this manipulation did not influence neurocognitive task performance. We discuss implications for the interpretation of BQSS and R-PAS scores and offer directions for future research.
Topics: Humans; Visual Perception; Bias; Attention; Functional Laterality
PubMed: 38253419
DOI: 10.1177/00315125241228128 -
MedRxiv : the Preprint Server For... Nov 2023Posterior Cortical Atrophy (PCA) is a syndrome characterized by a progressive decline in higher-order visuospatial processing, leading to symptoms such as space...
INTRODUCTION
Posterior Cortical Atrophy (PCA) is a syndrome characterized by a progressive decline in higher-order visuospatial processing, leading to symptoms such as space perception deficit, simultanagnosia, and object perception impairment. While PCA is primarily known for its impact on visuospatial abilities, recent studies have documented language abnormalities in PCA patients. This study aims to delineate the nature and origin of language impairments in PCA, hypothesizing that language deficits reflect the visuospatial processing impairments of the disease.
METHODS
We compared the language samples of 25 patients with PCA with age-matched cognitively normal (CN) individuals across two distinct tasks: a visually-dependent picture description and a visually-independent job description task. We extracted word frequency, word utterance latency, and spatial relational words for this comparison. We then conducted an in-depth analysis of the language used in the picture description task to identify specific linguistic indicators that reflect the visuospatial processing deficits of PCA.
RESULTS
Patients with PCA showed significant language deficits in the visually-dependent task, characterized by higher word frequency, prolonged utterance latency, and fewer spatial relational words, but not in the visually-independent task. An in-depth analysis of the picture description task further showed that PCA patients struggled to identify certain visual elements as well as the overall theme of the picture. A predictive model based on these language features distinguished PCA patients from CN individuals with high classification accuracy.
DISCUSSION
The findings indicate that language is a sensitive behavioral construct to detect visuospatial processing abnormalities of PCA. These insights offer theoretical and clinical avenues for understanding and managing PCA, underscoring language as a crucial marker for the visuospatial deficits of this atypical variant of Alzheimer's disease.
PubMed: 38045263
DOI: 10.1101/2023.11.21.23298864 -
Rinsho Shinkeigaku = Clinical Neurology Oct 2023A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right...
A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions. Although his overall cognitive function was almost normal, he exhibited reduced visual sensitivity in the homonymous lower left quadrant of the visual field, left unilateral spatial neglect (USN), and simultanagnosia. Left USN improved 4 months after the onset of infarction; however, simultanagnosia persisted. To the best of our knowledge, this is the first case of simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions.
Topics: Male; Humans; Aged; Pulvinar; Thalamus; Cerebral Infarction; Agnosia; Perceptual Disorders
PubMed: 37779025
DOI: 10.5692/clinicalneurol.cn-001846 -
Der Nervenarzt Aug 2023Neglect occurring after stroke, neoplasms or degenerative processes can lead to considerable disability in everyday life as can other disorders of spatial orientation....
Neglect occurring after stroke, neoplasms or degenerative processes can lead to considerable disability in everyday life as can other disorders of spatial orientation. Therefore, a dedicated examination and early diagnostic classification are obligatory. Behavioral tests are helpful in this respect, enabling the clinician to obtain an initial overview of the existing deficits even at the patient's bedside. The clinical (bedside) examination of spatial neglect as well as the corresponding differential diagnostic procedure for the clarification of (possibly additionally or exclusively existing) hemianopia and extinction, as well as the examination of disorders of visuospatial perception, visuoconstructive disorders, topographic disorders, Bálint's syndrome, simultanagnosia, and optic ataxia are presented. The presentation is based on the newly revised (year 2023) guidelines of the Association of the Scientific Medical Societies in Germany (AWMF) on this subject area.
Topics: Humans; Visual Perception; Cognition; Perceptual Disorders; Stroke; Apraxias
PubMed: 37535111
DOI: 10.1007/s00115-023-01525-0 -
Cognitive and Behavioral Neurology :... Jun 2023A selective impairment for making hand postures that are required to use specific tools has rarely been reported in individuals with acquired brain injury, and such an...
A selective impairment for making hand postures that are required to use specific tools has rarely been reported in individuals with acquired brain injury, and such an impairment has not been documented at all in individuals with degenerative disorders. We describe an individual with posterior cortical atrophy and probable corticobasal syndrome who was unable to use tools because of an inability to make the proper hand posture required for each tool. This individual was, however, able to use the tools properly once her hand postures were corrected, and her ability to manipulate the tools (ie, timing, arm posture, and amplitude) was intact. Also, she had no difficulty with a test of her manipulation knowledge. Areas of hypoperfusion observed by single-photon emission computerized tomography included the anterior intraparietal sulcus in the left parietal lobe, which is an area that has been proposed to control hand postures. This selective impairment might be explained by the reasoning-based hypothesis for apraxia, which attributes hand posture errors in the absence of manipulation errors to dysfunction in one of the three independent pathways that subserve tool use, rather than the manipulation-based hypothesis for apraxia, which attributes hand posture errors to impaired manipulation knowledge. This is the first case with a degenerative disorder that revealed a selective impairment for making hand postures for tool use, which might be explained mainly by apraxia of hand postures along with visuospatial dysfunction (simultanagnosia) and/or sensory disturbance.
Topics: Female; Humans; Corticobasal Degeneration; Apraxias; Posture; Neurodegenerative Diseases; Atrophy
PubMed: 36961317
DOI: 10.1097/WNN.0000000000000339