Biomedical subjects

F Eustache

Publications and source records attributed to F Eustache.

84 records · Page 5Linked to original sources

PubMed1989

Infarct of the anterior limb of the right internal capsule causing left motor neglect: case report and cerebral blood flow study.

A sixty-nine year old hypertensive man had left motor neglect following an infarct of the anterior limb of the right internal capsule. He also had left auditory extinction on verbal dichotic listening and a sligh constructional apraxia. Regional cerebral blood flow (CBF) was measured at rest with Xenon 133 inhalation and was found to be slightly decreased in a diffuse fashion. Motor activation of the right hand resulted in an increase of CBF in the contralateral superior rolandic area, whereas no such increase was found during motor activation of the left hand. This lack of cortical CBF increase on contralateral motor activation is interpreted as a consequence of the failure of some corticosubcortical connexions involved in motor arousal. The specifically dynamic appearance of regional CBF abnormalities, i.e. during selective activation as opposed to rest measurements, is consistent with the functional character of neglect.

Aged↗

PubMed1988

[Alzheimer's disease with early association of a hemi-parkinsonian syndrome].

A 66 year-old woman presented with severe memory disorders followed several months later with tremor of Parkinsonian type of the right upper limb totally relieved by treatment with levodopa-benserazide. Four years later she was admitted with memory disturbances, temporospatial disorientation, constructional and ideatory apraxia, dressing apraxia and language difficulties. Eight years later she had become bed-ridden, with deviation of head and eyes towards the left, hypertonus tremor and stereotyped movements. Neuropathologic examination showed neuronal loss in substantia nigra and left locus ceruleus, dorsal nucleus of the pneumogastric nerve and Meynert's basal nuclei on both sides. Neurofibrillary tangles affected the peri-aqueductal grey matter and Lewy's bodies were observed in the substantia nigra. Neurofibrillary tangles and granulovacuolar degeneration together with senile plaques were numerous in the hippocampus, but senile plaques and neurofibrillary tangles were rare in the remainder of the cortex. Combined Alzheimer's disease and Parkinson's disease could be due to simple coincidence, one of the diseases possibly predisposing to the appearance of the other.

Aged↗

PubMed1988

[Crying provoked by sound stimuli in a case of probable dementia of Alzheimer's type].

A case of pathological crying elicited only by non-verbal auditory stimulations in a woman with probable dementia of the Alzheimer type is reported. As neuropsychological data available in this case have suggested a greater involvement of left than right temporal cortex, the authors propose that the crying phenomenon could have been explained by a similar inter-hemispheric asymmetry in pathological involvement of the limbic structures.

Acoustic Stimulation↗

PubMed1987

[A case of aphasia with speech disorders by infarction of the left caudate nucleus and putamen].

An infarction involving the left putamen, caudate nucleus and the anterior limb of the internal capsule, resulted in aphasia with semantic paraphasias, verbal incoherence and verbal memory impairment. Cerebral blood flow (CBF) studies with 133Xe inhalation at 20 days post onset showed, on one hand, a bilateral lowering of cortical blood flow and on the other hand a left frontal-parietal hypoperfusion area. Spontaneous recovery occurred within 2 months. While the mean CBF became normal at 14 months post onset, a relative hypoperfusion area persisted on the anterior left hemispheric cortex. On the basis of these findings and current CBF and metabolic studies carried out in patients with subcortical lesions, the authors discuss the role of cortical and subcortical structures in subcortical aphasic syndromes. The importance of reciprocal connections between cortex, striatum and thalamus is stressed.

Aphasia↗

PubMed1984

[Visual and tactile agnosia].

A patient presented with visual and tactile agnosia due to a spontaneous left occipito-temporal hematoma. Major memory and spatial orientation disorders were also noted, but language, gestures, auditory and olfactory perception, and interior visual imagerie were unaffected. A review of the literature since 1970 found 6 cases of an association of this type among 17 patients with visual agnosia. There appears to be no relationship between the presence of tactile agnosia and the global or partial character of the visual agnosia, the severity of memory disturbances, the presence of visuoverbal disconnection or visual imagery disorders. In contrast, these cases differed in that the lesions were more extensive and extended beyond the internal occipital regions: they were widespread in 3 cases and in the left internal occipital and parietal region in 1 case. In the patient reported in this paper there was a wide lesion of the posterior white matter of the left hemisphere.

Agnosia↗

PubMed1984

[Case of cortical deafness sparing the music area].

A 33-year-old woman had developed cortical deafness with profound initial deafness lasting for eleven months after pneumococcal meningitis ten years previously. CT scan demonstrated bilateral temporal lobe lesions, predominantly on the left side where it extended into the adjacent parietal and frontal lobes. Audiometry suggested integrity of the internal ear and brain stem. Early auditory evoked potentials were present, while potentials of moderate latency and delayed potentials were abolished. Neuropsychological investigations demonstrated total absence of spoken language, contrasting with conservation of written language, though with agrammatism and an impossibility of identifying non-verbal noises, spoken language, and music. The patient could not identify rhythms, pitch, melodies or the different types of music. The musical quality of sound stimuli and musical pleasure were, however spared as shown by recognition of tape recorded sound stimuli with written denomination and designation of images in multiple choice tests. The relations between auditory agnosia, "pure" verbal deafness and cortical deafness are discussed. Reported cases are reviewed and an attempt is made to demonstrate the existence of several levels in the integration of musical stimuli, the most elementary of which could be the perception of the musical quality of sounds, as was the case in the present patient.

Adult↗

PubMedDate not supplied

Inter- and intra-individual probability maps in EEG cartography by use of nonparametric Fisher tests.

The three types of non-parametric permutation Fisher tests have been applied to inter-individual group studies and further to intra-individual multiple EEG recording sequences, providing computations of EEG probability maps testing two ordinal hypotheses. Two examples of previous group studies with "EEG local cerebral activation" are given: mental computation in a group of 20 controls and caffeine effects versus placebo in a group of 10 controls. For the intra-individual study, two successive recordings of 2.3 min eyes closed (EC1 and EC2), obtained at 50 min intervals, were compared by paired exact permutation Fisher tests (over 15 or 42 synchronous EEG sequences). These tests were applied to descriptive spectral parameters: RMS and % amplitudes, mean frequencies, resonance coefficient, for raw unfiltered EEG and delta, theta, alpha, alpha 1, alpha 2, beta 1, beta 2 frequency bands. Two hypotheses were tested for each of the computed 31 parameters, providing two probability maps indicating if the parameter was greater or lower in the first EEG recording or in the second. The second EEG sequence, EC2, was "EEG activated" compared to the first sequence EC1 if the following were present: decreased amplitudes mainly in raw EEG, low activity and alpha bands; increased frequencies mainly, in raw EEG, delta and beta 1 fast activities; increased fast activity percentages; decreased coefficient of resonance. The effect of choice of reference was also evaluated: probability maps for a frontal reference were different than other probability maps obtained after computation of average reference or source derivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Mapping↗

PubMedDate not supplied

[Schizophrenia and semantic priming effects].

INTRODUCTION: This article is a review of studies using the semantic priming paradigm to assess the functioning of semantic memory in schizophrenic patients. CONTEXT: Semantic priming describes the phenomenon of increasing the speed with which a string of letters (the target) is recognized as a word (lexical decision task) by presenting to the subject a semantically related word (the prime) prior to the appearance of the target word. This semantic priming is linked to both automatic and controlled processes depending on experimental conditions (stimulus onset asynchrony (SOA), percentage of related words and explicit memory instructions). Automatic process observed with short SOA, low related word percentage and instructions asking only to process the target, could be linked to the "automatic spreading activation" through the semantic network. Controlled processes involve "semantic matching" (the number of related and unrelated pairs influences the subjects decision) and "expectancy" (the prime leads the subject to generate an expectancy set of potential target to the prime). These processes can be observed whatever the SOA for the former and with long SOA for the later, but both with only high related word percentage and explicit memory instructions. LITERATURE FINDINGS: Studies evaluating semantic priming effects in schizophrenia show conflicting results: schizophrenic patients can present hyperpriming (semantic priming effect is larger in patients than in controls), hypopriming (semantic priming effect is lower in patients than in controls) or equal semantic priming effects compared to control subjects. DISCUSSION: These results could be associated to a global impairment of controlled processes in schizophrenia, essentially to a dysfunction of semantic matching process. On the other hand, efficiency of semantic automatic spreading activation process is controversial. These discrepancies could be linked to the different experimental conditions used (duration of SOA, proportion of related pairs and instructions), which influence on the degree of involvement of controlled processes and therefore prevent to really assess its functioning. In addition, manipulations of the relation between prime and target (semantic distance, type of semantic relation and strength of semantic relation) seem to influence reaction times. However, the relation between prime and target (mediated priming) frequently used could not be the most relevant relation to understand the way of spreading of activation in semantic network in patients with schizophrenia. Finally, patients with formal thought disorders present particularly high priming effects relative to controls. CONCLUSION: These abnormal semantic priming effects could reflect a dysfunction of automatic spreading activation process and consequently an exaggerated diffusion of activation in the semantic network. In the future, the inclusion of different groups schizophrenic subjects could allow us to determine whether semantic memory disorders are pathognomonic or specific of a particular group of patients with schizophrenia.

Cerebral Cortex↗

PubMedDate not supplied

[The assessment of episodic memory: theory and practice].

Episodic memory refers to a system which stores personally experienced events located in time and in space. It is characterized by autonoetic consciousness allowing a subject to be aware of his/her own identity throughout subjective time and to perceive the present as both a continuation of his/her past and as a prelude to his/her future. Current studies of episodic memory should take into account all these features. However, most episodic memory tests are restricted to memory performance and do not really measure episodic memory. In this article, after defining the terms of context and states of awareness, we describe two original tasks designed specially to investigate episodic memory: the 'Quoi-Où-Quand' (What-Where-When) and the 'TEMPau'. The first task allows the study of anterograde amnesia whereas the second consists of an assessment of retrograde amnesia. These two tasks include both scores of memory performance and measures of states of awareness using a procedure derived from the Remember/Know paradigm.

Amnesia, Retrograde↗

PubMedDate not supplied

Evaluation of flow cytometric methods to measure human sperm concentration.

Human sperm concentration is usually assessed using hemocytometry (HM). However, external and internal quality control schemes have shown that the accuracy of this method is low overall. Flow cytometry (FC) is a rapid, accurate, and reproducible technology for the quantification of various cell populations. We used 3 FC methods for human sperm counting from a 1:1 mixture of a diluted semen sample with a suspension of fluorospheres of known concentrations. The events that represented sperm cells were detected according to 1) gating on size and granularity (FCM1), 2) gating on DNA staining by propidium iodide (FCM2), and 3) a combination of FCM1 and FCM2 (FCM3). Sperm concentration was calculated from the ratio of detected events to fluorosphere counts and fluorosphere concentration. A pilot study undertaken by 12 technicians from different laboratories to compare FCM1 with HM showed a general agreement between both methods, despite wide variations in sperm concentration exhibited by HM due to the use of unoptimized procedures. A second experiment indicated that the overall variability in sperm concentration assessment by FCM1 was lower than that produced by HM when performed by 2 technicians using optimal procedures for 3 preparations of the same semen samples. The overall mean coefficients of variation were 3.9% for FCM1 vs 8.0% for technician 1, 12.3% for technician 2 (P < .05), and 15.7% for both technicians (P < .05). FCM1, FCM2, and FCM3 were compared with HM performed by a single trained technician for 39 semen samples (triplicates) of various quality. Compared with HM, FCM1 and FCM2 overestimated the sperm concentration by 14% and 8%, respectively, against only 4% per million sperm for FCM3, which was effective for the full spectrum of sperm concentrations (except azoospermia). In conclusion, this study demonstrates that human sperm concentration can be accurately assessed by the FC method combining gating on cell size, granularity, and DNA staining.

Coloring Agents↗

PubMedDate not supplied

[Hemispheric functional specialization and anxiety. Focus on an evaluation procedure].

Observations of brain-lesioned patients and experimental psychology studies have shown that the influence of the specific functioning of the two hemispheres of the brain on the regulation of emotional behaviour appears to be unequal and suggests a functional specialization of the right hemisphere for the expression and comprehension of the affective components of behaviour. However, the extension of this hypothesis to include all emotional experiences remains controversial. The observed superiority of the left hemisphere in the perception of positive emotions and the predominance of the right hemisphere in the treatment of negative emotions would appear to favour a joint and complementary participation of both cerebral hemispheres in emotional experiences. In the case of affective disorders, and particularly in anxiety symptoms, the hypothesis of a dysfunctioning of the right hemisphere is similarly questioned: while all metabolic studies corroborate this hypothesis, experimental psychological studies suggest the existence of a preferential involvement of one or the other hemisphere in relation to individual differences such as the "trait" anxiety score. Moreover, the few studies which have been undertaken with healthy volunteers raise the problem of their extrapolation to pathological situations. In view of the potential interest in the neuropsychological evaluations of subjects with different forms of pathological anxiety, we have developed an experimented with two tests aimed at evaluating the differential activity of the two hemispheres of the brain. These two tests, constructed on a "mirror-image" model from the specifications of a functional hemispheric specialization, are supposed to involve cognitive strategies pinpointing preferentially one hemisphere or the other.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Neuropsychology of musical identification].

Several neuropsychological observations have suggested that disturbances of the process involved in identifying music is related to lesions of the dominant cerebral hemisphere. The studies have been confirmed by different data from experimental psychology and functional brain imaging techniques. Based on these inference sources we propose different hypotheses to describe the cognitive processes involved in identifying music.

Cognition↗