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Biomedical subjects

F Rösler

Publications and source records attributed to F Rösler.

48 records · Page 3Linked to original sources
PubMed1986

Flupentixolhydrochloride in low dosages: effects on perceptual and psychomotor performance in emotionally stable and emotionally labile healthy subjects.

Effects of flupentixol on performance were evaluated in a double-blind study with 107 healthy male subjects. Experimental factors were dosage (0, 1, and 2 mg Fluanxol 0.5/day), the trait variable 'neuroticism' (high vs. low score on a questionnaire scale), and time of measurement (before and after 4 days of treatment). Drug effects were measured by means of seven paper-and-pencil tests and eight apparatus tests covering the following cognitive functions: endurance in attention, spacial orientation, flexibility and speed of closure, perceptual speed, response speed, psychomotor coordination, knowledge of traffic rules, and basic motoric tempo. Univariate and multivariate ANOVAs disclosed that flupentixol has detrimental effects on perceptual and psychomotor functions, in particular when administered in a dosage of 2 mg/day. These treatment effects did not interact with the trait variable neuroticism. Nevertheless, there were substantial differences between emotionally stable and emotionally labile subjects in both absolute performance level and change of performance over time.

Adult↗
PubMed1986

[Subjective findings in emotionally stable and labile subjects following oral application of flupenthixol in small doses].

The mood-changing effects of flupentixol (Fluanxol 0.5 mg) were evaluated in a double-blind study with 107 healthy male subjects. Experimental factors were dosage (0, 1 and 2 mg flupentixol/day), time of measurement (before, during, and after 4 days of treatment), and the trait variable "neuroticism" (high vs. low score on a questionnaire scale). Drug effects were measured by means of rating scales and symptom checklists. Statistical analyses revealed that state anxiety and bodily symptoms associated with depressive states were diminished by flupentixol. Moreover, emotionally labile subjects reported an impairment of vigilance under drug treatment. Placebo effects proved to be more substantiated in the group of emotionally stabile subjects than in the group of emotionally labile subjects.

Adult↗
PubMed1985

Delineation of pharmacopsychological effects by means of endogenous event-related brain potentials: an exemplification with flupentixol.

A new experimental paradigm for studying cognitive functions by means of endogenous event-related brain potentials is presented. The paradigm has the following characteristics: (1) subcomponents of 'P300' (P3a, P3b, positive slow wave) and subcomponents of 'CNV' (early and late wave) are separated in time; (2) probability effects known to work on P300 subcomponents are completely under experimental control; and (3) psychologically defined antecedent conditions which affect particular endogenous components can be manipulated precisely and independently of each other. The usefulness of the paradigm for monitoring pharmacopsychological effects on cognitive functions is exemplified by means of flupentixol (Fluanxol 0.5). Reliable drug effects were observed with a dosage of 2 mg/day after 4 days of treatment. The results can be taken as evidence that flupentixol has an impairing effect on human information processing resources; in particular functions related to motor preparation, perceptual analysis, and memory retrieval are affected.

Adult↗
PubMed1981

Principal components and varimax-rotated components in event-related potential research: some remarks on their interpretation.

Some properties of principal components analysis (PCA) and simple structure rotation, which are relevant to the study of event-related potentials (ERPs), were examined both in theory and with simulated data. The analysis casts some doubt on whether it is useful and desirable to rotate the loading pattern of a PCA of ERPs to simple structure. The evidence presented is more in favour of the unrotated solution. In particular we were able to demonstrate with simulated data that a solution rotated to simple structure may lead to false conclusions about the functional independence of ERP peaks. Beyond this, the more general question is asked of whether principal components should be accepted as basic waveforms, i.e. as physiologically meaningful entities which, for example, represent different ERP generators.

Contingent Negative Variation↗
PubMed1978

Cortical potential correlates of selective attention in multidimensional scaling.

Cortical evoked potentials were recorded from the vertex of subjects performing a similarity rating task. Proximity data were analysed according to INDSCAL (Carroll and Chang, 1970). Brain activity was averaged separately for different stimulus attributes and different stages of the judgement process. The amplitudes of the two positive deflections of the averaged evoked potential, peaking around 160 and 330 msec after stimulus onset respectively, were systematically influenced by two factors: The weight, which the evoking attribute received in the overall dissimilarity judgement, and the position of the evoking attribute in the stimulus train. The results support the hypothesis that differences in the perception of similarity are due to differences in attentional set. Reference is made to the 'additive-difference model' of scaling behaviour (Tversky and Krantz, 1970) and Broadbent's (1970) distinction between stimulus set and response set attention.

Adult↗
PubMed1975

[The effect of an antihypertensive drug during psychological stress. A double-blind study].

A sample of 20 patients suffering hypertension (with a moderate rise in blood pressure) was randomly divided into two treatment groups of equal size. The patients of one group received antihypertension treatment with the combination drug Briserin¿ (containing 0.1 mg reserpine, 5 mg clopamide, 0.5 mg dihydroergocristin/per tablet); the other patients who served as control group, received a matched placebo. After a fortnight's treatment, the responsiveness of both groups to five different psychologically stressing situations (those with cognitive and/or emotional overload) was tested. Analysis of covariance revealed clinically significant differences in the mean systolic and diastolic pressure scores of the two groups. The scores of the treatment group were lower not only under stress but also at rest. There was in interaction between rise of blood pressure under stress and kind of stress in the two groups, i.e., in situations with heavy emotional and/or cognitive load the differences in the pressure scores of the two groups were less substantial than in situations with a low or medium load. The treatment had no systematic effect on heart rate in this sample. In the treatment group reaction time, perceptual speed, and short-term memory were impaired as compared with the control group; but these differences did not reach a level of significance.

Adolescent↗