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Frontiers in Neurology 2017Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of... (Review)
Review
Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions.
PubMed: 28861031
DOI: 10.3389/fneur.2017.00389 -
Internal Medicine (Tokyo, Japan) 2017We herein report a 65-year-old man demonstrating dementia with Lewy bodies who first presented with Bálint's syndrome. Two years later, a mild cognitive impairment was...
We herein report a 65-year-old man demonstrating dementia with Lewy bodies who first presented with Bálint's syndrome. Two years later, a mild cognitive impairment was noted. From three years after onset, he developed progressive parkinsonism, visual hallucination, and autonomic dysfunction, in line with the deterioration of the cognitive function. Single photon emission computed tomography with a Tc-ethylcysteinate dimer performed two years after onset revealed hypoperfusion in the restricted area of the bilateral superior parietal lobule, which extended to the lateral occipital cortices within two years. It is suggested that the pathological process can extend from the parietal to occipital lobes.
Topics: Aged; Cognition; Disease Progression; Humans; Lewy Body Disease; Male; Nervous System Diseases; Syndrome; Tomography, Emission-Computed, Single-Photon
PubMed: 28566609
DOI: 10.2169/internalmedicine.56.7005 -
Case Reports in Ophthalmological... 2016Balint's syndrome is well described in adults, but not in children. It is caused by bilateral posterior parietal lobe damage and comprises a triad of simultanagnosia...
Balint's syndrome is well described in adults, but not in children. It is caused by bilateral posterior parietal lobe damage and comprises a triad of simultanagnosia (inability to simultaneously see more than a small number of items), optic ataxia (impaired visual guidance of movement of the limbs and body), and apraxia of gaze (inability to volitionally direct gaze despite the requisite motor substrate) often associated with homonymous lower visual field loss. We, here, describe five children (four males, one female; mean age 7.4 years, [range 4-11 years]; birth weight ≤ 2.5 kg; four were born ≤ 36 weeks of gestational age and one at 40 weeks) who presented to the Cerebral Visual Impairment Clinic at a tertiary care center in South India with clinical features remarkably consistent with the above description. In all children neuroimaging showed bilateral parietooccipital gliosis with regional white matter volume loss and focal callosal thinning, consistent with perinatal hypoxic ischemic encephalopathy and possible neonatal hypoglycemia.
PubMed: 27895948
DOI: 10.1155/2016/3806056 -
Bulletin of Emergency and Trauma Apr 2016Balint’s syndrome is a rare neurological disorder associated with bilateral parieto-occipital damage which was described by Rezsö Bálint in 1909.The syndrome is...
Balint’s syndrome is a rare neurological disorder associated with bilateral parieto-occipital damage which was described by Rezsö Bálint in 1909.The syndrome is manifested clinically by the presence of a hemispatial negligence. The lesion is usually inside parietooccipital region bilaterally in most cases but may also be compromised angular convolutions, the dorsolateral area of the occipital lobe as the superior parietal lobule. We herein report a 61-year-old man with traumatic brain injury who was diagnosed to have right parieto-occipital contusion in radiologic evaluation. Physical examination was consistent with Balint's syndrome. The patient was followed for 12 months post-injury and received 4-months of outpatient rehabilitation. Patient showed improvement of Balint’s syndrome 8 months after the starts of symptoms.
PubMed: 27331070
DOI: No ID Found -
BMC Ophthalmology Jun 2015Prominent visual symptoms can present in the visual variant of Alzheimer's disease (VVAD). Ophthalmologists have a significant role to play in the early diagnosis of...
BACKGROUND
Prominent visual symptoms can present in the visual variant of Alzheimer's disease (VVAD). Ophthalmologists have a significant role to play in the early diagnosis of VVAD.
METHODS
We retrospectively reviewed the files of ten consecutive patients diagnosed with VVAD. All patients had a full neuro-ophthalmologic examination, a formal neurological and neuro-psychological testing, and cerebral MRI to confirm diagnosis. In addition, functional neuroimaging was obtained in seven patients.
RESULTS
The common primary symptom at presentation with all patients was difficulty with near vision (reading difficulty n = 8, "visual blur" in near vision n = 2), and difficulty writing (n = 3). Following assessment, impaired reading and writing skills were evident in 9/10 and 8/10 patients respectively. Median distance visual acuity was 20/25 and at near the median visual acuity was J6. Partial homonymous visual field defect was detected in 80 % (8/10) of the patients. Color vision was impaired in all patients when tested with Ishihara pseudoisochromatic plates, but simple color naming was normal in 8/9 tested patients. Simultanagnosia was present in 8/10 patients. Vision dysfunction corresponded with cerebral MRI findings where parieto-occipital cortical atrophy was observed in all patients. PET scan (5 patients) or SPECT (2 patients) revealed parieto-occipital dysfunction (hypometabolism or hypoperfusion) in all 7 tested patients
CONCLUSIONS
Visual difficulties are prominent in VVAD. Dyslexia, incomplete homonymous hemianopia, preserved color identification with abnormal color vision on Ishihara, and simultanagnosia were all symptoms observed frequently in this patient series. Ophthalmologists should be aware of the possibility of neurodegenerative disorders such as VVAD in patients with unexplained visual complaints, in particular reading difficulties.
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Atrophy; Color Vision Defects; Early Diagnosis; Female; Hemianopsia; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Occipital Lobe; Parietal Lobe; Retrospective Studies; Visual Acuity; Visual Field Tests; Visual Fields
PubMed: 26122482
DOI: 10.1186/s12886-015-0060-9 -
Cortex; a Journal Devoted To the Study... Aug 2015Although it has been proposed that visuospatial working memory may be impaired in Bálint syndrome patients, neither a systematic study concerning this proposal nor a...
Although it has been proposed that visuospatial working memory may be impaired in Bálint syndrome patients, neither a systematic study concerning this proposal nor a comparison with patients having right-parietal damage has been made. Visuospatial working memory was assessed for six Bálint syndrome patients and members of two control groups-one composed of individuals with right-parietal damage (n = 15) and a second of age- and gender-matched healthy individuals (n = 26). We placed special emphasis on patients with a mild form of Bálint syndrome who can judge positional relationships between two objects. First, the participants were subjected to delayed visuospatial matching tasks. Next, their visuospatial-temporal integration abilities were assessed using a shape-from-moving-dots task. Visuospatial working memory was impaired for Bálint syndrome patients compared with controls according to the results of the tests. The differences between the Bálint syndrome and control subjects remained when only data for patients with the mild form of Bálint syndrome were included. We conclude that visuospatial working memory may be severely impaired in Bálint syndrome patients and, therefore, might influence their inability to properly execute movements and behaviours associated with daily living.
Topics: Aged; Brain Diseases; Female; Humans; Male; Memory Disorders; Memory, Short-Term; Middle Aged; Parietal Lobe; Pattern Recognition, Visual; Space Perception; Syndrome; Visual Perception
PubMed: 26117797
DOI: 10.1016/j.cortex.2015.05.023 -
Journal of Neurology Jun 2015The purpose of this study was to identify the clinical, [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and amyloid-PET findings in a large cohort of...
The purpose of this study was to identify the clinical, [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and amyloid-PET findings in a large cohort of posterior cortical atrophy (PCA) patients, to examine the neural correlates of the classic features of PCA, and to better understand the features associated with early PCA. We prospectively recruited 25 patients who presented to the Mayo Clinic between March 2013 and August 2014 and met diagnostic criteria for PCA. All patients underwent a standardized set of tests and amyloid imaging with [(11)C] Pittsburg compound B (PiB). Seventeen (68 %) underwent FDG-PET scanning. We divided the cohort at the median disease duration of 4 years in order to assess clinical and FDG-PET correlates of early PCA (n = 13). The most common clinical features were simultanagnosia (92 %), dysgraphia (68 %), poly-mini-myoclonus (64 %) and oculomotor apraxia (56.5 %). On FDG-PET, hypometabolism was observed bilaterally in the lateral and medial parietal and occipital lobes. Simultanagnosia was associated with hypometabolism in the right occipital lobe and posterior cingulum, optic ataxia with hypometabolism in left occipital lobe, and oculomotor apraxia with hypometabolism in the left parietal lobe and posterior cingulate gyrus. All 25 PCA patients were amyloid positive. Simultanagnosia was the only feature present in 85 % of early PCA patients. The syndrome of PCA is associated with posterior hemisphere hypometabolism and with amyloid deposition. Many of the classic features of PCA show associated focal, but not widespread, areas of involvement of these posterior hemispheric regions. Simultanagnosia appears to be the most common and hence sensitive feature of early PCA.
Topics: Aged; Amyloid; Aniline Compounds; Atrophy; Brain; Brain Mapping; Carbon Isotopes; Cohort Studies; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Neurologic Examination; Positron-Emission Tomography; Thiazoles; Tomography, X-Ray Computed
PubMed: 25862483
DOI: 10.1007/s00415-015-7732-5 -
Frontiers in Psychology 2015In combination with whole report and partial report tasks, the theory of visual attention (TVA) can be used to estimate individual differences in five basic attentional... (Review)
Review
In combination with whole report and partial report tasks, the theory of visual attention (TVA) can be used to estimate individual differences in five basic attentional parameters: the visual processing speed, the storage capacity of visual short-term memory, the perceptual threshold, the efficiency of top-down selectivity, and the spatial bias of attentional weighting. TVA-based assessment has been used in about 30 studies to investigate attentional deficits in a range of neurological and psychiatric conditions: (a) neglect and simultanagnosia, (b) reading disturbances, (c) aging and neurodegenerative diseases, and most recently (d) neurodevelopmental disorders. The article introduces TVA based assessment, discusses its methodology and psychometric properties, and reviews the progress made in each of the four research fields. The empirical results demonstrate the general usefulness of TVA-based assessment for many types of clinical neuropsychological research. The method's most important qualities are cognitive specificity and theoretical grounding, but it is also characterized by good reliability and sensitivity to minor deficits. The review concludes by pointing to promising new areas for clinical TVA-based research.
PubMed: 25852607
DOI: 10.3389/fpsyg.2015.00290 -
Annals of the New York Academy of... Mar 2015This study aims to investigate whether attention and spatiotemporal integration deficits are dissociated in patients with bilateral posterior cortical atrophy (PCA), and... (Randomized Controlled Trial)
Randomized Controlled Trial
This study aims to investigate whether attention and spatiotemporal integration deficits are dissociated in patients with bilateral posterior cortical atrophy (PCA), and whether it is their combination that leads to a severe clinical handicap. We recorded performance and ocular behavior of four PCA patients and four age-matched controls in visual search and counting tasks. We measured the percentage of targets detected and the mean detection time in a "pop-out" search. We also compared counting ability when a set of dots is presented briefly (in healthy individuals, the automatic deployment of attention over space allows a fast estimation of quantity) or for unlimited duration (favoring sequential counting, hence spatiotemporal integration). All patients showed reduced deployment of attention over space (simultanagnosia), resulting in increased visual search times and underestimations of the number of briefly presented dots. Only two patients showed ocular revisiting behavior that caused frequent omissions in visual search and overestimations of the number of dots presented for unlimited duration. The impairment to deploy attention is considered here as a bilateral covert attention deficit. Disorganized ocular exploration appears to be independent and is hypothesized to result from processes maintaining a salience map over time (spatial working memory) and especially across saccades.
Topics: Aged; Atrophy; Attention; Cerebral Cortex; Eye Movements; Female; Humans; Male; Memory Disorders; Memory, Short-Term; Middle Aged; Photic Stimulation
PubMed: 25708555
DOI: 10.1111/nyas.12731 -
Continuum (Minneapolis, Minn.) Aug 2014This article reviews the various types of visual dysfunction that can result from lesions of the cerebral regions beyond the striate cortex.
PURPOSE OF REVIEW
This article reviews the various types of visual dysfunction that can result from lesions of the cerebral regions beyond the striate cortex.
RECENT FINDINGS
Patients with dyschromatopsia can exhibit problems with color constancy. The apperceptive form of prosopagnosia is associated with damage to posterior occipital and fusiform gyri, and an associative/amnestic form is linked to damage to more anterior temporal regions. Pure alexia can be accompanied by a surface dysgraphia. New word-length effect criteria distinguish pure alexia from hemianopic dyslexia. Subtler problems with perception of numbers and faces can be seen in patients with pure alexia as well. Also, a developmental form of topographic disorientation, which is due to problems with forming cognitive maps of the environment, has been discovered. In Balint syndrome, added features of decreased flexibility of attention in simultanagnosia include local and global capture. Balint syndrome can affect not just localization in space, but also in time, as manifest in sequence agnosia.
SUMMARY
Lesions at intermediate levels of a processing hierarchy can cause difficulty with color perception or motion perception. At a higher level, ventral lesions of the occipitotemporal lobes can lead to a variety of problems with object recognition. Dorsal lesions of the occipitoparietal lobes can cause difficulty with spatial localization and guidance.
Topics: Adult; Aged; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Perceptual Disorders; Vision Disorders; Visual Cortex; Visual Pathways; Visual Perception
PubMed: 25099101
DOI: 10.1212/01.CON.0000453311.29519.67