Search results for "virtu"
showing 10 items of 1987 documents
Towards EEG-Based Haptic Interaction within Virtual Environments
2019
International audience; Current virtual environments (VE) enable perceiving haptic stimuli to facilitate 3D user interaction, but lack brain-interfacial contents. Using electroencephalography (EEG), we undertook a feasibility study on exploring event-related potential (ERP) patterns of the user's brain responses during haptic interaction within a VE. The interaction was flying a virtual drone along a curved transmission line to detect defects under the stimuli (e.g., force increase and/or vibrotactile cues). We found that there were variations in the peak amplitudes and latencies (as ERP patterns) of the responses at about 200 ms post the onset of the stimuli. The largest negative peak occu…
Use of a Virtual Environment to Engage Motor and Postural Abilities in Elderly Subjects With and Without Mild Cognitive Impairment (MAAMI Project)
2016
Objectives: In the context of rehabilitation, the use of new technology such as Virtual Reality Technology (VRT) offers multiple possibilities to modulate the functional stimulation of subjects according to needs. Material and methods: In this study, the validity and reliability of our VRT system were investigated in fifteen healthy aged adults (HAA) and seven aged subjects with mild cognitive impairment (MCI). One implicit session was designed through two virtual environments (VEs) in order to induce the adapted activities associated with balance and postural control. In comparison, the same activities were achieved in explicit sessions with a physiotherapist. This cross-over study made us…
The effect of immersion disinfection procedures on dimensional stability of two elastomeric impression materials
2008
The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with additionpolymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after th…
Virtual reality exposure-based therapy for the treatment of post-traumatic stress disorder: a review of its efficacy, the adequacy of the treatment p…
2015
Introduction The essential feature of post-traumatic stress disorder (PTSD) is the development of characteristic symptoms following exposure to one or more traumatic events. According to evidence-based intervention guidelines and empirical evidence, one of the most extensively researched and validated treatments for PTSD is prolonged exposure to traumatic events; however, exposure therapy can present some limitations. Virtual reality (VR) can help to improve prolonged exposure because it creates fictitious, safe, and controllable situations that can enhance emotional engagement and acceptance. Objective In addition to carrying out a review to evaluate the efficacy of VR exposure-based thera…
Application of Supervised Machine Learning for Behavioral Biomarkers of Autism Spectrum Disorder Based on Electrodermal Activity and Virtual Reality
2020
[EN] Objective: Sensory processing is the ability to capture, elaborate, and integrate information through the five senses and is impaired in over 90% of children with autism spectrum disorder (ASD). The ASD population shows hyper¿hypo sensitiveness to sensory stimuli that can generate alteration in information processing, affecting cognitive and social responses to daily life situations. Structured and semi-structured interviews are generally used for ASD assessment, and the evaluation relies on the examiner¿s subjectivity and expertise, which can lead to misleading outcomes. Recently, there has been a growing need for more objective, reliable, and valid diagnostic measures, such as biomar…
Visual and postural eye-height information is flexibly coupled in the perception of virtual environments.
2021
We conducted two experiments to investigate how observers integrate postural and visual eye-height information when estimating the layout of interior space. In Experiment 1, we varied postural and visual eye-height information independently of each other in a virtual-reality setup. Observers estimated the width, depth, and height of simulated rooms. All dimensions were perceived as larger when the virtual visual eye-height corresponded to sitting on the floor as compared with standing upright. In contrast, the estimates remained widely unaffected by the observer's physical posture (likewise sitting vs. standing). In Experiment 2, we studied effects of the viewing condition (real vs. virtual…
What is the accuracy of the surgical guide in the planning of orthognathic surgeries? A systematic review.
2021
BACKGROUND To investigate the true accuracy of the surgical guide in the planning of orthognathic surgeries, which are performed worldwide. MATERIAL AND METHODS A systematic search was conducted in the PubMed database, Web of science, Scopus and Embase, covering August 2020 to January 2021. Studies that included patients with dentofacial deformity including anteroposterior, vertical and asymmetry problems who were undergoing an orthognathic surgery procedure were included; QUADAS-2 was used to determine the risk of bias by analyzing the quality of the studies. A PRISMA (flowchart) was created to show the study selection, keywords, nomination processes, and inclusion and exclusion criteria. …
Stereoscopic Viewing Enhances Visually Induced Motion Sickness but Sound Does Not
2012
Optic flow in visual displays or virtual environments often induces motion sickness (MS). We conducted two studies to analyze the effects of stereopsis, background sound, and realism (video vs. simulation) on the severity of MS and related feelings of immersion and vection. In Experiment 1, 79 participants watched either a 15-min-long video clip taken during a real roller coaster ride, or a precise simulation of the same ride. Additionally, half of the participants watched the movie in 2D, and the other half in 3D. MS was measured using the Simulator Sickness Questionnaire (SSQ) and the Fast Motion Sickness Scale (FMS). Results showed a significant interaction for both variables, indicatin…
Innovative Educational Pathways in Spine Surgery: Advanced Virtual Reality–Based Training
2020
Background Over the past few years, a reorganization of the educational pathways has been promoted with the purpose of optimizing the acquisition of competences and their assessment, so as to reduce the risks to both health care professionals and end users. Virtual reality (VR) has been repeatedly tested, initially as a positive reinforcement for more traditional educational pathways and, more recently, as their potential substitute. The aim of this study was to demonstrate the potentiality of VR simulation training in spine surgery. Methods The VR simulator reproduced the lateral lumbar access to the spine. The simulation included a tutorial, the preoperative settings, and the surgical ses…
A multiparametric magnetic resonance imaging-based virtual reality surgical navigation tool for robotic-assisted radical prostatectomy
2019
Objective Increased computational power and improved visualization hardware have generated more opportunities for virtual reality (VR) applications in healthcare. In this study, we test the feasibility of a VR-assisted surgical navigation system for robotic-assisted radical prostatectomy. Material and methods The prostate, all magnetic resonance imaging (MRI) visible tumors, and important anatomic structures like the neurovascular bundles, seminal vesicles, bladder, and rectum were contoured on a multiparametric MRI using an in-house segmentation software. Three-dimensional (3-D) VR models were rendered and evaluated in a side room of the operating room. While interacting with the VR platfo…