Gait Metrics Research Articles

Trendelenburg-Like Gait, Instability and Altered Step Patterns in a Mouse Model for Limb Girdle Muscular Dystrophy 2i.

Limb-girdle muscular dystrophy type 2i (LGMD2i) affects thousands of lives with shortened life expectancy mainly due to cardiac and respiratory problems and difficulty with ambulation significantly compromising quality of life. Limited studies have noted impaired gait in patients and animal models of different muscular dystrophies, but not in animal models of LGMD2i. Our goal, therefore, was to quantify gait metrics in the fukutin-related protein P448L mutant (P448L) mouse, a recently developed model for LGMD2i. The Noldus CatWalk XT motion capture system was used to identify multiple gait impairments. An average galloping body speed of 35 cm/s for both P448L and C57BL/6 wild-type mice was maintained to ensure differences in gait were due only to strain physiology. Compared to wild-type mice, P448L mice reach maximum contact 10% faster and have 40% more paw surface area during stance. Additionally, force intensity at the time of maximum paw contact is roughly 2-fold higher in P448L mice. Paw swing time is reduced in P448L mice without changes in stride length as a faster swing speed compensates. Gait instability in P448L mice is indicated by 50% higher instances of 3 and 4 paw stance support and conversely, 2-fold fewer instances of single paw stance support and no instance of zero paw support. This leads to lower variation of normal step patterns used and a higher use of uncommon step patterns. Similar anomalies have also been noted in muscular dystrophy patients due to weakness in the hip abductor muscles, producing a Trendelenburg gait characterized by “waddling” and more pronounced shifts to the stance leg. Thus, gait of P448L mice replicates anomalies commonly seen in LGMD2i patients, which is not only potentially valuable for assessing drug efficacy in restoring movement biomechanics, but also for better understanding them.

Automated feet detection for clinical gait assessment.

The paper describes a computer vision method for estimating the clinical gait metrics of walking patients in unconstrained environments. The method employs background subtraction to produce a silhouette of the subject and a randomized decision forest to detect their feet. Given the feet detections, the stride and step length, cadence, and walking speed are estimated. Validation of the system is presented through an error analysis on manually annotated videos of subjects walking in different outdoor settings. This method is significant as it provides clinical therapists and non-specialists the opportunity to record from any camera and obtain high accuracy estimates of the clinical gait metrics for subjects walking at outdoor or at-home locations.

Validation of temporal gait metrics from three IMU locations to the gold standard force plate.

The purpose of this work is to compare temporal gait parameters from three different IMU locations to the gold standard force platform. 33 subjects (12 F, 21 M) performed twenty gait trials each while wearing inertial measurement units (IMUs) on the trunk, both shanks and both feet. Data was simultaneously collected from a laboratory embedded force plate. Step times were derived from the raw IMU data at the three IMU locations using methods that have been shown to be accurate. Step times from all locations were valid compared to the force plate. Foot IMU step time was the most accurate (Pearson = .991, CI width = 3.00e2), the trunk IMU was the next most accurate (Pearson = .974, CI width = 4.85e2) and shank step time was the least accurate (Pearson = .958, CI width = 6.80e2). All three sensing locations result in valid estimations of step time compared to the gold standard force plate. These results suggest that the foot location would be most appropriate for clinical applications where very precise temporal parameter detection is required.

The Effect of Keratin on Spinal Cord Injury Recovery

ObjectiveTo evaluate the ability of kertin nanomaterials to create an optimal environment for nerve regeneration and function restoration after spinal cord injury (SCI).IntroductionInflammation plays a vital role in the recovery after SCI. Recent studies have shown that macrophage polarization to the M2 anti‐inflammatory phenotype attenuates the inflammatory response, preventing the secondary injury due to inflammation, resulting in improved outcomes following SCI. Keratin nanomaterials may allow for macrophage polarization, therefore we tested the hypothesis that keratin treatments will improve recovery in a rat contusion model of spinal cord injury.MethodsAll aspects of the described protocol were reviewed and approved by the Institutions Animal Care and Use Committee. Female lewis rats were trained and baseline gait recordings were obtained on a DigiGait Imaging System treadmill for two weeks before receiving injury. Blunt SCI was induced with an IH‐0400, Precision Systems and Instrumentation LLC spinal cord impactor following laminectomy at T9 with a consistent force of 150Kdyn, producing a moderate injury with partial recovery. Treatment groups included intrathecal administration of keratin and a saline control. Functional recovery data assessed by the DigiGait were observed at 3 and 6 weeks post‐SCI and compared to pre‐SCI recordings and data.ResultsGait metrics were analyzed at pre‐SCI and post‐operative (PO) timepoints. Table 1 includes the percent changes from pre‐SCI recordings of gait metrics at 3 and 6 weeks PO for both hind limbs in saline control and keratin treatment groups. Brake duration was decreased in the control rat as compared to the keratin treatment rat. Overlap distance was increased in control rat compared to treatment rat. Paw angel, and swing duration, compared to pre‐operative measures, showed altered ambulation following injury in both groups with varying levels of recovery.ConclusionsThe quantitative data obtained from the DigiGait Imaging system elucidates the altered ambulation following SCI in rats and shows improved scores for the keratin treated group for several parameters. The DigiGait analyzes up to 40 different gait metrics and analysis of additional parameters could show differences between treated groups compared to controls. The keratin treatment seems to be beneficial in some parameters such as brake duration, as longer brake duration may indicate more precise control and distribution of loading during stance phase. Also, more open paw angels of the hind paws are associated with ataxia, spinal cord injury, and demyelinating diseases. Future studies will utilize histological data in addition to gait analysis to document the recovery following SCI in rats and include more keratin treatment delivery methods.Support or Funding InformationErrett Fisher Foundation Shows the Percent changes of gait metrics compared to baseline recordings for a non‐treated control rat and a keratin treated rat. DigiGait Imaging System Gait Analysis of SCI Rats Metric: Brake (sec) Paw angel (deg) Swing (sec) Overlap distance (cm) (Percent Changes compared to Baseline data) Control 3 weeks L − 37% + 34.7% − 2.2% + 529.6% 3 weeks R − 37.5% + 17.1% + 2.5% + 181.7% 6 weeks L − 40.1% + 329.9% + 8.1% + 637.8% 6 weeks R − 38.5% + 7.1% + 20.5% + 240.6% Keratin 3 weeks L − 15% + 157.39% + 20.4% + 92.9% 3 weeks R + 9.3% + 45.3% + 30.3% + 65.6% 6 weeks L − 13.4% + 148.7% + 2.7% + 67.5% 6 weeks R + 3.1% + 45.9% +18.8% + 193.3%

Balance and Gait Represent Independent Domains of Mobility in Parkinson Disease.

The Instrumented Stand and Walk (ISAW) test, which includes 30 seconds of stance, step initiation, gait, and turning, results in many objective balance and gait metrics from body-worn inertial sensors. However, it is not clear which metrics provide independent information about mobility. It was hypothesized that balance and gait represent several independent domains of mobility and that not all domains would be abnormal in individuals with Parkinson disease (PD) or would change with levodopa therapy. This was a cross-sectional study. A factor analysis approach was used to identify independent measures of mobility extracted from the ISAW in 100 participants with PD and 21 control participants. First, a covariance analysis showed that postural sway measures were independent of gait measures. Then, the factor analysis revealed 6 independent factors (mobility domains: sway area, sway frequency, arm swing asymmetry, trunk motion during gait, gait speed, and cadence) that accounted for 87% of the variance of performance across participants. Sway area, gait speed, and trunk motion differed between the PD group in the off-levodopa state and the control group, but sway frequency (but not sway area) differed between the PD group in the off-levodopa state and the control group. Four of the 6 factors changed significantly with levodopa (off to on): sway area, sway frequency, trunk motion during gait, and cadence. When participants were on levodopa, the sway area increased compared with off levodopa, becoming more abnormal, whereas the other 3 significant metrics moved toward, but did not reach, the healthy control values. Exploratory factor analysis was limited to the PD population. The different sensitivity various balance and gait domains to PD and to levodopa also support neural control of at least 6 independent mobility domains, each of which warrants clinical assessment for impairments in mobility.

Continuous real-world gait monitoring in community-based older adults.

This paper describes the collection of real-world gait data in a cohort of 7 community living older adults, who have fallen at least once in the previous year, while they live in a smart apartment for four days. It describes the approach used to collect various gait metrics, from inertial sensors placed on the lower shanks, where gait bouts can be contextualised by smart home data. Results from this study are presented with a brief discussion into the smart-home based contextualisation of outliers in the gait data. Future work will investigate the normative ranges of various gait metrics, and how such real-world gait data may be integrated into clinical practice.

Context focused older adult mobility and gait assessment.

This paper presents an initial overview of insights gained into how older adults mobilize in the home and community, based on data from inertial sensors which were worn by study participants over a 7-day period. The addition of a wearable camera provided additional contextual information which can be used to assess mobility and understand the factors that influence it in the free living environment. Seven days of data collected from a group of older adults who had experienced one or more falls in the previous six months was compared to that of a control group with no history of falling. Results showed that both groups spent relatively little time walking in challenging environmental conditions, and that the fallers spent significantly less time walking under regular conditions (no effect on gait) and outdoors. Analysis of gait metrics showed that the fallers were slightly slower in general, and more noticeable differences were observed when the participants were regrouped according to mobility levels determined from baseline assessments using traditional methods.

Deviations in gait metrics in patients with chronic ankle instability: a case control study.

BackgroundGait metric alterations have been previously reported in patients suffering from chronic ankle instability (CAI). Previous studies of gait in this population have been comprised of relatively small cohorts, and the findings of these studies are not uniform. The objective of the present study was to examine spatiotemporal gait metrics in patients with CAI and examine the relationship between self-reported disease severity and the magnitude of gait abnormalities.MethodsForty-four patients with CAI were identified and compared to 53 healthy controls. Patients were evaluated with spatiotemporal gait analysis via a computerized mat and with the Short Form (SF) - 36 health survey.ResultsPatients with CAI were found to walk with approximately 16% slower walking velocity, 9% lower cadence and approximately 7% lower step length. Furthermore, the base of support, during walking, in the CAI group was approximately 43% wider, and the single limb support phase was 3.5% shorter compared to the control group.All of the SF-36 8-subscales, as well as the SF-36 physical component summary and SF-36 mental component summary, were significantly lower in patients with CAI compared to the control group. Finally, significant correlations were found between most of the objective gait measures and the SF-36 mental component summary and SF-36 physical component summary.ConclusionsThe results outline a gait profile for patients suffering from CAI. Significant differences were found in most spatiotemporal gait metrics. An important finding was a significantly wider base of support. It may be speculated that these gait alterations may reflect a strategy to deal with imbalance and pain. These findings suggest the usefulness of gait metrics, alongside with the use of self-evaluation questionnaires, in assessing disease severity of patients with CAI.

Automated gait temporal–spatial assessment from non-motorized treadmill belt speed data

Non-motorized treadmills (NMT) provide belt speed data that can be used to estimate work output, and potentially, gait temporal–spatial parameters that provide an improved understanding of gait performance. The purpose of this study was to determine the validity of an automated technique that uses belt speed data from an NMT to estimate temporal–spatial gait parameters. Seventeen injury-free adult participants performed a series of 20-s, metronome-guided walking and running trials for each of eight predetermined cadence conditions (72–200steps/min). Two NMT-based cadence algorithms [PSD estimated cadence (PEC) and threshold estimated cadence (TEC)], and one NMT-based step length algorithm (NMT_SL) were evaluated for their ability to predict traditional motion analysis-based measures of cadence and step length (MAC and MA_SL, respectively). The results of this study demonstrate that both the PEC and TEC algorithms were capable of predicting MAC with a standard error of the estimate (SEE) less than four steps/min (R2=0.997 and R2=0.993, respectively). Predictions of MA_SL from NMT_SL were separated by gait type (walking vs. running) to account for an obvious separation in the step length data with a qualitative gait change. When applied to walking data, NMT_SL was capable of predicting MA_SL with an SEE of 23mm (R2=0.96). When applied to running data, NMT_SL was capable of predicting MA_SL with an SEE of 44mm (R2=0.80). The assessment of the novel technique suggests that it is feasible to use non-motorized treadmill belt speed data to predict gait events and analyze simple gait metrics. Future research should evaluate the applicability of these algorithms for use with participants/patients presenting with pathological gait.

Deviations in gait metrics in patients with chronic ankle instability

190 DEVIATIONS IN GAIT METRICS IN PATIENTS WITH CHRONIC ANKLE INSTABILITY R. Gigi y, A. Mor z, A. Haim y, E. Luger y, E. Melamed x, Y. Beer k, M. Nof k, M. Nyska{, A. Elbaz z. yDept. of Orthopedic Surgery, Tel Aviv Sourasky Med. Ctr., Tel Aviv, Israel; zApos Med. and Sports Technologies, Herzliya, Israel; xDept. of Orthopedic Surgery, Rambam Med. Ctr., Haifa, Israel, Haifa, Israel; kDept. of Orthopedic Surgery, Assaf Harofeh Med. Ctr., Zerifin, Israel., Zerifin, Israel; {Dept. of Orthopedic Surgery, Meir Med. Ctr., Kfar-Saba, Israel., Kfar Saba, Israel

Gait Metric Profile and Gender Differences in Hip Osteoarthritis Patients. A Case-Controlled Study

Hip osteoarthritis (OA) is a slowly progressive destructive disease that results in alterations in joint loads and biomechanics to which patients adapt compensatory alterations and abnormal gait patterns. This prospective cross-sectional, case-controlled study examined these alterations in gait metrics and evaluated gender differences in gait spatiotemporal parameters. Correlations between function and gait metrics were also investigated. Hip OA patients (138 females and 122 males) and healthy controls (14 females and 26 males) matched for age and gender underwent the same investigative protocol consisting of a spatiotemporal gait analysis followed by functional evaluations using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the SF-36 Health Survey (SF-36). Differences between the patient and the control groups were significant in all the spatiotemporal parameters. There were significant gender differences within the hip OA group in all parameters except for cadence and single limb support percentage. WOMAC and SF-36 scores revealed significant differences between the study and control groups in most components. Significantly higher scores in the three components of the WOMAC as well as in six SF-36 score components were found among males compared to females in the patient group. Gait, WOMAC and SF-36 were effective objective and subjective tools for evaluating a large cohort of patients with hip OA, and can be highly useful for supplementing the assessment of hip OA severity and enhancing treatment efficacy during the course of the disease.

Literature Review of Published Research Investigating Microprocessor-Controlled Prosthetic Knees

Since 2009, several articles on microprocessor-controlled prosthetic knee (MPK) joint mechanisms have been published. Recent published data are generally rated as providing moderate to low levels of evidence because of structural weakness of the study designs. These weaknesses are due to low statistical power, a lack of blinding, industry funding, precise measures with no estimate of minimal clinically important difference (MCID), or subjective participant responses on questionnaires. Strong support for the advantages of MPKs is not available within this cohort of studies. Statistically significant improvements were observed in some gait measures when comparing MPKs with non-MPKs (NMPKs), but the values are not close to those of intact individuals. For measures of gait kinematics, gait kinetics, gait parameters, gait symmetry, or performance time, MPKs seem to offer marginal improvements over NMPKs in a few measures. There are few data and information on the differences between the types of MPKs currently on the market. Several of the articles in this review do provide novel outcome measures that incorporate multiple domains in biomechanics, function, and patient perception. The strongest metric in all studies is patient preference for MPKs, as opposed to technical gait metrics, objective functional improvements in mobility, or the activity of prosthetic users. This patient preference might easily be influenced by marketing or design appeal rather than objective technical or functional outcome measures. Although MPKs seem to produce minor improvements in some aspects of gait over NMPKs, the cost-benefit ratio of MPKs is not available.

Objective biomarkers of balance and gait for Parkinson's disease using body‐worn sensors

Balance and gait impairments characterize the progression of Parkinson's disease (PD), predict the risk of falling, and are important contributors to reduced quality of life. Advances in technology of small, body-worn, inertial sensors have made it possible to develop quick, objective measures of balance and gait impairments in the clinic for research trials and clinical practice. Objective balance and gait metrics may eventually provide useful biomarkers for PD. In fact, objective balance and gait measures are already being used as surrogate endpoints for demonstrating clinical efficacy of new treatments, in place of counting falls from diaries, using stop-watch measures of gait speed, or clinical balance rating scales. This review summarizes the types of objective measures available from body-worn sensors. The metrics are organized based on the neural control system for mobility affected by PD: postural stability in stance, postural responses, gait initiation, gait (temporal-spatial lower and upper body coordination and dynamic equilibrium), postural transitions, and freezing of gait. However, the explosion of metrics derived by wearable sensors during prescribed balance and gait tasks, which are abnormal in individuals with PD, do not yet qualify as behavioral biomarkers, because many balance and gait impairments observed in PD are not specific to the disease, nor have they been related to specific pathophysiologic biomarkers. In the future, the most useful balance and gait biomarkers for PD will be those that are sensitive and specific for early PD and are related to the underlying disease process.

Asymmetric pedunculopontine network connectivity in parkinsonian patients with freezing of gait

Freezing of gait is one of the most debilitating symptoms in Parkinson's disease as it causes falls and reduces mobility and quality of life. The pedunculopontine nucleus is one of the major nuclei of the mesencephalic locomotor region and has neurons related to anticipatory postural adjustments preceding step initiation as well as to the step itself, thus it may be critical for coupling posture and gait to avoid freezing. Because freezing of gait and postural impairments have been related to frontal lesions and frontal dysfunction such as executive function, we hypothesized that freezing is associated with disrupted connectivity between midbrain locomotor regions and medial frontal cortex. We used diffusion tensor imaging to quantify structural connectivity of the pedunculopontine nucleus in patients with Parkinson's disease with freezing of gait, without freezing, and healthy age-matched controls. We also included behavioural tasks to gauge severity of freezing of gait, quantify gait metrics, and assess executive cognitive functions to determine whether between-group differences in executive dysfunction were related to pedunculopontine nucleus structural network connectivity. Using seed regions from the pedunculopontine nucleus, we were able to delineate white matter connections between the spinal cord, cerebellum, pedunculopontine nucleus, subcortical and frontal/prefrontal cortical regions. The current study is the first to demonstrate differences in structural connectivity of the identified locomotor pathway in patients with freezing of gait. We report reduced connectivity of the pedunculopontine nucleus with the cerebellum, thalamus and multiple regions of the frontal cortex. Moreover, these structural differences were observed solely in the right hemisphere of patients with freezing of gait. Finally, we show that the more left hemisphere-lateralized the pedunculopontine nucleus tract volume, the poorer the performance on cognitive tasks requiring the initiation of appropriate actions and/or the inhibition of inappropriate actions, specifically within patients with freezing. These results support the notion that freezing of gait is strongly related to structural deficits in the right hemisphere's locomotor network involving prefrontal cortical areas involved in executive inhibition function.

Correlations Between Physiological Response, Gait, Personality, and Presence in Immersive Virtual Environments

In previous work, we have found significant differences in the accuracy with which people make initial spatial judgments in different types of head-mounted, display-based immersive virtual environments (IVEs; Phillips, Interrante, Kaeding, Ries, & Anderson, 2010). In particular, we have found that people tend to less severely underestimate egocentric distances in a virtual environment that is a photorealistic replica of a real place that they have recently visited than when the virtual environment is either a photorealistic replica of an unfamiliar place, or a nonphotorealistically (NPR) portrayed version of a familiar space. We have also noted significant differences in the effect of environment type on distance perception accuracy between individual participants. In this paper, we report the results of two experiments that seek further insight into these phenomena, focusing on factors related to depth of presence in the virtual environment. In our reported first experiment, we immersed users (between-subjects) in one of the three different types of IVEs and asked them to perform a series of well-defined tasks along a delimited path, first in a control version of the environment, and then in a stressful variant in which the floor around the marked path was cut away to reveal a 20-ft drop. We assessed participants' sense of presence during each trial using a diverse set of measures, including: questionnaires, recordings of heart rate and galvanic skin response, and gait metrics derived from tracking data. We computed the differences in each of these measures between the stressful and nonstressful versions of each environment, and then compared the changes due to stress between the different virtual environment conditions. Pooling the data over all participants in each group, we found significant physiological indications of stress after the appearance of the pit in all three environments, but we did not find significant differences in the magnitude of the stress response between the different virtual environment locales. We also did not find any significant difference in the level of subjective presence reported in each environment. However, we did find significant differences in gait: participants in the photorealistic replica room showed a significantly greater reduction in stride speed and stride length between the control and pit version of the room than did participants in either the photorealistically rendered nonreplica environment or the NPR replica environment conditions. Our second experiment, conducted with a new set of participants, sought to more directly investigate potential correlations between distance estimation accuracy and personality, stress response, and reported sense of presence, comparatively across different immersive virtual environment conditions. We used pretest questionnaires to assess a variety of personality measures, and then randomly immersed participants (between-subjects) in either the photorealistic replica or photorealistic non-replica environment and assessed the accuracy of their egocentric distance judgments in that IVE, followed by control trials in a neutral, real-world location. We then had participants go through the same set of tasks as in our first experiment while we collected physiological measures of their stress level and tracked their gait, and we compared the changes in these measures between the neutral and pit-enhanced versions of the environment. Finally, we had people fill out a brief presence questionnaire.Analyzing all of these data, we found that participants made significantly greater distance estimation errors in the unfamiliar room environment than in the replica room environment, but no other differences between the two environments were significant. We found significant positive correlation between several of the personality measures, but we did not find any notable significant correlations between personality and presence, or between either personality or presence and gait changes or distance estimation accuracy. These results suggest to us that the relationship between personality, presence, and performance in IVEs is complicated and not easily captured by existing measures.

Reduction in knee adduction moment via non-invasive biomechanical training: A longitudinal gait analysis study

Biomechanical non-invasive interventions have been previously reported to reduce pain and facilitate superior levels of function in patients with medial knee osteoarthritis [OA]. One such treatment is the AposTherapy, a customized program utilizing a foot-worn biomechanical device allowing center of pressure modification and continuous perturbation during gait. The influence of this intervention on objective gait metrics has yet to be determined. The aim of the current study was to prospectively examine changes in kinetic and kinematic parameters in patients enrolled in this treatment program. Twenty-five females with symptomatic bilateral medial compartment knee OA were enrolled in the customized daily treatment program. All patients underwent barefoot gait analysis testing and completed subjective questionnaires prior to treatment initiation and on two follow-up visits. Significantly reduced knee adduction moment (KAM) magnitude was noted during barefoot walking after three and nine months of treatment. On average, the knee adduction impulse and the 1st and 2nd KAM peaks were reduced by 13%, 8.4%, and 12.7%, respectively. Furthermore, moment reduction was accompanied by elevated walking velocity, significant pain reduction, and increased functional activity. In addition to symptomatic improvement, our results suggest that this treatment program can alter kinetic gait parameters in this population. We speculate that these adaptations account for the symptomatic and functional improvement reported for this intervention.

Jay Nutt: a boatman's calling

Jay Nutt: a boatman's calling

Brace Evaluation in Children with Diplegic Cerebral Palsy with a Jump Gait Pattern

Brace prescription for children with diplegic cerebral palsy challenges the clinician with a variety of options and little evidence for rational decisions. Previous studies have indicated that ankle-foot orthoses improve toe-walking, but it is unclear if any brace is better than another. The goal of the present study was to compare the effectiveness of hinged and dynamic ankle-foot orthoses in terms of improving gait and motor function in a homogeneous group of children with diplegic cerebral palsy exhibiting a jump gait pattern. Fifteen children (mean age, 7.5 years) with spastic diplegic cerebral palsy who were able to walk independently with a jump gait pattern and twenty children (mean age, 10.6 years) with normal gait participated in the study. Standardized Gross Motor Function Classification System scores, Pediatric Outcomes Data Collection Instrument scores, and gait data were collected, analyzed, and compared. The subjects were tested while barefoot and while wearing hinged and dynamic ankle-foot orthoses. Data were analyzed to detect differences among these conditions. Significant improvements in gait metrics were seen during brace wear. No significant differences were seen between the two different braces used. The barefoot and braced conditions differed most significantly in terms of ankle kinematics and kinetics. Among the patients with cerebral palsy, no significant differences in the standardized outcome measurements were found between the braced and unbraced conditions or between the two braced conditions. Our data suggest that gait improves with brace wear in children with cerebral palsy with a level-I Gross Motor Function Classification System score. The Pediatric Outcomes Data Collection Instrument and the Gross Motor Function Measure were not sensitive to brace treatment in the population studied. The hinged and dynamic braces were equally effective for improving ankle kinematics and kinetics in these relatively highly functioning children with cerebral palsy.