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Biomedical subjects

I Petersén

Publications and source records attributed to I Petersén.

At least 19 recordsLinked to original sources
PubMed1984

The use of the EEG for assessment of vigilance changes caused by beta-blockers.

The aim of this study was to investigate the changes of vigilance caused by beta-blockers. A recently developed method to measure the vigilance fluctuations, based on the EEG spectra, was employed together with self-rating. Repeated vigilance measurements were made in 20 healthy volunteers before and after administration of placebo, propranolol and metoprolol in random sequence. Both EEG analysis and self-rating confirmed that the vigilance level was significantly decreased after administration of beta-blockers compared to placebo. No significant difference between propranolol and metoprolol could be found. The results suggest that the decrease in systolic blood pressure after beta-blockade may be responsible for the drug-induced drowsiness. However, some of the observations made in the study can be interpreted as indirect proof that central mechanisms are also involved, and that both propranolol and metoprolol have sedative properties comparable to those observed with conventional psychotropic drugs.

Adult↗
PubMed1983

A method for assessing alertness fluctuations from EEG spectra.

The object of the study was to develop a method for automatic evaluation of the vigilance level using the EEG frequency pattern. Forty-one EEG records were selected as training material, being considered representative of either a fully alert EEG, or sleep stage I. In the same epochs, 22 different variables based on EEG spectral analysis were calculated. Multiple regression analysis was applied to determine the correlation between the spectral values and the assigned levels of vigilance. The coefficients obtained were applied to the spectral values of 265 epochs belonging to another set of tracings, for estimation of the vigilance level. The correlation between the automatic and visual finding was 0.89 in the training material and 0.86 in the test material. The method can be used to evaluate the mean vigilance level and its variance, rhythmicity and trend during the examination. The preliminary results suggest that objective measurement of alertness can be of value in many applications, such as in pharmacological research, in evaluation of certain psychic symptoms and in working environment studies.

Arousal↗
PubMed1981

Shoulder pain in industry: an epidemiological study on welders.

The occurrence of supraspinatus tendinitis in a group of welders at a shipyard was investigated, and compared with the occurrence of this condition in a group of office clerks. The study showed a prevalence ratio of 18 per cent in the welders, significantly higher than in the clerks. The average age (39 year) in the group with pain did not differ significantly from the average age in the entire group of welders. It is concluded that supraspinatus tendinitis is not exclusively an aging phenomenon, but that welding as an occupation plays an etiological role.

Adult↗
PubMed1979

The effect on erection and orgasm of cystectomy, prostatectomy and vesiculectomy for cancer of the bladder: a clinical and electromyographic study.

Forty-three men who had been subjected to cystectomy and concomitant prostatectomy, vesiculectomy and urethrectomy were interviewed about their pre-operative and post-operative sexual activities at a mean of 3 (range 1 to 8) years after operation. Twenty-eight of the 38 men (74%) who had been sexually active continued to have some form of sexual activity, 21 of them achieving orgasm. Only 3 men had penile erection; 2 of them had been subjected to prostatectomy and 1 to prostatic resection. One of these men treated by prostatectomy had also had urethrectomy. Electromyographic registration from the striated external urethral sphincter, the bulbocavernosus muscle and the levator ani muscle showed normal duration of muscular contractions and length of interval between contractions after operation. The pattern of impulses during organs did not differ from that of normal men.

Adult↗
PubMed1979

Electroencephalographic investigation of patients with adolescent idiopathic scoliosis.

An EEG study was carried out on 57 children, aged 10--16 years, with idiopathic scoliosis. Treatment (brace or surgery) was required in 37 cases; 20 were being observed only. Controls were 10- to 16-year-old healthy children meeting well-defined criteria of normality. Thirty-four of the scoliotics fulfilled these criteria, thus providing a group matching the controls except for the presence of scoliosis. Thus, any differences occurring could, with reasonable probability, be referred to the disease in question. The comparison with healthy children showed a generally greater EEG pathology in the scoliotics. This was the case in all patients, even those meeting the same criteria of normality as the controls. A highly significant difference was noted in the occurrence of paroxysmal activity. Type and localization of abnormally (bilaterally synchronous discharges) indicated involvement of subcortical structures. Comparison within the scoliotic group showed that EEG abnormalities were not correlated with the magnitude of the disease except for the variable "paroxysmal activity at rest". Patients submitted to observation only presented paroxysmal activity significantly more often than patients requiring treatment. The localization of abnormality within the hemispheres did not agree or disagree systematically with the convexity of the curve. A possible relationship between the higher incidence of scoliosis in females and the higher sensitivity to afferent stimuli as found in the female EEG is also discussed.

Adolescent↗
PubMed1978

A method for continuous electrocardiodynamic monitoring.

A new method is presented for the monitoring of cardiac time intervals, e.g. in clinical and industrial work investigation. The methods yields 'on-line' the electrocardiodynamic time profile during rest as well as effort, and has applications in health care, sports and occupational medicine. By means of analog processing of an electrocardiographic signal, ear densitogram and beat-by-beat display of the measured cardiac time intervals as amplitude-modulated pulses, an 'electrocardiodynamic time profile' is obtained. In order to estimate the accuracy and the limitations of the method, a comparison with computerized methods was performed. In an ergonomic experiment carried out by a Romanian-Swedish research team, analog and digital methods for the detection of cardiac time intervals showed good agreement.

Adolescent↗
PubMed1977

An electromyographic index for localized muscle fatigue.

A new method for objective quantification of localized muscle fatigue is described. The method is based on power spectrum analysis of myoelectric signals obtained from the fatigued muscle. It permits real-time investigations and yields statistically based criteria for the occurrence of fatigue. The findings are interpreted in terms of muscle action potential conduction velocity changes and rate of the fatigue development.

Action Potentials↗
PubMed1976

Anorectal function after major resections of the sacrum with bilateral or unilateral sacrifice of sacral nerves.

The anorectal function in 3 patients with bilateral and 4 patients with unilateral well-defined loss of sacral nerves after radical tumour excision was studied by clinical examination and by simultaneous registration of the following variables: volume and pressure in the rectum, pressure in the internal anal sphincter area and myoelectrical activity in the external anal sphincter. The patients with bilateral loss of sacral nerves had serious impairment of function. Constipation was their only safeguard against incontinence. The preservation of the first and second sacral nerves bilaterally was not sufficient for discrimination between different qualities of rectal contents passing the anal canal. The sensation of rectal distension was also impaired. The reflex pattern of the internal anal sphincter was, however, intact. The external anal sphincter displayed a weak spontaneous myoelectrical activity in the patients who had at least one second sacral nerve intact, and a weak increase of the activity could be induced voluntarily. The normal transient increase of myoelectrical discharge from the external anal sphincter in response to rectal distension could not, however, be elicited. In patients with total unilateral loss of the sacral nerves no significant impairment of anorectal function was noted. Total one-sided denervation implied deficient sensibility of the anal canal unilaterally, but no disturbance of sphincter function as judged from the reflex response of the internal and external anal sphincters to rectal distension.

Adult↗