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Biomedical subjects

G Lelord

Publications and source records attributed to G Lelord.

At least 73 records · Page 4Linked to original sources
PubMed1984

Are there sex differences in averaged evoked responses produced by coupling sound and light in children and adults?

Averaged evoked response (AER) amplitudes have been reported to be larger in women than in men. The aim of this study was to determine whether AER changes produced by coupling sound and light differed between males and females (adults and children). Given the 3:1 male-female ratio in early infantile autism, we reasoned that information about sex-related differences in normal subjects might be important in interpreting the results in autism. We observed the characteristic AER changes when coupling sound and light: increased response amplitude over the occiput for both adults and children, decreased response amplitude over the vertex for adults and N1 decreased and P2 increased response amplitude over the vertex for children. Differences appeared as a function of sex in adults: the number and the amplitudes of AERs recorded in women were greater than in men with the exception of the P2 peak recorded over the occiput which was similar for males and females. The sex-related differences observed in the number and amplitudes of AERs are reduced when coupling sound and light.

Acoustic Stimulation↗
PubMed1984

[Relation between auditory evoked potentials (presence, amplitude) during sound and light conditioning and levels of dopamine derivatives in infantile autism].

The aim of this study was to study the relationships between conditioned AEPs and homovanillic acid (HVA) levels in autistic children (A, 9 boys, average age 6.3) compared to normal children (9 boys, average age 6.5) and to mentally retarded children (MR, 9 boys, average age 6.1) without any autistic behavior. AEPs were recorded at Cz and Oz during two sessions. The auditory stimulus (S) was first presented alone (habituation); the visual stimulus (L) was then presented 800 msec after S (conditioning). S was again presented alone (extinction). Urinary HVA dosage was performed on samples of urine taken after a 48-h tyrosine-free diet. Conditioning induced enhancement of AEPs. Latencies and amplitudes were smaller in autistic children. AEP presence was smaller in patients than in normal children and smaller in MR than in A children. Urinary HVA level was higher in patients and higher in the MR group than in the A group. A negative correlation between HVA level and Cz AEP presence was observed. Results showing higher Cz AEP variability and higher HVA level in MR than in autistic children tend to lead us to consider that both syndromes are related to common neurological dysfunctionings rather than indicating autistic syndrome behavioral specificity.

Attention Deficit Disorder with Hyperactivity↗
PubMed1984

[Brain stem auditory evoked potentials in the normal and autistic child].

From a neurophysiological viewpoint a hypothesis for the etiology of early infantile autism suggests that the symptoms are a result of abnormalities in processing sensory input at the level of the brain-stem. The methods for recording auditory evoked responses (BAERs) seemed particularly well suited to study a failure at this level. BAERs to brief monaural and binaural stimulation were studied in 17 autistic children ranging in age from 3 to 9 years (mean = 6.1). They were age and sex matched to normal controls. Electrodes were placed at the vertex and at the mastoid ipsilateral to the stimulation. Signals were amplified 10(5) using an amplifier with bandpass filters set at 160 Hz and 3 kHz. Stimuli were clicks (120 microsec) delivered to subjects through earphones at 2 intensities: 70 and 90 dB. Stimuli were presented in blocks of 3000 clicks (1500 clicks for each intensity) with a rate of 10/sec. No sedative medication was used. There was no difference between autistic and normal children for the latencies of peak I. Latencies of peaks II, III, IV and V were found to be shorter in autistic than in normal children. The I-II and II-III interpeak transmission times were significantly decreased in the autistic group, but not III-V interpeak transmission time. Autistic children showed V-VN amplitude greater than normal children. Our findings suggest that in the autistic syndrome, there is a defect of the modulation processing input related to intensity at brain-stem level.

Autistic Disorder↗
PubMed1983

[Monoamine and monoamine enzyme abnormalities in childhood autism].

According to monoaminergic hypothesis of psychosis, several symptoms observed in child autism may be related to anomalies of cerebral amines and/or synaptic dysfunctioning. The main amines concerned are serotonin and dopamine which are synthetized and catabolized following similar schemes. Methyl-indolamines production, mentioned in adult schizophrenia, has not been observed in child autism. Similarly, monoaminoxydase diminution has been observed in adults and not in children. Hyperserotoninemia does exist in some cases of child autism. Results concerning dopaminergic systems are more promising. The autistic behavioral syndrome suggests a dopaminergic dysfunctioning. Enhancement of homovanillic acid, the main metabolite of dopamine, has been found both in cerebrospinal fluid and in urines of some autistic children. Moreover, modifications of dopamine-beta-hydroxylase, an enzyme that changes dopamine into noradrenaline, have been mentioned in some cases of autism. A better definition of the autistic clinical syndromes associated with a more systematic study of monoamines plasmatic and urinary derivates will allow, in the near future, a better understanding of child autism and a clearer definition of therapeutic indications.

Amino Acids↗
PubMed1982

Clinical and biological effects of high doses of vitamin B6 and magnesium on autistic children.

In 1973 Rimland reported that some autistic children responded favorably to high doses of vitamin B6. Since this finding, different studies were performed to identify apparently B6 responsive subjects and to critically evaluate clinical and biological B6 responsiveness. Magnesium was included because large doses of B6 might increase irritability. 44 patients (mean age 9.3 years) were examined. All selected children had marked autistic symptoms. The children received a complete diagnostic work-up, including psychiatric, psychological, neurological and medical evaluation. Clinical data were scored using an estimate of global clinical state and numerical rating on a 18 item scale (Behavior Summarized Evaluation). In a first open trial 15 out of 44 children exhibited moderate clinical improvement with worsening on termination of the trial. Thirteen responders and 8 non responders were re-tested in a 2-week crossover, double-blind trial and the responses to the open trial were confirmed. Biochemical data analysis revealed that a significant decrease in urinary homovanillic acid (HVA) levels was observed during B6-Mg administration. During B6-Mg treatment, middle latency evoked potentials exhibited a significant increase of amplitude.

Adolescent↗
PubMed1981

Effects of pyridoxine and magnesium on autistic symptoms--initial observations.

In an open trial, a heterogeneous group of 44 children with autistic symptoms were treated with large doses of vitamin B6 and magnesium. Clinical improvement with worsening on termination of the trial was observed in 15 children. Thirteen responders and 8 nonresponders were retested in a 2-week, crossover, double-blind trial, and the responses to the open trial were confirmed.

Adolescent↗
PubMed1981

HVA and MHPG in urine of premature infants.

Higher levels of homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were observed in urines of 12 premature infants than in older children. An examination of the influence of age, sex, size, and head circumference revealed that the smaller the infants, the higher the HVA and MHPG values. Recently several investigators have reported an increased titer of urinary HVA in autistic children. It has been hypothesized that the increased levels of catecholamine metabolites (notable HVA and MHPG) could reflect accelerated catecholamine turnover. The elevated urinary HVA titers in infants as well as in autistic children may be due to an immaturity of the dopaminergic receptors.

Cephalometry↗
PubMed1981

Epidemiological and serological study of hepatitis A virus outbreaks in France: a comparison between immunoadherence and radioimmunoassay.

An epidemiological study and the simultaneous evaluation of anti-HAV antibody using radio immunoassay (RIA) and immunoadherence hemagglutination assay (IAHA) was performed during three hepatitis A epidemics in the Tours area (France). Fifty-seven sera from 35 subjects with viral hepatitis type A and 16 sera from nine children who did not develop any clinical signs of hepatitis were studied. The more explosive epidemic occurred in an institution for mentally retarded children (attack rate 68%). The two major outbreaks observed were due to the introduction of the institutions of individuals infected with hepatitis A virus. Two out of three of the index cases had a seafood dinner three to four weeks before onset of jaundice. Sera taken one week after jaundice were always found to be anti-HAV positive by both RIA and IAHA, and sera taken more than three days before the appearance of jaundice were negative by both methods. Sera taken at the peak of the transaminase elevation were anti-HAV positive by RIA but only one out of two were positive by IAHA. The anti-HAV titre by RIA increased from the time of the appearance of jaundice and the highest titres, over 1/20000 were seen only after several months. Observations of subjects in close contact with patients who seroconverted without any manifestation of hepatitis, confirmed the existence of clinically mute infections.

Adult↗
PubMed1981

Effects of vitamin B6 on averaged evoked potentials in infantile autism.

In autistic children, averaged evoked potentials have been reported to have lower amplitudes and shorter latencies than those of normal children. Also, moderate clinical improvement has been observed in some autistic children after treatment with vitamin B6 and magnesium. We have studied biochemical and electrophysiological effects of vitamin B6 and magnesium in 12 autistic children and in 11 normal children. During treatment of the autistic children with B6, an increase of amplitude of middle-latency evoked potentials and a decrease of urinary homovanillic acid were found. The reverse was noted in the normal subjects.

Autistic Disorder↗
PubMed1980

Event-related potentials evoked by sensory stimulation in normal mentally retarded and autistic children.

Evoked potentials (EPs) and slow potentials (SPs) were recorded during two sessions of sound (S) and light (L) conditioning (habituation: S alone; conditioning: coupling of SL; extinction: S alone after SL series). 125 children from 0 to 15 were examined: 82 exhibited signs of autistic behaviour and/or mental retardation; 43 were normally adapted. Two studies were performed. The first was an analysis of relationships: 65 clinical characters were noted for each child with behaviour scales and psychometric tests, 88 electrophysiological data were measured on averaged tracings. The second compared with t and chi 2 square methods the electrophysiological data of 3 groups clinically defined for age and typical syndrome. Results of the two studies supplemented each other. From the clinical point of view 3 major groups appeared: (1) autism, (2) mental retardation, (3) normal adaptation. From an electrophysiological point of view 2 major groups could be defined: (1) few conditioned EPs with small amplitude, generalized conditioned SPs, small unconditioned EPs, generalized unconditioned SPs, conditioning 'to time'; (2) many conditioned EPs, many conditioned rhythmic potentials, absence of generalized SPs, many localized vertex negative SPs (CNVs), large unconditioned EPs, no conditioning to time. Some differences were observed in generalized SPs, small and positive in mentally retarded children, negative or positive in autistic children. EP and SP data clearly help to differentiate pathological groups from a normal group but are insufficient to distinguish the autistic from the mentally retarded children.

Adolescent↗