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Biomedical subjects

H Damasio

Publications and source records attributed to H Damasio.

At least 73 records · Page 4Linked to original sources
PubMed1988

Intact recognition of facial expression, gender, and age in patients with impaired recognition of face identity.

We conducted a series of experiments to assess the ability to recognize the meaning of facial expressions, gender, and age in four patients with severe impairments of the recognition of facial identity. In three patients the recognition of face identity could be dissociated from that of facial expression, age, and gender. In one, all forms of face recognition were impaired. Thus, a given lesion may preclude one type of recognition but not another. We conclude that (1) the cognitive demands posed by different forms of recognition are met at different processing levels, and (2) different levels depend on different neural substrates.

Adult↗
PubMed1987

Global aphasia without hemiparesis.

Three patients acutely developed global aphasia, but did not manifest the typical accompanying right hemiparesis. Computed tomography and magnetic resonance imaging studies demonstrated that the patients had two discrete left hemisphere lesions, one in the anterior language cortices or language-related subcortical areas, and one in the posterior language cortices. Cerebral angiography showed that two patients had complete occlusion of the left internal carotid artery, and the third had an intraluminal "clot" in the supraclinoid portion of the left internal carotid, findings suggestive of an embolic etiology. Our cases indicate that global aphasia without hemiparesis predicts two discrete lesions and a particularly good recovery of speech and language.

Adult↗
PubMed1987

Dissociable visual and spatial impairments following right posterior cerebral lesions: clinical, neuropsychological and anatomical evidence.

A double dissociation of visual and spatial performance is reported in two men with chronic focal missile injuries of the right cerebral hemisphere. The clinical, neuropsychological and post-mortem anatomical data are considered in relation to evidence from physiological research of two major cortico-cortical pathways for object-recognition and spatial perception.

Brain Mapping↗
PubMed1987

A left hemisphere contribution to visuospatial processing.

Men with chronic, focal, unilateral missile injures of the brain--twenty-five with left hemisphere lesions (LH group) and twenty with right hemisphere lesions (RH groups)--and twenty-two control subjects were given two visuoperceptual and two visuospatial tests. The LH group was significantly impaired in relation to the control group on both the spatial tasks. A different pattern of dissociable perceptual and spatial deficits was found in the experimental groups: better preserved perceptual than spatial performance was observed more frequently in the LH group whereas the converse--relatively better spatial than perceptual performance--was more evident in the RH group. Double dissociations in performance on the two spatial tasks were found predominantly in the LH group. These findings suggest an important left hemisphere contribution to visuospatial processing and the possibility of a more focal representation of spatial abilities in the left hemisphere than in the right.

Aged↗
PubMed1987

Locus of lesion in impaired pantomime recognition.

This study was concerned with the relationship between intrahemispheric locus of lesion and defective pantomime recognition in a population of left hemisphere damaged aphasics. Defects in pantomime recognition appeared to result from lesions in basal ganglia and areas 40, 39, 37 and 22. At the same time, however, a significant minority of aphasics with lesions in these various loci did not show defects in pantomime recognition.

Adult↗
PubMed1987

Regional cerebral blood flow in normal pressure hydrocephalus.

Regional cerebral blood flow (rcbf) was studied preoperatively and at 2 and 6 months postoperatively in 22 normal pressure hydrocephalus patients using xenon-133 inhalation and single photon emission computed tomography. Sixteen of the 22 patients improved (improved group) and six did not (unimproved group). The following comparisons were made: (1) preoperative rcbf in the improved group, to 14 normal elderly volunteers and to that in 59 SDAT (senile dementia of the Alzheimer type) patients; (2) preoperative rcbf in the improved and unimproved groups to determine if rcbf could predict surgical outcome; (3) pre- to postoperative rcbf in the improved group to see if increased cbf accounted for clinical improvement. The findings were: (1) preoperative rcbf in the improved group was lower than that in normal controls but was the same as that in SDAT; however, the ratios of rcbf values in anterior and posterior brain regions were significantly different between improved group and SDAT (p = 0.02); (2) an anterior/posterior ratio of 1.05 correctly classified surgical outcome in 19/22 patients; five of six in the unimproved group were above this cut off while 14/16 in the improved group were below; (3) in the improved group rcbf increased at 2 but not at 6 months after surgery without a corresponding reduction of clinical signs, supporting the notion that increase in cbf probably does not account for clinical improvement in normal pressure hydrocephalus.

Alzheimer Disease↗
PubMed1986

CT scan correlates of sound recognition defect in aphasia.

This study was concerned with the relationship between defects in sound recognition and intrahemispheric locus of lesion. Previous studies have shown that defects in sound recognition are common in association with left hemisphere lesions resulting in aphasias with comprehension deficits and are uncommon in association with other unilateral lesions. Current findings indicate that defects in sound recognition, occurring within the first month post onset of aphasia, may be associated with lesions of basal ganglia, the auditory cortex (both primary and association cortices), supramarginal gyrus, angular gyrus, and area 37. At the same time, however, a number of patients with lesions in these areas failed to show sound recognition defects.

Adult↗
PubMed1985

Multimodal amnesic syndrome following bilateral temporal and basal forebrain damage.

A 55-year-old right-handed man (patient DRB) had a major amnesic syndrome following extensive bilateral damage to the temporal lobe and basal forebrain, caused by herpes simplex encephalitis. His amnesia was both anterograde and retrograde. The retrograde amnesia spanned the five decades of his life, sparing only generic (semantic) material and shreds of previous experiences devoid of appropriate temporal and spatial placement. The anterograde amnesia encompassed both generic (semantic) and contextual (episodic) material. With the exception of preserved learning of a visuomotor skill, the patient did not show acquisition of any new information since his illness in 1975. Elementary perceptual, intellectual, and linguistic abilities remained intact. Because several anatomic and behavioral characteristics of this case are different from those of previously reported cases of amnesia, they may provide new insight into the neuroanatomic substrate of human memory.

Amnesia↗
PubMed1985

Amnesia following basal forebrain lesions.

Of five patients with damage to the basal forebrain, four had lesions secondary to rupture of anterior cerebral or anterior communicating artery aneurysms, and one to the resection of an arteriovenous malformation. Computed tomographic scans and intraoperative reports confirmed damage to basal forebrain regions, which include septal nuclei, nucleus accumbens, substantia innominata, and related pathways. Behavioral disturbances featured a prominent amnesic syndrome and personality changes. The amnesia was distinguishable from that reported in patients HM and DRB and shared features with that seen in patients with Korsakoff's syndrome. We propose that the memory disorder can be explained by malfunctioning in the hippocampal system, secondary to damage in the basal forebrain structures with which it is strongly interconnected. The dysfunction might, in part, be caused by reduction of specific neurotransmitter innervation because the lesions are likely to damage cholinergic neurons and nearby catecholamine pathways within the basal forebrain.

Adult↗
PubMed1985

Computed tomographic and postmortem study of a nonhemorrhagic thalamic infarction.

A 70-year-old man had a stroke and became unconscious. High-resolution computed tomography (CT) with 5-mm cuts disclosed bilateral thalamic infarctions, larger on the left than the right. He died one week later, and a postmortem examination was performed. By plotting the CT on templates constructed to show the different vascular territories of the thalamus, the infarctions were predicted to be in the territories of the interpeduncular profunda arteries. Comparing sagittal reconstructions to the Schaltenbrand and Wahren atlas, the following thalamic nuclei were thought to be involved: dorsomedial, parafascicular, and centrum medianum bilaterally; and reticular, ventroanterior, and ventrolateral on the left. Pathologic study confirmed these findings. We believe that it is possible to predict the vascular territory of thalamic infarctions by plotting the CT on templates showing the different vascular territories of the thalamus. Sagittal reconstructions of CT scans also permit the determination of thalamic nuclei involved in a lesion.

Aged↗
PubMed1985

Blink reflex in patients with hemispheric cerebrovascular accident (CVA). Blink reflex in CVA.

A blink reflex consists of an early unilateral component, R1, and a late bilateral component, R2. During an acute phase of hemispheric cerebrovascular accident, R1 and R2 were abnormal in 30 and 50 of 66 patients, respectively. Paired stimuli usually corrected R1 but not R2, which was profoundly suppressed. The discrepancy between polysynaptic R2 and oligosynaptic R1 indicates a greater disfacilitation at the level of interneurons than at the motoneuron, which serves as the final common path. Abnormality of R2 occurred bilaterally with stimulation on the affected side of face and contralaterally after stimulation on the normal side in 31 patients. This finding suggests a diffuse loss of internuncial excitability, contralateral to the hemispheric lesion. Changes of R2 implicated the brainstem pathways forming the afferent and efferent arc of the reflex in 7 and 8 patients, respectively. The remaining 4 comatose patients had no R2 irrespective of stimulus sites. Clinical localization of the hemispheric lesion showed no consistent correlation with the type of blink reflex abnormalities. The CT scans revealed widely scattered changes in 29 patients with abnormal blink reflex but with a tendency to overlap in the inferior Rolandic area. This contrasted with conspicuous sparing of the inferior post-central region in 10 patients with normal blink reflex. These findings suggest the presence of crossed facilitation to this reflex from wide areas of the cortex but most prominently from the sensory representation of the face.

Acute Disease↗
PubMed1985

Nonhaemorrhagic thalamic infarction. Clinical, neuropsychological and electrophysiological findings in four anatomical groups defined by computerized tomography.

Twenty-five patients with nonhaemorrhagic infarcts of the thalamus were studied clinically and by neuropsychological testing, computerized tomography and somatosensory evoked response (SER) recordings. Our aim was to determine whether the findings in these different tests would form distinct symptom clusters associated with different anatomical territories of the thalamus. Infarction conforming to the tuberothalamic arterial territory caused a facial paresis for emotional movements, severe neuropsychological deficits and a delay of the SER after P14. Infarction conforming to the interpeduncular profundus arterial territory caused a supranuclear vertical gaze paresis, severe neuropsychological deficits and a delay in the P60 component of the SER. Infarction conforming to the anterior choroidal territory caused a hemiparesis, moderate neuropsychological deficits and varied sensory evoked responses. Patients with infarctions conforming to the entire geniculothalamic territory had sensory loss in multiple modalities, minimal neuropsychological deficits and absence of sensory evoked responses after P14. A lacune in this territory caused pure hemisensory loss involving part of the body for the modalities of pain and light touch but not proprioception or vibration. Neuropsychological deficits were uncommon and N32 and N60 were delayed in the SER.

Adult↗
PubMed1984

Examining the relationship between computed tomography and neuropsychological measures in normal and demented elderly.

Correlational analysis of CT and neuropsychological measures in patients with dementia revealed more predictive relationships in degenerative and vascular subgroups that in a multi-aetiology group. Normal and dementia patients were then matched for age, sex and educational background, and analysed together. The ventricular/brain ratios of the bodies of the lateral ventricles and of the third ventricle correlated most highly with neuropsychologic performance. Canonical analysis revealed a correlation coefficient of 0.725 between the sets of CT and neuropsychological measures, which increased to 0.78 when a degenerative subgroup only was considered. Discriminant function analysis indicated that the combination of CT and neuropsychological measures was more powerful in discriminating normals from dementia patients than CT or neuropsychological measures alone.

Aged↗