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PubMed2004

Auditory agnosia caused by a tectal germinoma.

The authors describe a patient with auditory agnosia caused by a tectal germinoma. Despite having normal audiometric tests, the patient failed to recognize words and musical characters. On head MRI, the inferior colliculi were infiltrated by tumor. Neuropsychological tests revealed severe impairment in recognition of environmental sounds and words, defective musical perception, and stop consonant-vowel discrimination. Inferior colliculus may play a role in the analysis of sound properties.

Acoustic Stimulation↗
PubMed2005

Gustatory agnosia.

OBJECTIVE: To report the assessment of a patient exhibiting gustatory agnosia. METHODS: Preoperative and postoperative neuropsychological, neuroimaging, and chemosensory evaluations were performed in a 39-year-old woman undergoing surgical treatment for intractable epilepsy. RESULTS: Preoperative MRIs showed bilateral (right > left) atrophy in the medial temporal lobes and complete atrophy of the left insula. Evaluation of gustatory function revealed normal suprathreshold intensity estimation, affective evaluation, and detection thresholds but elevated recognition thresholds. A functional neuroimaging study showed activation to stimulation of aversive taste in the left amygdala. Surgical treatment entailed resection from the left medial temporal lobe that included the region of amygdala that had responded to taste. Postoperatively, detection, naming, and intensity estimation for taste remained normal, but the patient was unable to recognize different tastes (sweet, sour, salty, and bitter). A second evaluation 2.5 years after her surgery revealed no change in taste ability. CONCLUSION: The anteromedial temporal lobe has an important role in recognizing taste quality.

Adult↗
PubMed2001

Agnosia for familiar faces and odors in a patient with right temporal lobe dysfunction.

The authors studied a 53-year-old man with progressive prosopagnosia and inability to recognize his favorite foods by smell. He could not identify pictures of familiar faces, but he could match unfamiliar faces and distinguish them from familiar ones. He could not identify familiar odors, but he could detect them and could perceive them as pleasant or familiar. Neuroimaging revealed temporal lobe changes, especially on the right. Right temporal lesions may produce face and odor agnosia by preventing perceptual familiarity units from accessing semantic associations.

Agnosia↗
PubMed1980

Middle components of the auditory evoked response in bilateral temporal lobe lesions. Report on a patient with auditory agnosia.

An investigation of the middle components of the auditory evoked response (10--50 msec post-stimulus) in a patient with auditory agnosia is reported. Bilateral temporal lobe infarctions were proved by means of brain scintigraphy, CAT scanning, and regional cerebral blood flow measurements. The middle components were found to be normal regarding latency (pa approximately 30 msec) and configuration of the recordings, when evaluated relative to the peripheral hearing loss in the patient and to the corresponding normative template. Based upon the combined procedures, it is concluded that the middle components cannot be generated exclusively, if at all, in the primary auditory cortex, located in the temporal lobe. Furthermore, the responses are found to be of neurogenic origin according to the methodological procedure applied.

Aged↗
PubMed1976

[A case of visual agnosia for objects (author's transl)].

Following an ischemic accident in the territory of the left posterior cerebral artery, a 71 year-old woman had a severe disorder of visual recognition of objects while she quickly identified them by touch. Visual recognition of pictures, written symbols, colours and, to a lesser degree, faces was also impaired. A careful examination showed that the patient's defect could not be accounted for by general intellectual impairment, language disorder, visual acuity, or pattern discrimination deficit. These findings are consistent with the classical concept of associative agnosia: the pathophysiology of the syndrome is discussed.

Aged↗
PubMedDate not supplied

Superior single dimension relative to "exclusive or" categorization performance by a patient with category-specific visual agnosia: empirical data and an ALCOVE simulation.

ELM, a patient with category-specific visual agnosia, was tested on a single-dimension categorization problem, and the "exclusive or" (XOR) categorization problem. Stimuli were computer-generated shapes in which exemplars within a shape set shared values across two visual dimensions (curvature and thickness). In single-dimension categorization only curvature was relevant, and ELM performed as well as normal participants. In the XOR problem, categorization depended on being able to extract from memory values on curvature AND thickness for each exemplar, and ELM was significantly impaired on this task. A computer simulation using ALCOVE (Kruschke, 1992) reproduced ELM's behavior by changing a single (specificity) parameter related to how easily proximate objects within a multidimensional shape space could be disambiguated.

Agnosia↗
PubMedDate not supplied

Musical instrument naming impairments: the crucial exception to the living/nonliving dichotomy in category-specific agnosia.

In category-specific agnosia (CSA) patients typically have more trouble naming animals, fruits, and vegetables than tools, furniture, and articles of clothing. A crucial exception to this living vs nonliving rule involves the category of musical instruments. Patients with problems naming living objects often repeatedly fail to name musical instruments. In CSA it is crucial to equate living and nonliving object lists on object name frequency, complexity, and familiarity. The present study shows, however, that even the most rigorously controlled object lists can lead to erroneous conclusions if nonliving stimuli contain an overrepresentation of musical instruments. Naming capabilities of a herpes encephalitis patient were assessed using matched lists of living and nonliving objects and showed no indication of category-specific deficits. When exemplars were separated into biological objects, musical instruments and man-made artifacts, strong category-specificity emerged: artifact naming was flawless whereas musical instrument and biological object naming were both severely impaired. It is concluded that CSA is a veridical phenomenon but that our understanding of CSA is limited by adhering to the spurious living/nonliving distinction.

Agnosia↗
PubMed2000

[Auditory and verbal agnosia in the left-handed patient: comparison of neuropsychological data, magnetic resonance and positron emission tomography].

A case of the post-traumatic auditory-and-speech agnosia in a left-handed female patient is presented. The patient (a professional painter) showed satisfactory recovery in painting, speech production, reading and writing, whereas a severe deficit in auditory recognition of speech, melodies and rhythms persisted over time. She was also impaired in some aspects of visual recognition including prosopagnosia. To study this patient comprehensively, a neuropsychological assessment was combined with structural (magnetic resonance imaging-MRI) and metabolic (positron emission tomography--PET) data. Both PET and MRI revealed a large bilateral cortical damage in the medial basal cortex of the frontal, temporal and occipital lobes along with the anterior half of the lateral temporal cortex. In the left hemisphere the damaged area involved the whole temporal lobe, a large part of the occipital lobe and the opercular frontal and parietal regions. The relationship of the symptoms with the brain damage extension is discussed taking into account the left-handedness of the patient.

Adult↗
PubMedDate not supplied

Visual object agnosia as a problem in integrating parts and part relations.

Current models of vision generally assume that the recognition of visual objects is achieved by encoding their component parts, as well as the spatial relations among parts. The current study examined how the processing of parts and their configurations may be affected in visual agnosia due to brain damage. Both a visual agnosic patient (AR) and healthy control subjects performed a visual search task in which they had to discriminate between targets and distractors that varied according to whether they shared their parts and/or their configuration. The results show that AR's visual search rates are disproportionally slow when targets and distractors share the same configuration than when they have different configurations. AR is also found to be disproportionately slow in discriminating targets and distractors that share identical parts when the targets and distractors share the same configuration. With differently configured targets and distractors, AR shows no part sharing effect. For controls, in contrast, the part and configuration sharing effects occur independently of one another. It is concluded that AR's object recognition deficit arises from difficulties in discriminating objects that share their configuration, and from an abnormal dependency of part information processing upon object configuration.

Adult↗
PubMedDate not supplied

[Posttraumatic visual agnosia and epilepsy as a consequence of gunshot injury to the head. Case report].

Half million people in the world, each year have a gunshot injury to the head and eighty thousand of them are hospitalized. Gunshot injuries to the head have became in Poland second most frequent cause of death from head trauma, and in some countries during peace became the most frequent cause of death among patient with head injury. Glasgow Coma Scale (GCS) is a useful prognostic factor for patients with gunshot injury to the head. Injury to the eloquent regions of the brain, commotion and contusion of the brain, intracranial hematomas, subarachnoid hemorrhage, cerebro-vascular spasm, injuries to the major vessels, liquorrhea, infections, coagulopathies and epilepsy are the most important and influential factors in the clinical status of the patient with gunshot injury to the head. The operation is the preferred treatment to all patient, no matter of their clinical status at the moment of the admission. The report presents the history of treatment of a patient with gunshot injury to the head. During the treatment extremely infrequently occurring posttraumatic visual agnosia and posttraumatic epilepsy were observed. Twenty-two months after operation the patient is independent and professionally active.

Adult↗
PubMed1975

[Audiological observations of a patient with auditory agnosia].

A case is reported in which a patient was become unable to identify all kinds of auditory material, including speech, despite only subnormal audiometric thresholds (i.e. "auditory agnosia"). The following audiological disorders were shown: some fragility in the perception of brief sound stimuli, difficulties to apprehending prolonged series of stimuli (rhythms), defective sound localization, an increase in the homolateral and in the contralateral effects of masking sounds. On the other hand, differential thresholds for frequency and for intensity, as well as fusion thresholds, were little affected, or unaffected. A complete dissociation appeared between the auditory evoked potentials and the audiometric thresholds; a year after the first examination, and the following years, the auditory potentials were largely reduced, or even have elapsed for one ear, while the audiometric thresholds seem to remain nearly the same.

Agnosia↗
PubMed1990

[Approaches to therapy of auditory agnosia].

In a 41-year-old stroke patient with bitemporal brain damage, we found severe signs of auditory agnosia 6 months after onset. Recognition of environmental sounds was extremely impaired when tested in a multiple choice sound-picture matching task, whereas auditory discrimination between sounds and picture identifications by written names was almost undisturbed. In a therapy experiment, we tried to enhance sound recognition via semantic categorization and association, imitation of sound and analysis of auditory features, respectively. The stimulation of conscious auditory analysis proved to be increasingly effective over a 4-week period of therapy. We were able to show that the patient's improvement was not only a simple effect of practicing, but it was stable and carried over to nontrained items.

Adult↗
PubMed1978

[Drawings by patients with unilateral visuospatial agnosia].

Drawings made by 25 patients with neurosurgical diseases causing focal lesions in the posterior areas of the right, not dominant cerebral hemisphere due to expanding changes. Experimental clinical investigations by the method of Luria demonstrated in these cases presence of left-sided visuospatial agnosia. The material was analysed from the point of view of the features of drawings characteristic for the syndrome of disturbances and the localizatory and diagnostic value of drawings. Characteristic disturbances of drawings and their placement were observed suggesting that the patients ignored the left half of the visual space due to damage to the right parieto-occipital non-dominant cerebral hemisphere. The drawing test is regarded as a valuable method for the diagnosis and localization of lesions in the neurological and neuropsychological practice.

Agnosia↗
PubMedDate not supplied

A case of isolated partial auditory agnosia associated with coiling of the left internal carotid artery.

A 64-year-old bilingual lawyer complained of an abrupt loss of comprehension of spoken words and much less severe loss of recognition of various sounds. An isolated partial auditory agnosia, due to a left-sided, temporal dysfunction was confirmed by the clinical neuropsychological and logopedic examination. Only a minimal left cortical, peri-insular hypodensity was suspected on CT-scan of the brain, while the NMR-scan was inconclusive. Arteriography showed a large coiling internal carotid artery on the left side, as a possible source of thrombo-embolism.

Agnosia↗
PubMed1979

Common dimensions of visual and auditory agnosia and an explanation of the auditory recognition deficit in aphasia.

An experimental analysis of auditory recognition disturbances was performed; 81 patients with localized cerebral lesions were examined with a recognition test for meaningful sounds and with a nonverbal intelligence test (Block Design). Sensory stimulation was 5 or 15 sec for each sound. Nonverbal intelligence accounted for a considerable and significant amount of variance in recognition performance. The aphasic group was more impaired in auditory recognition than were both the other groups, i.e., patients with right or left hemispheric lesions without aphasia. The auditory recognition disturbance in the aphasic group depended to a significant extent on stimulus duration, which means a slowing down of the recognition process in aphasia. The analogies to studies on visual agnosia are striking. In both modalities, recognition depends on intellectual functioning, sensory disturbances or reduced sensory input, and the presence of aphasia.

Adult↗
PubMed1980

[Visual agnosia without right hemianopia in a right-handed patient (author's transl)].

A right-handed 77-year-old man presented with a left homonymous lateral hemianopsia involving the macula. Consciousness, memory, and oral language were normal, but the patient experienced great difficulties in identifying objects and images by sight, even though he recognized their geometrical shapes. He also had prosopagnosia, and alexia without agraphia but no agnosia for colours. The patient died suddenly 6 weeks after the onset of the disorders. Pathological examination demonstrated the presence of a bilateral occipital infarct involving on the right, the inferior border of the calcarine fissure, and the lingual and fusiform gyri, and on the left the fusiform gyrus. This supports the role in man of the inferior occipitotemporal convolutions in the perceptual integration of visual informations, and suggests that this region of the cortex is analogous with the inferotemporal cortex of monkeys which has been shown to be a determinant for the elaboration of visual objects.

Aged↗
PubMed1995

[Posterior cortical atrophy with progressive visual agnosia].

Interest in progressive focal cerebral syndromes associated with classical degenerative diseases has increased in recent years. Descriptions of posterior cortical atrophy with progressive visual agnosia are relatively rare. We present 5 patients (2 women) ranging in age between 57 and 72 years old. In all cases symptoms began and progressed with no known etiology. All cases were sporadic. The main clinical signs are difficulty in recognizing objects, colors, persons or places; topographical disorientation and visual memory alterations; alexia, simultagnosia, loss of ocular fixing and optic ataxia. Some patients presented other disturbances of praxis or memory and 2 progressed to global dementia. Language function was preserved and behavioral disturbances did not develop. The amplitude of the P100 visual evoked potential was low but latency was normal in 4 patients and prolonged in 1. Brain images showed atrophy and hypoperfusion in the parieto-occipital area. The neuropathology status of these patients is unknown.

Adult↗
PubMed1977

Pure word deafness. (Auditory verbal agnosia).

The selective inability to comprehend the spoken word, in the absence of aphasia or defective or defective hearing, is defined as pure word deafness (auditory verbal agnosia). Reported cases of this rare disorder have suggested the site of involvement to be strategically placed, interrupting fibers from left and right primary auditory receptive areas which project to Wernicke's are in the dominant hemisphere. Our patient is a 44-year-old male who suffered from an uncertain illness complicated by fever, jaundice and generalized seizures seven years previously. Following an apparent convulsion, the patient was noted to be unable to understand spoken language without loss of ability to recognize and respond to sounds or marked impairment of speech or reading. The evidence suggested bilateral cerebral hemisphere disease more marked on the right. The abrupt onset without progression is consistent with a vascular or ischemic etiology. Conclusions about the nature of the lesion and areas involved must await further studies and ultimately tissue examination.

Adult↗