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Biomedical subjects

G Fehm-Wolfsdorf

Publications and source records attributed to G Fehm-Wolfsdorf.

At least 19 recordsLinked to original sources
PubMed1999

Cortisol responses to marital conflict depend on marital interaction quality.

A sample of 80 couples were videotaped discussing a marital conflict and were then grouped in 3 types according to their interaction behavior: both partners displaying predominantly negative behavior ( N = 36 couples); both partners showing positive behavior ( N = 26); and couples showing asymmetric behavior (one positive, one negative; N = 16). Positive o r negative in this context refers to the empirically defined quality of speaker and listener skills by the Kategoriensystem Partnerschaftlicher Interaktion. Psychophysiological responses were measured 5 times, both before and after the conflict discussion. Participants rated their overall marital quality, the number of marital problems, and their actual cognitions and emotions. Overall responses to the conflict revealed a greater cortisol response in women than in men. Couples grouped according to their interaction style showed significant differences in cortisol responses: In couples with positive interaction, cortisol increased markedly, whereas couples with negative interaction showed a nonresponse, that is, a slight decrease expected with diurnal variation, although they rated the actual conflict discussion as "stressful" like the other groups of couples. We conclude that marital interaction directly affects physiological responses to a conflict depending on interaction quality.

Journal Article↗
PubMed1998

The efficacy of a compact psychoeducational group training program for married couples.

There is a lack of psychoeducational programs for married couples who, although subjectively concerned about their marriages, do not seek marital therapy. In this study, the efficacy of a cognitive-behavioral program delivered on a weekend by 2 trainers for groups of 4 couples was investigated. Couples (n = 67) were recruited by newspaper announcements, then randomly assigned to the intervention program or a waiting-list control group. The program consisted of communication and problem-solving training, couples' discussions to clarify their relationship expectations, and exercises to enhance their sensual or sexual relationship. At postassessment, intervention couples emitted more positive verbal and nonverbal communication behaviors during a conflict discussion task than did control couples, who reported significantly more relationship problem areas and displayed more negative communication behaviors. At the 1-year follow-up, intervention couples reported fewer problem areas in comparison with preassessment.

Adult↗
PubMed1998

Acute stress modulates symptom awareness and hormonal counterregulation during insulin-induced hypoglycemia in healthy individuals.

The purpose of this study was to determine whether the perception of hypoglycemia is reduced during acute stress. In Session I each of our 40 healthy male volunteers received a bolus injection of human insulin (0.05 IU/kg) resulting in plasma glucose nadirs of below 2.8 mmo/L. In Session 2 participants received insulin or saline, with half of each group being stressed by having to prepare and give a speech. Data collection at 5- to 25-min intervals included a symptom checklist, blood pressure, heart rate, and blood sampling for measurement of plasma glucose and counterregulatory hormones. Individuals in the stress + insulin group were less sure of having received insulin and ate fewer cookies compared with controls. They reported lower intensity of the hypoglycemic symptoms of palpitations, tremor, dizziness, and blurred vision, in contrast to the reduced subjective and behavioral reactions, they showed the strongest hormonal counterregulation. We conclude that acute stress during hypoglycemia reduces symptom awareness and the ability to detect hypoglycemia.

Journal Article↗
PubMed1998

Memory deficits at 0.6 MPa ambient air pressure.

We investigated the effects of an elevated ambient air pressure of 0.6 MPa on verbal memory performance. Twenty-four experienced divers were compressed in a dry hyperbaric chamber to pressures equivalent to 0.5 meters of seawater (msw) (n = 12) and 50 msw (n = 12). Verbal memory was assessed by free recall and recognition of visually presented word lists. The testing procedure specified learning and testing at surface, learning at surface and testing at depth, learning and testing at depth, and learning at depth and testing at surface. Non-specific stress was assessed by measurement of salivary cortisol, heart rate, and subjective stress before, during, and after the dives. The 50-msw dive group showed a significant decrease of free recall performance when the material was learned at depth (P < 0.01). However, only postdive recall of material learned at depth remained significantly impaired (P < 0.05), whereas recognition performance was normal. For both groups no significant effects of depth on the investigated stress indices were obtained. These results are taken as evidence that inert gas narcosis may interfere with encoding and/or retrieval of verbal information, although the possibility that other stressors in the hyperbaric environment contributed to these deficits cannot be eliminated entirely.

Adult↗
PubMed1997

Symptom awareness is affected by the subjects' expectations during insulin-induced hypoglycemia.

OBJECTIVE: To assess how expectations and symptom beliefs based on a previous episode of insulin-induced hypoglycemia influence symptom awareness after a second insulin injection in healthy subjects. RESEARCH DESIGN AND METHODS: After a first episode of insulin-induced hypoglycemia in session 1, half of 40 healthy male subjects were told at the beginning of session 2 that they would receive human insulin (0.05 IU/kg), the other half saline. According to a 2 x 2 balanced placebo design, only half of each group received the announced substance, whereas the other half received the substance contrary to their expectations. Data collection at 10-15 min intervals included a symptom checklist, blood pressure, heart rate, plasma glucose, and counterregulatory hormone levels. RESULTS: The expectation of a repeated hypoglycemia clearly influenced the subjects' psychophysiological responses. Without knowledge about the actual treatment, there was only an average maximum confidence of 65% of having received insulin. Expecting the insulin injection led to an increased sum score of neuroglycopenic symptoms but not of autonomic symptoms. Subjects expecting the insulin injection reported more weakness, blurred vision, and inner restlessness than those subjects expecting the saline injection. Those subjects correctly informed about receiving insulin experienced the most drowsiness, dizziness, and headaches. The expectations of the insulin injection increased the norepinephrine levels and the heart rate. The told insulin/given insulin group showed the highest glucagon levels. CONCLUSIONS: The results support the hypothesis that the subjects' expectations influence their perceived symptoms.

Adrenocorticotropic Hormone↗
PubMed1996

Olfactory information processing during the course of the menstrual cycle.

In the present study we examined whether olfactory information processing depends on the phase of the menstrual cycle. Five female subjects were investigated during three phases (follicular, ovulatory, luteal) of their menstrual cycle. In each session chemosensory (olfactory) event-related potentials (CSERP) were recorded and olfactory thresholds and the hedonic tone of the test stimulus (citral) were determined. Threshold values were correlated with the salivary cortisol level. The results show that olfactory perception changes during the menstrual cycle. After the first stimulus presentations in a recording session, odors were perceived as more complex or novel during the ovulatory period (enhanced amplitude of P3-1). With continued stimulation, odor processing became faster (reduced latency of NI, P2 and P3-2) around ovulation and slower during the follicular phase. Moreover, odors were described more differentially during the ovulatory period. Olfactory sensitivity was correlated positively with the peripheral cortisol level.

Adult↗
PubMed1996

Differential effects of glucocorticoids on human auditory perception.

It is assumed that glucocorticoids and mineralocorticoids, the hormones produced by the adrenal cortex, act as modulators of central nervous functions in addition to their well-known role in endocrine stress responses. More specifically, it has been suggested that adrenal corticoids cause changes in sensory thresholds. In two double-blind crossover studies we evaluated auditory perception in healthy volunteers after treatment with hydrocortisone, dexamethasone, and the respective placebos. Stapedial reflexes, pure tone and speech audiograms, and brainstem electric response audiometry served as the dependent variables. As circadian changes in the density and occupancy of the brain corticosteroid receptors have been postulated, we performed Study I in the morning and Study II in the evening. Treatment effects clearly varied with time of day. A differential effect of the two corticoids occurred on contralateral stapedial reflexes. These results parallel results obtained with gustatory stimuli, and suggest that glucocorticoids modulate sensory perception across modalities.

Adult↗
PubMed1996

Analgesic effect of ceruletide in men is limited to specific pain qualities.

Cholecystokinin (CCK) and related peptides are supposed to be potent analgesic neuropeptides. Studies in rodents suggest a dose-dependent biphasic effect. The present study aimed to examine the pain modulating effect of different doses (0.5 microgram and 5 micrograms) of ceruletide (CRL), infused i.v. for 30 min. Pain thresholds were obtained for ischemic, mechanical, and thermal pain. In addition, pain tolerance was measured for mechanical pain. According to a placebo-controlled double-blind within-subject design 25 healthy men attended three experimental sessions each. Pain perception was measured as a baseline and twice after the infusion. The effect of both doses of CRL to enhance the pain threshold for thermal stimuli is in line with former studies. However, perception of heat stimuli above or below the threshold was not substantially affected by CRL treatment. Algesic properties of CRL are also indicated, because the tolerance for mechanical pain decreased after administration of the high dose of CRL. Perception of ischemic pain was not obviously influenced by any of the treatments. The role of CRL in human pain modulation seems to vary, depending on the type of experimental pain.

Adult↗
PubMed1996

Modulation of pain perception in man by a vasopressin analogue.

The aim of the present experiment was to test whether vasopressin modulates pain perception in man. Twenty-four male volunteers participated in four sessions, each 2 weeks apart. After an adaptation session the subjects were treated intranasally with either 30 or 60 micrograms desmopressin (DDAVP) or placebo according to a cross-over double-blind design. Pain induction involved mechanical, thermal, and ischemic stimulation DDAVP had no unitary effects on pain perception in the different pain tests. The 30 micrograms dose induced sensitization to thermal stimuli. Neither treatment influenced ischemic pain perception. The mechanical pain threshold of the index finger was increased by the 60 micrograms dose only. After treatment with either dosage of DDAVP the subjects generally tolerated the pressure on their index finger for a longer time than after placebo treatment.

Administration, Intranasal↗
PubMed1993

Classically conditioned changes of blood glucose level in humans.

Procedures of classical conditioning in animals and man have provided evidence that most psychophysiological responses can be acquired by repeated association with previous neutral stimuli. Many animal studies reported on conditioned changes in the blood glucose level; the nature of the conditioned response (CR), hypo- or hyperglycemia, however, seems to vary with experimental procedures. The present study aimed to elicit conditioned blood glucose changes in human subjects. Thirty male volunteers participated in five sessions each. The sessions were separated by 3 days, with identical time course and procedure. The subjects were informed that we wanted to test the effects of insulin or placebo injections on cognitive functioning, and were kept busy with pseudotests. In four sessions, subjects were injected with 0.035 IU/kg body weight of human insulin as the unconditioned stimulus (US), which induced the expected fall in blood glucose level below 50 mg/dl (UR). Injections were accompanied by a specific stimulus compound (conditioned stimulus, CS) in half of the subjects. In the fifth session, the CS was associated with a placebo injection. About half of the subjects showed a change from the baseline level of blood glucose of more than 10 mg/dl, which we would interpret as a conditioned response. Conditioning occurred more often in those subjects who were given a CS compound in addition to the injection, which itself together with the experimental environment may have been a sufficient CS.

Adult↗
PubMed1993

Auditory reflex thresholds elevated by stress-induced cortisol secretion.

To study steroid effects on auditory perception, 24 volunteers were unexpectedly confronted with a psychological stressor. Auditory reflexes to pure tones and noise were recorded before stress exposure, up to 100 min afterwards and in a second control session. Repeated measurements of cortisol and testosterone in saliva, as well as blood pressure, heart rate, and subjective feelings confirmed the stressful nature of the test. Following stress induction the auditory reflex of the contralateral ear needed significantly higher loudness (i.e. more decibels) to be elicited than at baseline or control measures. Two lines of evidence suggest that this stress-induced change may be specifically related to glucocorticoid actions: (1) In a previous study similar elevations in auditory reflex threshold had been obtained by the administration of exogenous glucocorticoids (hydrocortisone), and (2) in the present study the overall effect of stress induction on acoustic reflex described above was mainly observed in a subgroup of subjects, who responded to the stressor with a marked rise in free cortisol.

Acoustic Stimulation↗
PubMed1990

Hormonal responses to exhausting physical exercise: the role of predictability and controllability of the situation.

Psychological conditions which produce sustained activation have been clearly identified. Among these are the predictability and the controllability of the situation. We studied the impact of these psychological variables on hormone secretion (cortisol, ACTH, vasopressin, prolactin, and hGH plasma levels) under a standardized physical load. Sixteen subjects participated in four sessions each, one week apart, with the task of riding a bicycle until exhaustion. During three sessions, all experimental conditions were held identical to ensure the situation was a predictable as possible. During the fourth session, instructions induced a certain level of uncontrollability. Whereas physiological and performance measures did not vary with experience in the task, cortisol, ACTH, and vasopressin responses declined with increasing experience. This emphasizes the importance of the psychological definition of the situation for endocrine stress responses.

Adrenocorticotropic Hormone↗
PubMed1989

The influence of a vasopressin-analogue (DGAVP) on event-related potentials in a stimulus-mismatch paradigm.

To assess the influence of DGAVP (des-glycinamide-arginine-8-vasopressin, a synthetic vasopressin analogue) on the processing of stimuli and stimulus deviance in humans in a double-blind cross-over experiment, 13 subjects received 60 IU DGAVP versus placebo intranasally 48, 24, and 1 h prior to the experimental session. Auditory event-related potentials (ERPs) were taken as a tool to investigate central nervous processing in an experimental task that required the subjects to count different kinds of rare tone pips deviating in pitch and probability compared to frequent standard tones. Direction of attention was manipulated by instructing the subject to count a different class of deviating tone pips in each attention condition. DGAVP enhanced the N2 of the ERP to tone pips deviating extremely in pitch from standard tones, whether or not the extremely deviating pips were to be attended to by the subjects. This influence suggests an intensified mismatch processing under DGAVP that may result from a general excitatory effect of this substance on cortical activity.

Administration, Intranasal↗
PubMed1989

Taste thresholds in man are differentially influenced by hydrocortisone and dexamethasone.

The present study focused on sensory processing (taste threshold) in healthy young men given different cortisol doses within the normal physiological range. It aimed to differentiate the effects of dexamethasone, a synthetic pure glucocorticoid, compared to hydrocortisone, which has both glucocorticoid and mineralocorticoid properties. In a double-blind, cross-over design, 18 male subjects participated in three sessions. Subjects were pretreated orally with hydrocortisone (50 mg), dexamethasone (2 mg) or placebo. Taste detection was tested by a forced-choice three stimulus drop technique to determine detection acuity and a signal detection procedure to determine the ability to detect differences in NaCl concentration. Cortisol concentrations were determined in blood and saliva. Hydrocortisone and dexamethasone had opposite effects on taste detection acuity. With the highest cortisol levels after intake of hydrocortisone, subjects made more errors in detection trials with respect to stimuli close to the absolute taste detection threshold than after intake of dexamethasone. Detection of differences was impaired by both glucocorticoids. This type of behavioral study in man may help clarify the roles of heterogeneous corticosteroid receptor systems within the human brain.

Adolescent↗
PubMed1988

Vasopressin but not oxytocin enhances cortical arousal: an integrative hypothesis on behavioral effects of neurohypophyseal hormones.

Behavioral changes after administration of the neurohypophyseal hormones vasopressin and oxytocin can be observed in animal and man. Several groups attempted to specify these changes in terms of memory or attention processing enhancement for vasopressin and amnesic properties for oxytocin. These interpretations, however, were targets for recent criticism. In a double-blind between-subject comparison with male volunteers receiving arginine-vasopressin (AVP), oxytocin or placebo intranasally prior to the experimental session, we tried to develop an alternative hypothesis on the basis of behavioral and EEG measures. At the beginning of the session subjects had to learn a list of 25 unrelated nouns within five trials. Recall was assessed 1 h later. Neither learning nor long-term recall were affected by peptide treatments. In a second vigilance task subjects had to covertly count eight series of tone pips. Averaged auditory evoked potentials to these tones showed the expected habituation during the course of the task within all three groups. Vasopressin-treated subjects, however, displayed significantly higher amplitudes of the vertex potential as compared to the other treatment groups. AVP effects were most prominent with the longest interstimulus interval. No influences on heart rate or blood pressure were found. Results indicate that vasopressin induces an enhancement of stimulus-related phasic cortical arousal, and that in this respect oxytocin has no effect.

Adult↗
PubMed1987

Dose-dependent influences on electrophysiological signs of attention in humans after neuropeptide ACTH 4-10.

The afferent humoral system exerts significant influences on brain activity. Central nervous actions of the adrenocorticotropic hormone (ACTH) are most likely to be mediated by information coded in a portion of this hormone structure corresponding to ACTH 4-10. Our previous research suggested an impairing effect of ACTH 4-10 on electrophysiological signs of selective attention in humans. The present experiments in 12 male subjects investigated the influences of ACTH 4-10 on different aspects of attention as indicated by auditory event-related potential (AERP) components. Furthermore, dose-response characteristics of these influences should be examined. Attention performance was tested in a dichotic listening paradigm, after 0, 0.1, 1.0, and 10 mg ACTH 4-10, administered intravenously 1 h prior to testing according to a double-blind latin-square design. Different aspects of attention were measured by brain electrical responses evoked either by frequent standard or rare target tone pips, which the subject had to attend to, or to ignore. The selective type of attention was reflected by the Nd determined as mean difference in amplitude between AERPs to tone pips when attended and when unattended, for a latency range between 0-460 ms post-stimulus. In addition, plasma cortisol, heart rate, blood pressure, and behavioral performance were measured. Results indicated a clear reduction of the Nd amplitude after all doses of ACTH 4-10. Other indicators of attention mechanisms such as mismatch processing were not affected by the peptide. The diminished Nd after ACTH 4-10 was due to an increased processing of unattended stimuli, but simultaneously attended tones were processed less intensively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Influences of ACTH 4-10 on event-related potentials reflecting attention in man.

The present paper is concerned with effects of the 4-10 sequence of the endogenous ACTH on electrophysiological measures of attention in humans. It was attempted to replicate previous findings of an impaired selective attention following administration of an analog of ACTH 4-9. The effect of this analog had been found to dominate in the beginning of the blocks of an attention task, but to fade away with time on task. In the present study, fourteen male students were tested in a dichotic listening paradigm, 40 min after intranasal application of either 0.4 mg ACTH 4-10, or placebo. Averaged auditory evoked potentials (AEPs) to attended and inattended tone pips, EEG power spectra, heart rate and blood pressure, and behavioral performance were measured during task performance. ACTH 4-10 appeared to slightly impair selective attention as indicated by AEP responses. In particular, the positive shift of the AEP waveforms to inattended stimuli was reduced at the beginning of each block of tone pips under ACTH 4-10. The pattern of actions resembled the effects observed after administration of the more potent synthetic analog of ACTH 4-9 in the previous experiment. Effects of ACTH 4-10 on the AEPs to inattended stimuli, however, differed from influences of the synthetic analog in that they did not affect a rather wide latency range but concentrated on the latency range of the P200 component.

Adolescent↗