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Biomedical subjects

M Poncet

Publications and source records attributed to M Poncet.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Clinical aspects and course of Alzheimer's disease].

The diagnosis of Alzheimer's disease must be considered in all subjects over 40 years of age whose mental functions have insidiously become altered and are progressively getting worse. The initial phase of the disease, which precedes dementia, is characterized by disorders of memory often associated with changes in personality and behaviour and with subtle disorders of speech, reasoning and abstraction ability and visuo-constructive capabilities. The results of neurological and paraclinical examinations are normal. This phase lasts from two to four years and may be diagnosed as "possible Alzheimer's disease". When the disease is established the patient has lost his autonomy and can only be kept at home with the help of his relatives. Dementia gradually becomes worse, with a combination of memory disturbance, aphasia-apraxia-agnosia syndrome, impaired intellectual faculties and disorders of behaviour. Computerized tomography shows evidence of cerebral atrophy. This phase lasts from three to six years and may be called "probable Alzheimer's disease". The terminal phase of the disease includes somatic lesions, and all mental functions are profoundly altered. Death occurs seven to ten years after the first symptoms. Histopathological data are necessary to make a diagnosis of "confirmed Alzheimer's disease", since there is no clinical, morphological, electrophysiological or radiological sign that is pathognomonic of that disease.

Alzheimer Disease↗
PubMed1989

Spontaneous disseminated panarteritis in laboratory beagle dogs in a toxicity study: a possible genetic predilection.

Disseminated panarteritis was found in 16 (9 males and 7 females) of 49 laboratory beagle dogs (25 males and 24 females) from one breeding kennel. The dogs had been used in a 6-month oral toxicity study. Panarteritis was not associated with clinical or gross abnormalities. The incidence was similar in the control and test article-treated groups. Mainly medium-sized arteries throughout the body, particularly intercostal arteries (at their aortic origin), and coronary, epididymal and thymic vessels were affected. Chronic mononuclear-cell periarteritis was the predominant feature. Mixed cellular inflammation of the wall, proliferation or degeneration of muscle cells, focal "fibrinoid" material in the tunica media, fragmented internal elastic lamina and intimal thickening associated with myointimal cellular proliferation also occurred. These histologic changes are compatible with those of immune arteritis. Round worm intestinal infestation and granulomas of visceral larva migrans were common in several organs. Statistical analyses suggested that the pedigree of dogs is related to panarteritis, but the presence or absence of parasitization alone is not. The possible roles of genetic predilection and/or parasites in the pathogenesis are discussed. This panarteritis is spontaneous and may complicate the interpretation of lesions in toxicity studies.

Animals↗
PubMed1989

[Early right posterior cerebral hemispheric lesion and right speech dominance in 2 right-handed female patients].

Two female patients presented a severe partial epilepsy of early onset and an extended right posterior hemispheric lesion of prenatal or perinatal origin. They were right-handed and all their first degree relatives were right-handed. Nevertheless, evidence of right hemispheric speech was documented in both patients, on the basis of a bilateral sodium amytal test in one case, and of a persistent aphasia after neurosurgical treatment in the other. The possible consequences of an early cerebral pathology on cerebral lateralization are discussed, including pathological right-handedness.

Adolescent↗
PubMed1989

[Are the lesions responsible for prosopagnosia always bilateral?].

To localize the lesions responsible for prosopagnosia one must first consider how recent anatomico-physiological data have modified our view of the visual system: the visual cortex has been parceled into a mosaic of visual areas, each of them processing preferentially a particular feature (form, colour, movement); there is evidence of a face area in the monkey temporal lobe, and a new model of the inferior longitudinal fasciculus has been offered. It is currently accepted that face recognition deficits are due to bilateral occipito-temporal lesions, but in view of several recent reports in which the lesions were localized on CT or MRI one may doubt that these lesions are necessarily bilateral. In some cases a right unilateral lesion seemed to be sufficient to induce prosopagnosia.

Agnosia↗
PubMed1988

[Loss of vitality, of interest and of the affect (athymhormia syndrome) in lacunar lesions of the corpus striatum].

Two men in their 6th decade were referred for dramatic changes in their affect and personality resulting from multiple lacunar infarcts bilaterally involving the striatum, especially caudate nuclei, as shown on MRI. These changes included: specific loss of desire and interest toward previous motivations, loss of drive and search for satisfaction, lack of curiosity, loss of tastes and preferences, flattened affect. Interestingly, there were neither the necessary subjective criteria for the diagnosis of depressive syndrome nor major defect in intellectual or cognitive functioning: specifically, language, memory, and psychometric performances were roughly normal. Neither dopaminergic nor antidepressant agents could modify these patients deficits. It is suggested that this syndrome be referred to as "athymhormia syndrome" (from the Greek roots thumos: mood and horme: ardor, spirit, élan), a term coined by Dide and Guiraud to define the behavior of some schizophrenics, ascribed by these authors to a disruption of the so-called "hormothymic system" that they proposed to locate to subcortical brain structures. Referring to similar behavioral changes previously reported with lesions involving bilaterally either the globus pallidus or the periventricular white matter of the frontal lobes, it is proposed that a distinct pathway could constitute the neural substrate of the "hormothymic" system. This pathway, following a cortico-subcortical limbic loop, would include: striatal afferents from the limbic frontal cortex, striatum itself (especially its limbic component), globus pallidus, and dorso-medial thalamic nucleus.

Activities of Daily Living↗
PubMed1987

Age-related changes in aphasia type and stroke location.

Two-hundred consecutive CT scans of patients with an infarction in the territory of the middle cerebral artery (MCA) were examined for evaluation of a possible relationship between age and stroke location. Two distinct procedures, one evaluating the incidence of four areas within the MCA territory and the other measuring some quantified parameters, were used. Statistical studies failed to show any significant correlation between these parameters and the age of patients. These results lead to refute previous claims that semiological changes in aphasia type with age in stroke patients may be due to a posterior shift of cerebral infarcts with age.

Adult↗
PubMed1987

Deep left parietal lobe syndrome: conduction aphasia and other neurobehavioural disorders due to a small subcortical lesion.

A patient with sudden onset of conduction aphasia in the context of an ischaemic stroke is reported. Other neurological and neuropsychological findings included bilateral ideomotor apraxia, right hemisensory defect and paradoxical left ear extinction on a dichotic listening test. Lesion location, as inferred from magnetic resonance imaging, involved a restricted subcortical area in the left parietal lobe, near the lateral wall of the cerebral ventricle. The anatomical correlate for each of the clinical findings is discussed in the light of classical anatomo-clinical correlations. It is concluded that this tetrad constitutes a specific syndrome which may be easily recognised and ascribed to a single lesion in the deep white matter of the left parietal lobe.

Aged↗
PubMed1987

[Aphasia without amusia in a blind organist. Verbal alexia-agraphia without musical alexia-agraphia in braille].

A 77 year old right handed male was blind since the age of 2. He presented with an infarction involving the territory of the left middle cerebral artery involving the temporal and the inferior parietal lobes. He had learned to read and write language as well as read and write music in braille, ultimately becoming a famous organist and composer. There were no motor or sensory deficits. Wernicke's aphasia with jargonaphasia, major difficulty in repetition, anomia and a significant comprehension deficit without word deafness was present; verbal alexia and agraphia in braille were also present. There was no evidence of amusia. He could execute in an exemplary fashion pieces of music for the organ in his repertory as well as improvise. All his musical capabilities: transposition, modulation, harmony, rythm, were preserved. The musical notation in braille remained intact: he could read by touch and play unfamiliar scores, he could also read and sing the musical notes, he could copy and write a score. Nine months after the stroke his aphasia remained unchanged. Nevertheless he composed pieces for the organ which were published. Such data highly suggest the independence of linguistic and musical competences, defined as the analysis and organization of sounds according to the rules of music. This independence in an extremely talented musician leads to a discussion of the role of the right hemisphere in the anatomical-functional processes at the origin of musical competence. The use of braille in which the same constellations of dots correspond either to letters of the alphabet or musical notes supports the independence between language and music.

Aged↗
PubMed1987

[In vivo location of the cortical language areas (correlation between anatomy, x-ray computed tomography and magnetic resonance imaging)].

Cortical language areas were identified by CT scan or NMR imaging, using planes of horizontal sections parallel to the orbitomeatal plane and therefore indirectly to the bicommissural plane. Sections 45 and 50 mm above the bicommissural plane pass electively through temporal structures i.e. the posterior part of T1 and T2, while sections at 60 and 70 mm pass through the angular gyrus and supramarginal gyrus.

Brain Mapping↗
PubMed1986

Deep dysphasia in a case of phonemic deafness: role of the right hemisphere in auditory language comprehension.

Deep dysphasia, an analogue of deep dyslexia in the auditory modality is a rare and peculiar pattern of repetition disturbance, which has been used to validate Morton's (Deep Dyslexia, pp. 189-196. Routledge & Kegan Paul, London, 1980) logogen theory. Such a case is reported here in which there was strong evidence of destruction of the left temporal lobe auditory areas. Examination of linguistic performance emphasized levels of auditory speech decoding. It was found that this patient had a profound phonemic discrimination deficit, yet could accomplish many lexical operations. It is argued that this case, in which a left temporal lobe lesion was associated with impaired phonological analysis, provides evidence that deep dysphasia may reflect the right hemisphere's non-phonological mode of speech processing.

Aphasia↗
PubMed1984

[Behavior and mental activity disorders after carbon monoxide poisoning. Bilateral pallidal lesions].

Two patients who had suffered severe carbon monoxide intoxication showed lasting neuropsychologic sequelae: 1) deep inertia involving the whole behaviour and expressed by an almost complete lack of activity if not induced by someone else; a mental gap when the patients were left to themselves and a tendency to give up the mental activity when stimuli ceased; an apparent affective indifference connected with a lack of spontaneous expression of the affects; 2) pseudo-obsessionnal activities: coprolalia with sexual themes in one patient, obsessive collecting and tidying up activities in the other one. Neurologic examination was normal, particularly no parkinsonian syndrome was present. CT scans showed bilateral pallidal low density areas. Both patients had moderate intellectual impairment in psychometric tests and amnestic disorders. There is a possible relationship between memory and cognitive impairment and mental inertia. The onset of pseudo-obsessional signs following basal ganglia lesions is emphasized. The central semeiological fact seems to be a disorder of the initiation and the carrying on of any external action as well as mental activity itself. This may be related with the activity disorders represented at a more elementary level by motion impairment in parkinsonian akinesia.

Adolescent↗
PubMed1983

Crossed aphasia in dextrals: a case report with special reference to site of lesion.

A strictly right-handed man showed aphasia and left hemiplegia following a deep infarct of the right hemisphere. Aphasic semeiology was characterized by an oral and written jargon while comprehension was almost intact. Several hypotheses previously put forward fail to account for the patient's aphasia. Emphasizing the frequency of deep structures involvement in the published cass of crossed dextral aphasias, it is suggested that site of lesion may have a certain part to play in the occurrence of such aphasias.

Aphasia↗
PubMed1983

[Development of aphasic symptomatology with age. Discussion apropos of an anatomo-clinical case].

Clinical data suggesting that aphasic semeiology undergo some evolution with age are summarized. Three kinds of hypotheses may account for this evolution: (1) a possible evolution with age of the site and extent of ischaemic lesions: (2) an evolution according to age of brain functional organization for language; and (3) evolution with age of psychological and/or social aspects of individuals in whom aphasia occurs. These hypotheses are discussed in the light of a clinico-pathological case of Wernicke's aphasia with logorrheic jargon due to an infarct involving both anterior and posterior parts of the left cortical speech area. This observation does not support the first set of hypotheses implying the lesion's site. On the other hand, as regards the second hypothesis, it is conceivable that the most instrumental features of speech functional organization may undergo a progressive subcorticalization process with age so that it possibly accounts for some age specificity in aphasic semeiology. Finally, the last set of hypotheses--individual's psychological and/or social aspects--although untested here, is thought to be also of some relevance.

Aged↗