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Biomedical subjects

G Demeurisse

Publications and source records attributed to G Demeurisse.

At least 19 recordsLinked to original sources

Pure topographical disorientation due to a deep-seated lesion with cortical remote effects.

Lesions producing pure topographical disorientation syndromes are classically located either in the right parietal region either in the right parahippocampal gyrus. The patient described in the present study was admitted to hospital after sudden onset of a left hemiparesis. The lesion at CT scan was located in the posterior limb of the right internal capsule. Neuropsychological assessment was normal except for the presence of a major topographical disorientation and of mnestic disturbances for visuo-spatial material leading us to attribute topographical disorientation to a specific loss of topographical memory. Regional cerebral blood flow measurements disclosed a right parietal hypoperfusion. This remote cortical effect could account for the presence of the neuropsychological disorders.

Aged

Seasonal variation of cerebral hemorrhage in 236 consecutive cases in Brussels.

BACKGROUND AND PURPOSE: Seasonal variation in the incidence of cerebral hemorrhage has been previously demonstrated. In this study, we sought to identify the climatological data best correlated with this seasonal variation. METHODS: In a retrospectively studied sequential series of 236 patients with nontraumatic cerebral hemorrhage observed in Brussels over a period of 8 years, we cumulatively grouped the dates of stroke occurrence into a single calendar year. RESULTS: We found marked seasonal variation in incidence, with the highest value (23%) observed in November-December and the lowest (10%) in July-August. Seasonal variations in incidence of cerebral hemorrhage were shown to be correlated not only with the inverse of ambient temperature, but also with the inverse of hours of sunshine and with ambient humidity. We found no difference between hypertensive and normotensive patients. CONCLUSIONS: Our study fails to bear out the hypothesis that the higher incidence of cerebral hemorrhage in late autumn and winter is due to the influence of low ambient temperature on blood pressure.

Adolescent

Brain activation during a linguistic task in conduction aphasia.

In order to investigate functional cortical reorganization during recovery from conduction aphasia, regional cerebral blood flows (rCBF) were measured by the two-dimensional 133 Xenon inhalation method in ten stroke patients. rCBF measurements were performed at rest and during the performance of a linguistic task, one month and three months after onset. The analysis of flow changes from rest to test condition indicates an increasing contribution of the right hemisphere as time goes on. The absence of flow increase in Broca's region suggests that this region is definitively disconnected from posterior language "centers" by the arcuate fasciculus lesion.

Aged

Remote cortical dysfunction in aphasic stroke patients.

We studied the effect of deep-seated left hemispheric lesions on cortical blood flow in 18 right-handed aphasic stroke patients. Regional cerebral blood flow was measured at rest and during the performance of a functional naming test using the two-dimensional xenon-133 inhalation method. Compared with 10 controls, at rest the patients showed regional cortical hypoperfusion in the left frontoparietal region. In the controls, activation patterns from the rest to the test condition involved mainly the left hemisphere areas. In the patients, a lack of blood flow change was observed in several areas that were usually hypoperfused at rest. However, in patients with slight verbal expression disorders there were obvious blood flow increases in other brain regions in both hemispheres. Such cortical functional reorganization and the presence of a remote cortical dysfunction could play a role in the pathophysiology of language disorders.

Aged

Pathogenesis of aphasia in deep-seated lesions: likely role of cortical diaschisis.

In order to study the pathophysiology of language disorders due to deep-seated left-hemisphere lesions not involving the cortex, a population of 43 right-handed stroke patients (29 aphasic) presenting with such lesions was studied clinically and by regional cerebral blood flow measurements (two-dimensional xenon-133 inhalation method). Most of the patients were studied sequentially between the 1st and 3rd months after stroke. Cortical diaschisis did not account for the whole clinical picture: the remote effect on the cortex could explain the occurrence of aphasia and its severity but not the type of aphasia. Furthermore, the clinical improvement observed in most cases was not accompanied by the disappearance of the diaschisis.

Adult

Remote effect of deep-seated vascular brain lesions on cerebral blood flow.

We measured regional cerebral blood flow using the xenon-133 inhalation method, at approximately 1 month after onset, in 60 stroke patients who had no evidence of major carotid artery stenosis or occlusion. Their single lesions (43 infarcts and 17 hematomas) were located in the capsulothalamolenticular region, sparing the cortex. Hemispheric mean cerebral blood flow was reduced on the side of the lesion in 25 patients and on both sides in 20. Regional hypoperfusion was observed in 46 patients (ipsilaterally in 34, bilaterally in 10, and contralaterally in two). Regional hypoperfusion was observed most frequently in the frontal lobe, particularly in the motor and premotor cortices of the prerolandic area. The 46 patients with regional hypoperfusion were compared with the 14 patients without regional hypoperfusion, considering the size and location of the lesion as well as the functional and analytic motor performances. As a rule, the lesion was slightly smaller and more posterior and the functional (p less than 0.001) and analytic (p less than 0.05) motor performances were significantly better in the 14 patients without regional hypoperfusion. Since the xenon-133 inhalation method examines cortical blood flow, we can attribute blood flow reductions resulting from deep-seated lesions to a functional depression akin to diaschisis. Interpretation of the clinical consequences and pathogenesis of this phenomenon requires further sequential and pathologic studies.

Administration, Inhalation

Evidence of cortical reorganization in hemiparetic patients.

We studied the mechanisms underlying the recovery of motor function of the hand using a bidimensional xenon-133 inhalation technique to measure regional cerebral blood flow at rest and during the performance of a motor task (test condition). The regional cerebral blood flow patterns under rest and test conditions were compared in normal control and in stroke patients with either a cortico-subcortical or a deep-seated lesion. Functional recovery appears to depend upon cortical reorganization involving both hemispheres, particularly in both parietal regions in the subgroup of patients with cortico-subcortical lesions.

Adult

Assessment of hemispheric dominance for language in crossed aphasia by two atraumatic methods.

In a right handed patient with crossed aphasia, two atraumatic techniques (regional cerebral blood flow measurements during the performance of a linguistic task and dichotic listening test) were used to assess language lateralization. The prominence of rCBF activation patterns in the right hemisphere and the presence of a clear-cut right ear extinction on the dichotic listening test provide evidence that, is this case, the right hemisphere was dominant for language.

Aged

Prognostic value of computed tomography in aphasic stroke patients.

In order to evaluate the prognostic value of CT scan in aphasic stroke patients, a prospective study was performed during the first 3 months of the disease. The severity of the language disorders was assessed by means of a quantitative method. In cortico-subcortical lesions, the verbal expression recovery rate and the final verbal expression and comprehension status depended on the infarct size. No relation was observed between the latter and the verbal comprehension recovery rate. In deep-seated lesions, computed tomography provided no information concerning the prognosis.

Aged

Resting CBF sequential study during recovery from aphasia due to ischemic stroke.

Cerebral blood flow (133Xenon inhalation method) has been studied in 30 aphasic stroke patients at 15, 30, 60 and 90 days after onset. In total aphasia the CBF values are low and the regional hypoperfused areas are extensive. In Broca's, Wernicke's and nominal aphasias, resting CBF measurements do not provide the clinician with useful additional information and clinical improvement can by no means be attributed to a resting CBF rise during the observation period.

Adult

[Etiology of urinary sphincter disorders following cerebral vascular accidents].

Urological and neurological investigations were carried out in a homogeneous population of 77 hemiplegic patients treated in a neurological rehabilitation department, in an attempt to identify the etiology of secondary bladder dysfunction in such cases, with the aid of computerized data. The following conclusions were reached. Bladder retention was proved to result invariably from a mechanical obstacle. Permanent bladder incontinence was always due to urinary infection and/or mental deterioration. Exclusively nocturnal incontinence was shown to be a "pseudo-incontinence". It was shown that an uninhibited bladder played no part in incontinence but was always present in cases of an urgent need to urinate.

Adult

Semiological value of the palmo-mental reflex in vascular hemiplegia.

The palmo-mental reflex has been described, together with other neurological signs, in senile dementia. It is, however, found in normal adults, where its frequency increases with age. In vascular hemiplegia it has a considerably higher incidence, nevertheless it is not a sign of mental deterioration.

Adolescent

Study of two cases of aphasia by infarction of the left thalamus, without cortical lesion.

Two patients suffering from a left thalamus infarct were studied over a long period. The precise location of the lesion has been demonstrated by the C.T. scan. In spite of the absence of any cortical lesion, both presented with aphasia and other neuropsychological disorders (left-right confusion, dyscalculia and possible finger agnosia). Their speech disorders although different, had several features in common. The observations were compared with the other cases reported in the literature.

Aged