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Biomedical subjects

D Bente

Publications and source records attributed to D Bente.

At least 19 recordsLinked to original sources
PubMed1984

[Electroencephalographic correlates of vigilance: methods and examples].

Quantitative methods for electroencephalographic assessment of vigilance must be oriented along certain principal sign patterns on the one hand, and must also take into account the dynamics of vigilance on the other. The more differentiated the approach, the more efficient will the determination be. Such quantitative methods can supply us with on-target and detailed information on the structure and dynamics of the neural processes involved in the regulation of vigilance, over and above the information supplied via visual analyses.

Alpha Rhythm↗
PubMed1983

[Changes in the electric organization of the brain in visual search and discrimination processes of different degrees of difficulty].

EEG activity during visual search processes with different degrees of discrimination difficulty was investigated in 13 male subjects. In accordance with the paradigm used by Neisser, 17 corresponding lists of rounded or angular letters were displayed. The task was to select the target letter Z from each list. The discrimination of the letter Z out of the lists of angular letters is the more difficult task. Spectral analysis shows a significant change in alpha-frequency structure during the more difficult search process. There is a shift of the dominant alpha-frequency from 11.5 to 10 Hz with a significant increase and concentration of power in the dominant frequency. This concentration of alpha-power around 10 Hz is more pronounced in the right occipital region than in the left. Concomitantly, there is a significant increase of power in subharmonic theta-frequencies. By consecutive principal analysis of spectral data these results were further differentiated and confirmed. The changes in the alpha- and theta-band during the more difficult search process are the expression of a complex transformation of EEG-frequency structure and patterning which cannot be interpreted by the usual concepts based on the theory of activation. Moreover, they seem to be the neurophysiological correlate of the accommodation (Piaget) of the neurodynamic processes to the altered perceptual conditions and to their effects on the internal matching process.

Adult↗
PubMed1979

Vigilance and evaluation of psychotropic drug effects on EEG.

Dynamics and structure of EEG-patterning are highly sensitive indicators of psychotropic drug effects on the regulation of vigilance. Methodological requirements for an adequate evaluation of these effects and appropriate procedures for their measurement are discussed. The kind of information to be obtained by using these strategies is illustrated by the results of comparative investigations concerning the action of Viloxazine, a new antidepressant drug, on the resting activity and on the waking EEG during performance of various tracking tasks.

Arousal↗
PubMed1979

[Factor analysis of spectral EEG-data. Models of application in pharmaco-elektroencephalography (author's transl)].

The factor analysis of spectral EEG values is a data-reducing and also a structural analytical procedure. This procedure enables the numerous frequency variables obtained by spectral analysis to be replaced by a more clearly arranged system of independent complex spectral variables (spectral or frequency factors), while at the same time the interrelations which exist between the individual frequency variables are taken into consideration. The use of this information elucidates the substantial dimensions of spectral configurations, the relationship of the frequency components which constitute them and their factor scores under various conditions. We have used several application models obtained in the course of pharmacoencephalographical examinations which are based on the procedure of a not fully developed multi-model factor analysis; on the basis of these models we have shown how, in a problem-orientated application of the factor analysis, well interpretable information can be gained on the relevant dimensions of the pattern of the brain electric activity, their dynamics and their topical localisation.

Cerebral Cortex↗
PubMed1979

[Quantitative EEG examinations on the vigilance stabilizing effect of nicergoline / Results of a double blind study with gerontopsychiatric patients (author's transl)].

A randomized, double blind, cross-over study was carried out on long-term gerontopsychiatric patients. The aim of the study was to compare the EEG effects of a four weeks' treatment with 10-methoxy-1,6-dimethyl-ergoline-8 beta-methanol-(5-bromonicotinate) (nicergoline, Sermion) with those of dihydroergotoxin-mesylate (DHETM) and a four weeks' placebo period. The results of the power spectrum analysis with a consecutive factor analysis of the spectral data show that nicergoline and DHETM have a vigilance stabilizing effect which is characterized by a decrease in the relative power of slow delta-theta frequencies and an increase in the alpha power. As opposed to DHETM, for which this effect could not be proved, nicergoline produces a significant increase in power of the fast alpha frequencies as well as of the beta 1, beta 2, and beta 3 band.

Aged↗
PubMed1978

[Synopsis of psychopathological, electroencephalographical, and pharmacokinetic variables during antidepressive treatment with viloxazine (author's transl)].

In order to achieve a more differentiated assessment of the profile and time course of treatment with a new antidepressant drug, several psychiatric, neurophysiological, and biochemical parameters were examined in a double-blind study (viloxazine versus amitriptyline). Special attention was directed to the use of a time-blind audiovisual technique. The TV technique allowed to demonstrate an earlier onset of the therapeutic effect under viloxazine, which is in good agreement with the cross-sectional and longitudinal profile of viloxazine as regards pharmacokinetics and EEG.

Amitriptyline↗
PubMed1978

[Piracetam and vigilance. A study of EEG changes and clinical effects in gerontopsychiatric patients (author's transl)].

The electroencephalographic and clinical effects of piracetam were studied in a group of 11 hospitalized gerontopsychiatric patients treated with a daily dosage of 4.8 g for 8--13 months. The EEG was evaluated by power spectral analysis, followed by a principal component analysis of frequency parameters. The statistical analysis of the resulting factor scores shows that piracetam induces significant EEG changes: decrease of slow frequencies, augmentation and acceleration of alpha-activity and increase of beta-activity. These EEG changes, indicating an increase in vigilance, correspond clinically to an improvement of communicative behavior and cognitive functioning.

Aged↗
PubMed1978

[On the effect of the antidepressant viloxazin on EEG and optimization of the system driver-vehicle-road (author's transl)].

The effects of a single dose of 100 mg 2-[(o-ethoxyphenoxy)-methyl]-morpholine hydrochloride (viloxazin) on EEG and optimizing control behaviour of drivers were investigated under double-blind conditions in 5 male subjects with many years' driving experience. The study was carried out on a special test course using a car equipped with measuring devices. The following signals were recorded: EEG and EOG, driving speed, steering torque, steering angle and angle rate, longitudinal and lateral acceleration, and yaw rate. As evaluated by means of spectral analysis with a subsequent principal component analysis the EEG showed an increase of the power in alpha- and beta-frequencies indicating a drug induced decrease of EEG vigilance. In correspondence the optimization of the system driver-vehicle-road was reduced indicating an impairment of the driver's control behaviour.

Adult↗
PubMed1976

Mianserin versus amitriptyline. A double-blind-trial evaluated by the AMP system.

Amitriptyline and mianserin were compared in a double-blind trial. Most of the depressive symptoms were influenced by both drugs, though quantitative and qualitative differences became evident. Amitriptyline predominantly influenced anxiety, despair and suicidal tendencies, while mianserin was particularly effective in psychomotor inhibition and the reduction of vegitative complaints. Mianserin did not show anticholinergic side effects.

Amitriptyline↗
PubMed1976

[Psychophysiological studies of EEG, operational performance and the dynamics of vigilance regulation. I. The EEG during performance of Brickenkamp's attention-concentration test (test d 2) (author's transl)].

During the performance of the d 2 test developed by Brickenkamp (standardized test of attention and concentration), occipital EEG activity was registered telemetrically in 10 male students aged 25 to 32 years. Simultaneously, the pencil markings performed by the subjects, indicating the time course of their pattern recognition and discrimination, were recorded by means of a piezo-electrical transducer. The EEG behavior during test performance was evaluated by serial spectral analysis. The analysis of the EEG parameters derived from it (total power, absolute and relative alpha-power) showed that there is a relationship between these EEG measures reflecting the regulation of cortical vigilance and the error rate in the concentration test. While subjects with low error rate present a heightening of cortical arousal focused in the right occipital area, subjects with higher error rate tend to have a higher degree of general cortical activation.

Adult↗
PubMed1976

[Psychophysiological studies of EEG, operational performance and the dynamics of vigilance regulation. II. EEG activity and reactivity during tracking performance in a control loop with varying degrees of difficulty (author's transl)].

In ten male students the EEG occipital activity was recorded during a visuo-motor task consisting of pursuit-tracking. The degree of task difficulty varied systematically depending on the modification of the transfer function of control element dynamics. The EEG data were evaluated by serial spectral analysis. The distribution functions of the total power estimates and their minima and maxima reflect the dynamics of the regulation of cortical vigilance and permit to differentiate the degree of effort which corresponds to the varying degree of task difficulty. The study of task-irrelevant acoustically evoked potentials showed that with increasing cortical activation the amplitudes of N1-P2 and P2-N2 are diminished. These results might suggest that evoked potentials induced by task-irrelevant stimuli can serve as indicators of the neuronal capacity available for information processing that is not task-oriented.

Adult↗
PubMed1976

[EEG aspects of waking-sleep behaviour and the chronophysiology of endogenous depressions].

1. The resting EEG in endogenous depressions, characterized by an increase of slow alpha- and subalphacomponents and a change of spatial organization of background activity, indicates a lowered level of vigilance, If the physiological diurnal increase of the dominant alpha-frequency compensates the described slowing of alpha-rhythm, the typical daily mood fluctuation of endogenous depressions will result. 2. Changes in the resting activity occurring during arousal are probably related to the functional alteration of the EEG-sleep activity, especially to the diminishing of phasic REM-activity. 3. It is suggested that the alterations in EEG pattern during sleep and wakeful state, indicating a dissolution of slow sleep activity and a deficiency of the arousal functions, represent a regression towards an immature functioning of the vigilance regulation.

Alpha Rhythm↗
PubMed1976

[Signal analysis of EEG-changes induced by nomifensin - a new antidepressant (author's transl)].

Ten healthy volunteers received a single oral dose of 100 mg nomifensive, a new antidepressant (tetragtdriusiqyubikube deruvatuve; Hoe 36-984). The drug-induced effects on the EEG were compared with those of placebo. The statistically proved results show that nomifensine causes a distinct shift in vigilance with two different partial processes. After an initially occurring stabilization of the dominant alpha-frequency there appears a polyrhythmic disintegration of the alpha-rhythm with increase of slower and faster frequencies. At the same time a shifting takes place within the beta-range with increasing of 23.5-32.0 Hz-components. Accordingly it is evident that nomifensine results in a typical pharmaco-electroencephalographic profile.

Alpha Rhythm↗
PubMed1975

[Spectral-analytical studies of the action of etifoxin on the human EEG].

Spectral analysis of EEG in healthy volunteers shows that Etifoxin, the hydrochloride of 6-chloro-4-methyl-4-phenyl-2-ethylamino-4H-3,1-benzoxazine (Hoe 36,801), in an oral dosage of 100 mg has a differential effect in function of the individual alpha organization. This differential effect appearing in the course of the quantitative evaluation can be interpreted, from a morphological point of view, as an expression of various partial phases and patterns of a process leading to reduced vigilance.

Alpha Rhythm↗
PubMed1975

[Clinical effects of moderate and high doses of carpipramine (author's transl)].

An open trial of Carpipramine which chemically is a synthesis of a tricyclic antidepressant and the side chain of a butyrophrenone has been performed in 75 acute and chronic schizophrenics over a period of 30 days. The daily dose was 400-800 mg exeeding the recommendations of the manufacturer. The psychopathological changes were documented and evaluated by means of the AMP and the AMPAS-system. In 50 of the patients the trial could be completed. Only the productive symptoms and disturbance of sleep showed a significantly decreased frequency before day 10. It seems remarkable that the symptom of somatic hallucinations responded very rapidly under treatment with Carpipramine. Significant sedative or extrapyramidal side-effects were not observed; anticholinergic effects were moderate. There seems to be evidence of a slight centrally stimulating component. The substance cnnot be classified as a typical neuroleptic nor as an antidepressant drug. A differential action depending on the initial syndrome constellation is discussed.

Acute Disease↗