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Biomedical subjects

F Strian

Publications and source records attributed to F Strian.

At least 37 records · Page 2Linked to original sources
PubMed1991

Anxiety induced by cardiac perceptions in patients with panic attacks: a field study.

In panic disorder bodily sensations appear to play an important role as a trigger for anxiety. In our psychophysiological model of panic attacks we postulate the following vicious circle: individuals with panic attacks perceive even quite small increases in heart rate and interpret these changes as being catastrophic. This elicits anxiety and a further increase in heart rate. To evaluate this model we conducted a field study of 28 subjects with panic attacks and 20 healthy controls. A 24 hr ambulatory ECG was recorded and the subjects were instructed to report any cardiac perceptions during this period and to rate the anxiety elicited by these perceptions. The incidence of cardiac perceptions was about the same in both groups, but only subjects with panic attacks reported anxiety associated with such perceptions. Analysis of the ECGs revealed that in both groups heart rate accelerations preceded cardiac perceptions. Following cardiac perceptions, the healthy controls showed a heart rate deceleration, whereas the subjects with panic attacks had a further acceleration. This heart rate increase after cardiac perceptions was positively related to the level of anxiety elicited by the perceptions. These results provide clear evidence in support of the vicious circle model of panic attacks.

Adult↗
PubMed1991

Dieting and pain sensitivity: a validation of clinical findings.

To validate findings of a reduced pain sensitivity in anorexia and bulimia nervosa, the effects of dieting on somatosensation (especially pain sensitivity) were investigated in healthy young women. One group of subjects (n = 11) received a calorically reduced balanced diet for 21 days, while the other group (n = 14) continued to eat normally. The fasting state induced in the dieting subjects was comparable to that of eating disorder patients, since the dieters showed a reduction of the body mass index, a decrease in triiodothyronine and an increase in beta-hydroxybutyric acid plasma levels. However, neither the thresholds of pain, warmth, cold and vibration sensitivity nor the peripheral skin temperature changed systematically under the diet. Therefore, the reduced pain sensitivity in eating disorder patients is apparently not a mere effect of fasting, but a true pathological feature.

3-Hydroxybutyric Acid↗
PubMed1991

Heartbeat and arrhythmia perception in diabetic autonomic neuropathy.

A comparative study of diabetics with autonomic neuropathy (N = 13) as against non-neuropathic diabetics (N = 16) and healthy control persons (N = 20) was carried out with respect to heart rate both at rest and under stress, frequency of cardiac arrhythmias in a 24-h ECG and accuracy of heartbeat and arrhythmia perception. In the subjects with diabetic autonomic neuropathy, the spontaneous variability and stress-induced reactivity of the heart rate as well as the number of tachycardic episodes were reduced, whereas the frequency of ventricular extrasystoles was somewhat increased. Impaired heartbeat perception and a complete loss of perception of arrhythmias as a consequence of neuropathic deafferentation could be demonstrated. Cardiac perception disorders also play a vital role in other clinical problems, e.g. silent myocardial infarction and lack of awareness of hypoglycaemia in diabetes mellitus.

Adult↗
PubMed1991

Disturbances of C-fibre-mediated sensibility in lumbosacral disc disease.

In nine patients with chronic lumbosacral disc disease and radicular symptoms clearly restricted to one leg, C-fibre-mediated sensibility was measured by determination of the thresholds for heat pain and warmth on the foot, ipsi- and contralaterally to the nerve root compression. The thresholds were compared with the values for 19 healthy subjects. In the patients the warmth threshold was increased in the ipsilateral dermatome and normal in the contralateral dermatome. In contrast, the heat pain threshold was near normal ipsilaterally but was clearly decreased contralaterally. These findings are discussed with respect to a possible pain sensitisation resulting from nerve root compression.

Adult↗
PubMed1991

Sex differences in pain and thermal sensitivity: the role of body size.

Sex differences in heat-pain and thermal sensitivity were investigated in 32 women (20 to 60 years of age) and 32 men (17 to 63 years of age) who had no somatosensory impairments. Pain thresholds were measured with stimuli of two different durations (phasic and tonic). Warmth and cold thresholds were assessed as indices of thermal sensitivity. Stimulation was applied to the hand and to the foot by an apparatus containing a Peltier thermode. There were no sex differences in heat-pain thresholds. Women had significantly lower warmth thresholds than men (more pronounced on the foot than on the hand), but similar cold thresholds. Measures of body size (weight, height) correlated much more strongly with thermal than with pain sensitivity, and helped to explain the sex difference in the warmth threshold. A reduction of sex differences to body-measure differences appears likely, but could not be demonstrated unequivocally.

Adolescent↗
PubMed1991

[Cardiovascular factors of cardiac phobia--a field study].

The interaction between psychological and physiological factors was studied with a field approach in 28 patients with cardiac phobia and 20 healthy controls. A 24-hour ambulatory ECG was recorded, and the subjects were instructed to report their activities and any cardiac perception during this period. Additionally, psychological tests assessing well-being (Bf-S), bodily complaints (B-L), and state and trait anxiety (Stai-S and Stai-T) were administered. The groups did not differ in the mean cardiovascular parameters, however patients with cardiac phobia and healthy controls showed clear differences in the strength and direction of correlations between psychological and physiological variables. The incidence of cardiac perceptions was about the same in both groups, but only patients with cardiac phobia attributed the perceptions to an internal stimulus and associated the perceptions with anxiety. Depending on the anxiety elicited by the cardiac perceptions, the patients with cardiac phobia showed heart rate accelerations, which did not occur in healthy controls. This study confirms a psychosomatic process between psychological and physiological variables, which seems to be able to explain the development and maintenance of cardiac phobia.

Adult↗
PubMed1990

[Studies on orocecal transit in diabetes mellitus].

The present study investigated changes of gastrointestinal transit in diabetes mellitus by a variant of the hydrogen exhalation method, which produces reliable estimates of oro-cecal transit times of a lactulose test meal. Relation to metabolic state and small fibre neuropathy was also evaluated. The latter was indexed by Airaksinen's variability score for resting pulse frequency, Ewing's index of respiratory sinus arrhythmia, and warm and cold thresholds at the foot. 15 inpatients with verified type I diabetes (nine female, six male) and eleven healthy controls (nine female, two male) were under investigation. Ages ranged from 19 to 47 and 27 to 49 years, respectively. No clearcut signs of angiopathy or neuropathy were present in patients. HbA1c values were moderately high (means +/- s = 8.2 +/- 1.6). Diabetes patients showed prolonged transit compared to controls (means +/- s = 102.7 +/- 28.2 min, and 79.6 +/- 15.4, resp.; p = 0.02, U-test). Two patients had extremely long transit times, none showed acceleration. However, neither indices of small fibre neuropathy nor metabolic parameters were significantly correlated with transit measures. Prolonged oro-cecal transit, therefore, seems to be due to a specific visceral-autonomic or primary enteric neuropathy, which is still limited to the gastrointestinal system in this stage, and/or metabolic effects.

Adult↗
PubMed1990

Heart rate changes as an autonomic component of the pain response.

Autonomic variables have been recommended as measures of the affective-motivational component of the pain response in objective algesimetry. In the present study components of heart rate responses to painful heat stimuli and their relation to stimulus and sensation variables were analyzed. Twelve healthy subjects served. Sixty phasic stimuli of varying temperatures above and below pain threshold were delivered through a Marstock thermode in 1 session. Heart rate, respiration, and subjective stimulus ratings were recorded simultaneously. Phasic heat stimulation above and below pain threshold induced a tonic increase of the heart rate lasting up to more than 20 sec. High intensity stimulation generated steeper rises and greater mean increase than low intensity stimulation. In general, heart rate responses were more closely related to subjective sensation than to stimulus intensity. However, differential temporal analysis demonstrates that, until about 3 sec after stimulation, the autonomic response is determined solely by stimulus temperature, whereas, after approximately 6 sec, it is related only to subjective judgement. Accordingly, the heart rate responses reflect both a brief nocifensive reflex induced by the sensory component and, subsequently, a longer-lasting response which seems to be related to affective and/or cognitive evaluation. This separation of different stages of pain-processing by an autonomic indicator may be useful in clinical algesimetry.

Adult↗
PubMed1990

[Diagnostic and clinical aspects of neuropathy of small nerve fibers].

Small fibre neuropathy, a phenomenon that neurologists have always been familiar with as an accidental or independent pattern of signs and symptoms in "sensitive" or "painful" neuropathy, has become interesting once again as a result of progress in diagnostic methods. The A-delta and C fibres as well as the B fibres (of the vegetative nervous system) are known as "small", i.e. thin, weak or non-myelinated nerve fibres of slow conductivity. More than 80% of the nerve fibre mass of the peripheral somatic nerve is accounted for by the small fibres; moreover, the small fibres make up the peripheral vegetative nervous system. However, their importance especially for the afferent functions has hardly been sufficiently appreciated to date. The present article surveys the forms of neuropathies and other lesions of the nerves where functional disturbance of the small nerve fibres is prominent, on the one hand for the peripheral somatic and on the other hand for the peripheral vegetative nervous system. A few methods of measurement for testing the function of the small fibres at the somatic nervous system (determination of temperature and pain threshold, specific pain measurement methods) and at the peripheric vegetative nervous system (autonomic function tests) are described.

Humans↗
PubMed1990

Effects of chronic back pain on the perception of experimental heat pain.

19 patients between 23 and 65 yr. of age whose chronic back pain was caused by lumbosacral disk disease and 19 healthy volunteers matched for age and sex were studied. Pain thresholds under phasic and tonic heat stimulation and thermal thresholds for warmth and cold were measured on the right hand. The patients rated any current back pain on a visual analog scale. There was a significant negative correlation between current back pain and the threshold for tonic pain, but there was no correlation between current back pain and either the threshold for phasic pain or temperature sensitivity. Hence, current back pain and experimental tonic pain seem to have an additive effect on pain perception because perceptual qualities are similar. Reduced somatosensory perception of chronic back pain patients could be demonstrated for temperature sensitivity and to a lesser degree for phasic pain, but as a consequence of the "opposing" effect of current back pain, not for tonic pain perception.

Arousal↗
PubMed1989

Diurnal variations in pain perception and thermal sensitivity.

Pain and thermal sensitivity thresholds in healthy volunteers were examined for diurnal variations. The subjects were 11 men aged between 22 and 27 years (means = 23.5, S.D. = 1.5). Data were collected for 2 days, with 7 measurements per day. To ensure the pain specificity of the results the subliminal modality, i.e., thermal sensitivity thresholds to warm and cold stimuli, was investigated in addition to the threshold for perception of heat pain. Assessments were made on the right hand and foot, the stimuli being presented with a thermoelectric contact-thermode. Despite the influence of variables other than time of day (45-56% of the total variance), diurnal variations were found for some subjects on the pain threshold measure (significant correlation between days and relatively high frequency of 24 h component in Fourier analysis spectra). However, they could not be demonstrated for the thermal sensitivity measures. The diurnal variations in pain perception thresholds did not have a consistent pattern over all subjects (Friedman test). The small diurnal variations with interindividual differences in the pattern are therefore not sufficient to explain the variations seen in clinical pain, but they may be useful in detecting pain modulators by investigating correlations.

Adult↗
PubMed1989

SDT analysis of experimental thermal pain, with "signal" and "no-signal" being determined psychophysically.

In a signal-detection experiment, the effects of repeated pain stimulation and the induction of fear on pain thresholds and SDT parameters were studied. "Signal" and "no-signal" were not defined physically, but by means of an independent criterion as the primary sensations "pain" and "no-pain." First, the relationship between sensation levels for "phasic" (short stimulus, used in the SDT procedure) and "tonic" (longer stimulus, used in the criterion measurement) heat stimuli was determined in 14 subjects. It was quadratic (polynomial regression) and sufficient to define the distinction between "signal/pain" and "no-signal/no-pain." In the signal-detection experiment, a significant upward trend (adaptation) in threshold parameters, but no systematic change in the SDT parameters (discrimination ability and response bias) was found. Manipulation of anxiety by instructions caused unsystematic changes in discrimination ability. The procedure employed determines both the absolute strength of pain sensation and the ability to discriminate pain from no pain. These variables proved to be independent.

Adult↗
PubMed1989

Threshold tracking for assessment of long-term adaptation and sensitization in pain perception.

To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures.

Adaptation, Physiological↗
PubMed1987

[Neuroendocrine effects on one's awareness of the action of the heart].

Heart rate under mental and physical stress and the incidence of cardiac arrhythmias (by 24-hour ECG monitoring) as well as their awareness of these two types of cardiac activity were analysed in 11 insulin-dependent diabetics (manifestation before the age of 40 years) with autonomic neuropathy, five patients with hyperthyroidism and 13 healthy subjects. In hyperthyroidism the heart rate was increased as was the incidence of ventricular premature systoles; spontaneous variations and exercise-induced adaptation in heart rate were preserved. In diabetic neuropathy spontaneous heart-rate variations were absent, but adaptation reactions to mental and physical stress were normal. Patients of both groups had an impaired awareness of normal and arrhythmic cardiac activity. Lack of vagal inhibition in diabetic neuropathy and noradrenergic activation in hyperthyroidism may be the respective causative factors in the described disorders of regulation and awareness.

Adaptation, Physiological↗