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Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis.

Fling BW, Dutta GG, Schlueter H, Cameron MH, Horak FB - Front Hum Neurosci (2014)

Bottom Line: We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC).Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS.These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, School of Medicine, Oregon Health & Science University , Portland, OR , USA ; Portland VA Medical Center , Portland, OR , USA.

ABSTRACT
Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

No MeSH data available.


Related in: MedlinePlus

Microstructural integrity of the entire cortical proprioceptive fiber tracts (A) and fiber tracts of the same pathway restricted to solely those that originate/terminate in Brodmann area 3a (B). For both plots, PwMS have significantly greater radial diffusivity of tracts within the right and left hemispheres compared to HC. Data are mean (± SD); *P < 0.05.
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Figure 4: Microstructural integrity of the entire cortical proprioceptive fiber tracts (A) and fiber tracts of the same pathway restricted to solely those that originate/terminate in Brodmann area 3a (B). For both plots, PwMS have significantly greater radial diffusivity of tracts within the right and left hemispheres compared to HC. Data are mean (± SD); *P < 0.05.

Mentions: Whole-brain voxelwise tract (TBSS) analysis of RD revealed significant differences between groups in multiple regions. In particular, PwMS had significantly higher RD principally within periventricular regions, corticospinal, and callosal fiber tracts (Figure 3A). The cortical proprioceptive tract was identified in all participants within both the right and left hemispheres (Figures 3B,C). When computed for the entire cortical proprioceptive tract, no group differences were observed (P > 0.3) for FA values in either the right (PwMS = 0.30 ± 0.02; HC = 0.32 ± 0.03) or left hemispheres (PwMS = 0.33 ± 0.03; HC = 0.34 ± 0.02). Conversely, we report a significant main effect of group such that PwMS had significantly greater RD (F1,43 = 4.3; P < 0.05) compared to HC. There was no group × hemisphere interaction (F1,43 = 0.4; P > 0.5), indicating poorer tract integrity in PwMS in both the right (PwMS = 0.96 × 10−3 mm2/s ± 0.15: HC = 0.88 × 10−3 mm2/s ± 0.09) and left hemispheres (PwMS = 0.89 × 10−3 mm2/s ± 0.11: HC = 0.83 × 10−3 mm2/s ± 0.09) (Figure 4A). Additionally, we found a main effect of hemisphere (F1,43 = 19.0; P < 0.001) such that fiber tracts within the right hemisphere had significantly greater RD (0.92 × 10−3 mm2/s ± 0.13) than the left (0.86 × 10−3 mm2/s ± 0.11).


Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis.

Fling BW, Dutta GG, Schlueter H, Cameron MH, Horak FB - Front Hum Neurosci (2014)

Microstructural integrity of the entire cortical proprioceptive fiber tracts (A) and fiber tracts of the same pathway restricted to solely those that originate/terminate in Brodmann area 3a (B). For both plots, PwMS have significantly greater radial diffusivity of tracts within the right and left hemispheres compared to HC. Data are mean (± SD); *P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202774&req=5

Figure 4: Microstructural integrity of the entire cortical proprioceptive fiber tracts (A) and fiber tracts of the same pathway restricted to solely those that originate/terminate in Brodmann area 3a (B). For both plots, PwMS have significantly greater radial diffusivity of tracts within the right and left hemispheres compared to HC. Data are mean (± SD); *P < 0.05.
Mentions: Whole-brain voxelwise tract (TBSS) analysis of RD revealed significant differences between groups in multiple regions. In particular, PwMS had significantly higher RD principally within periventricular regions, corticospinal, and callosal fiber tracts (Figure 3A). The cortical proprioceptive tract was identified in all participants within both the right and left hemispheres (Figures 3B,C). When computed for the entire cortical proprioceptive tract, no group differences were observed (P > 0.3) for FA values in either the right (PwMS = 0.30 ± 0.02; HC = 0.32 ± 0.03) or left hemispheres (PwMS = 0.33 ± 0.03; HC = 0.34 ± 0.02). Conversely, we report a significant main effect of group such that PwMS had significantly greater RD (F1,43 = 4.3; P < 0.05) compared to HC. There was no group × hemisphere interaction (F1,43 = 0.4; P > 0.5), indicating poorer tract integrity in PwMS in both the right (PwMS = 0.96 × 10−3 mm2/s ± 0.15: HC = 0.88 × 10−3 mm2/s ± 0.09) and left hemispheres (PwMS = 0.89 × 10−3 mm2/s ± 0.11: HC = 0.83 × 10−3 mm2/s ± 0.09) (Figure 4A). Additionally, we found a main effect of hemisphere (F1,43 = 19.0; P < 0.001) such that fiber tracts within the right hemisphere had significantly greater RD (0.92 × 10−3 mm2/s ± 0.13) than the left (0.86 × 10−3 mm2/s ± 0.11).

Bottom Line: We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC).Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS.These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, School of Medicine, Oregon Health & Science University , Portland, OR , USA ; Portland VA Medical Center , Portland, OR , USA.

ABSTRACT
Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

No MeSH data available.


Related in: MedlinePlus