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Biomedical subjects

G Lelord

Publications and source records attributed to G Lelord.

At least 19 recordsLinked to original sources
PubMed1992

Blood flow response to auditory stimulations in normal, mentally retarded, and autistic children: a preliminary transcranial Doppler ultrasonographic study of the middle cerebral arteries.

Using the noninvasive transcranial ultrasonic Doppler method, flow dynamics of the middle cerebral arteries were investigated in relation to auditory stimulations in 12 children with autistic behavior compared with 12 normal controls and 10 mentally retarded children. In normal children, auditory stimulation evoked lateralized modifications: blood flow increased and resistance index decreased on the left side; such modifications were not recorded on the right side. This pattern should indicate vasodilatation mechanisms induced by changes in the metabolism of the brain areas supplied by the left middle cerebral arteries (MCA). Although less asymmetrical, this pattern was also found in the mentally retarded children. Autistic children significantly differed from these two groups. They displayed a symmetric pattern of responses with a blood flow decrease and resistance-index increase on both sides; this could suggest abnormal metabolic mechanisms induced by auditory stimulation in autistic children and could be related to the previous hypothesis of impairment in the development of cerebral lateralization in autism. These preliminary results show that transcranial Doppler ultrasonography may be a valuable and practicable tool for the noninvasive study of evoked blood flow responses in psychopathology.

Arousal↗
PubMed1992

Unimodal and crossmodal reactivity in autism: presence of auditory evoked responses and effect of the repetition of auditory stimuli.

Using auditory evoked responses, this work compares the reactivities to unimodal and crossmodal stimuli and the main neurocognitive functions most often disturbed in autism. With the aim of testing the hypothesis that the deficit in the ability to form crossmodal associations in autism is linked to a cognitive abnormality, auditory evoked responses to simple and to crossmodal (auditivo-visual) stimuli were recorded in 30 autistic children and compared with those of 30 normal and 30 mentally retarded children. Relationships between electrophysiological reactivity and neurocognitive functions showed that the cognitive deficit in the ability to maintain crossmodal associations is preceded by a more elementary perceptive abnormality in autistic children.

Acoustic Stimulation↗
PubMed1992

Sensitivity and specificity of the Behavioral Summarized Evaluation (BSE) for the assessment of autistic behaviors.

The Behavior Summarized Evaluation (BSE), developed for the assessment of autistic behavior, was specifically designed to evaluate the severity of behavioral problems in autistic children involved in bioclinical and therapeutic studies. The reliability studies and the factorial analysis of this scale have been previously published. The present paper examines the effectiveness of the BSE to discriminate 58 autistic from 58 nonautistic mentally retarded children. The BSE clearly separated the two samples of children. A most efficient combination of 8 items emerged from the stepwise item selection procedure. The between-group differences were highest on 4 items, indicating that the most particular pattern in autistic compared to nonautistic children could be the association of autistic withdrawal and stereotypic behaviors. Our findings suggest that the BSE could help in the detection and evaluation of autistic developmental deviance. Implications for further research are discussed.

Autistic Disorder↗
PubMed1992

Electrophysiological evidence of different abilities to form cross-modal associations in children with autistic behavior.

This study evaluates the amplitudes of auditory evoked responses and the variability of evoked responses, using a signal-to-noise ratio (SNR) method applied to individual evoked potential in a cross-modal (sound and light) association paradigm in 17 children with autistic behavior matched for sex and chronological age with normal children. Auditory evoked responses were smaller in children with autistic behavior than in normal children. The modifications of amplitudes and of SNR during cross-modal associations allowed the separation of children with autistic behavior into 3 subgroups who presented different patterns of ability to form cross-modal associations. These 3 subgroups of children presented different clinical profiles demonstrating that the differences observed in the ability to form cross-modal associations can be related to differences in the main psychophysiological functions such as attention, intention, motility, association, contact and communication.

Acoustic Stimulation↗
PubMed1992

[Development in the metabolism of dopamine and its derivatives. Application to gross development disorders].

Dopamine (DA) and its metabolites homovanillic acid (HVA) in total, free and conjugated forms, dihydroxyphenylacetic acid (DOPAC) in total, free and conjugated forms, and 3 methoxytyramine (3 MT) levels were determined in the urine of autistic children from 2 years 8 months to 12 years of age and compared to those in normal children of identical age. Very significant group and age effects were found for DA, HVA and 3 MT. In the discussion, results are related to the hypothesis of a disorder in the maturation of the dopaminergic systems in infantile autism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Monoamines (serotonin and catecholamines) and their derivatives in infantile autism: age-related changes and drug effects.

Levels of dopamine (DA) and its derivatives homovanillic acid (HVA), 3-4 dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3MT) and norepinephrine+epinephrine (NE + E), and serotonin (5HT) and its derivative 5-hydroxyindolacetic acid (5HIAA) were determined from the urine of 156 autistic children aged two to 12 years 6 months, and compared with those of age-matched mentally retarded non-autistic and normal controls. Very significant group and age effects were found for DA, HVA, 3MT, NE + E and 5HT. High HVA, 3MT, NE + E and 5HT levels were found in autistic and non-autistic children. The DA, HVA, 3MT, NE + E, 5HT and 5HIAA levels decreased significantly with age in the three groups. Significantly decreased levels of DA and HVA were observed in autistic children on haloperidol, compared with non-medicated autistic children. The results are discussed in relation to the hypothesis of a maturation defect of monoaminergic systems in autism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Regional cerebral blood flow in childhood autism: a SPECT study.

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.

Autistic Disorder↗
PubMed1992

[Demonstration of cerebral lateralisation disorder in autistic children: study of auditory reactivity by transcranial pulsed Doppler].

Transcranial Doppler Ultrasonographic recordings of the middle cerebral arteries were performed on children with autistic behavior (AUT), compared to retarded children without autistic behavior (NON-AUT) and normal children (NOR). Blood flow measurements (resistance index) were performed at rest and during auditory stimulations. Compared to NOR and NON-AUT, significant differences of the resistance index were found in AUT on the left side, thus suggesting differences in metabolic mechanisms evoked by auditory stimulations. This result confirms the hypothesis of abnormal development of cerebral lateralization in autism.

Autistic Disorder↗
PubMed1992

The assessment of psychophysiological dysfunction in children using the BSE scale before and during therapy.

The purpose of exchange and development therapies (EDT) is to reduce the behavioural problems which are the expression of psychophysiological dysfunction. The aim of this study was to reveal the most disturbed psychophysiological functions and their evolution during the course of EDT in 42 children divided into three groups; group I--15 children with pure autism (A); group II--16 children with autism associated with neurological disorders (AA); and group III--11 children with pervasive developmental disorders (PDD). Among the 12 functions analysed, groups AA, A and APDD had respectively 8, 6 and 4 functions in which the score was high (> 2.5), indicating serious disorders (maximum 4). All the dysfunctions improved during EDT. However, each group had certain areas which were more susceptible to treatment. Further analysis of behaviour problems led to a more precise definition of the objectives and to the adaptation of the therapeutic methods to obtain greater effectiveness.

Adolescent↗
PubMed1990

The Behavioral Summarized Evaluation: validity and reliability of a scale for the assessment of autistic behaviors.

The Behavioral Summarized Evaluation (BSE), is a 20-item paper-and-pencil rating scale specifically designed for the measurement of behavioral parameters which could be related to biological data in autistic children involved in educational programs, neurophysiological studies, and therapeutic trials. The development of the scale, the validity, and reliability studies are presented in this paper. The results suggest that the BSE is an acceptable tool for the assessment of autistic behaviors, easy to handle, and accessible to both professionals and paraprofessionals of the medico-educative staff. It is a useful addition to the bioclinical researcher's evaluation battery for bioclinical and therapeutic studies. However, more work is suggested to further investigate the psychometric properties of this behavior assessment instrument.

Adolescent↗
PubMed1989

Urinary dopamine metabolites as indicators of the responsiveness to fenfluramine treatment in children with autistic behavior.

Modifications in serotonin and dopamine metabolism were evaluated in 13 children with autistic behavior and related to their responsiveness to fenfluramine treatment. A double-blind medication-placebo crossover design was used. Each patient received 1.5 mg/kg fenfluramine daily for 3 months followed and preceded by placebo for 1 month. Clinical improvement was observed in 6 children (responders). It included reduction of behavioral symptoms such as motor activity, anxiety, mood disturbances, and distractibility. Modifications of serotonin (5-HT), dopamine (DA), and DA metabolites [homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC)] were assessed at urinary levels. Responders and nonresponders showed a significant decrease of urinary 5-HT levels on fenfluramine. The main differences between the two groups of subjects were found with HVA, the major metabolite of DA. Fenfluramine significantly increased HVA levels in responders whereas no significant modification was found in nonresponders. Moreover the initial level of HVA (lower in responders) significantly differentiated the two groups. These results suggest that the clinical response to fenfluramine could be related to the dopaminergic action of this drug and that urinary DA metabolite levels could be considered as indicators of the responsiveness to fenfluramine treatment in children with autistic behavior.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Electrophysiological effects of fenfluramine or combined vitamin B6 and magnesium on children with autistic behaviour.

The authors compared the effects of fenfluramine or combined vitamin B6 and magnesium treatment on the evoked potential conditioning of 12 children whose autistic behaviour had improved clinically following treatment. The children who were clinically sensitive to combined vitamin B6 and magnesium developed a conditioning phenomenon and the fenfluramine-sensitive children showed an enhancement of the Cz evoked response amplitude. Results are discussed with reference to behaviour modifications observed during treatment.

Autistic Disorder↗
PubMed1989

Auditory evoked potential modifications according to clinical and biochemical responsiveness to fenfluramine treatment in children with autistic behavior.

Evoked potentials to auditory stimulations varying in intensity were studied in 13 children with autistic behavior treated with fenfluramine. Modifications of both amplitude and single-trial potential variability were considered according to the clinical and biochemical responsiveness to this drug. Six children (responders) were clinically improved by the treatment. Electrophysiological data were affected according to the clinical and biochemical responsiveness to fenfluramine: the auditory evoked potential amplitude increased, and the single-trial potential variability decreased at each intensity level only in responders whose dopaminergic metabolism was significantly modified by fenfluramine treatment. No modification was found in nonresponders. Both biochemical and electrophysiological results argued for an amphetamine-like action of fenfluramine in those autistic children whose attention deficits are associated with motor disturbances including hyperactivity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Use of bioclinical markers for the assessment and treatment of children with pervasive developmental disorders.

The method presented is based on the 3-dimensional bioclinical examination of autistic children. The covariations of behavior ratings, electrophysiological (cortical evoked potentials) and biochemical (urinary monoamine metabolites) measurements are analyzed. The systematic application of these markers provides precise information for a more rational application of therapeutics. It could help to better understand the underlying mechanisms of autism.

Arousal↗
PubMed1989

[Measurement of cerebral blood flow by transcranial Doppler ultrasonography in children presenting with autistic behavior. Preliminary results].

Transcranial Doppler ultrasonographic recordings of the middle cerebral arteries were performed on eight children with autistic behavior compared to eight controls. Blood flow measurements were assessed at rest and during auditory and visual stimulations. The main result was obtained during the auditory stimulations and concerned the left artery blood flow which is lower in autistics than in controls in these conditions (p less than .02). This result confirms the possibility of a left hemisphere dysfunctioning in autistics and may be related to clinical features as language disabilities and paradoxical reactivity to auditory stimuli.

Acoustic Stimulation↗
PubMed1988

Urinary free and conjugated catecholamines and metabolites in autistic children.

Urinary catecholamines (DA, NE, E) and their main metabolites (HVA, DOPAC, MHPG) were analyzed both as free and conjugates in eight children diagnosed as autistic according to DSM-III criteria and eight normal children. Significant differences appeared for the urinary excretion of both DA and NE and their respective metabolites: Autistic children showed low DA, high HVA, high NE, low MHPG urinary levels. These results are consistent with previous findings on altered catecholamine metabolism in autistic children. They suggest that autistic behaviors might be related to an abnormal functional imbalance among monoamines either at a molecular level or at a system level. Furthermore, they emphasize the special interest of urinary assays in pediatric research.

3,4-Dihydroxyphenylacetic Acid↗