Robot-supported assessment of balance in standing and walking.
Ontology highlight
ABSTRACT:
SUBMITTER: Shirota C
PROVIDER: S-EPMC5556664 | biostudies-other | 2017 Aug
REPOSITORIES: biostudies-other
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Project description:Human walking has previously been described as "controlled falling." Some computational models, however, suggest that gait may also have self-stabilizing aspects requiring little CNS control. The fore-aft component of walking may even be passively stable from step to step, whereas lateral motion may be unstable and require motor control for balance, as through active foot placement. If this is the case, walking humans might rely less on integrative sensory feedback, such as vision, for anteroposterior (AP) than for mediolateral (ML) balance. We tested whether healthy humans (n=10) exhibit such direction-dependent control, by applying low-frequency perturbations to the visual field (a projected virtual hallway) and measuring foot placement during treadmill walking. We found step variability to be nearly 10 times more sensitive to ML than to AP perturbations, as quantified by the increase in root-mean-square step variability per unit change in perturbation amplitude. This is not simply due to poorer physiological sensitivity of vision in the AP direction: similar perturbations applied to quiet standing produced reversed direction dependence, with an AP sensitivity 2.3-fold greater than that of ML. Tandem (heel-to-toe) standing yielded ML sensitivity threefold greater than that of AP, suggesting that the base of support influences the stability of standing. Postural balance nevertheless appears to require continuous, integrative motor control for balance in all directions. In contrast, walking balance requires step-by-step, integrative control for balance, but mainly in the lateral direction. In the fore-aft direction, balance may be maintained through an "uncontrolled," yet passively stabilized, series of falls.
| S-EPMC2746770 | biostudies-literature
Project description:Standing and walking balance control in humans relies on the transformation of sensory information to motor commands that drive muscles. Here, we evaluated whether sensorimotor transformations underlying walking balance control can be described by task-level center of mass kinematics feedback similar to standing balance control. We found that delayed linear feedback of center of mass position and velocity, but not delayed linear feedback from ankle angles and angular velocities, can explain reactive ankle muscle activity and joint moments in response to perturbations of walking across protocols (discrete and continuous platform translations and discrete pelvis pushes). Feedback gains were modulated during the gait cycle and decreased with walking speed. Our results thus suggest that similar task-level variables, i.e. center of mass position and velocity, are controlled across standing and walking but that feedback gains are modulated during gait to accommodate changes in body configuration during the gait cycle and in stability with walking speed. These findings have important implications for modelling the neuromechanics of human balance control and for biomimetic control of wearable robotic devices. The feedback mechanisms we identified can be used to extend the current neuromechanical models that lack balance control mechanisms for the ankle joint. When using these models in the control of wearable robotic devices, we believe that this will facilitate shared control of balance between the user and the robotic device.
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Project description:Maintaining balance is a complex process requiring multisensory processing and coordinated muscle activation. Previous studies have indicated that the cortex is directly involved in balance control, but less information is known about cortical flow of signals for balance. We studied source-localized electrocortical effective connectivity dynamics of healthy young subjects (29 subjects: 14 male and 15 female) walking and standing with both visual and physical perturbations to their balance. The goal of this study was to quantify differences in group-level corticomuscular connectivity responses to sensorimotor perturbations during walking and standing. We hypothesized that perturbed visual input during balance would transiently decrease connectivity between occipital and parietal areas due to disruptive visual input during sensory processing. We also hypothesized that physical pull perturbations would increase cortical connections to central sensorimotor areas because of higher sensorimotor integration demands. Our findings show decreased occipito-parietal connectivity during visual rotations and widespread increases in connectivity during pull perturbations focused on central areas, as expected. We also found evidence for communication from cortex to muscles during perturbed balance. These results show that sensorimotor perturbations to balance alter cortical networks and can be quantified using effective connectivity estimation.
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Project description:ObjectiveTo analyze how Pilates exercises affect standing, walking, and balance in children with diplegic cerebral palsy throughout a 10-week program.MethodsWe included 40 children aged 7-9 years with diplegic cerebral palsy, and randomly allocated them into two groups of the same size: conventional therapy group (group A) and conventional therapy+Pilates group (group B). We administered the same conventional physical therapy program to both groups for 45 minutes, with group B receiving additional Pilates exercises for 45 minutes. Both groups attended the intervention program three times/week for 10 weeks. We used the Growth Motor Function Measure Scale (GMFM-88) to evaluate standing and walking (Dimensions D and E), and the Pediatric Balance Scale to evaluate balance function before and after treatment.ResultsComparison of the average values of all measured variables before and after therapy showed a statistically significant difference (p<0.05) between the two groups. All measured variables showed a significant difference between groups A and B, in favor of group B (p<0.05).ConclusionPilates exercise in addition to conventional therapy is more effective in improving balance and gross motor function in children with diplegic cerebral palsy than the conventional therapy alone.
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Project description:BackgroundThe Romberg test is used to identify balance issues in patients with Cervical Spondylotic Myelopathy (CSM), but has subjective interpretation. The purpose of this study is to evaluate force plate pressure readings during a Romberg test to quantify postural control.MethodsQuantitative Romberg force plate readings with eyes open and closed in patients with CSM were obtained and changes in balance measurements were compared to a normal population (N = 28, mean age 39 ± 7 years).ResultsWe identified 30 CSM patients with a mean age of 58 ± 10 years. Majority of patients presented with pain (90%) and neurologic symptoms (83%). Cord compression on imaging was identified in 90%. Mean eyes closed Romberg measurements were larger compared to eyes open measurements in CSM patients (p < 0.01). There was a larger change in Romberg (∆R) measurements in CSM compared to normals for total sway area (TSA, 14.18 vs 0.02 cm2, p < 0.001) and average speed (AS, 2.07 vs 0.23 cm/s, p < 0.001). The presence of long tract signs produced larger ∆R (TSA, 15.35 vs 0.02 cm2, p = 0.003; AS, 2.21 vs 0.23 cm/s, p = 0.001), and those with identified cord compression on imaging also had larger ∆R (TSA, 15.1 vs 0.02 cm2, p < 0.001; AS, 2.17 vs 0.23 cm/s, p < 0.001).ConclusionsStanding balance can be quantified in patients with CSM and is worse when compared to a normal population. Long tract signs and cord compression in imaging translates to worse balance in myelopathic patients. The use of quantitative Romberg measurements help evaluate balance in CSM.
| S-EPMC8820038 | biostudies-literature
Project description:BackgroundPostural instability and gait disability threaten the independence and well-being of people with Parkinson's disease and increase the risk of falls and fall-related injuries. Prospective research has shown that commonly-used clinical assessments of balance and walking lack the sensitivity to accurately and consistently identify those people with Parkinson's disease who are at a higher risk of falling. Wearable sensors provide a portable and affordable alternative for researchers and clinicians who are seeking to objectively assess movements and falls risk in the clinical setting. However, no consensus currently exists on the optimal placements for sensors and the best outcome measures to use for assessing standing balance and walking stability in Parkinson's disease patients. Hence, this systematic review aimed to examine the available literature to establish the best sensor types, locations and outcomes to assess standing balance and walking stability in this population.MethodsPapers listed in three electronic databases were searched by title and abstract to identify articles measuring standing balance or walking stability with any kind of wearable sensor among adults diagnosed with PD. To be eligible for inclusion, papers were required to be full-text articles published in English between January 1994 and December 2014 that assessed measures of standing balance or walking stability with wearable sensors in people with PD. Articles were excluded if they; i) did not use any form of wearable sensor to measure variables associated with standing balance or walking stability; ii) did not include a control group or control condition; iii) were an abstract and/or included in the proceedings of a conference; or iv) were a review article or case study. The targeted search of the three electronic databases identified 340 articles that were potentially eligible for inclusion, but following title, abstract and full-text review only 26 articles were deemed to meet the inclusion criteria. Included articles were assessed for methodological quality and relevant data from the papers were extracted and synthesized.ResultsQuality assessment of these included articles indicated that 31% were of low methodological quality, while 58% were of moderate methodological quality and 11% were of high methodological quality. All studies adopted a cross-sectional design and used a variety of sensor types and outcome measures to assess standing balance or walking stability in people with Parkinson's disease. Despite the typically low to moderate methodological quality, 81% of the studies reported differences in sensor-based measures of standing balance or walking stability between different groups of Parkinson's disease patients and/or healthy controls.ConclusionThese data support the use of wearable sensors for detecting differences in standing balance and walking stability between people with PD and controls. Further high-quality research is needed to better understand the utility of wearable sensors for the early identification of Parkinson's disease symptoms and for assessing falls risk in this population.Prospero registrationCRD42014010838.
| S-EPMC4403989 | biostudies-literature
Project description:ObjectiveThe Standing and Walking Assessment Tool (SWAT) standardizes the timing and content of walking assessments during inpatient rehabilitation by combining 12 stages ranging from lowest to highest function (0, 0.5, 1A, 1B, 1C, 2A, 2B, 2C, 3A, 3B, 3C, and 4) with 5 standard measures: the Berg Balance Scale, the modified Timed "Up & Go" test, the Activities-specific Balance Confidence Scale, the modified 6-Minute Walk Test, and the 10-Meter Walk Test (10MWT). This study aimed to determine if the SWAT at rehabilitation discharge could predict outdoor walking capacity 1-year after discharge in people with traumatic spinal cord injury.MethodsThis retrospective study used data obtained from the Rick Hansen Spinal Cord Injury Registry from 2014 to 2020. Community outdoor walking capacity was measured using the Spinal Cord Independence Measure III (SCIM III) outdoor mobility score obtained 12 (±4) months after discharge. Of 206 study participants, 90 were community nonwalkers (ie, SCIM III score 0-3), 41 were community walkers with aids (ie, SCIM III score 4-6), and 75 were independent community walkers (ie, SCIM III score 7-8). Bivariate, multivariable regression, and an area under the receiver operating characteristic curve analyses were performed.ResultsAt rehabilitation discharge, 3 significant SWAT associations were confirmed: 0-3A with community nonwalkers, 3B/higher with community walkers with and without an aid, and 4 with independent community walkers. Moreover, at discharge, a higher (Berg Balance Scale, Activities-specific Balance Confidence Scale), faster (modified Timed "Up & Go," 10MWT), or further (10MWT) SWAT measure was significantly associated with independent community walking. Multivariable analysis indicated that all SWAT measures, except the 10MWT were significant predictors of independent community walking. Furthermore, the Activities-Specific Balance Confidence Scale had the highest area under the receiver operating characteristic score (0.91), demonstrating an excellent ability to distinguish community walkers with aids from independent community walkers.ConclusionThe SWAT stage and measures at discharge can predict community outdoor walking capacity in persons with traumatic spinal cord injury. Notably, a patient's confidence in performing activities plays an important part in achieving walking ability in the community.ImpactThe discharge SWAT is useful to optimize discharge planning.
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Project description:BackgroundRapid compensatory stepping plays an important role in preventing falls when balance is lost; however, these responses cannot be accurately quantified in the clinic. The Microsoft Kinect™ system provides real-time anatomical landmark position data in three dimensions (3D), which may bridge this gap.MethodsCompensatory stepping reactions were evoked in 8 young adults by a sudden platform horizontal motion on which the subject stood or walked on a treadmill. The movements were recorded with both a 3D-APAS motion capture and Microsoft Kinect™ systems. The outcome measures consisted of compensatory step times (milliseconds) and length (centimeters). The average values of two standing and walking trials for Microsoft Kinect™ and the 3D-APAS systems were compared using t-test, Pearson's correlation, Altman-bland plots, and the average difference of root mean square error (RMSE) of joint position.ResultsThe Microsoft Kinect™ had high correlations for the compensatory step times (r = 0.75-0.78, p = 0.04) during standing and moderate correlations for walking (r = 0.53-0.63, p = 0.05). The step length, however had a very high correlations for both standing and walking (r > 0.97, p = 0.01). The RMSE showed acceptable differences during the perturbation trials with smallest relative error in anterior-posterior direction (2-3%) and the highest in the vertical direction (11-13%). No systematic bias were evident in the Bland and Altman graphs.ConclusionsThe Microsoft Kinect™ system provides comparable data to a video-based 3D motion analysis system when assessing step length and less accurate but still clinically acceptable for step times during balance recovery when balance is lost and fall is initiated.
| S-EPMC5339957 | biostudies-literature
Project description:When walking on an uneven surface or complex terrain, humans tend to gaze downward. This behaviour is usually interpreted as an attempt to acquire useful information to guide locomotion. Visual information, however, is not used exclusively for guiding locomotion; it is also useful for postural control. Both locomotive and postural control have been shown to be sensitive to the visual flow arising from the respective motion of the individual and the three-dimensional environment. This flow changes when a person gazes downward and may present information that is more appropriate for postural control. To investigate whether downward gazing can be used for postural control, rather than exclusively for guiding locomotion, we quantified the dynamics of standing and walking posture in healthy adults, under several visual conditions. Through these experiments we were able to demonstrate that gazing downward, just a few steps ahead, resulted in a steadier standing and walking posture. These experiments indicate that gazing downward may serve more than one purpose and provide sufficient evidence of the possible interplay between the visual information used for guiding locomotion and that used for postural control. These findings contribute to our understanding of the control mechanism/s underlying gait and posture and have possible clinical implications.
| S-EPMC8074885 | biostudies-literature
Project description:BackgroundConsiderable effort has been devoted to mapping the functional and effective connectivity of the human brain, but these efforts have largely been limited to tasks involving stationary subjects. Recent advances with high-density electroencephalography (EEG) and Independent Components Analysis (ICA) have enabled study of electrocortical activity during human locomotion. The goal of this work was to measure the effective connectivity of cortical activity during human standing and walking.MethodsWe recorded 248-channels of EEG as eight young healthy subjects stood and walked on a treadmill both while performing a visual oddball discrimination task and not performing the task. ICA parsed underlying electrocortical, electromyographic, and artifact sources from the EEG signals. Inverse source modeling methods and clustering algorithms localized posterior, anterior, prefrontal, left sensorimotor, and right sensorimotor clusters of electrocortical sources across subjects. We applied a directional measure of connectivity, conditional Granger causality, to determine the effective connectivity between electrocortical sources.ResultsConnections involving sensorimotor clusters were weaker for walking than standing regardless of whether the subject was performing the simultaneous cognitive task or not. This finding supports the idea that cortical involvement during standing is greater than during walking, possibly because spinal neural networks play a greater role in locomotor control than standing control. Conversely, effective connectivity involving non-sensorimotor areas was stronger for walking than standing when subjects were engaged in the simultaneous cognitive task.ConclusionsOur results suggest that standing results in greater functional connectivity between sensorimotor cortical areas than walking does. Greater cognitive attention to standing posture than to walking control could be one interpretation of that finding. These techniques could be applied to clinical populations during gait to better investigate neural substrates involved in mobility disorders.
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