Brynjar Karlsson

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In this study, we report a new and original device called the "echorheometer," comprising a suction system with an ultrasound scanner (A-mode, TM-mode and B-mode) that enables the simultaneous visualization and measurement of the deformation of skin structures in vivo. With the scanner described here, high resolution is obtained using a strongly focused,(More)
The objective of this paper is to evaluate the novel method for analyzing the nonlinear correlation of the uterine electromyography (EMG). The application of this method may improve monitoring in pregnancy, labor detection, and preterm labor detection. Uterine EMG signals recorded from a 4 × 4 matrix of electrodes on the subjects' abdomen are used here. The(More)
Recently, much attention has been paid to the use of nonlinear analysis techniques for the characterization of biological signals. Several measures have been proposed to detect nonlinear characteristics in time series. The sensitivity of several nonlinear methods to the actual nonlinearity level and their sensitivity to noise have never been evaluated. In(More)
Numerous studies have observed and analyzed the external electrical activity of the uterus, the so-called electrohysterogram (EHG), associated with contractions during pregnancy and labor. The EHG is mainly composed of two distinct frequency components, FWL (Fast Wave Low, low frequency component) and FWH (Fast Wave High, high frequency component). It has(More)
The electrohysterogram (EHG) is often corrupted by electronic and electromagnetic noise as well as movement artifacts, skeletal electromyogram, and ECGs from both mother and fetus. The interfering signals are sporadic and/or have spectra overlapping the spectra of the signals of interest rendering classical filtering ineffective. In the absence of efficient(More)
Investigations have shown that Baltic grey seal (Halichoerus grypus) and ringed seal (Phoca hispida) suffer from a disease complex described as a primary lesion in the adrenals causing secondary reactions in various other organs. Studies on historical Baltic grey seal skull bone material show that the prevalence of affected animals started to increase after(More)
Detection of nonlinearity should be the first step before any analysis of nonlinearity or nonlinear behavior in biological signal. The question is which method should be used in each case and which one can best respect the different characteristics of the signals under investigation. In this paper we compare three methods widely used in nonlinearity(More)
Frequency-related parameters derived from the uterine electromyogram (EMG) signals are widely used in many pregnancy monitoring and preterm delivery prediction studies. Although they are classical parameters, they are well suited for quantifying uterine EMG signals and have many advantages over amplitude-related parameters. The present work aims to compare(More)
Fetal heart rate (FHR) monitoring is widely used to evaluate fetal health and is based on the detection of movements of the fetal heart by Doppler ultrasound. Fetal health can also be evaluated by prolonged observation of body- and pseudo-respiratory movements using two-dimensional ultrasound. Fetal breathing movements are in particular considered to be an(More)