Search results for "process"
showing 10 items of 22310 documents
Directional Control Mechanisms in Multidirectional Step Initiating Tasks.
2020
Typical anticipatory postural adjustments (APAs) in forward gait or step initiation tasks to prepare for possible disturbances caused by prime voluntary movements and to accelerate the body forward have been previously reported. However, it is not clear how wide the variations in step directions are differentiated and controlled in non-forward step initiation tasks during the APA phase. The main goal of this study is to explain the directional control mechanisms by investigating the APA of step initiation tasks in forward, diagonal, lateral, and posterior directions. The center of pressure (COP) trajectories and related muscle (soleus, tibialis anterior, and gluteus medius of both lower lim…
DHEA, DHEAS and PCOS.
2014
Approximately 20-30% of PCOS women demonstrate excess adrenal precursor androgen (APA) production, primarily using DHEAS as a marker of APA in general and more specifically DHEA, synthesis. The role of APA excess in determining or causing PCOS is unclear, although observations in patients with inherited APA excess (e.g., patients with 21-hydroxylase deficient congenital classic or non-classic adrenal hyperplasia) demonstrate that APA excess can result in a PCOS-like phenotype. Inherited defects of the enzymes responsible for steroid biosynthesis, or defects in cortisol metabolism, account for only a very small fraction of women suffering from hyperandrogenism or APA excess. Rather, women wi…
Modelling cardiac mechanics of left ventricular noncompaction
2020
Left ventricular noncompaction (LVNC) can be defined as a cardiomyopathy characterised by a pattern of prominent trabecular structure and deep intertrabecular recesses, that is thought to be caused by an arrest of normal endomyocardial morphogenesis. Using patient-specific computational modelling, we assessed the cardiac mechanics of five patients with LVNC and compared myocardial stress and pump performance to those of healthy controls. Findings shown that patients with LVNC have impaired left ventricular (LV) function, making it possible that the lack of fibre shortening of noncompacted layer can determine poor heart function. Pronounced end-systolic wall stress on left ventricular wall o…
Neuroplasticity in the Adjustment to Blindness
1999
Loss of vision due to injury to the eyes results in deafferentation of very large areas of the human cortex and poses striking demands on other sensory systems to adjust to blindness in a society that heavily relies on vision. Blind subjects need to extract crucial spatial information from touch and hearing. To accomplish this, plastic trans-modal changes appear to take place by which a larger area of the sensorimotor cortex is devoted to the representation of the reading finger in Braille readers, and parts of the former visual cortex are recruited for the processing of tactile and auditory information.
Postoperative Lens Position Preoperatively Determined by Scheimpflug Photography
1999
The position of the artificial lens has an important influence on refractive power calculation. We compared the position of the crystalline lens with that of the artificial lens after cataract surgery by means of Scheimpflug photography. A difference in position of approximately 0.8 mm in the anterior direction could be determined.
Long-term physical activity modifies automatic visual processing
2017
Electrophysiologically registered visual mismatch negativity (vMMN) is known to represent automatic visual processing in human visual cortex. Since physical activity (PA) is generally beneficial to cerebrovascular function, we wanted to find out if automatic visual processing is affected by PA. We investigated the connection between long-term leisure-time PA and precognitive visual processing in 32 healthy young males. Participants were divided into active (n = 16) and inactive (n = 16) group according to their leisure-time PA records from the past three years. vMMN was recorded with electroencephalogram using passive oddball paradigm with visual bars. Standard (90%) and deviant (10%) stimu…
The Effects of Stochastic Galvanic Vestibular Stimulation on Body Sway and Muscle Activity
2020
Objective: This study aimed to investigate whether galvanic vestibular stimulation with stochastic noise (nGVS) modulates the body sway and muscle activity of the lower limbs, depending on visual and somatosensory information from the foot using rubber-foam.Methods: Seventeen healthy young adults participated in the study. Each subject maintained an upright standing position on a force plate with/without rubber-foam, with their eyes open/closed, to measure the position of their foot center of pressure. Thirty minutes after baseline measurements under four possible conditions (eyes open/closed with/without rubber-foam) performed without nGVS (intensity: 1 mA, duration: 40 s), the stimulation…
Risk Factors Regarding Portal Vein Thrombosis in Chronic Liver Disease
2020
Abstract The portal vein thrombosis (PVT) is one of the most frequent vascular diseases of the liver, with a high rate of morbidity and mortality. The most common causes of the PVT are hepatic cirrhosis, hepatobiliary neoplasms, inflammatory and infectious abdominal diseases, and myeloproliferative syndromes.(1,2) The natural progress of the PVT has as a result portal hypertension which leads to splenomegaly and the formation of portosystemic collateral vessels, as well as gastroesophageal, duodenal and jejunal varices. Ultrasonography, especially Doppler ultrasound, is the most widely used imaging method to asses, supervise and diagnose PVT in patients with hepatopathies. The purpose of ac…
Mapping symbols to sounds: electrophysiological correlates of the impaired reading process in dyslexia
2012
Dyslexic and control first-grade school children were compared in a Symbol-to-Sound matching test based on a non-linguistic audiovisual training which is known to have a remediating effect on dyslexia. Visual symbol patterns had to be matched with predicted sound patterns. Sounds incongruent with the corresponding visual symbol (thus not matching the prediction) elicited the N2b and P3a event-related potential (ERP) components relative to congruent sounds in control children. Their ERPs resembled the ERP effects previously reported for healthy adults with this paradigm. In dyslexic children, N2b onset latency was delayed and its amplitude significantly reduced over left hemisphere whereas P…
Early cortical processing of vection-inducing visual stimulation as measured by event-related brain potentials (ERP)
2019
Abstract Visual motion stimuli can induce the perception of self-motion in stationary observers (known as vection). In the present study, we investigated the sensory processing underlying vection by measuring the human event-related brain potentials (ERPs) elicited by the movement onset of a visual stimulus. We presented participants a visual stimulus consisting of alternating black-and-white vertical bars that moved in horizontal direction, creating the sensation of vection. The stimulus was presented on a screen that was divided into a central and a surrounding peripheral visual area. Both areas moved independently from each other, resulting in four different movement patterns: the periph…