scholarly journals Regional Associations of Cortical Thickness With Gait Variability: The Tasmanian Study of Cognition and Gait

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 232-233
Author(s):  
Oshadi Jayakody ◽  
Monique Breslin ◽  
Richard Beare ◽  
Velandai Srikanth ◽  
Helena Blumen ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Step Length ◽  
Gait Variability ◽  
Thickness Ratio ◽  
Sensory Function ◽  
Time Variability ◽  
Step Width ◽  
Time Step ◽  
Cortical Regions ◽  
Regional Associations

Abstract Gait variability is a marker of cognitive decline. However, there is limited understanding of the cortical regions associated with gait variability. We examined associations between regional cortical thickness and gait variability in a population-based sample of older people without dementia. Participants (n=350, mean age 71.9±7.1) were randomly selected from the electoral roll. Variability in step time, step length, step width and double support time (DST) were calculated as the standard deviation of each measure, obtained from the GAITRite walkway. MRI scans were processed through FreeSurfer to obtain cortical thickness of 68 regions. Bayesian regression was used to determine regional associations of mean cortical thickness and thickness ratio (regional thickness/overall mean thickness) with gait variability. Smaller overall cortical thickness was only associated with greater step width and step time variability. Smaller mean thickness in widespread regions important for sensory, cognitive and motor functions were associated with greater step width and step time variability. In contrast, smaller thickness in a few frontal and temporal regions were associated with DST variability and the right cuneus was associated with step length variability. Smaller thickness ratio in frontal and temporal regions important for motor planning, execution and sensory function and, greater thickness ratio in the anterior cingulate was associated with greater variability in all measures. Examining individual cortical regions is important in understanding the relationship between gray matter and gait variability. Cortical thickness ratio highlights that smaller regional thickness relative to global thickness may be important for the consistency of gait.

scholarly journals Regional Associations of Cortical Thickness With Gait Variability—The Tasmanian Study of Cognition and Gait

2020 ◽  
Vol 75 (8) ◽  
pp. 1537-1544
Author(s):  
Oshadi Jayakody ◽  
Monique Breslin ◽  
Richard Beare ◽  
Helena M Blumen ◽  
Velandai K Srikanth ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Step Length ◽  
Gait Variability ◽  
Thickness Ratio ◽  
Sensory Function ◽  
Time Variability ◽  
Step Width ◽  
Time Step ◽  
Cortical Regions ◽  
Regional Associations

Abstract Background Gait variability is a marker of cognitive decline. However, there is limited understanding of the cortical regions associated with gait variability. We examined associations between regional cortical thickness and gait variability in a population-based sample of older people without dementia. Method Participants (n = 350, mean age 71.9 ± 7.1) were randomly selected from the electoral roll. Variability in step time, step length, step width, and double support time (DST) were calculated as the standard deviation of each measure, obtained from the GAITRite walkway. Magnetic resonance imaging (MRI) scans were processed through FreeSurfer to obtain cortical thickness of 68 regions. Bayesian regression was used to determine regional associations of mean cortical thickness and thickness ratio (regional thickness/overall mean thickness) with gait variability. Results Smaller global cortical thickness was only associated with greater step width and step time variability. Smaller mean thickness in widespread regions important for sensory, cognitive, and motor functions were associated with greater step width and step time variability. In contrast, smaller thickness in a few frontal and temporal regions were associated with DST variability and the right cuneus was associated with step length variability. Smaller thickness ratio in frontal and temporal regions important for motor planning, execution, and sensory function and greater thickness ratio in the anterior cingulate was associated with greater variability in all measures. Conclusions Examining individual cortical regions is important in understanding the relationship between gray matter and gait variability. Cortical thickness ratio highlights that smaller regional thickness relative to global thickness may be important for the consistency of gait.

Abstract 1: Improvement of Sensory Function Following Rehabilitation in Chronic Stroke Is Associated With Increased Cortical Thickness

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Svetlana Pundik ◽  
Aleca Scoco ◽  
Margaret Skelly ◽  
Jessica McCabe ◽  
Janis J Daly
Keyword(s):  
Cortical Thickness ◽  
Structural Changes ◽  
Chronic Stroke ◽  
Sensory Function ◽  
Middle Temporal Gyrus ◽  
Complex Nature ◽  
Middle Temporal ◽  
Sensory Recovery ◽  
Cortical Regions ◽  
Sensory Acuity

Introduction: Loss of somatosensory function after stroke weakens the ability to adequately relate to our environment, thus significantly reduces quality of life. Neuroplastic processes of sensory recovery are poorly understood. The objective of this study was to identify cortical regions that undergo structural changes (measured by change in cortical thickness (CT)) during sensory recovery. The hypothesis was that for subjects who improve sensory acuity, CT change in regions of the bilateral sensory network correlates with change in sensory acuity. Methods: Chronic stroke survivors were treated with 12-weeks rehabilitation. Outcome measures were sensory acuity (monofilament), Fugl-Meyer upper limb coordination and CT (T1 Magnetic Resonance Imaging). CT change was calculated based on T1 images using Freesurfer longitudinal processing stream. General linear regression modeling identified cortical regions where change in CT was associated with change in sensory acuity after controlling for baseline sensory impairment and change in motor function. Cluster-wise correction for multiple comparisons was conducted using Monte-Carlo simulation at p<0.05. Results: Subjects, who improved in sensory acuity (n=18), were 55.8±13.7 year old; 10% female; 1.8±0.9 years after first ever stroke. Acuity improved from 43.9±14mm to 40.53±13mm (p=0.004). FM improved from 22.4±8 to 34.5±10 (p<0.0001). For the ipsilesional hemisphere, CT increase correlated with sensory improvement in lateral occipital gyrus (size=1543mm2; peak vertex coordinates in MNI space x=-10.9, y=-97, z=10.9, cluster wise p=0.0002) and in middle temporal gyrus (795mm2, x=-57.2, y=-56.5,z=0.9, p=0.002). For the contralesional hemisphere, increased CT was associated with improved monofilament acuity within supramarginal gyrus (930mm2 ; x=47.2, y=-43.0, z=43.2, p=0.0002) and middle temporal gyrus (974mm2; x=53.5, y=-59.6, z=-1.7; p= 0.0001). Conclusion: Rehabilitation produces modality-specific structural brain changes that can be measured by changes in cortical thickness. Improved sensation correlates with increased thickness in bilateral high-order association sensory cortices reflecting a complex nature of sensory rehabilitation.

scholarly journals Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251229
Author(s):  
Cesar R. Castano ◽  
Helen J. Huang
Keyword(s):  
Step Length ◽  
Gait Variability ◽  
The Self ◽  
Step Width ◽  
Step Frequency ◽  
Gait Biomechanics ◽  
Treadmill Speed ◽  
Gait Parameters ◽  
Walking Speeds ◽  
Speed Fluctuations

Self-paced treadmills are being used more frequently to study humans walking with their self-selected gaits on a range of slopes. There are multiple options to purchase a treadmill with a built-in controller, or implement a custom written self-paced controller, which raises questions about how self-paced controller affect treadmill speed and gait biomechanics on multiple slopes. This study investigated how different self-paced treadmill controller sensitivities affected gait parameters and variability on decline, level, and incline slopes. We hypothesized that increasing self-paced controller sensitivity would increase gait variability on each slope. We also hypothesized that detrended variability could help mitigate differences in variability that arise from differences in speed fluctuations created by the self-paced controllers. Ten young adults walked on a self-paced treadmill using three controller sensitivities (low, medium, and high) and fixed speeds at three slopes (decline, -10°; level, 0°; incline, +10°). Within each slope, average walking speeds and spatiotemporal gait parameters were similar regardless of self-paced controller sensitivity. With higher controller sensitivities on each slope, speed fluctuations, speed variance, and step length variance increased whereas step frequency variance and step width variance were unaffected. Detrended variance was not affected by controller sensitivity suggesting that detrending variability helps mitigate differences associated with treadmill speed fluctuations. Speed-trend step length variances, however, increased with more sensitive controllers. Further, detrended step length variances were similar for self-paced and fixed speed walking, whereas self-paced walking included substantial speed-trend step length variance not present in fixed speed walking. In addition, regardless of the self-paced controller, subjects walked fastest on the level slope with the longest steps, narrowest steps, and least variance. Overall, our findings suggest that separating gait variability into speed-trend and detrended variability could be beneficial for interpreting gait variability among multiple self-paced treadmill studies and when comparing self-paced walking with fixed speed walking.

scholarly journals Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

2021 ◽  
Author(s):  
Cesar R. Castano ◽  
Helen J. Huang
Keyword(s):  
Step Length ◽  
Gait Variability ◽  
The Self ◽  
Step Width ◽  
Step Frequency ◽  
Gait Biomechanics ◽  
Treadmill Speed ◽  
Gait Parameters ◽  
Walking Speeds ◽  
Speed Fluctuations

AbstractSelf-paced treadmills are being used more and more to study humans walking with their self-selected gaits on a range of slopes. There are multiple options to purchase a treadmill with or implement a custom written self-paced controller, which raises questions about how self-paced controller affect treadmill speed and gait biomechanics on multiple slopes. This study investigated how different self-paced treadmill controller sensitivities affected gait parameters and variability on a decline, level, and incline slopes. We hypothesized that increasing self-paced controller sensitivity would increase gait variability on each slope. We also hypothesized that detrended variability could help mitigate differences in variability that arise from differences in speed fluctuations created by the self-paced controllers. Ten young adults walked on a self-paced treadmill using three self-paced controller sensitivities (low, medium, and high) and fixed speeds at three slopes (decline, −10°; level, 0°; incline, +10°). Within each slope, average walking speeds and spatiotemporal gait parameters were similar regardless of self-paced controller sensitivity. With higher controller sensitivities on each slope, speed fluctuations, speed variance, and step length variance increased whereas step frequency variance and step width variance were unaffected. Detrended variance was not affected by controller sensitivity suggesting that detrending variability helps mitigate differences associated with treadmill speed fluctuations. Speed-trend step length variances, however, increased with more sensitive controllers. Further, detrended step length variances were similar for self-paced and fixed speed walking, whereas self-paced walking included substantial speed-trend step length variance not present in fixed speed walking. In addition, regardless of the self-paced controller, subjects walked fastest on the level slope with the longest steps, widest steps, and least variance. Overall, our findings suggest that separating gait variability into speed-trend and detrended variability could be beneficial for interpreting gait variability among multiple self-paced treadmill studies and when comparing self-paced walking with fixed speed walking.

scholarly journals Does increased gait variability improve stability when faced with an expected balance perturbation during treadmill walking?

2020 ◽  
Author(s):  
Jacqueline Nestico ◽  
Alison Novak ◽  
Stephen D. Perry ◽  
Avril Mansfield
Keyword(s):  
Research Question ◽  
Step Length ◽  
Gait Variability ◽  
Treadmill Walking ◽  
Step Width ◽  
Movement Variability ◽  
Foot Placement ◽  
Motion Simulator ◽  
Improve Stability

AbstractBackgroundCurrently, there is uncertainty as to whether movement variability is errorful or exploratory.Research questionThis study aimed to determine if gait variability represents exploration to improve stability. We hypothesized that 1) spatiotemporal gait features will be more variable prior to an expected perturbation than during unperturbed walking, and 2) increased spatiotemporal gait variability pre-perturbation will correlate with improved stability post-perturbation.MethodsSixteen healthy young adults completed 15 treadmill walking trials within a motion simulator under two conditions: unperturbed and expecting a perturbation. Participants were instructed not to expect a perturbation for unperturbed trials, and to expect a single transient medio-lateral balance perturbation for perturbed trials. Kinematic data were collected during the trials. Twenty steps were recorded post-perturbation. Unperturbed and pre-perturbation gait variabilities were defined by the short- and long-term variabilities of step length, width, and time, using 100 steps from pre-perturbation and unperturbed trials. Paired t-tests identified between-condition differences in variabilities. Stability was defined as the number of steps to centre of mass restabilization post-perturbation. Multiple regression analyses determined the effect of pre-perturbation variability on stability.ResultsLong-term step width variability was significantly higher pre-perturbation compared to unperturbed walking (mean difference=0.28cm, p=0.0073), with no significant differences between conditions for step length or time variabilities. There was no significant relationship between pre-perturbation variability and post-perturbation restabilization.SignificanceIncreased pre-perturbation step width variability was neither beneficial nor detrimental to stability. However, the increased variability in medio-lateral foot placement suggests that participants adopted an exploratory strategy in anticipation of a perturbation.

scholarly journals Is faster always better? The walking speed-dependency of gait variability in bilateral vestibulopathy

2018 ◽  
Author(s):  
Christopher McCrum ◽  
Florence Lucieer ◽  
Raymond van de Berg ◽  
Paul Willems ◽  
Angélica Pérez Fornos ◽  
...  
Keyword(s):  
Older Adults ◽  
Walking Speed ◽  
Clinical Care ◽  
Vestibular Function ◽  
Step Length ◽  
Gait Variability ◽  
Vestibular Evoked Myogenic Potentials ◽  
Step Width ◽  
Bilateral Vestibulopathy ◽  
Walking Speeds

AbstractStudy of balance and gait deficits associated with vestibulopathy is important for improving clinical care and is critical to our understanding of the vestibular contributions to gait and balance control. Previous studies report a speed-dependency of the vestibular contributions to gait, so we examined the walking speed effects on gait variability in healthy young and older adults and in adults with bilateral vestibulopathy (BVP). Forty-four people with BVP, 12 healthy young adults and 12 healthy older adults completed walking trials at 0.4m/s to 1.6m/s in 0.2m/s intervals on a dual belt, instrumented treadmill. Using a motion capture system and kinematic data, the means and coefficients of variation for step length, time, width and double support time were calculated. The BVP group also completed a video head impulse test and examinations of ocular and cervical vestibular evoked myogenic potentials and dynamic visual acuity. Walking speed significantly affected all assessed gait parameters. Step length variability at slower speeds and step width variability at faster speeds were the most distinguishing parameters between the healthy participants and people with BVP, and within people with BVP with different locomotor capacities. We observed for step width variability, specifically, an apparent persistent importance of vestibular function at increasing speeds. Gait variability was not associated with the clinical vestibular tests. Our results indicate that gait variability at multiple walking speeds has potential as an assessment tool for vestibular interventions.New & Noteworthy:Walking speed significantly but differentially affects gait variability in healthy adults and in adults with bilateral vestibulopathy. Gait variability at different speeds distinguishes between participants with and without bilateral vestibulopathy, but also between more and less able walkers with bilateral vestibulopathy. Specifically, for step width variability, an apparent persistent importance of vestibular function at increasing walking speeds was observed. Gait variability was generally not correlated with clinical tests of vestibular function.

scholarly journals The walking speed-dependency of gait variability in bilateral vestibulopathy and its association with clinical tests of vestibular function

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christopher McCrum ◽  
Florence Lucieer ◽  
Raymond van de Berg ◽  
Paul Willems ◽  
Angélica Pérez Fornos ◽  
...  
Keyword(s):  
Walking Speed ◽  
Assessment Tool ◽  
Clinical Care ◽  
Vestibular Function ◽  
Step Length ◽  
Gait Variability ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Step Width ◽  
Bilateral Vestibulopathy

AbstractUnderstanding balance and gait deficits in vestibulopathy may help improve clinical care and our knowledge of the vestibular contributions to balance. Here, we examined walking speed effects on gait variability in healthy adults and in adults with bilateral vestibulopathy (BVP). Forty-four people with BVP, 12 healthy young adults and 12 healthy older adults walked at 0.4 m/s to 1.6 m/s in 0.2 m/s increments on a dual belt, instrumented treadmill. Using motion capture and kinematic data, the means and coefficients of variation for step length, time, width and double support time were calculated. The BVP group also completed a video head impulse test and examinations of ocular and cervical vestibular evoked myogenic potentials and dynamic visual acuity. Walking speed significantly affected all gait parameters. Step length variability at slower speeds and step width variability at faster speeds were the most distinguishing parameters between the healthy participants and people with BVP, and among people with BVP with different locomotor capacities. Step width variability, specifically, indicated an apparent persistent importance of vestibular function at increasing speeds. Gait variability was not associated with the clinical vestibular tests. Our results indicate that gait variability at multiple walking speeds has potential as an assessment tool for vestibular interventions.

BIASED RANDOM WALKS, PARTIAL DIFFERENTIAL EQUATIONS AND UPDATE SCHEMES

2013 ◽  
Vol 55 (2) ◽  
pp. 93-108 ◽  
Author(s):  
JACK D. HYWOOD ◽  
KERRY A. LANDMAN
Keyword(s):  
Statistical Physics ◽  
Planck Equation ◽  
Step Length ◽  
Physical Object ◽  
Cell Diameter ◽  
Agent Based Models ◽  
Time Step ◽  
Partial Differential ◽  
Agent Based ◽  
Random Walkers

AbstractThere is much interest within the mathematical biology and statistical physics community in converting stochastic agent-based models for random walkers into a partial differential equation description for the average agent density. Here a collection of noninteracting biased random walkers on a one-dimensional lattice is considered. The usual master equation approach requires that two continuum limits, involving three parameters, namely step length, time step and the random walk bias, approach zero in a specific way. We are interested in the case where the two limits are not consistent. New results are obtained using a Fokker–Planck equation and the results are highly dependent on the simulation update schemes. The theoretical results are confirmed with examples. These findings provide insight into the importance of updating schemes to an accurate macroscopic description of stochastic local movement rules in agent-based models when the lattice spacing represents a physical object such as cell diameter.

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