Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AGNOSIA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1991

A historic case of visual agnosia revisited after 40 years.

In one of the seminal works on visual agnosia, Adler (1944, 1950) presented the case of a 22-yr-old woman who sustained carbon monoxide cerebral toxicity in the Cocoanut Grove nightclub diaster of 1942. We located this patient 40 yrs after injury and performed a detailed reevaluation. The patient demonstrated persistent deficits in visual recognition, characterized most prominently by defective recognition of elemental shape and form, associated with alexia, prosopagnosia, visuospatial disorientation and impaired visual imagery. Visual acuity, colour recognition, writing ability and verbal intelligence were relatively preserved. Isolated bilateral occipital injury was demonstrated by CT and MRI scanning. On comparison with previously reported cases, our results support the hypothesis that carbon monoxide toxicity can induce a visual agnosia of the apperceptive type with well defined characteristics, seldom seen with other types of cerebral injury. Prognosis for long-term recovery is poor.

Accidents↗
PubMed1995

Knowledge, implicit knowledge and metaknowledge in visual agnosia and pure alexia.

Residual or implicit knowledge has been observed in patients with object agnosia, optic aphasia and pure alexia. Previous investigators have considered implicit knowledge in these patients to be dissociated from awareness on the basis of intact semantic capabilities that are consistent with right hemisphere processing. The absence of explicit verbal identification is presumably dependent upon damaged left hemisphere systems. We describe a 72-year-old woman with a left occipital infarction, object agnosia and pure alexia who was unable to explicitly identify visual stimuli (objects and words), but was able to make reliable judgements of her residual knowledge on forced-choice matching tasks. While the patient could not consistently demonstrate awareness of knowledge prior to stimulus matching ('Do you know what this is?'), she was able to reliably demonstrate awareness of knowledge for response accuracy ('Are you sure?') assessed after stimulus matching. Further, the extent of the patient's metaknowledge corresponded to her degree of preserved knowledge. We propose that this pattern of performance suggests limited or partial access to preserved semantic knowledge which, though degraded, is not 'non-conscious'.

Aged↗
PubMed1996

Tactile agnosia. Underlying impairment and implications for normal tactile object recognition.

In a series of experimental investigations of a subject with a unilateral impairment of tactile object recognition without impaired tactile sensation, several issues were addressed. First, is tactile agnosia secondary to a general impairment of spatial cognition? On tests of spatial ability, including those directed at the same spatial integration process assumed to be taxed by tactile object recognition, the subject performed well, implying a more specific impairment of high level, modality specific tactile perception. Secondly, within the realm of high level tactile perception, is there a distinction between the ability to derive shape ('what') and spatial ('where') information? Our testing showed an impairment confined to shape perception. Thirdly, what aspects of shape perception are impaired in tactile agnosia? Our results indicate that despite accurate encoding of metric length and normal manual exploration strategies, the ability tactually to perceive objects with the impaired hand, deteriorated as the complexity of shape increased. In addition, asymmetrical performance was not found for other body surfaces (e.g. her feet). Our results suggest that tactile shape perception can be disrupted independent of general spatial ability, tactile spatial ability, manual shape exploration, or even the precise perception of metric length in the tactile modality.

Agnosia↗
PubMed2006

Finger agnosia in Alzheimer disease.

BACKGROUND AND OBJECTIVE: The purpose of this study was to learn if a deficit of finger naming (finger agnosia or anomia) is a sensitive test for Alzheimer disease (AD) and the best means of testing for finger agnosia. METHODS: The subjects were 38 patients with AD and 10 matched normal controls. All subjects were asked to name the thumb, index, and pinky fingers. RESULTS: No control subject had trouble naming any of these fingers, but 37% of the AD subjects did. When AD patients had difficulty with finger naming, they always had trouble naming the index finger. CONCLUSIONS: In the absence of stroke, the inability to name the index finger seems as an indicator of dementia. Although brief, this test is not extremely sensitive test for AD.

Agnosia↗
PubMed1980

Prosopo-affective agnosia and computerized tomography findings in patients with cerebral disorders.

Thirty-nine male patients (median age 61, range 19-92) from a neurologic ward were examined by a test for prosopo-affective agnosia (PAA), i.e., impairment in the recognition of facial affect (emotions) with no impairment in the recognition of facial features (PA, prosopo-agnosia). The scores for patients without hemispheric damage were close to those of normal subjects; the scores for patients with right and left hemispheric disease were lower; and the worst performers were patients with diffuse bilateral disease. The relative independence of PAA from PA was re-affirmed. The neurologic findings on 21 patients were confirmed by computerized tomography (CT). On the PAA test, patients with negative CT results had scores close to those of normal subjects; patients with right or left hemispheric disease had lower scores; and the worst performers were patients with diffuse cortical atrophy. All patients who scored 87.5 percent or lower showed positive results with the CT scan, indicating that the PAA test may have some value in predicting positive CT findings. A significant deterioration in the ability to recognize facial affect was evident in the group of 15 patients aged 65 or older.

Adult↗
PubMed1992

"Numb, clumsy hands" and tactile agnosia secondary to high cervical spondylotic myelopathy: a clinical and electrophysiological correlation.

Four patients presented with a distinctive syndrome of "numb, clumsy hand" and tactile agnosia. Myelography and computed tomographic myelography (CTM) of the cervical spine documented major spondylotic compressive lesions mainly between the C3 and C5 levels. The cortical responses of dermatomal somatosensory evoked potentials (DSEPs) revealed progressively prolonged peak latencies and progressively decreased amplitudes of early components from C6 to C8 dermatomal stimulation. In comparison, the C5 and L2 DSEPs were affected to a lesser extent. This finding suggests that high cervical cord compression may produce dysfunction of the dorsal column caudal to the direct compressive sites. In other words, the funiculus cuneatus of C6-8 cord is most affected in high cervical myelopathy. Moreover, the funiculus cuneatus is within the border zone susceptible to an overall reduction in blood flow. We conclude therefore, that ischemia secondary to cord compression is the pathophysiology resulting in this unique syndrome of "numb, clumsy hands" and tactile agnosia.

Aged↗
PubMed1986

Pantomime agnosia.

Visual agnosia is impaired visual recognition not explained by defective visual acuity, visual fields, attention, or general mental ability. Two nonapraxic patients with lesions in the left occipital lobe could imitate pantomimes they could not recognise. Although both patients had a hemianopia, sparing of gesture imitation shows that no visual defect accounts for their inability to recognise pantomimes. Both patients were amnestic and alexic but had no general impairment of cognitive ability to account for a pantomime-recognition disorder. These patients seem to have agnosia for pantomime. From the computed tomograms from these patients, we propose that inferior visual association cortex is critical for gesture comprehension, whereas superior portions of these structures are critical for imitating or performing pantomime to an object presented visually.

Aged↗
PubMed1994

Capgras syndrome: agnosia of identification and delusion of reduplication.

In the Capgras syndrome (CS) there is a natural dissociation between recognition and identification and it deserves to be designated as an agnosia of identification. Joseph Capgras who first introduced this concept of agnosia, also suggested that the syndrome might be studied within the framework of 'méconnaissance systématique' (translated here as systématic unawareness), thus anticipating a type of interpretation in which the basis of CS (and other delusional misidentification syndromes) would be a lack of corporeal and/or egocentric space awareness. From two examples, it is suggested that the basic phenomenon of unawareness may be due to sensory deprivation. A particular process of awareness concerning personal objects is hypothesized which would explain the specific delusion of reduplication that occurs when these objects are misidentified.

Agnosia↗
PubMed1979

The anatomic basis of visual agnosia.

In a patient with associative visual agnosia without alexia, there was bilateral infarction in the distribution of the posterior cerebral arteries, with corticosubcortical lesions in both occipitotemporal regions, sparing the corpus callosum. Bilateral loss of visual-limbic connections may underlie associative visual agnosia, and bilateral lesions of the inferior longitudinal fasciculi may be the necessary and sufficient lesions for this syndrome. Alexia was absent in this case, perhaps because the corpus callosum was intact.

Agnosia↗
PubMed1984

Visual agnosia without alexia.

A 41-year-old man presented with bilateral posterior cerebral artery infarcts. He had visual object agnosia and prosopagnosia with preservation of reading abilities. There was also defective visual memory, topographic orientation, and color perception, as well as simultanagnosia. From the clinical facts and CT findings, it was postulated that bilateral visual-limbic disconnection accounted for the patient's visual agnosia and related disturbances.

Adult↗
PubMed1986

Multimodal agnosia after unilateral left hemisphere lesion.

Agnosia is an abnormality of recognition that is not explained by sensory or cognitive disorders. We studied a patient who had combined visual-tactile agnosia without prosopagnosia after a left hemisphere infarct. Although he copied figures presented visually and he performed intramodal or crossmodal visual-tactile matches, he could not indicate recognition by either sight or touch. The lesion involved areas of the occipital and temporal lobes that may be important for human performance of tasks that require construction and application of meaning to percepts presented both visually and tactually.

Agnosia↗
PubMed1998

A case of verbal auditory agnosia: missing the word ... missing the sound....

The neuropsychological nature of verbal auditory agnosia is not fully understood. This study aims to describe the language deficits and the remediation strategies used in a person with verbal auditory agnosia. In addition, it will address the theoretical issues concerning the nature of the phenomenon and the clinical implications in the management of people with this disorder.

Aged↗
PubMed2000

[A case of agnosia for streets and houses unaccompanied by prosopagnosia of familiar faces due to the right occipital lobe infarction].

We reported a patient who showed agnosia for streets and homes unaccompanied by prosopagnosia of familiar faces following infarction in the right occipital lobe. A 70-years-old right-handed man admitted to our department because of sudden development of visual impairment. He had left hemianopsia, left unilateral spatial neglect and slight visual memory disturbance but no other neurological abnormalities. His verbal memory was maintained intact. He was, however, unable to distinguish the sceneries of buildings and streets regardless of their familiarities and often got lost in the hospital. His topographical abilities in map-sketching and route-description were partially impaired depending upon the familiarity of targets; the disability was observed toward unfamiliar targets. His ability in facial recognition was also partially impaired depending upon the familiarity of persons. The patient was unable to distinguish faces of unfamiliar persons, such as nurses and doctors whom he met following stroke, whereas he was able to distinguish faces of familiar persons, such as his family and friends. The brain MRI demonstrated infarction in the right medial occipital lobe including parahippocampal gyrus, lingual gyrus and fusiform gyrus. In general, the manifestation of agnosia for streets and houses is associated with prosopagnosia. The present case, however, exhibited only the former in association with the partial manifestation of the latter. The fact suggests that those two are independent syndromes. The present case also showed a dissociation in the abilities of topographical and facial recognition according to the familiarity of targets. The process for the retrieval and reference of acquired information and that for the acquirement of new visual information may work in an independent manner.

Aged↗
PubMed1975

[Eye movement disorders in visual agnosia].

By the aid of photooptical methods the authors studied eye movements in 6 patients with disorders of visual gnosis due to focal lesions in the occipitallbrain lobes. The examination included studies of a fixation of immovable objects, a tracing of linear and pendulum moving objects and a voluntary change of points of fixation in space. It was demonstrated that expressed symptoms of agnosia are accompanied by defects in the organization of all forms of opticomotor activity. The authors discuss problems of the pathogenesis of oculomotor disorders in optical agnosia.

Agnosia↗
PubMed2002

[A case of slowly progressive aphasia accompanied with auditory agnosia].

A 68-year-old right-handed woman was admitted to our hospital because of difficulty to speak and understand conversation over 10 years. She was able to make herself by writing. No change in her personality or behavioral abnormality was observed so that she could live without help. Although her WAIS score and auditory brain stem response were normal, she could not understand the speech or distinguish the sound. She also spoke plenty of words fluently, resulting in undifferentiated jargon. She did not make any effort in speaking. Her speech was, however, unclear and hard to understand. Brain MRI scan disclosed a moderate atrophy of bilateral temporal lobe and enlargement of Sylvius fissure. A three-dimension reconstructed brain surface image showed enlargement of the perisylvian fissure, and atrophy of the gyrus frontalis inferior, operculum, gyrus temporal superior, bilaterally. Reduced cerebral blood flow was demonstrated on 99mTc-ECD SPECT in the left thalamus and bilateral fronto-temporal lobe. A diagnosis of slowly progressive aphasia with auditory agnosia was made. Our case suggests that bilateral disturbance of neuronal network between the primary auditory area and the secondary auditory area is responsible to the consequence of auditory agnosia.

Aged↗
PubMed1992

[Non-verbal auditory agnosia with EEG abnormalities and epilepsy; an unusual case of Landau-Kleffner syndrome].

A case of unusual Landau-Kleffner syndrome was reported. She was an 8 year-old girl and showed non-verbal agnosia, diffuse EEG abnormalities and convulsions. Her responses to both verbal and non-verbal sounds remained inconsistent and unstable. When a continuous spike-wave complexes on EEG was detected, she paid no attention to any sound in spite of her fair consciousness. Auditory brainstem response and magnetic resonance imaging of her brain were normal. Auditory agnosia was correlated well with EEG abnormalities, and valproic acid and clonazepam were effective for EEG improvement. After the EEG improvement, clinical responses to sounds recovered well; firstly she could pay attention to sounds and then she could distinguish between verbal and non-verbal sounds. Finally, she could speak a few words after the learning letters.

Agnosia↗
PubMed2003

[A case of agnosia for streets without visual memory disturbance].

A 70-year-old, right-handed man was admitted to our hospital for his sudden-onset topographical disorientation. He failed to find his way to familiar places, but he knew distance and direction to the places. Neurological examination revealed homonymous left-upper quadrantanopsia on Goldmann perimeter and hypoesthesia over the left side of his body. Magnetic resonance imaging showed an abnormal intensity area at the right medial temporo-occipital region, due to the infarct of the right posterior cerebral arterial territory. The neuropsychological examination revealed agnosia for streets, and prosopagnosia without any other disturbance of visual perception. Both visual and topographical memories were intact. It is suggested that, in this case, the agnosia for streets was caused by impairment of recognizing familiar streets and houses or disconnection between their recognition and memory.

Aged↗
PubMed1991

[Right unilateral auditory agnosia following left lenticular hemorrhage].

A 33-year old patient who had had left lenticular hemorrhage presented with an inability to understand with the right ear oral language and, in a less dramatic way, nonverbal sounds. This unilateral auditory agnosia was first associated with a right motor underutilization and right motor, sensitive, visual and auditive extinctions. Speech discrimination scores were 100% with the left ear and 15% with the right ear, even less in dichotic conditions. Tonal audiogram, as well as early and late components of the auditory evoked potentials were normal. Cerebral regional perfusion and metabolism were impaired over the left parietotemporal area. There was severe hypoactivation of the left hemisphere with right monaural verbal stimulations. Rehabilitation consisting of non-specific attention tasks and repetitions of words reaching only the right ear was undertaken 15 months after the stroke. The oral language comprehension improved, as did the left hemisphere activation, and the extinction phenomena disappeared, except for the auditory one. The unilaterality of the auditory agnosia could be due, in part, to a peculiar physiological processing in this patient, such as poor performance of his right ipsilateral auditory pathway which could be improved with practice. A striatal lesion could induce a spatial hemi-inattention as reflected by the multimodal extinction in this case. Besides, a lack of selective activation for verbal stimulation of the left hemisphere is suggested.

Adult↗