Can optical flow perturbations detect walking balance impairment in people with multiple sclerosis?

Selgrade, Brian P.; Meyer, Diane; Sosnoff, Jacob J.; Franz, Jason R.

doi:10.1371/journal.pone.0230202

Cited by 13 publications

(11 citation statements)

References 53 publications

(70 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…multiple sclerosis (MS; n = 37), clinically isolated syndrome (CIS; n = 2)). Whereas previous studies identified this gait parameter as important hallmark of MS-related gait deficits 37 , 51 , 52 there are, to our knowledge, no findings that related enhanced step width variability with increased risk of falls in patients with MS or CIS.…”

Section: Discussioncontrasting

confidence: 59%

Fall-related functional impairments in patients with neurological gait disorder

Ehrhardt

Hostettler

Widmer

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Falls are common in patients with neurological disorders and are a primary cause of injuries. Nonetheless, fall-associated gait characteristics are poorly understood in these patients. Objective, quantitative gait analysis is an important tool to identify the principal fall-related motor characteristics and to advance fall prevention in patients with neurological disorders. Fall incidence was assessed in 60 subjects with different neurological disorders. Patients underwent a comprehensive set of functional assessments including instrumented gait analysis, computerized postural assessments and clinical walking tests. Determinants of falls were assessed by binary logistic regression analysis and receiver operator characteristics (ROC). The best single determinant of fallers was a step length reduction at slow walking speed reaching an accuracy of 67.2% (ROC AUC: 0.669; p = 0.027). The combination of 4 spatio-temporal gait parameters including step length and parameters of variability and asymmetry were able to classify fallers and non-fallers with an accuracy of 81.0% (ROC AUC: 0.882; p < 0.001). These findings suggest significant differences in specific spatio-temporal gait parameters between fallers and non-fallers among neurological patients. Fall-related impairments were mainly identified for spatio-temporal gait characteristics, suggesting that instrumented, objective gait analysis is an important tool to estimate patients' fall risk. Our results highlight pivotal fall-related walking deficits that might be targeted by future rehabilitative interventions that aim at attenuating falls.

show abstract

Section: Discussioncontrasting

confidence: 59%

Fall-related functional impairments in patients with neurological gait disorder

Ehrhardt

Hostettler

Widmer

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…First, our sample size was relatively small (11 and 14 for controls and PwMS respectively). This sample size was chosen based on: (1) our previous work [ 53 ] investigating differences in standing balance and visual oscillations between controls and PwMS, in which sample sizes of 10 and 10, respectively, produced significant results; (2) published work [ 17 ] which reported that visual perturbations during gait produce a significant difference between controls and PwMS with a sample size of 14 and 14; and (3) despite our small sample size we obtained adequate effect sizes and relatively high power (on average > 0.85). However, we do suggest that given the nonhomogeneous nature of MS, the results may have limited applicability to cases that differed from our sample and a larger group may be needed for broader interpretation.…”

Section: Discussionmentioning

confidence: 99%

“…The response to visual oscillation, referred to as visuomotor entrainment, characterizes the ability to synchronize or adapt motor responses to a visual stimulus [ 30 ]. Visual field-of-view oscillations and their resulting effect on sway and foot placement have been used to demonstrate increased reliance on vision with age [ 31 ] and MS [ 8 , 17 ]. Interestingly, the effect of object motion within a scene, which places additional demands on visual processing of movement, has not been studied in PwMS.…”

Section: Introductionmentioning

confidence: 99%

Visual oscillation effects on dynamic balance control in people with multiple sclerosis

Riem

Beardsley

Obeidat

et al. 2022

J NeuroEngineering Rehabil

View full text Add to dashboard Cite

Background People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial–lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR). Methods Fourteen PwMS (mean age 49 ± 11 years, functional gait assessment score of 27.8 ± 1.8, and Berg Balance scale score 54.7 ± 1.5) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants walked on a treadmill at a self-selected speed while wearing a VR headset that projected an immersive forest scene. Visual conditions consisted of (1) no visual manipulations (speed-matched anterior/posterior optical flow), (2) 0.175 m mediolateral translational oscillations of the scene that consisted of low pairing (0.1 and 0.31 Hz) or (3) high pairing (0.15 and 0.465 Hz) frequencies, (4) 5 degree medial–lateral rotational oscillations of virtual trees at a low frequency pairing (0.1 and 0.31 Hz), and (5) a combination of the tree and scene movements in (3) and (4). Results We found that both PwMS and controls exhibited greater instability and visuomotor entrainment to simulated mediolateral translation of the visual field (scene) during treadmill walking. This was demonstrated by significant (p < 0.05) increases in mean step width and variability and center of mass sway. Visuomotor entrainment was demonstrated by high coherence between center of mass sway and visual motion (magnitude square coherence = ~ 0.5 to 0.8). Only PwMS exhibited significantly greater instability (higher step width variability and center of mass sway) when objects moved within the scene (i.e., swaying trees). Conclusion Results suggest the presence of visual motion processing errors in PwMS that reduced dynamic stability. Specifically, object motion (via tree sway) was not effectively parsed from the observer’s self-motion. Identifying this distinction between visual object motion and self-motion detection in MS provides insight regarding stability control in environments with excessive external movement, such as those encountered in daily life.

show abstract

“…In addition, PwMS have altered temporalspatial gait patterns [6] as well as increased variability of trunk movement [7] and footfall placement variability [8] during gait, all of which are expected to contribute to the increased likelihood of balance loss and falls [9][10][11][12]. To compensate for the impact of the loss in proprioception on balance, PwMS might have greater reliance on the vestibular or visual systems for balance control [13], as documented by a decrease in stability when visual feedback is removed during standing [14][15][16] and increased sensitivity to visual stimuli during gait [17]. Because of the potential increased importance of vision on gait stability in PwMS, the effects of visual perturbations of different types on body sway and foot placement during gait were examined in this study.…”

Section: Introductionmentioning

confidence: 99%

“…The response to visual oscillation, referred to as visuomotor entrainment, characterizes the ability to synchronize or adapt motor responses to a visual stimulus [30]. Visual eld-of-view oscillations and their resulting effect on sway and foot placement have been used to demonstrate increased reliance on vision with age [31] and MS [8,17]. Interestingly, the effect of object motion within a scene, which places additional demands on visual processing of movement, has not been studied in PwMS.…”

Section: Introductionmentioning

confidence: 99%

Visual oscillation effects on dynamic balance control in people with multiple sclerosis

Riem

Beardsley

Obeidat

et al. 2022

Preprint

View full text Add to dashboard Cite

Background: People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial-lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR).Methods: Fourteen PwMS (mean age 49 ± 11 years) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants walked on a treadmill at a self-selected speed while wearing a VR headset that projected an immersive forest scene. Visual conditions consisted of (1) no visual manipulations (speed-matched anterior/posterior optical flow), (2) 0.175 meter mediolateral translational oscillations of the scene that consisted of low pairing (0.1 and 0.31 Hz) or (3) high pairing (0.15 and 0.465 Hz) frequencies, (4) 5 degree medial-lateral rotational oscillations of virtual trees at a low frequency pairing (0.1 and 0.31 Hz), and (5) a combination of the tree and scene movements in (3) and (4).Results: We found that both PwMS and controls exhibited greater instability and visuomotor entrainment to simulated mediolateral translation of the visual field (scene) during treadmill walking. This was demonstrated by significant (p<0.05) increases in mean step width and variability and center of mass sway. Visuomotor entrainment was demonstrated by high coherence between center of mass sway and visual motion (magnitude square coherence = ~ 0.5 to 0.8). Only PwMS exhibited significantly greater instability (higher step width variability and center of mass sway) when objects moved within the scene (i.e., swaying trees).Conclusion: Results suggest the presence of visual motion processing errors in PwMS that reduced dynamic stability. Specifically, object motion (via tree sway) was not effectively parsed from the observer’s self-motion. Identifying this distinction between visual object motion and self-motion detection in MS provides insight regarding stability control in environments with excessive external movement, such as those encountered in daily life.

show abstract

Can optical flow perturbations detect walking balance impairment in people with multiple sclerosis?

Cited by 13 publications

References 53 publications

Fall-related functional impairments in patients with neurological gait disorder

Fall-related functional impairments in patients with neurological gait disorder

Visual oscillation effects on dynamic balance control in people with multiple sclerosis

Visual oscillation effects on dynamic balance control in people with multiple sclerosis

Contact Info

Product

Resources

About