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Biomedical subjects

A Waltregny

Publications and source records attributed to A Waltregny.

At least 19 recordsLinked to original sources
PubMed1999

Early thalamic and cortical hypometabolism in adult-onset dementia due to metachromatic leukodystrophy.

A case of early-onset adult dementia with family history of dementia is reported, characterised by neuropsychological deficits, suggesting frontal involvement, with mild non specific white matter abnormalities on CT scan. Familial Alzheimer's disease was suspected but the neuropathological diagnosis on brain biopsy was metachromatic leukodystrophy. 18FDG-PET revealed a very peculiar pattern of metabolic impairment in thalamic areas, in medial and frontopolar regions, and in occipital lobes. Neuropsychological follow-up showed relatively stable difficulties of long-term memory and signs of frontal lobe dysfunction, similar to those observed in subcortical dementias. MRI subsequently showed periventricular leukoencephalopathy. The brain metabolic pattern observed in that case of metachromatic leukodystrophy was quite different from that reported in other types of dementia.

Adult↗
PubMed1996

Traumatic brain injury, cognitive and emotional dysfunction. Impact of clinical neuropsychology research.

It is well established that head injury often causes brain damage leading to long term physical, cognitive and behavioural changes in the injured patients. Whereas the physical effects ranging from sensori-motor disturbances to posttraumatic epilepsy are often reported as well as cognitive sequelae, deteriorations of emotional and behavioural aspects are often neglected. Recent advances in imaging technology and clinical neuropsychology research have greatly contributed to increase our understanding of the effect of traumatic brain injury on diverse behavioural functions. After a brief review of the current status of problems facing the brain injured patients, this paper discusses the neuropsychological aspects of 3 long term brain injured patients. All 3 patients showed important behavioural and emotional distress several years after the accident. Whereas case report of patient A and C discuss the emotional and personality disturbance characterised by anxiety, depression and irritability, case report of patient C which is a case of classic frontal syndrome showed important memory impairment with emotional disturbance characterised by apathy, lack of motivation and complete indifference to his surrounding environment. Whatever the mechanisms involved, psychoaffective disturbances in the brain injured patients appear as important problems in the long term. These emotional difficulties must be considered in the treatment and rehabilitation procedures of these victims in order to help them to improve their social adjustment and quality of life aspects. Neuropsychological test data can be used to develop treatment strategies tailored for an individual's specific cognitive strengths and deficits.

Adult↗
PubMed1993

Stereotaxy and behavioural disorders.

A series of 35 selected non senile patients was investigated with stereotactic brain biopsies in frontal and temporal lobes including the rhinencephalon. Results of neuropathological studies are confronted with clinical proposals. Alzheimer's disease is diagnosed in about 10% of the cases under 50 years of age, but more than 50% after 50. In the whole series only 10 clinical diagnoses (29%) were confirmed by neuropathological findings, 14 cases (40%) were fully corrected, 5 out of 7 undefined demented patients were specified but 6 cases (17%) remained unspecified because only nonspecific gliosis was found. Thus stereotactic biopsies were without real interest in 10 confirmed diagnosis (29%), of relatively poor interest in 6 nonspecific gliosis (17%), but of great interest in 19 cases (40% corrected + 14% specified = 54%). It can be considered from a general point of view that in our series more than 50% of diagnoses benefit definitively by stereotactic brain biopsies bearing in mind that the clinical diagnosis fails in one case out of two. It is clearly demonstrated that this stereotactic methodology has a significantly higher score than conventional biopsies.

Adult↗
PubMed1990

Contribution of stereotactic brain biopsies to the diagnosis of presenile dementia.

Precise diagnosis of presenile dementia is a great challenge. The only valuable classification of dementia is the neuropathological one. We present the first series of stereotactic biopsies in 28 presenile patients (18 males, age 39 less than or equal to 58 less than or equal to 69 years, and 10 females, age 23 less than or equal to 52 less than or equal to 66 years). The results demonstrate that the clinical and paraclinical diagnosis (including positron emission tomography scan, neuropsychological examinations, computed tomography scan, electroencephalogram) in only one third of all cases and only in 50% of the Alzheimer and Creutzfeld-Jakob cases. This is very important to be kept in mind when epidemiology or efficacy of drugs are investigated without any neuropathological confirmation.

Adult↗
PubMed1990

Dopamine and acetylcholine release in thalamus of non-parkinsonian and parkinsonian subjects.

A study of neurotransmitter release has been performed on human brain biopsies obtained during the course of a therapeutic neurosurgical procedure. The electrically evoked-release of 3H-dopamine and 3H-acetylcholine was studied on slices from the thalamus of two parkinsonian and two non-parkinsonian subjects. Electrical stimulation of the non-parkinsonian thalamus increased the dopamine release but had no effect on acetylcholine release. This characteristic response had been previously observed in the normal rat thalamus. In contrast, the parkinsonian thalamus responded with a sharp increase in acetylcholine release without concomitant increase in dopamine release indicating the possible existence of an inhibitory control effect action of dopamine on acetylcholine release as seen in rat striatum.

Acetylcholine↗
PubMed1988

Regarding the experimental neurophysiological basis of psychosurgery.

A survey is given, on reports in the literature and personal experiences, on the neurophysiological basis of psychosurgery. Animal experiments as well as clinical-experimental observations in human beings are reviewed, following the usual present day targets: frontal lobe, cingulum, amygdala, thalamic and hypothalamic areas and anterior internal capsule. As a result, it has to be stated that there are no definite data resulting from animal experiments which could sustain the neurophysiological basis of psychosurgery. For psychiatric diseases animals are definitely not an adequate model. Therefore it is considered to be our neurosurgical duty to collect experimental data in human beings in a methodically proper manner and with respect to our ethical precepts.

Amygdala↗
PubMed1987

Stereotactic brain biopsies in presenile dementia.

Early detection and precise diagnosis of presenile dementias are important since they determine subsequent medical care. Presently the only way to classify these syndromes is by neuropathological examination. Between 1972 and 1987, 222 stereotactic serial brain biopsies were performed in 25 selected demented patients. Comparison between preoperative clinical diagnosis and histological finding gives the following results: in 32% the clinical diagnosis has been confirmed, in 60% the diagnosis has been corrected or specified and in 8% the stereotactic brain biopsies only showed unspecific pathological gliosis.

Biopsy↗
PubMed1986

[Application of the Talairach stereotaxic system for the purpose of establishing a common reference plane for brain imaging technics (CAT scan, NMRI, PET scan)].

Confrontation of data obtained from several modern imaging techniques (CAT Scan, NMR Scan, PET Scan) is a fundamental problem in actual neurological practice and must be correlated with histology. For that purpose, we use the referential plane of the stereotactic Talairach frame. Using teflon intraosseous buttons, the referential plane and a common zero reference point can be objectivated by CAT, NMR and/or PET Scans. A computer program gives the exact coordinates of the chosen target. These coordinates are immediately usable in the operating room for stereotactic serial biopsies.

Brain↗
PubMed1977

Auditory evoked potentials recorded from chronic implanted gyrus of Heschl in man.

By means of implanted multileads electrodes, responses to clicks and prolonged sound stimulations were recorded from the Heschl gyrus of 2 human brains. These responses were strictly localized to this structure. Cortical averaged auditory evoked potentials (c.AEP) to clicks are consistent with scalp averaged auditory evoked potentials (s.AEP). So, Na Pa, Nb, P1, N1, waves have similar latencies and none of them in the s.AEP may be correlated with myogenic potentials (in opposition with the suggestions of Bickford et al. 1964 and Celesia et al. 1968). Increasing the duration of sound stimulation resulted in changes of the response. For a duration longer than 20ms, an "on-response" and an "off-response" were noted. No satisfying physiological explanation of these events is retained despite data obtained with monaural homo and heterolateral stimulations and with variation of tone of sound stimulation.

Auditory Cortex↗