Search results for " processing"

Clinical evaluation of a wireless ECG sensor system for arrhythmia diagnostic purposes

2013

Accepted version of an article in the journal: Medical Engineering and Physics. Also available from the publisher at: http://dx.doi.org/10.1016/j.medengphy.2013.03.002 In a clinical study, a novel wireless electrocardiogram (ECG) recorder has been evaluated with regard to its ability to perform arrhythmia diagnostics. As the ECG recorder will detect a "non-standard" ECG signal, it has been necessary to compare those signals to "standard" ECG recording signals in order to evaluate the arrhythmia detection ability of the new system. Simultaneous recording of ECG signals from both the new wireless ECG recorder and a conventional Holter recorder was compared by two independent cardiology specia…

Two-dimensional echocardiographic evaluation of left ventricular ejection fraction by the ellipsoid single-plane algorithm: a reliable method for ass…

1995

The reliability of two-dimensional (2D) echocardiographic estimation of left ventricular ejection fraction (EF) is commonly recognized, but no satisfactory data are available about the accuracy of low or very low EF values determined by 2D echocardiography (ECHO-EF). The purpose of our study was to assess the reliability of low ECHO-EF values obtained using a simple time-economical algorithm such as the ellipsoid single-plane area-length method. Radionuclide angiography (RAD-EF) was taken as the standard of comparison. We studied 59 consecutive patients (31 women and 28 men) referred to our echocardiographic laboratory. Both 2D echocardiography and radionuclide angiography were blindly perf…

Relation between late potentials and echocardiographically determined left ventricular mass in healthy subjects.

1991

Imaging the visual autokinetic illusion with fMRI

2005

During fixation of a stationary, dim light-emitting diode (LED) in complete darkness, a subtle, apparent motion is perceived which is called autokinesis. This autokinetic illusion increases with increasing fixation time. Eleven healthy subjects were examined by fMRI while fixating an LED in darkness for 35 s. BOLD signal changes of the first and the second half of the fixation period were compared. While the stimulus was the same for both periods, perception differed in that autokinesis was more pronounced in the second half. This second half of the period was associated with bilateral activations in the motion-sensitive middle occipito-temporal area known as MT/V5. Our finding suggests tha…

Conditional Self-Entropy and Conditional Joint Transfer Entropy in Heart Period Variability during Graded Postural Challenge.

2015

Self-entropy (SE) and transfer entropy (TE) are widely utilized in biomedical signal processing to assess the information stored into a system and transferred from a source to a destination respectively. The study proposes a more specific definition of the SE, namely the conditional SE (CSE), and a more flexible definition of the TE based on joint TE (JTE), namely the conditional JTE (CJTE), for the analysis of information dynamics in multivariate time series. In a protocol evoking a gradual sympathetic activation and vagal withdrawal proportional to the magnitude of the orthostatic stimulus, such as the graded head-up tilt, we extracted the beat-to-beat spontaneous variability of heart per…

Clinical aspects of the apparent diffusion coefficient in 3He MRI: results in healthy volunteers and patients after lung transplantation.

2007

Purpose To measure the apparent diffusion coefficient (ADC) after inhalation of hyperpolarized 3He in healthy volunteers and lung transplant recipients, and demonstrate the gravity dependence of ADC values. Materials and Methods Six healthy volunteers, 10 patients after single-lung transplantation, and six patients after double-lung transplantation were examined at 1.5T during inspiration and expiration. The inhalation of 300 mL of hyperpolarized 3He was performed with a computer-controlled delivery device. A two-dimensional fast low-angle shot (FLASH) sequence measured the 3He diffusive gas movement. From these data the ADC was calculated. Results The mean ADC was 0.143 cm2/second in healt…

Effects of post-extinction l-DOPA administration on the spontaneous recovery and reinstatement of fear in a human fMRI study

2015

Relapse is a pertinent problem in the treatment of anxiety disorders. In the laboratory, relapse is modeled as return of conditioned fear responses after successful fear extinction and is explained by insufficient retrieval and/or expression of the fear-inhibitory extinction memory that is generated during extinction learning. We have shown in mice and humans that return of fear can be prevented by administration of a single dose of the dopamine precursor l-3,4-dihydroxyphenylalanine (l-DOPA) immediately after extinction. In mice, this effect could be attributed to an enhancement of extinction memory consolidation. In our human study, we could not exclude that l-DOPA might have acted by int…

Excitability regulation in the dorsomedial prefrontal cortex during sustained instructed fear responses: a TMS-EEG study

2018

AbstractThreat detection is essential for protecting individuals from adverse situations, in which a network of amygdala, limbic regions and dorsomedial prefrontal cortex (dmPFC) regions are involved in fear processing. Excitability regulation in the dmPFC might be crucial for fear processing, while abnormal patterns could lead to mental illness. Notwithstanding, non-invasive paradigms to measure excitability regulation during fear processing in humans are missing. To address this challenge we adapted an approach for excitability characterization, combining electroencephalography (EEG) and transcranial magnetic stimulation (TMS) over the dmPFC during an instructed fear paradigm, to dynamica…

Soluble Interleukin-2 Receptor Secretion Defectin Vitroin HLA-B8, DR3 Positive Subjects

1990

Several studies have shown that HLA-B8,DR3 positive subjects may display T cell dysfunctions. Recently, a soluble form of the receptor for IL-2 (sIL-2R) has been demonstrated in human sera and in vitro-stimulated culture supernatant from human T lymphocytes. In the present paper we report sIL-2R serum levels and sIL-2R production from peripheral blood mononuclear cells in HLA-B8,DR3 positive subjects. We found that HLA-B8,DR3 positive subjects have the highest values of serum sIL-2R, but comparing the values of these subjects with those of negative ones no significant difference was observed. As regards the in vitro production of sIL-2R, no difference exists for unstimulated cultures, where…

Clavicle aseptic nonunion: is there a place for cortical allogenic strut graft?

2017

Abstract We investigated functional and radiological outcome in 57 cases of midshaft clavicle nonunion treated with open reduction and internal fixation with plate and screws over a 13 year-period. Intercalary bone graft was used in 42 patients; opposite autologous strut graft was used in 31 cases to provide mechanical support to the host bone. Patients were analysed using chart and radiological review and assessed with DASH questionnaire obtained at the latest follow-up. 37 patients were male while 20 were females, with a mean age of 35 years (63–17). All cases were of nonunion, 35 atrophic and 22 hypertrophic. The dominant side was injured in 32 cases and the non dominant in 25 cases. Pri…