Search results for "imulation"

Visual cortex hyperexcitability in migraine in response to sound-induced flash illusions

2015

Objective: Sound-induced flash illusions depend on visual cortical excitability. In this study, we explored whether sound-induced flash illusions are perceived differently in migraine, a condition associated with pathologic cortical hyperexcitability. Methods: Sound-induced flash illusions were examined in 59 migraine patients (mean age = 32 ± 16 years; 36 females), 32 without aura and 27 with aura, and in 24 healthy controls (mean age = 42 ± 17 years; 16 females). Patients were studied during attacks and interictally. Visual stimuli (flashes) accompanied by sounds (beeps) were presented in different combinations: a single flash with multiple beeps was given to induce the perception of mult…

Flexible multibody simulation approach in the analysis of tibial strain during walking.

2007

Strains within the bone tissue play a major role in bone (re)modeling. These small strains can be assessed using experimental strain gage measurements, which are challenging and invasive. Further, the strain measurements are, in practise, limited to certain regions of superficial bones only, such as the anterior surface of the tibia. In this study, tibial strains occurring during walking were estimated using a numerical approach based on flexible multibody dynamics. In the introduced approach, a lower body musculoskeletal model was developed by employing motion capture data obtained from walking at a constant velocity. The motion capture data were used in inverse dynamics simulation to teac…

Determining the location of the body׳s center of mass for different groups of physically active people

2013

The purpose of the present study was to compare the location of the body center of mass (CoM) determined by using a high accuracy reaction board (RB) and two different segment parameter models for motion analysis (Dempster, 1955, DEM and de Leva, 1996 adjusted from Zatsiorsky and Seluyanov, ZAT). The body CoM (expressed as percentage of the total body height) was determined from several subjects including athletes as well as physically active students and sedentary people. Some significant differences were found in the location of the body CoM between the used segment models and the reaction board method for all male subjects (n=58, 57.03±0.79%, 56.20±0.76% and 57.60±0.76% for RB, ZAT and D…

A novel minimally invasive, dorsolateral, tubular partial odontoidectomy and autologous bone augmentation to treat dens pseudarthrosis: cadaveric, 3D…

2017

OBJECTIVE The goal of this study was to demonstrate the clinical and technical nuances of a minimally invasive, dorsolateral, tubular approach for partial odontoidectomy, autologous bone augmentation, and temporary C1–2 fixation to treat dens pseudarthrosis. METHODS A cadaveric feasibility study, a 3D virtual reality reconstruction study, and the subsequent application of this approach in 2 clinical cases are reported. Eight procedures were completed in 4 human cadavers. A minimally invasive, dorsolateral, tubular approach for odontoidectomy was performed with the aid of a tubular retraction system, using a posterolateral incision and an oblique approach angle. Fluoroscopy and postprocedur…

Modulation of cortical motor outputs by the symbolic meaning of visual stimuli.

2010

Abstract The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is p…

Anticipatory strategies of team-handball goalkeepers

2011

This study seeks to discover whether handball goalkeepers employ a general anticipatory strategy when facing long distance throws and the effect of uncertainty on these strategies. Seven goalkeepers and four throwers took part. We used a force platform to analyse the goalkeeper's movements on the basis of reaction forces and two video cameras synchronised at 500 Hz to film the throw using 3D video techniques. The goalkeepers initiated their movement towards the side of the throw 193 ± 67 ms before the release of the ball and when the uncertainty was reduced the time increased to 349 ± 71 ms. The kinematics analysis of their centre of mass indicated that there was an anticipatory strategy of…

Conduction times of cortical projections to paravertebral muscles in controls and in patients with multiple sclerosis

1994

Changes in power curve shapes as an indicator of fatigue during dynamic contractions.

2010

The purpose of this study was to analyze exercise-induced leg fatigue during a dynamic fatiguing task by examining the shapes of power vs. time curves through the combined use of several statistical methods: B-spline smoothing, functional principal components and (supervised and unsupervised) classification. In addition, granulometric size distributions were also computed to allow for comparison of curves coming from different subjects. Twelve physically active men participated in one acute heavy-resistance exercise protocol which consisted of five sets of 10 repetition maximum leg press with 120 s of rest between sets. To obtain a smooth and accurate representation of the data, a basis of …

Effect of chronic unloading and rehabilitation on human Achilles tendon properties: a velocity-encoded phase-contrast MRI study

2008

The objective of this study was to measure and monitor changes in Achilles tendon mechanical properties and force production capability of triceps surae muscles after 4 wk of limb suspension and 6 wk of physical rehabilitation. Five healthy volunteers underwent unilateral lower limb suspension followed by weekly physiotherapy. A velocity-encoded, phase-contrast magnetic resonance imaging (VE-PC-MRI) technique was used to estimate the tendon strain as a function of force produced during the submaximal isometric contractions. After limb suspension, triceps surae muscle strength decreased to 53.2 ± 15.6% (mean ± SD) of the presuspension level ( P < 0.05). Young's modulus, estimated from the…

The Laparoscopic Approach to Control Intractable Pelvic Neuralgia: From Laparoscopic Pelvic Neurosurgery to the LION Procedure

2007

OBJECTIVE: To present different aspects and advantages of the laparoscopic approach to the pelvic nerves aimed at treating intractable pelvic neuralgia. METHODS: We report on a nonconsecutive series of 7 patients with different types and etiologies of chronic pelvic neuralgia, all of whom underwent laparoscopy. In all 7 cases, the neuralgia was refractory to medical management and had profound socioeconomic consequences for the patients. RESULTS: Techniques of laparoscopic transperitoneal neurolysis of several pelvic somatic nerves are described but also our technique of laparoscopic implantation of neuroprothesis for neuromodulation on somatic pelvic nerves or on autonomic pelvic nerves as…