scholarly journals Progressive lenses distortions effect on postural stability in virtual reality environment

2010 ◽  
Vol 7 (9) ◽  
pp. 1026-1026
Author(s):  
J.-m. Hanssens ◽  
R. Allard ◽  
J. Faubert
Keyword(s):  
Virtual Reality ◽  
Postural Stability ◽  
Virtual Reality Environment ◽  
Progressive Lenses

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

DEFORMATION OF B-SPLINE BASED PLASTICINE MATERIAL MODEL IN VIRTUAL REALITY ENVIRONMENT

2017 ◽  
Vol 5 (3) ◽  
pp. 15
Author(s):  
GANDOTRA SANDEEP ◽  
Pungotra Harish ◽  
Moudgil Prince Kumar ◽  
◽  
◽  
...  
Keyword(s):  
Virtual Reality ◽  
Material Model ◽  
Virtual Reality Environment ◽  
B Spline

scholarly journals Combining tDCS With a Motor-Cognitive Task to Reduce the Negative Impact of Dual-Tasking on the Gait of Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 287-288
Author(s):  
Jeffrey Hausdorff ◽  
Nofar Schneider ◽  
Marina Brozgol ◽  
Pablo Cornejo Thumm ◽  
Nir Giladi ◽  
...  
Keyword(s):  
Older Adults ◽  
Virtual Reality ◽  
Executive Function ◽  
Dual Task ◽  
Gait Speed ◽  
Negative Impact ◽  
Virtual Reality Environment ◽  
Dual Tasking ◽  
Concurrent Performance ◽  
Dual Task Cost

Abstract The simultaneous performance of a secondary task while walking (i.e., dual tasking) increases motor-cognitive interference and fall risk in older adults. Combining transcranial direct current stimulation (tDCS) with the concurrent performance of a task that putatively involves the same brain networks targeted by the tDCS may reduce the negative impact of dual-tasking on walking. We examined whether tDCS applied while walking reduces the dual-task costs to gait and whether this combination is better than tDCS alone or walking alone (with sham stimulation). In 25 healthy older adults (aged 75.7±10.5yrs), a double-blind, within-subject, cross-over pilot study evaluated the acute after-effects of 20 minutes of tDCS targeting the primary motor cortex and the dorsal lateral pre frontal cortex during three separate sessions:1) tDCS while walking on a treadmill in a virtual-reality environment (tDCS+walking), 2) tDCS while seated (tDCS+seated), and 3) walking in the virtual-reality environment with sham tDCS (sham+walking). The complex walking condition taxed motor and cognitive abilities. During each session, single- and dual-task walking and cognitive function were assessed before and immediately after stimulation. Compared to pre-tDCS performance, tDCS+walking reduced the dual-task cost to gait speed (p=0.004) and other gait features (e.g., variability p=0.02), and improved (p<0.001) executive function (Stroop interference score). tDCS+seated and sham+walking did not affect the dual-task cost to gait speed (p>0.17). These initial findings demonstrate that tDCS delivered during challenging walking ameliorates dual-task gait and executive function in older adults, suggesting that the concurrent performance of related tasks enhances the efficacy of the neural stimulation and mobility.

scholarly journals Kinematic of the Position and Orientation Synchronization of the Posture of a n DoF Upper-Limb Exoskeleton with a Virtual Object in an Immersive Virtual Reality Environment

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1069
Author(s):  
Deyby Huamanchahua ◽  
Adriana Vargas-Martinez ◽  
Ricardo Ramirez-Mendoza
Keyword(s):  
Virtual Reality ◽  
Upper Limb ◽  
Human Performance ◽  
Early Stage ◽  
Inverse Kinematic ◽  
Virtual Object ◽  
Immersive Virtual Reality ◽  
Virtual Reality Environment ◽  
Upper Limb Exoskeleton ◽  
Position And Orientation

Exoskeletons are an external structural mechanism with joints and links that work in tandem with the user, which increases, reinforces, or restores human performance. Virtual Reality can be used to produce environments, in which the intensity of practice and feedback on performance can be manipulated to provide tailored motor training. Will it be possible to combine both technologies and have them synchronized to reach better performance? This paper consists of the kinematics analysis for the position and orientation synchronization between an n DoF upper-limb exoskeleton pose and a projected object in an immersive virtual reality environment using a VR headset. To achieve this goal, the exoskeletal mechanism is analyzed using Euler angles and the Pieper technique to obtain the equations that lead to its orientation, forward, and inverse kinematic models. This paper extends the author’s previous work by using an early stage upper-limb exoskeleton prototype for the synchronization process.

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