Biomedical subjects
Publications and source records attributed to G Denes.
In a 35-year-old right-handed man who had no personal or family history of left-handedness, left hemiparesis and predominantly motor aphasia suddenly developed following cerebrovascular accident. Clinical and laboratory data, including computerized tomographic scan, showed a clearly defined right hemisphere lesion. On dichotic listening test, a clear-cut right ear extinction was present.
A tactile version of the Vanderplas and Garvin random shapes was given to 80 right-handed subjects, ranging in age from 6 to 13 years. Complexity was constant across the patterns: half of them were chosen from the High Association Group while the remaining patterns were selected from the Low-Association Group. Stimuli were dichhaptically presented, each pair being composed of a High Association and Low Association stimulus. The subject's response was given on each trial by pointing to the corresponding shapes froma visual display presented following the removal of the test stimuli. Analysis of the data showed that age of subjects, hemisphere (R.H. better than L.H.) and Association Value (High Association better than Low Association) were significant factors in recognition. Sex was not significant as well as none of the the interactions. Results were discussed in terms of hemispheric specialisation.
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Different strategies in copying designs were investigated in unilaterally brain-damaged patients. Site of lesions (right or left) and presence or absence of aphasia, seen as a planning disorder, were taken in consideration. Aphasic patients proved to be more inclined to use an analytic strategy rather than a global one, differing from both other brain-damaged patients and normals. A comparison between patients with right and left brain lesion failed to yield a significant difference.
Musical segments convey at least two kinds of meaning: The "real-world" events referred to by lyrics and by occasions of performance constitute musical denotation: the formal expressive patterns suggested by such constituents as pitch, timbre, and intensity constitute musical connotation. To ascertain sensitivity to these musical facets among brain-injured patients, tests assessing appreciation of musical denotation and connotation were administered to unilaterally brain-injured subjects in the United States and Italy. On the musical denotation test, right hemisphere patients excelled on items where knowledge of lyrics was required; in contrast, anterior aphasics surpassed both posterior aphasics and right hemisphere patients on items where acquaintance with lyrics was unnecessary. On the musical connotation test, right hemisphere patients performed relatively better in matching sound patterns to temporally-sequenced designs than to gestalten; these patients also performed better than left hemisphere patients on a number of other dimensions. The relatively high performance of posterior aphasics on the connotation test, along with the lack of correlation between connotative and denotative scores received by aphasic patients, suggest a behavioral and neurological dissociation between the two forms of musical sensitivity.
A multiple choice test was devised in order to assess some aspects of the aphasic's semantic field; patient's task was to match a given picture with one out of three alternatives: one of them was linked by a class relationship, one was linked by a property relationship and the last was an unrelated item. Results clearly show that Broca's aphasics make their choice according to class criteria whereas Wernicke's and controls make their choice according to property criteria. Results are discussed in the light of Jakobson linguistic hypothesis which postulates that Broca's and Wernicke's aphasia are subdued by a contiguity and similarity disorder.
A sentence-reading test was devised in order to assess the aphasic's ability to detect errors in written discourse. One hundred pairs of sentences, each containing one correct and one erroneous sentence, were presented to the patients, who were required to locate the error in one of the two sentences. So that comprehension in the auditory and visual modalities might be compared, the identical test was administered orally to a subset of the aphasic population. Contrary to expectations, there was no difference in overall scores between patients with anterior and posterior pathology. Anterior patients performed somewhat better on the oral version, posterior patients on the written version of the test. Finally, an examination of errors revealed a regular order of difficulty in sentences which featured contradictions to "real-world" knowlege, irrespective of the locus of brain damage, while the order of difficulty of sentences featuring syntactic deviations differed appreciably, depending on the locus of lesion. An attempt is made to relate these findings to current experimental and clinical knowledge.
In a patient with a classical syndrome of pure word deafness following a cerebrovascular accident detailed neuropsychological examination showed an almost absolute inability to name meaningful non verbal sounds, in spite of normal recognition as demonstrated by ability to match the sound with the corresponding natural source. This selective anomia, confined to auditory modality, is discussed in view of the previous researches regarding the general field in naming disturbances, which showed that for the vaste majority of aphasics, anomia was not modality dependent. Besides that the contrasting performance of the patient who showed complete lack of phonemic analysis matched with normal recognition of some acoustic parameters of speech as prosody and stress is discussed.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.