scholarly journals Adaptation effects in static postural control by providing simultaneous visual feedback of center of pressure and center of gravity

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Kenta Takeda ◽  
Hiroki Mani ◽  
Naoya Hasegawa ◽  
Yuki Sato ◽  
Shintaro Tanaka ◽  
...  
Keyword(s):  
Postural Control ◽  
Visual Feedback ◽  
Center Of Pressure ◽  
Center Of Gravity ◽  
Adaptation Effects

scholarly journals Attentional demands associated with augmented visual feedback during quiet standing

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5101 ◽  
Author(s):  
Krzysztof Kręcisz ◽  
Michał Kuczyński
Keyword(s):  
Postural Control ◽  
Visual Feedback ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Postural Control System ◽  
Power Frequency ◽  
Auditory Reaction Time ◽  
Anterior Posterior

To investigate how additional visual feedback (VFB) affects postural stability we compared 20-sec center-of-pressure (COP) recordings in two conditions: without and with the VFB. Seven healthy adult subjects performed 10 trials lasting 20 seconds in each condition. Simultaneously, during all trials the simple auditory reaction time (RT) was measured. Based on the COP data, the following sway parameters were computed: standard deviation (SD), mean speed (MV), sample entropy (SE), and mean power frequency (MPF). The RT was higher in the VFB condition (p < 0.001) indicating that this condition was attention demanding. The VFB resulted in decreased SD and increased SE in both the medial-lateral (ML) and anterior-posterior (AP) planes (p < .001). These results account for the efficacy of the VFB in stabilizing posture and in producing more irregular COP signals which may be interpreted as higher automaticity and/or larger level of noise in postural control. The MPF was higher during VFB in both planes as was the MV in the AP plane only (p < 0.001). The latter data demonstrate higher activity of postural control system that was caused by the availability of the set-point on the screen and the resulting control error which facilitated and sped up postural control.

Stroboscopic Vision to Induce Sensory Reweighting During Postural Control

2017 ◽  
Vol 26 (5) ◽  
Author(s):  
Kyung-Min Kim ◽  
Joo-Sung Kim ◽  
Dustin R. Grooms
Keyword(s):  
Postural Control ◽  
Visual Feedback ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Somatosensory System ◽  
Lower Extremity Injury ◽  
Somatosensory Processing ◽  
Sensory Reweighting ◽  
Eyes Open ◽  
Almost All

Context: Patients with somatosensory deficits have been found to rely more on visual feedback for postural control. However, current balance tests may be limited in identifying increased visual dependence (sensory reweighting to the visual system), as options are typically limited to eyes open or closed conditions with no progressions between. Objective: To assess the capability of stroboscopic glasses to induce sensory reweighting of visual input during single-leg balance. Design:Descriptive Setting: Laboratory Participants: 18 healthy subjects without vision or balance disorders or lower extremity injury history (9 females; age = 22.1 ± 2.1 y; height = 169.8 ± 8.5 cm; mass = 66.5 ± 10.6 kg) participated. Interventions: Subjects performed 3 trials of unipedal stance for 10 s with eyes open (EO) and closed (EC), and with stroboscopic vision (SV) that was completed with specialized eyewear that intermittently cycled between opaque and transparent for 100 ms at a time. Balance tasks were performed on firm and foam surfaces, with the order randomized. Main Outcome Measures: Ten center-of-pressure parameters were computed. Results: Separate ANOVAs with repeated measures found significant differences between the 3 visual conditions on both firm (P-values =< .001) and foam (P-values =< .001 to .005) surfaces for all measures. For trials on firm surface, almost all measures showed that balance with SV was significantly impaired relative to EO, but less impaired than EC. On the foam surface, almost all postural stability measures demonstrated significant impairments with SV compared with EO, but the impairment with SV was similar to EC. Conclusions:SV impairment of single-leg balance was large on the firm surface, but not to the same degree as EC. However, the foam surface disruption to somatosensory processing and sensory reweighting to vision lead to greater disruptive effects of SV to the same level as EC. This indicates that when the somatosensory system is perturbed even a moderate decrease in visual feedback (SV) may induce an EC level impairment to postural control during single-leg stance.

scholarly journals Influence of Augmented Visual Feedback on Balance Control in Unilateral Transfemoral Amputees

2021 ◽  
Vol 15 ◽  
Author(s):  
Katharina Fuchs ◽  
Thomas Krauskopf ◽  
Torben B. Lauck ◽  
Lukas Klein ◽  
Marc Mueller ◽  
...  
Keyword(s):  
Postural Control ◽  
Real Time ◽  
Visual Feedback ◽  
Lower Limb ◽  
Center Of Pressure ◽  
Sensory Modality ◽  
Control Group ◽  
Eyes Open ◽  
Transfemoral Amputees ◽  
Lower Limb Amputees

Patients with a lower limb amputation rely more on visual feedback to maintain balance than able-bodied individuals. Altering this sensory modality in amputees thus results in a disrupted postural control. However, little is known about how lower limb amputees cope with augmented visual information during balance tasks. In this study, we investigated how unilateral transfemoral amputees incorporate visual feedback of their center of pressure (CoP) position during quiet standing. Ten transfemoral amputees and ten age-matched able-bodied participants were provided with real-time visual feedback of the position of their CoP while standing on a pressure platform. Their task was to keep their CoP within a small circle in the center of a computer screen placed at eye level, which could be achieved by minimizing their postural sway. The visual feedback was then delayed by 250 and 500 ms and was combined with a two- and five-fold amplification of the CoP displacements. Trials with eyes open without augmented visual feedback as well as with eyes closed were further performed. The overall performance was measured by computing the sway area. We further quantified the dynamics of the CoP adjustments using the entropic half-life (EnHL) to study possible physiological mechanisms behind postural control. Amputees showed an increased sway area compared to the control group. The EnHL values of the amputated leg were significantly higher than those of the intact leg and the dominant and non-dominant leg of controls. This indicates lower dynamics in the CoP adjustments of the amputated leg, which was compensated by increasing the dynamics of the CoP adjustments of the intact leg. Receiving real-time visual feedback of the CoP position did not significantly reduce the sway area neither in amputees nor in controls when comparing with the eyes open condition without visual feedback of the CoP position. Further, with increasing delay and amplification, both groups were able to compensate for small visual perturbations, yet their dynamics were significantly lower when additional information was not received in a physiologically relevant time frame. These findings may be used for future design of neurorehabilitation programs to restore sensory feedback in lower limb amputees.

Sign in / Sign up

Export Citation Format

Share Document