Effect of visual field locus and oscillation frequencies on posture control in an ecological environment

Piponnier, Jean-Claude; Hanssens, Jean-Marie; Faubert, Jocelyn

doi:10.1167/9.1.13

Cited by 25 publications

(26 citation statements)

References 28 publications

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“…This is a measure of velocity indicating the total body displacement in the horizontal plane (AP ''z-axis'' and ML displacements ''x-axis'') in meters per second. 14,22,23 The data analysis for postural instability is expressed as a ratio of the global postural reactivity in dynamic conditions over the reactivity in static conditions for each subject. Knowing that postural reactivity varies from one individual to another, this method of comparison allows using participants as their own control.…”

Section: Discussionmentioning

confidence: 99%

Myopes Show Greater Visually Induced Postural Responses Than Emmetropes

Sayah

Asaad

Hanssens

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. The literature already establishes that vision plays a crucial role in postural control and that this visual dependence shows intra-and interindividual variability. However, does ametropia also have an effect on postural control? This question leads to our study, which aims primarily to determine if myopes and emmetropes behave differently in terms of postural control when subjected to visual stimulation, and secondarily, if this difference persists in the presence of barrel and pincushion distortions. The results could lead, among other things, to improved lens design.METHODS. Twenty-four subjects (12 myopes of À2.00 to À9.00 diopters [D] and 12 emmetropes of À0.50 to þ0.50 D), between 19 and 35 years of age, participated in the study after comprehensive eye examinations were carried out. Of the 12 myopes, the preferred type of correction was divided equally within the group. While standing in front of a projection system and fixating on an immobile point, a checkerboard stimulus was displayed in their peripheral visual field, in either a static or dynamic state. Three conditions of optical distortion (plan, pincushion, and barrel distortions) were presented to the subjects. Their postural response was measured and recorded using a system of infrared cameras and optical sensors positioned on a helmet. RESULTS.The results show that postural instability induced by a dynamic peripheral stimulus is higher for myopes compared with emmetropes (ANOVA Refractive Error, F 1,22 ¼ 5.92, P ¼ 0.0235). When exposed to optical distortions, the two groups also have significant differences in postural behaviors (ANOVA Refractive Error*Optical Distortion, F 2,44 ¼ 5.67, P ¼ 0.0064).CONCLUSIONS. These results suggest that refractive error could be a factor in explaining individual variations of the role of vision in postural control.

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Section: Discussionmentioning

confidence: 99%

Myopes Show Greater Visually Induced Postural Responses Than Emmetropes

Sayah

Asaad

Hanssens

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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“…38, 39 Piponnier et al 23 used a tunnel paradigm consisting of a CAVE (cave automatic virtual environment) room where the subject was immersed in a 3D displayed virtual environment to study the roles of central and peripheral vision in the control of posture in healthy individuals. The authors showed that, under static conditions, central and peripheral visual fields appear to have equal importance in the control of stance.…”

Section: Discussionmentioning

confidence: 99%

“…25, 40 As glaucoma has a relatively larger effect on peripheral compared to central vision, this may help explain the better performance of postural metrics obtained in dynamic versus static visual stimuli conditions in our study. Our methodology for assessment of postural reactivity to optic flow has major differences compared to that employed by Piponnier et al 23 We used an Oculus Rift stereoscopic head-mounted display for stimuli presentation. This allows for a much simpler and less costly setup, albeit preserving the ability to present ecologically valid perturbations.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Postural Control in Patients with Glaucoma Using a Virtual Reality Environment

et al. 2015

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Purpose To evaluate postural control using a dynamic virtual reality environment and the relationship between postural metrics and history of falls in glaucoma patients. Design Cross-sectional study. Participants The study involved 42 glaucoma patients with repeatable visual field defects on standard automated perimetry (SAP) and 38 control healthy subjects. Methods Patients underwent evaluation of postural stability by a force platform during presentation of static and dynamic visual stimuli on stereoscopic head-mounted goggles. The dynamic visual stimuli presented rotational and translational ecologically valid peripheral background perturbations. Postural stability was also tested in a completely dark field to assess somatosensory and vestibular contributions to postural control. History of falls was evaluated by a standard questionnaire. Main Outcome Measures Torque moments around the center of foot pressure on the force platform were measured and the standard deviations (STD) of these torque moments were calculated as a measurement of postural stability and reported in Newton meter (Nm). The association with history of falls was investigated using Poisson regression models. Age, gender, body mass index, severity of visual field defect, best-corrected visual acuity, and STD on dark field condition were included as confounding factors. Results Glaucoma patients had larger overall STD than controls during both translational (5.12 ± 2.39 Nm vs. 3.85 ± 1.82 Nm, respectively; P = 0.005) as well as rotational stimuli (5.60 ± 3.82 Nm vs. 3.93 ± 2.07 Nm, respectively; P = 0.022). Postural metrics obtained during dynamic visual stimuli performed better in explaining history of falls compared to those obtained in static and dark field condition. In the multivariable model, STD values in the mediolateral direction during translational stimulus were significantly associated with history of falls in glaucoma patients (incidence-rate ratio = 1.85; 95% CI: 1.30 – 2.63; P = 0.001). Conclusions The study presented and validated a novel paradigm for evaluation of balance control in glaucoma patients based on the assessment of postural reactivity to dynamic visual stimuli using a virtual reality environment. The newly developed metrics were associated with history of falls and may help to provide a better understanding of balance control in glaucoma patients.

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“…The viewing distance and angle of regard are also key components [7][8][9][10]. The efficiency of visual stabilization also depends on many factors such as target‚ size‚ luminance location, visual acuity, and posture [11][12][13][14][15]. However, Atchinson et al assessed the Hess-Gullstrand theory where with increasing age there is an increasing excess amount of ciliary muscle contraction beyond the ability of the lens and capsule to respond to it [16].…”

Section: Introductionmentioning

confidence: 99%