Biomedical subjects

J F Dereux

Publications and source records attributed to J F Dereux.

At least 19 recordsLinked to original sources

PubMed1991

[Late auditory evoked potentials in subcortical cognitive deterioration].

Late auditory evoked potentials (AEPs) were recorded by the odd-ball method in 55 non-deteriorated parkinsonians (NP) and in 27 parkinsonians with cognitive deterioration (CDP), compared with 20 controls (C) and 24 patients with Alzheimer-type senile dementia (ATSD). The latency of P 300 was prolonged in the CDP and ATSD groups (410.72 +/- 24.45 and 433.62 +/- 38.30 respectively; P less than 0.001. The latency of N 100 was prolonged only in the CDP group (106.6 +/- 4.82; P less than 0.001). Late AEPs were also studied in 63 subjects with possible or confirmed disseminated sclerosis (DS) compared with 33 controls of similar mean age. The ERFC test divided these patients into 38 with non-deteriorated DS (NDS) and 25 with deteriorated DS (DDS). The latency of P 300 was prolonged in both groups: NDS 331.14 +/- 25.89; DDS 376.64 +/- 29.51 (P less than 0.001). The latency of N 100 was prolonged in the NDS group (100.25 +/- 9.20) and the DDS group (104.43 +/- 9.01). Following a study of correlations between the degree of mental deterioration and the electrophysiological parameters in these populations, the significance of the N 100 latency as electrophysiological marker of subcortical dementia is discussed.

Aged↗

PubMed1989

[Motor impersistance of the eyelids. Study of 93 cases and a discussion of pathogenic mechanisms].

In a prospective study, 252 subjects were investigated for motor impersistence of the eyelids (MIE) by means of a protocol that evaluated its intensity and detected associated signs, notably other phenomena of motor impersistence. MIE was frequent, being found in 93 subjects. It was usually observed in diffuse brain lesions, then in lesions of the right hemisphere, particularly in the posterior and deep cortex. In right hemisphere lesions, MIE was significantly associated with constructional apraxia, visual neglect and Anton-Babinski syndrome. In diffuse cerebral lesions, MIE was accompanied by other phenomena of motor impersistence on a background of dementia. In these cases the P 300 wave latency was significantly prolonged. Three main mechanisms may be regarded as responsible for the occurrence of MIE: apraxia, disturbance of the interhemispheric balance (notably in lesions of the right hemisphere) and disorders of attention (predominant in diffuse lesions). Actually, in every case MIE should be inserted in a continuum the extremities of which are represented by the above mentioned mechanisms.

Aged↗

PubMed1989

[Asymmetry of visual perceptive activity of faces and emotional facial expressions].

Eye movements were studied in 40 right-handed subjects during perception of symmetrical chimerical faces. These movements were recorded using an original system based on a differential optical method for the detection of corneal reflection and of the pupil made shiny. Under basal conditions, the first fixation was usually located in the left visual hemifield. The subjects spent more time gazing at the right hemiface (P less than 0.04). This visuo-spatial asymmetry in favour of the left hemispace was increased when the subject was requested to determine the emotional expressions of a new series of faces (P less than 0.002). Compared with basal conditions, the increase in the percentage of time spent in the left area was significant (P less than 0.035). An analysis performed on the first 3 seconds confirmed and amplified the differences observed. These results can partly be explained by reading habits and exploratory activity for symmetrical shapes. However, activation of the right hemisphere, specialized in the perception of faces and facial expressions, probably influenced visual exploration by drawing attention to the left area and favouring the left visual hemifield.

Adult↗

PubMed1988

[The delusion of place: contribution of the measurement of cerebral deficit].

The authors report the observation of a 61-year-old female patient who, following a right frontal-temporal ischemia, presented disorientation with respect to her surroundings. She was convinced during her hospital stay that her house had been transformed into a hospital. There was no evidence of intellectual confusion or deterioration, and the neuropsychological examination revealed visuo-spatial disturbances only. A low basal cerebral blood flow was found in the right anterior hemisphere which further decreased when the patient was asked where he was. It is hypothesized that confabulatory responses corresponded to a disinhibition of the left hemisphere from the control of the hemisphere dominant in dealing with visuo-spatial data.

Brain↗

PubMed1988

[Disconnection and recognition of faces. A case with lesions of the left visual cortex and the splenium].

We report the clinical findings in a case of alexia without agraphia, due to a left posterior cerebral artery infarction, in which C.T. showed occipital and splenial lesions. There were in addition a right homonymous hemianopsia and agnosia for colors, objects and pictures, with both associative and disconnective aspects. The hypothesis of an occipito-occipital disconnection, depriving the left visual associative areas of inputs, could explain this agnosia. The most striking findings in this case was, besides an anomia for faces, a peculiar difficulty to recognize her own face. The patient seemed to recognize herself. The patient spoke about herself in the third person, giving genuine autobiographical details, without being able to say: "it is me". This phenomenon is discussed in terms of disconnection: the right hemisphere sending information from the semantic field evoked by her own face, through the anterior part of the corpus callosum, to the left hemisphere. We discuss the hemispheric contribution within cognitive experience, and the role of language concerning the conscious experience in man.

Brain↗

PubMed1987

[Association of cerebral cysticercosis and multifocal glioma. Discussion of interactions].

Diagnosis in a case of cerebral parenchyma cysticercosis was based on conventional arguments described in the literature. The patient died after progression of the disease over 6 months, despite two courses of Praziquantel. Results of neuropathologic examination confirmed diagnosis of cysticercosis and the discovery of a multifocal astrocytic tumor involving mainly the periventricular regions. Possible interactions between parasitic infection and glioma are discussed but it is difficult to determine the precise role played by the parasitosis in the evolution of the tumor, the hypothesis of a simple coincidence being most likely. Periventricular images of an inflammatory nature observed after PZQ treatment should not be accepted unreservedly, and when an unfavorable course is apparent the periventricular histopathologic lesions should be compared with results of CT scan imaging qualified as periventricular in origin.

Brain Diseases↗

PubMed1985

[Hemiballism caused by metastasis to Luys' body].

A 66 year-old man suddenly developed a left-sided hemiballism. CT scan revealed 3 metastases, one of them in the area of the right subthalamic nucleus (corpus Luysii). A primary lung tumor was suspected. Haloperidol and tiapride were unsuccessful to control the hemiballism. The patient died 5 months later. Pathological examination confirmed the diagnosis. The pathophysiology of this case is discussed with regard to the pathological findings. Hemiballism secondary to a metastasis is rare, 9 cases have been reported during the past 65 years. Vascular lesions are the usual cause (75 per cent); on rare occasions degenerative disorders (14 per cent), destructive (tumors: 10 per cent or surgical lesions: 0,3-9 per cent) can also result in hemiballism.

Adenocarcinoma↗

PubMed1985

[The gaze and functional hemispheric activation in normal subjects].

The aim of this work was to determine whether the study of lateral and vertical conjugated eye movement could serve as an indicator of the functional hemispheric activation. Questions of vocabulary, calculation, logic (V.C.L.) and visuo-spatial instructions, as well as music-listening (V.S.M.), were proposed to 60 control subjects (21 men, 39 women). They were divided in 4 groups of 15 according to their laterality (complete right handed, incomplete right handed, ambidextrous, left handed). Eye movements were recorded using a video system. Deviations of the eyes towards the right and left, upwards and downwards, as well as episodes of staring were noted. Concerning V.C.L. questions, there was a significant correlation between conjugated lateral eye movements and the contralateral hemisphere activation. The study of vertical eye movements revealed a correlation only in complete right-handed and left-handed subjects: deviation upwards during the left hemisphere activation, and downwards during the right hemisphere activation. This pattern of response was no longer found during V.S.M. questions which, in the 4 groups, evoked staring episodes in 56 to 72 per cent of the cases. The negative emotional stimuli (emotional words, non verbal stimuli, stressful situations) evoked preferentially, but independently of laterality, deviations towards the left and downwards in favor of the right hemisphere activation. This method of observation of eye movements seems therefore of significant interest in Neuropsychology, provided that methodologic rules are rigorously respected.

Adult↗

PubMed1981