Visual oscillation effects on dynamic balance control in people with multiple sclerosis
Abstract 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 res...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2022-08-01
|
| Series: | Journal of NeuroEngineering and Rehabilitation |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12984-022-01060-0 |
| _version_ | 1798038795326586880 |
|---|---|
| author | Lara Riem Scott A. Beardsley Ahmed Z. Obeidat Brian D. Schmit |
| author_facet | Lara Riem Scott A. Beardsley Ahmed Z. Obeidat Brian D. Schmit |
| author_sort | Lara Riem |
| collection | DOAJ |
| description | Abstract 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. |
| first_indexed | 2024-04-11T21:45:14Z |
| format | Article |
| id | doaj.art-cab5cdabc0084e5098e3dbf1207c108b |
| institution | Directory Open Access Journal |
| issn | 1743-0003 |
| language | English |
| last_indexed | 2024-04-11T21:45:14Z |
| publishDate | 2022-08-01 |
| publisher | BMC |
| record_format | Article |
| series | Journal of NeuroEngineering and Rehabilitation |
| spelling | doaj.art-cab5cdabc0084e5098e3dbf1207c108b2022-12-22T04:01:27ZengBMCJournal of NeuroEngineering and Rehabilitation1743-00032022-08-0119111610.1186/s12984-022-01060-0Visual oscillation effects on dynamic balance control in people with multiple sclerosisLara Riem0Scott A. Beardsley1Ahmed Z. Obeidat2Brian D. Schmit3Department of Biomedical Engineering, Marquette University and Medical College of WisconsinDepartment of Biomedical Engineering, Marquette University and Medical College of WisconsinDepartment of Neurology, Medical College of WisconsinDepartment of Biomedical Engineering, Marquette University and Medical College of WisconsinAbstract 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.https://doi.org/10.1186/s12984-022-01060-0Multiple sclerosisVirtual realityBalanceVisual motionGaitObject motion |
| spellingShingle | Lara Riem Scott A. Beardsley Ahmed Z. Obeidat Brian D. Schmit Visual oscillation effects on dynamic balance control in people with multiple sclerosis Journal of NeuroEngineering and Rehabilitation Multiple sclerosis Virtual reality Balance Visual motion Gait Object motion |
| title | Visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| title_full | Visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| title_fullStr | Visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| title_full_unstemmed | Visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| title_short | Visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| title_sort | visual oscillation effects on dynamic balance control in people with multiple sclerosis |
| topic | Multiple sclerosis Virtual reality Balance Visual motion Gait Object motion |
| url | https://doi.org/10.1186/s12984-022-01060-0 |
| work_keys_str_mv | AT larariem visualoscillationeffectsondynamicbalancecontrolinpeoplewithmultiplesclerosis AT scottabeardsley visualoscillationeffectsondynamicbalancecontrolinpeoplewithmultiplesclerosis AT ahmedzobeidat visualoscillationeffectsondynamicbalancecontrolinpeoplewithmultiplesclerosis AT briandschmit visualoscillationeffectsondynamicbalancecontrolinpeoplewithmultiplesclerosis |