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Biomedical subjects

H Hécaen

Publications and source records attributed to H Hécaen.

At least 19 recordsLinked to original sources
PubMed1983

Acquired aphasia in children: revisited.

Observations of acquired aphasia in a more numerous series of children with cortical lesions modifies somewhat the conclusions of an earlier study. Aphasic syndromes in these children seem to result almost exclusively from left hemispheric lesions in right-handers. Aphasia is more frequent, at least among the youngest children, than in adults. The factors most responsible for language disorders in these children are lesion localization and etiology.

Adolescent↗
PubMed1983

Patterns of cerebral organization.

An analysis of the concurrent incidence of aphasia and spatial disorder in 270 patients with unilateral brain damage suggests that the two functions are statistically independent. These data can also be used to estimate the distribution of left, right, and bilateral representation of linguistic and spatial functions in the population. In right-handers, sex affects the pattern of cerebral asymmetries, while the familial history of sinistrality has a stronger effect on the pattern of cerebral asymmetries in left-handers. These findings suggest that complementary specialization exists only as a statistical norm: It is suggested that differences in complementary and noncomplementary specialization may underlie individual differences in cognitive skills.

Aphasia↗
PubMed1980

[Development and perspectives of neuropsychology].

Neuropsychology is a new discipline placed between neurosciences (neurophysiology, neurochemistry, comparative neuroanatomy) and psychology (experimental psychology. psycholinguistics, linguistics). History of neuropsychology shows, during last and the beginning of the present centuries, a marked trend to localization and association (one center for each function, followed later by a period where globalistic trends predominate, according to which a localized lesion is important mostly because of the modification it produces in the functions of brain as a whole. During the last 30 years, the development of anatomoclinical methods and experimental neuropsychology have again given impulse to a neoassociational trend. By their importance, recent advances in the following topics are underlined: (1) The study of behaviour, particularly regarding the role of neurotransmitters. (2) The concept of "hemispheric specialization" in substitution of "hemispheric dominance". (3) The mechanisms of functional reestablishment in the central nervous system. (4) The role of genetic background and experience in the development of functions of the central nervous system.

Animals↗
PubMed1977

[Deficitis in the "verbal fluency" test in left-handed subject with unilateral hemispheric lesions].

In contrast to findings in right-handed subjects with a unilateral hemispheric lesion, in the left-handed there is no significant difference in "verbal fluency) test scores between right and left lesions, nor between anterior and posterior lesions. These findings are in favour of a certain degree of cerebral ambilaterality and of a lesser focalisation of the mechanisms responsible for language in the left-handed than in the right right-handed.

Adolescent↗
PubMed1976

Effects of unilateral hemispheric lesions on two types of optico-geometric illusions.

Two optico-geometrical illusions--the Müller-Lyer (ML) and the Ponzo (P) illusion--have been studied in normal subjects and in patients with unilateral cortical lesions. Patients with left-sided lesions have stronger illusions than normal subjects, the increase being significant only for the ML illusion. In the case of right-sided lesions, the P illusion is weakened while the ML illusion is equivalent to that of control subjects. The findings are discussed in relation to the mode of apprehension of information.

Adult↗
PubMed1976

Lateralization and language representation.

The hypothesis is advanced that cerebral dominance includes two elements, interhemispheric specification for language (lateralization) and intrahemispheric language, specification (localization). Consequently, each type of aphasia is determined by the degree of dominance establishment (i.e., lateralization and localization) existing at the moment of brain damage. Evidence for this concept is presented through a comparison of aphasia in left-handers and "anomalous" dextrals with aphasia in childhood.

Adult↗
PubMed1971

Disturbances of the body schema in relation to language impairment and hemispheric locus of lesion.

The relationship of disturbances of the body schema to hemispheric locus of lesion and sensory aphasic disorder was assessed by giving verbal and non-verbal tests of right-left orientation, finger recognition, and autotopagnosis to patients with unilateral cerebral disease. The study was restricted to right-handed patients who were free from general mental impairment or confusion. The tests were also given to a group of control patients whose performances defined the range of normal performance in each test. A significant proportion of patients with sensory aphasic disorder performed defectively on all the tests, non-verbal as well as verbal, the relative frequency of failure in this group ranging from 10 to 67% for the different tests. There were, however, a number of patients with sensory aphasic disorder who performed adequately on most of the tests. Defective performance on the part of non-aphasic patients with lesions of either the left or the right hemisphere was quite rare in the case of 19 of the 20 tests. The exceptional test was the task of imitating lateral movements from Head's battery, on which both non-aphasic groups performed relatively poorly. The patients with lesions of the right hemisphere were significantly inferior to those with left hemisphere disease on this test. The findings are interpreted as indicating that sensory aphasic disorder is a necessary but not sufficient condition for the occurrence of some types of bilateral `body schema' disturbance in patients with unilateral disease. It is postulated that the sufficient condition is a combination of aphasic disorder with somatosensory impairment. Bilateral impairment of the `body schema' does not appear to have a differential relationship to hemispheric locus of lesion per se.

Adult↗