PubMed Health⌕ Search

Biomedical subjects

G Verdeaux

Publications and source records attributed to G Verdeaux.

At least 19 recordsLinked to original sources
PubMed1983

[Computerized quantitative topo-electroencephalography].

A method is described which has been developed to topographically display the values of spectral EEG analysis from 11 electrodes on each hemisphere and 5 electrodes on the midline. The EEG from 16 channels at a time is multiplexed and sampled at 3.2 kHz. From power spectra averaged every 10 sec for 5 min a few spectral parameters are computed among which are the spectral intensities within the delta, theta, alpha and beta bands. The whole values are then displayed on maps representing lateral views of cerebral hemispheres by means of spectral iso-intensity surfaces with extrapolation of the intermediate points. Different spectral intensities are coded by means of different gray levels. These maps clearly illustrate the topographical distribution of EEG rhythms and their peculiarities related to the side of the head recorded.

Alpha Rhythm↗
PubMed1983

[Topographic aspects of drug-induced fast rhythms in quantitative topo-electroencephalography].

The topographical aspects of fast rhythms induced by different psychotropic drugs have been studied in patients by means of a previously described method. This method is based on the spectral analysis of 28 EEG channels over both cerebral hemispheres. The spectral parameters, computed over 2 min 40 sec, are put into a data base. The clinician can then decide which of these parameters will be extracted from the data base and then displayed by means of maps on a graphic terminal. Those maps are useful for immediate comparison not only of the fast rhythms' characteristic values but also of those from other spectral bands. As quantitative EEG analysis is more and more frequently used in psychotropic drug studies, a good knowledge of the topography of the rhythms induced by these drugs will help in the selection of the most useful derivations.

Adult↗
PubMed1982

[Multivariate correspondence analysis of a visually screened EEG. Application to a study of psychotropic drugs compared with placebos (author's transl)].

Eighty-seven EEG recordings were obtained from 9 healthy volunteers, medical students who were part of a controlled, double-blind, randomized study. After a first control recording, they received orally, at 1 week interval, either 3 placebos or 3 compounds: yohimbine chlorhydrate (4 mg), propranolol (40 mg), a psychotropic compound in experimentation. The polygraphic recordings were obtained 2 or 6 h after placebos or active compounds. Four EEG channels were recorded simultaneously (T4-C4, T3-C3, P4-O2, P3-O1). The EEGs were sampled at 200 Hz, for 120 successive epochs, free of artifacts. The recordings of 5 min were then submitted to spectral analysis followed by data reduction providing characteristic spectral parameters. A descriptive questionnaire of EEG made of 100 items was filled out by two electroencephalographists for each of 87 recordings. The items, with dichotomic choices, described 4 EEG frequency bands: delta, theta, alpha, and fast frequencies (beta). For each frequency band the following was evaluated: frequency, amplitude, asymmetry, morphology, relative abundance, irregularity, lability of frequency, diffusion, dominant localization, EMG activity and superposition of rhythms. The number of periods of drowsiness in 5 min and fluctuations of rhythms were also ascertained in the same way. The items were coded on punch cards and submitted to a first analysis of correspondences. The 3 factorial planes were plotted with the projections of each item together with the centers of gravity of placebos and treatments. The first factor can be interpreted as a bipolar axis 'mental activation-diffused vigilance', the first pole being characterized by a 'beta cluster' and the second by alpha and theta superimposed clusters. The second factor can be also considered as a bipolar axis 'drowsiness -quiet wakefulness', the first pole being characterized by a 'theta cluster' and a larger 'delta cluster' containing a smaller 'alpha cluster' of labile alpha rhythm intermingled with slower rhythms. In respect to the barycentric centers of gravity, yohimbine and propranolol are opposed to the placebo center along the factor-two axis. This may be considered as an 'anti-sedation effect'. However, along the first factor axis, the propranolol center can be associated with a greater diffusion of vigilance than the yohimbine center.

Adult↗
PubMed1979

Intra- and interhemispheric EEG differences quantified by spectral analysis. Comparative study of two groups of schizophrenics and a control group.

In this work we have studied comparatively the relationships between alpha intensity, alpha frequency, root-mean-square amplitude and their standard deviations, versus the location of the four recorded EEG channels: left and right rolando-parietal, left and right parieto-occipital. Twenty-four spectral parameters were computed for each 5-min EEG recording, in the eyes closed situation. The hebephrenic group (36 EEGs from six patients) presented higher values of alpha intensity and RMS amplitudes with low coefficient of variation when compared with the other groups. The left/right rolando-parietal amplitude ratio was 0.73 versus 1.52 for the parieto-occipital ratio. An amplitude hypovariability in the central regions, probably associated with hyperarousal, especially in the left hemisphere, can then be observed in hebephrenics, together with high alpha intensity on the left parieto-occipital area. The two groups of schizophrenics differ from the control group (27 EEGs from 12 subjects) in terms of spectral parameters, the hebephrenic group presenting a possible interhemispheric dysfunction.

Adult↗
PubMed1978

[Alpha activity in a group of schizophrenics: spectral analysis and comparison with a control group (author's transl)].

Spectral analysis of tracings from four leads; C3-P3, P3-O1, C4-P4, and P4-O2, were used to compare the results of fiftyseven electroencephalograms from 10 schizophrenics, and 14 normal subjects used as controls. The results show that the mean frequencies of the alpha waves are identical in schizophrenics and controls. Patients with hebephrenia show the lowest variations in alpha wave frequency but with the highest voltage, whereas paranoid schizophrenics have tracings with the lowest amplitude and the greatest variation in frequency. There is also better left intrahemispheric correlation of relative alpha intensities in those patients with the lowest variation in right alpha intensity in relation to controls. The preliminary results suggest that there is a reduction in functional asymmetry of the hemispheres in the electroencephalograms from schizophrenics, when looking at the alpha activity.

Adult↗
PubMed1978

[Statistical spectral study of alpha rhythms: modifications due to the tardive action of a hypnotic (author's transl)].

In a simple blind study to evaluate electroencephalographic criteria objectively, and to continue characterization of psychotropic compounds, 5 mg of nitrazepam, a hypnotic derivative, was given to seven subjects the night before the recording. We noted that in most subjects there was a reduction in the spectral intensity of the alpha rhythm, associated with a greater frequency instability, several hours after the absorption of nitrazepam. This corresponds to the tardive hypnotic action of the psychotrope, the importance of which is wellknown at the present time. In the same way as the increase in rapid rhythms, the slipping of 0.5 c/s of the dominant alpha frequency to the top could be characteristic of the action of nitrazepam.

Adult↗
PubMed1977

[A new psychotropic drug: carpipramine, intermediate compound between 2 therapeutic classes].

An open clinical study was conducted with carpipramine in 100 hospitalized subjects presenting various mental disorders. The therapeutic results on symptoms were assessed both as a whole and with the help of a rating scale. Doses varied from 50 to 400 mg per day. Carpipramine seems to be particularly efficient on schizophrenias, 66 cases of which were tested. The best results were observed in hebephrenic forms and depressive syndroms during the illness; in these indications, carpipramine exerts a clear psychomotor stimulating activity which is useful in decreasing indifference, apathy and ideomotor slowness. Schizophrenias with paranoid delusions or depersonalization anxiety tend to be somehow aggravated. Carpipramine does not seem to be a true antidepressant despite its desinhibitory properties. The compound proves useful in deficits of the psychomotor tone such as those occuring in psychasthenia or the deficit syndrom which follows withdrawal from opiates. Clinical and biological tolerances seem to be excellent and extrapyramidal side effects are exceptional. Carpipramine may be considered as a strongly desinhibitory neuroleptic agent which bears some resemblance to antidepressants because of its psychoanaleptic effect. The authors raise the question of possible antipsychotic properties in higher doses in relation to pharmacological data and a bipolar, antipsychotic and predominantly desinhibitory, therapeutic action.

Anti-Anxiety Agents↗
PubMed1977

[Relationship between blood zinc level and EEG changes under the influence of hyperpnea in normal subjects].

The red blood cell and serum zinc levels have been determined by atomic absorption spectrophotometry on 27 human subjects in apparent good state of health, tested monthly for five months successively. The subjects who present a decreased frequency of the E.E.G. pattern during hyperventilation, also show a diminished red blood cell Zn level, by comparison with the other subjects. This phenomenon suggests a possible relationship between red blood cell zinc concentration and E.E.G. signs of cortical hyperexcitability. These findings are discussed in the light of the recent literature.

Adolescent↗
PubMed1975

[Clinical and electroencephalographic study of a new antidepressive agent, mono-methyl-amino-propyl-dibenzo-bicyclo-octadine hydrochloride (Ciba 34, 276 Ba)].

A clinical trial on fifty patients studied a new compound with a quadricyclic structure, Ciba 34.276-Ba or Maprotiline in any category of depression. The product was found to have notable antidepressive properties, capable to act on the melancholic depressions of the manic depressive psychosis and of involutive melancholia. The best results were noted in the neurotic and reactive depressions perhaps because a tranquilizing activity marked in the majority of the cases. The clinical tolerance was found good and the side effects which reminded of those caused by derivates of Imipramine, remained moderate while the biological tolerance was perfect. The modifications of the electroencephalogram were of two types, one of them suggesting thymoanaleptic activity, the other suggesting rather a sedative activity.

Adjustment Disorders↗