89 results match your criteria alexia prosopagnosia


The inferior longitudinal fasciculus: anatomy, function and surgical considerations.

J Neurosurg Sci 2021 May 3. Epub 2021 May 3.

Institute of Functional Genomics, University of Montpellier, CNRS UMR5203, INSERM U1191, Montpellier, France.

The inferior longitudinal fasciculus (ILF) is a large association white matter tract that interconnects, in a bidirectional manner, the occipital cortex to anterior temporal structures. In view of both its pattern of cortical projections and its recently evidenced multilayered anatomical organization, the ILF has been supposed to be vital for maintaining a wide range of cognitive and affective processes operating on the visual modality. As tumors commonly damage the temporal cortex, an updated knowledge of the functional anatomy of this ventral tract is needed to better map and monitor online its potential functions and thus to improve surgical outcomes. Read More

View Article and Full-Text PDF

Rehabilitation of visual disorders.

Handb Clin Neurol 2021 ;178:361-386

Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, and Psychology, University of British Columbia, Vancouver, BC, Canada.

While there is a long history of rehabilitation for motor deficits following cerebral lesions, less is known about our ability to improve visual deficits. Vision therapy, prisms, occluders, and filters have been advocated for patients with mild traumatic brain injury, on the premise that some of their symptoms may reflect abnormal visual or ocular motor function, but the evidence for their efficacy is modest. For hemianopia, attempts to restore vision have had unimpressive results, though it appears possible to generate blindsight through training. Read More

View Article and Full-Text PDF
January 2021

Object recognition and visual object agnosia.

Handb Clin Neurol 2021 ;178:155-173

Department of Psychology, University of Copenhagen, Copenhagen, Denmark.

The term visual agnosia is used to refer to recognition disorders that are confined to the visual modality, that are not due to an impairment in sensory functions, and that cannot be explained by other cognitive deficits or by general reduction in intellectual ability. Here, we describe the different types of visual agnosia that have been reported (form agnosia, integrative agnosia, associative agnosia, transformational and orientation agnosia as well as category-specific impairments such as pure alexia and prosopagnosia) and how they relate to the current understanding of visual object recognition. Together with related disorders such as simultanagnosia, texture agnosia, aphantasia, and optic aphasia, these visual perceptual impairments can have severe consequences for those affected. Read More

View Article and Full-Text PDF
January 2021

Category-selective deficits are the exception and not the rule: Evidence from a case-series of 64 patients with ventral occipito-temporal cortex damage.

Cortex 2021 May 19;138:266-281. Epub 2021 Feb 19.

Department of Psychology, University of Copenhagen, Denmark. Electronic address:

The organisational principles of the visual ventral stream are still highly debated, particularly the relative association/dissociation between word and face recognition and the degree of lateralisation of the underlying processes. Reports of dissociations between word and face recognition stem from single case-studies of category selective impairments, and neuroimaging investigations of healthy participants. Despite the historical reliance on single case-studies, more recent group studies have highlighted a greater commonality between word and face recognition. Read More

View Article and Full-Text PDF

Complementary deficits in perceptual classification in pure alexia and acquired prosopagnosia - New insights from two classic cases.

Neuropsychologia 2021 05 5;155:107820. Epub 2021 Mar 5.

Institute of Medical Psychology, University of Munich, Germany.

Pure alexia and prosopagnosia traditionally have been seen as prime examples of dissociated, category-specific agnosias affecting reading and face recognition, respectively. More recent accounts have moved towards domain-independent explanations that postulate potential cross-links between different types of visual agnosia. According to one proposal, abnormal crowding, i. Read More

View Article and Full-Text PDF

Face recognition in developmental dyslexia: evidence for dissociation between faces and words.

Cogn Neuropsychol 2021 Feb 26;38(1):107-115. Epub 2020 Nov 26.

Department of Psychology, University of Copenhagen, Copenhagen, Denmark.

Developmental dyslexia is primarily a reading disorder, but recent studies have indicated that face processing problems may also be present. Using a case-series approach, we tested face recognition and visual word recognition in 24 high school students diagnosed with developmental dyslexia. Contrary to previous findings, no face recognition problems were found on the group-level. Read More

View Article and Full-Text PDF
February 2021

Alternating dual-task interference between visual words and faces.

Brain Res 2020 11 29;1746:147004. Epub 2020 Jun 29.

Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, Psychology, University of British Columbia, Vancouver, Canada. Electronic address:

The many-to-many hypothesis proposes that face and visual word recognition share and even compete for high-level perceptual resources in both hemispheres. However, it is still not clear whether the processing performed by the two hemispheres on faces and visual words is equivalent or complementary. We performed an alternating dual-task experiment to determine if the processing of visual words and faces interfered with each other, and if such interference depended upon the stimulus attribute being processed. Read More

View Article and Full-Text PDF
November 2020

A case of aneurysmal subarchnoid haemorrhage and superficial siderosis complicated by prospagnosia, simultagnosia and alexia without agraphia.

Br J Neurosurg 2019 Dec 2:1-4. Epub 2019 Dec 2.

Department of Neurosurgery, NHS Tayside, Dundee, United Kingdom.

A 42-year-old lady presented with acute aneurysmal subarachnoid haemorrhage and developed difficulty recognising faces (prosopagnosia), inability to process visual information in busy environments (simultagnosia) and difficulty to read (alexia). She was subsequently found to have superficial siderosis on MRI. Read More

View Article and Full-Text PDF
December 2019

Perception of musical pitch in developmental prosopagnosia.

Neuropsychologia 2019 02 6;124:87-97. Epub 2019 Jan 6.

Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Science, University of British Columbia, Vancouver, Canada.

Studies of developmental prosopagnosia have often shown that developmental prosopagnosia differentially affects human face processing over non-face object processing. However, little consideration has been given to whether this condition is associated with perceptual or sensorimotor impairments in other modalities. Comorbidities have played a role in theories of other developmental disorders such as dyslexia, but studies of developmental prosopagnosia have often focused on the nature of the visual recognition impairment despite evidence for widespread neural anomalies that might affect other sensorimotor systems. Read More

View Article and Full-Text PDF
February 2019

Atypical non-progressive semantic impairment following allogeneic bone marrow transplantation in a patient with Waldenström's macroglobulinemia: A case report.

Clin Neuropsychol 2019 05 23;33(4):798-810. Epub 2018 Nov 23.

a Clinical Neuropsychology, Cognitive Disorders and Dyslexia Unit, Department of Neurology , Arcispedale Santa Maria Nuova-IRCCS , Reggio Emilia , Italy.

Objective: A case report of a 74-year-old male presenting with an atypical multimodal semantic impairment. The patient was diagnosed with Waldenström macroglobulinemia (WM) for which he received allogeneic bone marrow transplantation (BMT) due to disease progression. Following BMT, he developed a sudden onset of semantic difficulties that have remained unchanged for eight years. Read More

View Article and Full-Text PDF

Developmental Perceptual Impairments: Cases When Tone-Deafness and Prosopagnosia Co-occur.

Front Hum Neurosci 2018 30;12:438. Epub 2018 Oct 30.

Music and Neuroimaging Laboratory, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States.

Studies have shown subtle gray and white matter abnormalities in subjects with several developmental disorders including prosopagnosia, tone-deafness, and dyslexia. Correlational evidence suggests that tone-deafness and dyslexia tend to co-occur, suggesting a link between these two developmental disorders. However, it is not known whether tone-deafness can also be associated with other developmental disorders such as impaired face recognition or prosopagnosia. Read More

View Article and Full-Text PDF
October 2018

Functional Anatomy of the Inferior Longitudinal Fasciculus: From Historical Reports to Current Hypotheses.

Front Neuroanat 2018 19;12:77. Epub 2018 Sep 19.

Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, Montpellier, France.

The inferior longitudinal fasciculus (ILF) is a long-range, associative white matter pathway that connects the occipital and temporal-occipital areas of the brain to the anterior temporal areas. In view of the ILF's anatomic connections, it has been suggested that this pathway has a major role in a relatively large array of brain functions. Until recently, however, the literature data on these potential functions were scarce. Read More

View Article and Full-Text PDF
September 2018

[F]THK-5351 PET imaging in early-stage semantic variant primary progressive aphasia: a report of two cases and a literature review.

BMC Neurol 2018 Aug 8;18(1):109. Epub 2018 Aug 8.

Department of Psychiatry, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata City, Yamagata, 990-9585, Japan.

Background: Semantic variant primary progressive aphasia (svPPA) is a subtype of primary progressive aphasia characterized by two-way anomia and disturbance in word comprehension, with focal atrophy in the left temporal lobe. [F]THK-5351 was originally developed to trace tau protein. However, it has recently been suggested that [F]THK-5351 binds to monoamine oxidase B in astrocytes, which reflects gliosis. Read More

View Article and Full-Text PDF

Visual crowding in pure alexia and acquired prosopagnosia.

Cogn Neuropsychol 2018 10 14;35(7):361-370. Epub 2018 Jun 14.

a Department of Psychology , University of Copenhagen , Copenhagen , Denmark.

Visual crowding is a phenomenon that impairs object recognition when the features of an object are positioned too closely together. Crowding limits recognition in normal peripheral vision and it has been suggested to be the core deficit in visual agnosia, leading to a domain-general deficit in object recognition. Using a recently developed tool, we test whether crowding is the underlying deficit in four patients with category specific agnosias: Two with pure alexia and two with acquired prosopagnosia. Read More

View Article and Full-Text PDF
October 2018

Reading in developmental prosopagnosia: Evidence for a dissociation between word and face recognition.

Neuropsychology 2018 02;32(2):138-147

Department of Psychology, University of Southern Denmark.

Objective: Recent models suggest that face and word recognition may rely on overlapping cognitive processes and neural regions. In support of this notion, face recognition deficits have been demonstrated in developmental dyslexia. Here we test whether the opposite association can also be found, that is, impaired reading in developmental prosopagnosia. Read More

View Article and Full-Text PDF
February 2018

Face perception in pure alexia: Complementary contributions of the left fusiform gyrus to facial identity and facial speech processing.

Cortex 2017 11 4;96:59-72. Epub 2017 Sep 4.

Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, Psychology, University of British Columbia, Vancouver, Canada. Electronic address:

Recent concepts of cerebral visual processing predict from overlapping patterns of face and word activation in cortex that left fusiform lesions will not only cause pure alexia but also lead to mild impairments of face processing. Our goal was to determine if alexic subjects had deficits in facial identity processing similar to those seen after right fusiform lesions, or complementary deficits affecting different aspects of face processing. We studied four alexic patients whose lesions involved the left fusiform gyrus and one prosopagnosic subject with a right fusiform lesion, on standard tests of face perception and recognition. Read More

View Article and Full-Text PDF
November 2017

The Visual Agnosias and Related Disorders.

J Neuroophthalmol 2018 09;38(3):379-392

Department of Neurology (SH, CJL), The Canberra Hospital, Canberra, Australia; Departments of Ophthalmology (MV), Neurology, and Neurosurgery, University of Alabama, Birmingham, Alabama; and Australian National University Medical School (CJL), Canberra, Australia.

Background: There are many disorders of higher visual processing that result from damage to specific areas of the cerebral cortex that have a specific role in processing certain aspects (modalities) of vision. These can be grouped into those that affect the ventral, or "what?", pathway (e.g. Read More

View Article and Full-Text PDF
September 2018

Face and Word Recognition Can Be Selectively Affected by Brain Injury or Developmental Disorders.

Front Psychol 2017 6;8:1547. Epub 2017 Sep 6.

Department of Psychology, University of CopenhagenCopenhagen, Denmark.

Face and word recognition have traditionally been thought to rely on highly specialised and relatively independent cognitive processes. Some of the strongest evidence for this has come from patients with seemingly category-specific visual perceptual deficits such as pure prosopagnosia, a selective face recognition deficit, and pure alexia, a selective word recognition deficit. Together, the patterns of impaired reading with preserved face recognition and impaired face recognition with preserved reading constitute a double dissociation. Read More

View Article and Full-Text PDF
September 2017

Visual agnosia and focal brain injury.

Authors:
O Martinaud

Rev Neurol (Paris) 2017 Jul - Aug;173(7-8):451-460. Epub 2017 Aug 24.

Department of neurology, Rouen university hospital, CHU Charles-Nicolle, 1, rue de Germont, 76031 Rouen cedex, France; Inserm U1077, pôle des formations et de recherche en santé, université de Caen-Normandie, UMR-S1077, 2, rue des Rochambelles, 14032 Caen cedex, France. Electronic address:

Visual agnosia encompasses all disorders of visual recognition within a selective visual modality not due to an impairment of elementary visual processing or other cognitive deficit. Based on a sequential dichotomy between the perceptual and memory systems, two different categories of visual object agnosia are usually considered: 'apperceptive agnosia' and 'associative agnosia'. Impaired visual recognition within a single category of stimuli is also reported in: (i) visual object agnosia of the ventral pathway, such as prosopagnosia (for faces), pure alexia (for words), or topographagnosia (for landmarks); (ii) visual spatial agnosia of the dorsal pathway, such as cerebral akinetopsia (for movement), or orientation agnosia (for the placement of objects in space). Read More

View Article and Full-Text PDF

Hemispheric Organization in Disorders of Development.

Vis cogn 2017 2;25(4-6):416-429. Epub 2017 Nov 2.

Department of Psychology, Carnegie Mellon University and Center for the Neural Basis of Cognition, 5000 Forbes Avenue, Pittsburgh, PA 15213-3890.

A recent theoretical account posits that, during the acquisition of word recognition in childhood, the pressure to couple visual and language representations in the left hemisphere (LH) results in competition with the LH representation of faces, which consequently become largely, albeit not exclusively, lateralized to the right hemisphere (RH). We explore predictions from this hypothesis using a hemifield behavioral paradigm with words and faces as stimuli, with concurrent ERP measurement, in a group of adults with developmental dyslexia (DD) or with congenital prosopagnosia (CP), and matched control participants. Behaviorally, the DD group exhibited clear deficits in both word and face processing relative to controls, while the CP group showed a specific deficit in face processing only. Read More

View Article and Full-Text PDF
November 2017

Impaired functional differentiation for categories of objects in the ventral visual stream: A case of developmental visual impairment.

Neuropsychologia 2015 Oct 10;77:52-61. Epub 2015 Aug 10.

INSERM, U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France.

We report the case of a 14-year-old girl suffering from severe developmental visual impairment along with delayed language and cognitive development, and featuring a clear-cut dissociation between spared dorsal and impaired ventral visual pathways. Visual recognition of objects, including faces and printed words, was affected. In contrast, movement perception and visually guided motor control were preserved. Read More

View Article and Full-Text PDF
October 2015

Imaging of Retrochiasmal and Higher Cortical Visual Disorders.

Neuroimaging Clin N Am 2015 Aug;25(3):411-24

Division of Neuroradiology, Department of Radiology, University of California Los Angeles, 757 Westwood Plaza, Suite 1621D, Los Angeles, CA 90095, USA.

Retrochiasmal visual pathways include optic tracts, lateral geniculate nuclei, optic radiations, and striate cortex (V1). Homonymous hemianopsia and field defect variants with relatively normal visual acuity suggest that the lesions involve retrochiasmal pathways. From V1, visual input is projected to higher visual association areas that are responsible for perception of objects, faces, colors, and orientation. Read More

View Article and Full-Text PDF

Higher cortical visual deficits.

Authors:
Jason J S Barton

Continuum (Minneap Minn) 2014 Aug;20(4 Neuro-ophthalmology):922-41

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. Read More

View Article and Full-Text PDF

Bilateral hemispheric processing of words and faces: evidence from word impairments in prosopagnosia and face impairments in pure alexia.

Cereb Cortex 2014 Apr 18;24(4):1102-18. Epub 2012 Dec 18.

Department of Psychology, Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213-3890, USA.

Considerable research has supported the view that faces and words are subserved by independent neural mechanisms located in the ventral visual cortex in opposite hemispheres. On this view, right hemisphere ventral lesions that impair face recognition (prosopagnosia) should leave word recognition unaffected, and left hemisphere ventral lesions that impair word recognition (pure alexia) should leave face recognition unaffected. The current study shows that neither of these predictions was upheld. Read More

View Article and Full-Text PDF

Cotard syndrome in semantic dementia.

Psychosomatics 2011 Nov-Dec;52(6):571-4

Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.

View Article and Full-Text PDF
February 2012

Disorders of higher visual processing.

Authors:
Jason J S Barton

Handb Clin Neurol 2011 ;102:223-61

Departments of Medicine (Neurology), Ophthalmology, and Visual Sciences and Psychology, University of British Columbia, Vancouver, Canada.

A significant proportion of human cortex is involved in visual processing. Cerebral regions beyond striate cortex show specialization for specific stimulus properties: damage to these regions leads to syndromes that also reflect this specialization. These syndromes can be grouped into two broad categories. Read More

View Article and Full-Text PDF

Curiouser and curiouser: genetic disorders of cortical specialization.

Authors:
Kevin J Mitchell

Curr Opin Genet Dev 2011 Jun 4;21(3):271-7. Epub 2011 Feb 4.

Smurfit Institute of Genetic and Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.

The processes by which cortical areas become specialized for high-level cognitive functions may be revealed by the study of familial developmental disorders such as dyslexia, dyscalculia, prosopagnosia, color agnosia and amusia. These disorders are characterised by the inability to integrate information across multiple areas and the consequent failure to develop representations of the knowledge of some category based on its associated attributes. In contrast, synesthesia may be seen as a hyper-associative condition, possibly due to a failure to properly segregate areas into distinct networks. Read More

View Article and Full-Text PDF

"Seeing but not identifying": pure alexia coincident with prosopagnosia in occipital arteriovenous malformation.

Graefes Arch Clin Exp Ophthalmol 2011 Jul 18;249(7):1087-9. Epub 2011 Jan 18.

Department of Ophthalmology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan.

Background: Pure alexia and prosopagnosia are two separate and uncommon disorders of visual recognition in neuro-ophthalmology. We report an extremely rare case of pure alexia coincident with prosopagnosia secondary to occipital arteriovenous malformation. The manifestations of these two visual recognition disorders are also described. Read More

View Article and Full-Text PDF

Disorder of higher visual function.

Authors:
Jason J S Barton

Curr Opin Neurol 2011 Feb;24(1):1-5

Department of Medicine (Neurology), Psychology, University of British Columbia, Vancouver, British Columbia, Canada.

Purpose Of Review: Both monkey and human neuroimaging studies show that visual processing beyond the striate cortex involves a highly complex network of regions with modular functions. Lesions within this network lead to specific clinical syndromes. In this review we discuss studies on blindsight, which is the ability of remaining regions to support vision in the absence of striate cortex or visual awareness, recent work on 'ventral stream' syndromes such as object agnosia, alexia, prosopagnosia, and topographagnosia, which follow damage to medial occipitotemporal structures, and simultanagnosia, the classic 'dorsal stream' deficit related to bilateral occipitoparietal lesions. Read More

View Article and Full-Text PDF
February 2011