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Scientific Reports Jul 2021Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to...
Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to which DP is associated with broader visual deficits beyond face processing is unclear. Here we investigate whether DP is accompanied by deficits in colour perception. We tested a large sample of 92 DP individuals and 92 sex/age-matched controls using the well-validated Ishihara and Farnsworth-Munsell 100-Hue tests to assess red-green colour deficiencies and hue discrimination abilities. Group-level analyses show comparable performance between DP and control individuals across both tests, and single-case analyses indicate that the prevalence of colour deficits is low and comparable to that in the general population. Our study clarifies that DP is not linked to colour perception deficits and constrains theories of DP that seek to account for a larger range of visual deficits beyond face recognition.
Topics: Adult; Color Perception; Discrimination, Psychological; Electroencephalography; Facial Recognition; Female; Humans; Male; Middle Aged; Pattern Recognition, Visual; Photic Stimulation; Prosopagnosia; Visual Perception; Young Adult
PubMed: 34215772
DOI: 10.1038/s41598-021-92840-6 -
Cortex; a Journal Devoted To the Study... Sep 1994Disagreement over the neuroanatomical substrate of associative visual agnosia encompasses such basic issues as: (1) the necessity for bilateral lesions; (2) the...
Disagreement over the neuroanatomical substrate of associative visual agnosia encompasses such basic issues as: (1) the necessity for bilateral lesions; (2) the intrahemispheric locus of damage; and (3) the roles of disconnection versus cortical damage. We examined three patients whose associative visual agnosia encompassed objects and printed words but spared faces. CAT scans revealed unilateral dominant occipitotemporal strokes. CAT scans of four previously reported cases with this same profile of associative agnosia were obtained. Dominant parahippocampal, fusiform and lingual gyri were the most extensively damaged cortical regions surveyed and were involved in all cases. Of white matter tracts surveyed, only temporal white matter including inferior longitudinal fasciculus was severely and universally involved. Splenium of the corpus callosum was frequently but not always involved. We conclude there is a form of associative visual agnosia with agnosia for objects and printed words but sparing face recognition which has a characteristic unilateral neuropathology. Damage or disconnection of dominant parahippocampal, fusiform and lingual gyri is the necessary and sufficient lesion.
Topics: Aged; Agnosia; Association Learning; Brain Damage, Chronic; Brain Mapping; Cerebral Cortex; Cerebrovascular Disorders; Dominance, Cerebral; Dyslexia, Acquired; Female; Hippocampus; Humans; Male; Mental Recall; Middle Aged; Neuropsychological Tests; Pattern Recognition, Visual; Tomography, X-Ray Computed
PubMed: 7805382
DOI: 10.1016/s0010-9452(13)80337-1 -
Psychiatria Danubina Jun 2010Neuropsychology includes both the psychiatric manifestations of neurological illness (primary brain-based disorders) and neurobiology of "idiopathic" psychiatric... (Review)
Review
Neuropsychology includes both the psychiatric manifestations of neurological illness (primary brain-based disorders) and neurobiology of "idiopathic" psychiatric disorders. Neurological primary brain disorders provoke broad spectrum of brain pathophysiology that cause deficit sin human behaviour, and the magnitude of neurobehavioral-related problems is a world wide health concern. Speech disorders of aphasic type, unilateral neglect, anosognosia (deficit disorders), delirium and mood disorders (productive disorders) in urgent neurology, first of all in acute phase of stroke are more frequent disorders then it verified in routine exam, not only in the developed and large neurological departments. Aphasia is common consequence of left hemispheric lesion and most common neuropsychological consequence of stroke, with prevalence of one third of all stroke patients in acute phase although exist reports on greater frequency. Unilateral neglect is a disorder that mostly effects the patient after the lesion of the right hemisphere, mostly caused by a cerebrovascular insult (infarct or haemorrhage affecting a large area - up to two thirds of the right hemisphere), and in general the left-side neglect is the most widespread neuropsychological deficit after the lesion of the right cerebral hemisphere. Reports on the incidence of visual neglect vary and they range from 13 to 85%. Anosognosia is on the second place as neuropsychological syndrome of stroke in right hemisphere, characterized by the denial of the motor, visual or cognitive deficit. This syndrome, defined as denial of hemiparesis or hemianopsia, is a common disorder verified in 17-28% of all patents with acute brain stoke. There are different reports on frequency of delirium in acute stroke, from 24 to 48%, and it is more frequent in hemorrhagic then ischemic stoke. Post stroke depression (PSD) is one of the more frequent consequences on the stroke, and the prevalence of PSD has ranged from 5 to 63% of patients in several cross-sectional studies, peaking three to six months after a stroke.
Topics: Agnosia; Aphasia; Awareness; Cerebral Infarction; Delirium; Denial, Psychological; Depressive Disorder; Dominance, Cerebral; Hemianopsia; Hemiplegia; Humans; Neurocognitive Disorders; Perceptual Disorders
PubMed: 20562762
DOI: No ID Found -
OTJR : Occupation, Participation and... Apr 2018Unilateral neglect (neglect) and anosognosia often co-occur post stroke. It is unknown whether anosognosia of neglect varies for different types of daily activities. The...
Unilateral neglect (neglect) and anosognosia often co-occur post stroke. It is unknown whether anosognosia of neglect varies for different types of daily activities. The objective is to examine the frequency of anosognosia of neglect for items on the Catherine Bergego Scale (CBS) and to determine the level of agreement between participant/assessor item ratings and total scores. Secondary analysis of data was carried out. We conducted descriptive analyses and interrater reliability analyses (Cohen's kappa) to determine the level of agreement between assessor and participant item ratings. A paired t test was conducted to compare assessor and participant total scores. The frequency of anosognosia among items varied (29.2%-83.3%) and Kappa statistics ranged from -0.07 (no agreement) to 0.23 (fair agreement) for item ratings. There was a significant difference- t(36) = 3.02, p ≤ .01)-between assessor ( M = 8.0, SD = 5.2) and participant-rated ( M = 5.3, SD = 4.5) total CBS scores. Anosognosia is prevalent among those with neglect. Findings highlight the importance of assessing for anosognosia.
Topics: Aged; Agnosia; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Neuropsychological Tests; Observer Variation; Perceptual Disorders; Prevalence; Psychometrics; Reproducibility of Results; Stroke
PubMed: 29251546
DOI: 10.1177/1539449217747586 -
The Tohoku Journal of Experimental... Aug 1990Visual information processing are realized by the posterior association cortex spreading in front of the striate and parastriate areas from which two major visual... (Review)
Review
Visual information processing are realized by the posterior association cortex spreading in front of the striate and parastriate areas from which two major visual association pathways arise. The dorsal or the occipito-parietal pathway which transmits the inputs from the peripheral as well as the central visual field to the parietal association cortex is responsible for the visuospatial analysis of the visual informations. The occipito-temporal or the ventral pathway originates only from the foveal vision area, and sends the visual inputs to the inferior temporal lobe which engages in visual pattern or whole gestalt recognition of the visual informations. In addition to this dichotomous disposition of the dorsal and the ventral visual association pathways in each cerebral hemisphere, there is another type of functional specialization which is hierarchical rather than dichotomous. In the left cerebral hemisphere, the collateral pathways arise from both dorsal and ventral main streams and engage in the process of reading, or the verbal mode of visual information processing.
Topics: Agnosia; Agraphia; Association; Brain Damage, Chronic; Corpus Callosum; Culture; Discrimination, Psychological; Dyslexia, Acquired; Functional Laterality; Humans; Japan; Language; Memory; Parietal Lobe; Pattern Recognition, Visual; Reading; Semantics; Temporal Lobe; Visual Pathways; Visual Perception
PubMed: 2082505
DOI: 10.1620/tjem.161.supplement_61 -
Brain : a Journal of Neurology Feb 2021Vestibular dysfunction, causing dizziness and imbalance, is a common yet poorly understood feature in patients with TBI. Damage to the inner ear, nerve, brainstem,...
Vestibular dysfunction, causing dizziness and imbalance, is a common yet poorly understood feature in patients with TBI. Damage to the inner ear, nerve, brainstem, cerebellum and cerebral hemispheres may all affect vestibular functioning, hence, a multi-level assessment-from reflex to perception-is required. In a previous report, postural instability was the commonest neurological feature in ambulating acute patients with TBI. During ward assessment, we also frequently observe a loss of vertigo sensation in patients with acute TBI, common inner ear conditions and a related vigorous vestibular-ocular reflex nystagmus, suggesting a 'vestibular agnosia'. Patients with vestibular agnosia were also more unbalanced; however, the link between vestibular agnosia and imbalance was confounded by the presence of inner ear conditions. We investigated the brain mechanisms of imbalance in acute TBI, its link with vestibular agnosia, and potential clinical impact, by prospective laboratory assessment of vestibular function, from reflex to perception, in patients with preserved peripheral vestibular function. Assessment included: vestibular reflex function, vestibular perception by participants' report of their passive yaw rotations in the dark, objective balance via posturography, subjective symptoms via questionnaires, and structural neuroimaging. We prospectively screened 918 acute admissions, assessed 146 and recruited 37. Compared to 37 matched controls, patients showed elevated vestibular-perceptual thresholds (patients 12.92°/s versus 3.87°/s) but normal vestibular-ocular reflex thresholds (patients 2.52°/s versus 1.78°/s). Patients with elevated vestibular-perceptual thresholds [3 standard deviations (SD) above controls' average], were designated as having vestibular agnosia, and displayed worse posturography than non-vestibular-agnosia patients, despite no difference in vestibular symptom scores. Only in patients with impaired postural control (3 SD above controls' mean), whole brain diffusion tensor voxel-wise analysis showed elevated mean diffusivity (and trend lower fractional anisotropy) in the inferior longitudinal fasciculus in the right temporal lobe that correlated with vestibular agnosia severity. Thus, impaired balance and vestibular agnosia are co-localized to the inferior longitudinal fasciculus in the right temporal lobe. Finally, a clinical audit showed a sevenfold reduction in clinician recognition of a common peripheral vestibular condition (benign paroxysmal positional vertigo) in acute patients with clinically apparent vestibular agnosia. That vestibular agnosia patients show worse balance, but without increased dizziness symptoms, explains why clinicians may miss treatable vestibular diagnoses in these patients. In conclusion, vestibular agnosia mediates imbalance in traumatic brain injury both directly via white matter tract damage in the right temporal lobe, and indirectly via reduced clinical recognition of common, treatable vestibular diagnoses.
Topics: Adolescent; Adult; Aged; Agnosia; Brain Injuries, Traumatic; Dizziness; Female; Humans; Male; Middle Aged; Postural Balance; Reflex, Righting; Vestibule, Labyrinth; White Matter; Young Adult
PubMed: 33367536
DOI: 10.1093/brain/awaa386 -
Proceedings. Biological Sciences May 1997Normal people rarely confuse the mirror image of an object with a real object so long as they realize they are looking into a mirror. We report a new neurological sign,...
Normal people rarely confuse the mirror image of an object with a real object so long as they realize they are looking into a mirror. We report a new neurological sign, 'mirror agnosia', following right parietal lesions in which this ability is severely compromised. We studied four right hemisphere stroke patients who had left visual field 'neglect'. i.e. they were indifferent to objects in their left visual field even though they were not blind. We then placed a vertical parasagittal mirror on each patients' right so that they could clearly see the reflection of objects placed in the (neglected) visual field. When shown a candy or pen on their left, the patients kept banging their hand into the mirror or groped behind it attempting to grab the reflection; they did not reach for the real object on the left, even though they were mentally quite lucid and knew they were looking into a mirror. Remarkably, all four patients kept complaining that the object was 'in the mirror', 'outside my reach' or 'behind the mirror'. Thus, even the patients' ability to make simple logical inferences about mirrors has been selectively warped to accommodate the strange new sensory world that they now inhabit. The finding may have implications for understanding how the brain creates representations of mirror reflections.
Topics: Aged; Aged, 80 and over; Agnosia; Cerebral Infarction; Humans; Male; Middle Aged; Visual Fields
PubMed: 9178535
DOI: 10.1098/rspb.1997.0091 -
Cortex; a Journal Devoted To the Study... Jan 2018An influential model of vision suggests the presence of two visual streams within the brain: a dorsal occipito-parietal stream which mediates action and a ventral...
An influential model of vision suggests the presence of two visual streams within the brain: a dorsal occipito-parietal stream which mediates action and a ventral occipito-temporal stream which mediates perception. One of the cornerstones of this model is DF, a patient with visual form agnosia following bilateral ventral stream lesions. Despite her inability to identify and distinguish visual stimuli, DF can still use visual information to control her hand actions towards these stimuli. These observations have been widely interpreted as demonstrating a double dissociation from optic ataxia, a condition observed after bilateral dorsal stream damage in which patients are unable to act towards objects that they can recognize. In Experiment 1, we investigated how patient DF performed on the classical diagnostic task for optic ataxia, reaching in central and peripheral vision. We replicated recent findings that DF is remarkably inaccurate when reaching to peripheral targets, but not when reaching in free vision. In addition we present new evidence that her peripheral reaching errors follow the optic ataxia pattern increasing with target eccentricity and being biased towards fixation. In Experiments 2 and 3, for the first time we examined DF's on-line control of reaching using a double-step paradigm in fixation-controlled and free-vision versions of the task. DF was impaired when performing fast on-line corrections on all conditions tested, similarly to optic ataxia patients. Our findings question the long-standing assumption that DF's dorsal visual stream is functionally intact and that her on-line visuomotor control is spared. In contrast, in addition to visual form agnosia, DF also has visuomotor symptoms of optic ataxia which are most likely explained by bilateral damage to the superior parietal-occipital cortex (SPOC). We thus conclude that patient DF can no longer be considered as an appropriate single-case model for testing the neural basis of perception and action dissociations.
Topics: Agnosia; Ataxia; Female; Humans; Middle Aged; Psychomotor Performance; Reaction Time; Visual Perception
PubMed: 28532578
DOI: 10.1016/j.cortex.2017.04.004 -
Philosophical Transactions of the Royal... Aug 1997A brain-damaged patient (D.F.) with visual form agnosia is described and discussed. D.F. has a profound inability to recognize objects, places and people, in large part...
A brain-damaged patient (D.F.) with visual form agnosia is described and discussed. D.F. has a profound inability to recognize objects, places and people, in large part because of her inability to make perceptual discriminations of size, shape or orientation, despite having good visual acuity. Yet she is able to perform skilled actions that depend on that very same size, shape and orientation information that is missing from her perceptual awareness. It is suggested that her intact vision can best be understood within the framework of a dual processing model, according to which there are two cortical processing streams operating on different coding principles, for perception and for action, respectively. These may be expected to have different degrees of dependence on top-down information. One possibility is that D.F.'s lack of explicit awareness of the visual cues that guide her behaviour may result from her having to rely on a processing system which is not knowledge-based in a broad sense. Conversely, it may be that the perceptual system can provide conscious awareness of its products in normal individuals by virtue of the fact that it does interact with a stored base of visual knowledge.
Topics: Adult; Agnosia; Carbon Monoxide Poisoning; Cognition; Female; Humans; Magnetic Resonance Imaging; Occipital Lobe; Pattern Recognition, Visual; Temporal Lobe; Tomography, Emission-Computed; Vision Disorders; Visual Perception
PubMed: 9304691
DOI: 10.1098/rstb.1997.0107 -
Indian Journal of Ophthalmology Dec 1972
Topics: Agnosia; Hemiplegia; Humans; Intracranial Arteriosclerosis; Male; Visual Perception
PubMed: 4671311
DOI: No ID Found