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Biomedical subjects

E M Saffran

Publications and source records attributed to E M Saffran.

33 records · Page 2Linked to original sources

Evidence for preserved reading in 'pure alexia'.

We describe 4 patients who developed pure alexia after infarctions of the left cerebral hemisphere. All subjects employed a letter-by-letter strategy (with varying degrees of success) to explicitly identify visually presented words. Although all 4 subjects explicitly denied that they could identify briefly presented words, they all performed significantly better than chance on lexical decision and forced-choice semantic categorization tasks with briefly presented words which they could not explicitly identify. Three subjects regained the ability to explicitly identify briefly presented words; these subjects were more accurate with nouns than functors and words of high as compared with low imageability. Additionally, these subjects were impaired in the processing of suffixes. These data are not accommodated by the 'disconnection' account of pure alexia but are more consistent with the hypothesis that reading in these patients is mediated by the right hemisphere.

Adult↗

Preserved object recognition and reading comprehension in optic aphasia.

Optic aphasia is characterized by the ability to name from description and palpation but an inability to name visually-presented objects. Although originally attributed to a disconnection of visual information from object names, optic aphasia is often considered to be a mild form of visual agnosia. We describe a patient with optic aphasia who could access semantic information relevant to objects he could not name and comprehend written words he could not read. These data suggest that, at least in certain cases, this visual modality-specific naming impairment may not be attributable to impaired visual recognition. We suggest that this patient's preserved object recognition and reading comprehension was mediated by a semantic system supported by the right hemisphere.

Aged↗

Neuropsychological approaches to the study of language.

This paper discusses recent studies of aphasia from the perspective of theories of normal language structure and processing. Patterns of language breakdown are considered to reflect the componential structure of the language system. In some cases, brain damage is seen to fractionate language along lines suggested by existing psycholinguistic models: certain syndromes can be viewed as more or less isolated disturbances involving lexical, syntactic or phonological components of the language system, or psychological functions such as short-term memory. In other cases, aphasic deficits point to levels of language function not yet well specified by normative models. This review of psycholinguistically oriented research on aphasia supports the effort to construct integrated theories of language functioning on the basis of both normal and pathological performances.

Aphasia↗

[Nature of repetition disorders in conduction aphasia].

The skeptic over the existence of this important clinical entity, are now very few. Anatomo-clinical studies and the analysis of altered cognitive procedures suggest, however, that we are dealing with a heterogeneous group. Two models of conduction apahasias are presented, in which the mechanism of the altered repetition, as well as the probable localization of the lesion, differ considerably. One has a lesion in the posterior parietal region of the left hemisphere and it exemplifies an acoustic verbal memory deficit (short term memory). The other points at a functional disconnection between the decodification and verbal processes and those of expression. In this case, we are dealing with a left temporal lesion in a left-handed individual. The analysis of our material and of the clinical literature upholds the idea of a plurality of the altered mechanisms in the verbal repetition and suggest that the conduction aphasia is a syndrome.

Adolescent↗

Agnosic behavior in anomia: a case of pathological verbal dominance.

The interrelation of perceptual and verbral process was explored in a fluent aphasic with a naming disorder. This patient performed extremely well on complex perceptual tasks as long as he was instructed to remain silent or to count aloud. Whe he began to talk about what he was doing, he misnamed many test items and behaved as if they were what he had called them. The verbal interference effect is explained in terms of cerebral dominance and interhemispheric interaction and it is suggested that a similar mechanism may apply in classical cases of agnosia.

Agnosia↗