Repeatability and validation of gait deviation index in children: typically developing and cerebral palsy

Three-Dimensional Gait Analysis as a Biomarker for GTP Cyclohydrolase 1-Deficient Dopa-Responsive Dystonia

BACKGROUND

GTP-cyclohydrolase 1-deficient dopa-responsive dystonia (GTPCH1-deficient DRD) typically presents in childhood with dystonic posture of the lower extremities, gait impairment, and a significant response to levodopa. We performed three-dimensional gait analysis (3DGA) to quantitatively assess the gait characteristics and changes associated with levodopa treatment in patients with GTPCH1-deficient DRD.

METHODS

Three levodopa-treated patients with GTPCH1-deficient DRD underwent 3DGA twice, longitudinally. Changes were evaluated for cadence; gait speed; step length; gait deviation index; kinematic data of the pelvis, hip, knee, and ankle joints; and foot progression angle.

RESULTS

Levodopa treatment increased the cadence and gait speed in one of three patients and increased the gait deviation index in two of three patients. The kinematic data for each joint exhibited different characteristics, with some improvement observed in each of the three patients. There was consistent marked improvement in the abnormal foot progression angle; one patient had excessive external rotation of one foot, another had excessive bilateral internal rotation, and the other had excessive internal rotation of one foot and excessive external rotation of the opposite foot, all of which improved.

CONCLUSION

The 3DGA findings demonstrate that the gait pathology and recovery process in GTPCH1-deficient DRD vary from case to case. Changes in the foot progression angle and gait deviation index can enable the effects of treatment to be more easily evaluated.

Body composition and motor function in children born large for gestational age at term

BACKGROUND

This cross-sectional study compared body composition and motor function between children who were born large for gestational age (LGA) and those born appropriate for gestational age (AGA) and to investigate the association between gait quality and other variables.

METHODS

Body composition was determined using a bioelectrical impedance analyzer. Motor functions were assessed using one-leg standing time, timed up-and-go test, five times sit-to-stand test, and three-dimensional gait analysis. We compared the results between two groups. We performed multiple regression analysis to evaluate the association between gait deviation index and variables of LGA, fat mass index, and motor functions (adjusted for age and sex).

RESULTS

Children aged 6-12 years who were born LGA at term (n = 23) and those who were born AGA at term (n = 147) were enrolled. The LGA group had a higher fat mass index (2.9 vs. 2.2, p = 0.006) and lower gait deviation index (91.4 vs. 95.4, p = 0.011) than the AGA group. On multiple regression analysis, gait deviation index was associated with being LGA and fat mass index.

CONCLUSIONS

In school-aged children who were born LGA, monitoring increased fat mass index and decreased gait deviation index could lessen the risk of metabolic syndrome and reduced gait function.

IMPACT

Children aged 6-12 years who were born large for gestational age (LGA) at term showed a higher fat mass index and lower gait deviation index than those who were born appropriate for gestational age at term. No significant differences in balance function or muscle strength were observed between groups. On multiple regression analysis, gait deviation index was associated with being LGA at birth and fat mass index. In school-aged children who were born LGA, monitoring increased fat mass index and decreased gait deviation index could lessen the risk of metabolic syndrome and reduced gait function.

Machine learning approach to gait deviation prediction based on isokinetic data acquired from biometric sensors

BACKGROUND

Analyzing gait deviation is one of the crucial factors during the diagnosis and treatment of children with Cerebral Palsy (CP). The typical diagnostic procedure requires an expensive and complicated three-dimensional gait analysis system based on visual sensors. In this work, we focus on predicting well-known gait pathology scores using only information collected from the BS4P, the affordable isokinetic dynamometer. Using such equipment, it is possible to determine gait pathological indices such as the gait deviation index (GDI) or the Gillette gait index (GGI).

RESEARCH QUESTION

Are there correlations between the results of examining patients with CP on the Biodex Pro 4 device and the gait quality metrics (GDI and GGI)?

METHODS

The isokinetic data acquired from biometric sensors (74 records) were analyzed using big data methods. We used several Machine Learning methods to find the correlation between gait deviation and isokinetic data: Adaptive Boosting Regression, K-nearest Neighbor, Decision Tree Regression, Random Forest Regression, and Gradient Boost Regression.

RESULTS

In this paper, we provided a detailed comparison of different machine learning regression models in predicting gait quality in patients with CP based only on the data gathered from affordable Biodex 4 Pro device. The best result was obtained using the gradient boosting regression model with Mean Absolute Percentage Error of 6%. However, it was not possible to precisely predict the GGI index using this method.

SIGNIFICANCE

The results obtained showed promising results in the evaluation of gait index scores, which gives the possibility of diagnosing patients with CP without the use of expensive optometric systems. Evaluating gait metrics using the approach proposed in this paper could be very helpful for both physicians and physiotherapists in assessing the condition of patients with CP, as well as other diseases related to gait problems.

Gait performance and dual-task costs in school-aged children with Down syndrome

OBJECTIVE

This cross-sectional observational study aimed to assess gait performance, its correlation with physical functions, and its dual-task costs in children with Down syndrome (DS), to investigate their gait adaptations.

METHODS

Gait performance with or without movie-watching tasks was evaluated in 17 children with DS (age, 6-12 years) and 51 age- and sex-matched controls, using three-dimensional gait analysis. We compared participants' demographics, physical functions, and gait performance without tasks between the two groups. In the DS group, correlations between physical functions, the intelligence quotient, and gait variables were assessed. Dual-task costs for gait variables were also compared between the two groups.

RESULTS

Children with DS showed poorer balance function and muscle strength and lower gait quality than the control group. In the DS group, there was a significant positive correlation between gait speed, step length, and intelligence quotient. There were no correlations between the balance function, muscle strength, intelligence quotient, and gait quality. Dual-task costs for gait speed, step length, and cadence were greater in the DS group; however, there was no significant difference in dual-task costs for gait quality between the two groups.

CONCLUSION

These findings highlight the importance of providing appropriate interventions for motor functions in school-aged children with DS based on their gait performance in single- and dual-task conditions, as well as on their intelligence quotient.

Derivation of the Gait Deviation Index for Spinal Cord Injury

The Gait Deviation Index (GDI) is a dimensionless multivariate measure of overall gait pathology represented as a single score that indicates the gait deviation from a normal gait average. It is calculated using kinematic data recorded during a three-dimensional gait analysis and an orthonormal vectorial basis with 15 gait features that was originally obtained using singular value decomposition and feature analysis on a dataset of children with cerebral palsy. Ever since, it has been used as an outcome measure to study gait in several conditions, including spinal cord injury (SCI). Nevertheless, the validity of implementing the GDI in a population with SCI has not been studied yet. We investigate the application of these mathematical methods to derive a similar metric but with a dataset of adults with SCI (SCI-GDI). The new SCI-GDI is compared with the original GDI to evaluate their differences and assess the need for a specific GDI for SCI and with the WISCI II to evaluate its sensibility. Our findings show that a 21-feature basis is necessary to account for most of the variance in gait patterns in the SCI population and to provide high-quality reconstructions of the gait curves included in the dataset and in foreign data. Furthermore, using only the first 15 features of our SCI basis, the fidelity of the reconstructions obtained in our population is higher than that when using the basis of the original GDI. The results showed that the SCI-GDI discriminates most levels of the WISCI II scale, except for levels 12 and 18. Statistically significant differences were found between both indexes within each WISCI II level except for 12, 20, and the control group (p < 0.05). In all levels, the average GDI value was greater than the average SCI-GDI value, but the difference between both indexes is larger in data with greater impairment and it reduces progressively toward a normal gait pattern. In conclusion, the implementation of the original GDI in SCI may lead to overestimation of gait function, and our new SCI-GDI is more sensitive to larger gait impairment than the GDI. Further validation of the SCI-GDI with other scales validated in SCI is needed.

Causal Effects of Motor Control on Gait Kinematics After Orthopedic Surgery in Cerebral Palsy: A Machine-Learning Approach

Background

Altered motor control is common in cerebral palsy (CP). Understanding how altered motor control affects movement and treatment outcomes is important but challenging due to complex interactions with other neuromuscular impairments. While regression can be used to examine associations between impairments and movement, causal modeling provides a mathematical framework to specify assumed causal relationships, identify covariates that may introduce bias, and test model plausibility. The goal of this research was to quantify the causal effects of altered motor control and other impairments on gait, before and after single-event multi-level orthopedic surgery (SEMLS).

Methods

We evaluated the impact of SEMLS on change in Gait Deviation Index (ΔGDI) between gait analyses. We constructed our causal model with a Directed Acyclic Graph that included the assumed causal relationships between SEMLS, ΔGDI, baseline GDI (GDIpre), baseline neurologic and orthopedic impairments (Imppre), age, and surgical history. We identified the adjustment set to evaluate the causal effect of SEMLS on ΔGDI and the impact of Imppre on ΔGDI and GDIpre. We used Bayesian Additive Regression Trees (BART) and accumulated local effects to assess relative effects.

Results

We prospectively recruited a cohort of children with bilateral CP undergoing SEMLS (N = 55, 35 males, age: 10.5 ± 3.1 years) and identified a control cohort with bilateral CP who did not undergo SEMLS (N = 55, 30 males, age: 10.0 ± 3.4 years). There was a small positive causal effect of SEMLS on ΔGDI (1.70 GDI points). Altered motor control (i.e., dynamic and static motor control) and strength had strong effects on GDIpre, but minimal effects on ΔGDI. Spasticity and orthopedic impairments had minimal effects on GDIpre or ΔGDI.

Conclusion

Altered motor control did have a strong effect on GDIpre, indicating that these impairments do have a causal effect on a child's gait pattern, but minimal effect on expected changes in GDI after SEMLS. Heterogeneity in outcomes suggests there are other factors contributing to changes in gait. Identifying these factors and employing causal methods to examine the complex relationships between impairments and movement will be required to advance our understanding and care of children with CP.

Three decades of gait index development: A comparative review of clinical and research gait indices

BACKGROUND

A wide variety of indices have been developed to quantify gait performance markers and associate them with their respective pathologies. Indices scores have enabled better decisions regarding patient treatments and allowed for optimized monitoring of the evolution of their condition. The extensive range of human gait indices presented over the last 30 years is evaluated and summarized in this narrative literature review exploring their application in clinical and research environments.

METHODS

The analysis will explore historical and modern gait indices, focusing on the clinical efficacy with respect to their proposed pathology, age range, and associated parameter limits. Features, methods, and clinically acceptable errors are discussed while simultaneously assessing indices advantages and disadvantages. This review analyses all indices published between 1994 and February 2021 identified using the Medline, PubMed, ScienceDirect, CINAHL, EMBASE, and Google Scholar databases.

FINDINGS

A total of 30 indices were identified as noteworthy for clinical and research purposes and another 137 works were included for discussion. The indices were divided in three major groups: observational (13), instrumented (16) and hybrid (1). The instrumented indices were further sub-divided in six groups, namely kinematic- (4), spatiotemporal- (5), kinetic- (2), kinematic- and kinetic- (2), electromyographic- (1) and Inertial Measurement Unit-based indices (2).

INTERPRETATION

This work is one of the first reviews to summarize observational and instrumented gait indices, exploring their applicability in research and clinical contexts. The aim of this review is to assist members of these communities with the selection of the proper index for the group in analysis.

Application of the Gait Deviation Index to Study Gait Impairment in Adult Population With Spinal Cord Injury: Comparison With the Walking Index for Spinal Cord Injury Levels

The Gait Deviation Index (GDI) is a multivariate measure of overall gait pathology based on 15 gait features derived from three-dimensional (3D) kinematic data. GDI aims at providing a comprehensive, easy to interpret, and clinically meaningful metric of overall gait function. It has been used as an outcome measure to study gait in several conditions: cerebral palsy (CP), post-stroke hemiparetic gait, Duchenne muscular dystrophy, and Parkinson’s disease, among others. Nevertheless, its use in population with Spinal Cord Injury (SCI) has not been studied yet. The aim of the present study was to investigate the applicability of the GDI to SCI through the assessment of the relationship of the GDI with the Walking Index for Spinal Cord Injury (WISCI) II. 3D gait kinematics of 34 patients with incomplete SCI (iSCI) was obtained. Besides, 3D gait kinematics of a sample of 50 healthy volunteers (HV) was also gathered with Codamotion motion capture system. A total of 302 (iSCI) and 446 (HV) strides were collected. GDI was calculated for each stride and grouped for each WISCI II level. HV data were analyzed as an additional set. Normal distribution for each group was assessed with Kolmogorov-Smirnov tests. Afterward, ANOVA tests were performed between each pair of WISCI II levels to identify differences among groups (p < 0.05). The results showed that the GDI was normally distributed across all WISCI II levels in both iSCI and HV groups. Furthermore, our results showed an increasing relationship between the GDI values and WISCI II levels in subjects with iSCI, but only discriminative in WISCI II levels 13, 19, and 20. The index successfully distinguished HV group from all the individuals with iSCI. Findings of this study indicated that the GDI is not an appropriate multivariate walking metric to represent the deviation of gait pattern in adult population with iSCI from a normal gait profile when it is compared with the levels of walking impairment described by the WISCI II. Future work should aim at defining and validating an overall gait index derived from 3D kinematic gait variables appropriate for SCI, additionally taking into account other walking ability outcome measures.

Physical functions and gait performance in school-aged children born late preterm

BACKGROUND

Children born late preterm (LP) have an increased risk of poor developmental motor outcomes.

AIMS

This study aimed to assess physical functions and gait performance in school-aged children born LP.

STUDY DESIGN

Cross-sectional study.

SUBJECTS

Physical functions and gait performance were evaluated in 277 children aged 6-10 years born LP (n = 22) and full-term (FT) (n = 255).

OUTCOME MEASURES

Physical function tests consisted of five times sit-to-stand test (FTSST), one-leg standing time, and grip strength. FTSST was used to assess the functional muscle strength of the lower limbs and dynamic balance function. Gait performance tests included gait quality, spatiotemporal gait parameters, and gait variability. Clinical data, physical functions, and gait performance were compared between two groups. Furthermore, logistic regression analysis was performed to assess the association between all variables and LP birth.

RESULTS

In physical function tests, children born LP showed poorer FTSST than those born FT (p = 0.039). No significant difference in gait performance tests were identified between the two groups. Logistic regression analysis of FTSST for LP (adjusted for age at assessment) revealed that FTSST was significantly associated with LP birth (p = 0.004, odds ratio = 1.579, 95% confidence interval = 1.160-2.149).

CONCLUSIONS

We demonstrated the physical functions and gait performance in school-aged children born LP. Our findings indicate that it is important to focus on the decreased functional muscle strength of the lower limbs and reduced dynamic balance function related to LP birth to improve functional mobility in children born LP.

The Utility of Gait Deviation Index (GDI) and Gait Variability Index (GVI) in Detecting Gait Changes in Spastic Hemiplegic Cerebral Palsy Children Using Ankle-Foot Orthoses (AFO)

Background: Cerebral palsy (CP) children present complex and heterogeneous motor disorders that cause gait deviations. Clinical gait analysis (CGA) is used to identify, understand and support the management of gait deviations in CP. Children with CP often use ankle–foot orthosis (AFO) to facilitate and optimize their walking ability. The aim of this study was to assess whether the gait deviation index (GDI) and the gait variability index (GVI) results can reflect the changes of spatio-temporal and kinematic gait parameters in spastic hemiplegic CP children wearing AFO. Method: The study group consisted of 37 CP children with hemiparesis. All had undergone a comprehensive, instrumented gait analysis while walking, both barefoot and with their AFO, during the same CGA session. Kinematic and spatio-temporal data were collected and GVI and GDI gait indexes were calculated. Results: Significant differences were found between the barefoot condition and the AFO conditions for selected spatio-temporal and kinematic gait parameters. Changes in GVI and GDI were also statistically significant. Conclusions: The use of AFO in hemiplegic CP children caused a statistically significant improvement in spatio-temporal and kinematic gait parameters. It was found that these changes were also reflected by GVI and GDI. These findings might suggest that gait indices, such as GDI and GVI, as clinical outcome measures, may reflect the effects of specific therapeutic interventions in CP children.

Structural Brain Lesions and Gait Pathology in Children With Spastic Cerebral Palsy

The interaction between brain damage and motor function is not yet fully understood in children with spastic cerebral palsy (CP). Therefore, a semi-quantitative MRI (sqMRI) scale was used to explore whether identified brain lesions related to functional abilities and gait pathology in this population. A retrospective cohort of ambulatory children with spastic CP was selected [N = 104; 52 bilateral (bCP) and 52 unilateral (uCP)]. Extent and location-specific scores were defined according to the sqMRI scale guidelines. The gross motor function classification system (GMFCS), the gait profile score (GPS), GPSs per motion plane, gait variable scores (GVS) and multiple-joint (MJ) gait patterns were related to brain lesion scores. In all groups, the global total brain scores correlated to the GPS (total: r_s = 0.404, p ≤ 0.001; bCP: r_s = 0.335, p ≤ 0.05; uCP: r_s = 0.493, p ≤ 0.001). The global total hemispheric scores correlated to the GMFCS (total: r_s = 0.392, p ≤ 0.001; bCP: r_s = 0.316, p ≤ 0.05; uCP: r_s = 0.331, p ≤ 0.05). The laterality scores of the hemispheres in the total group correlated negatively to the GMFCS level (r_s = −0.523, p ≤ 0.001) and the GVS-knee sagittal (r_s = −0.311, p ≤ 0.01). Lesion location, for the total group demonstrated positive correlations between parietal lobe involvement and the GPS (r_s = 0.321, p ≤ 0.001) and between periventricular layer damage and the GMFCS (r_s = 0.348, p ≤ 0.001). Involvement of the anterior part of the corpus callosum (CC) was associated with the GVS-hip sagittal in all groups (total: r_pb = 0.495, p ≤ 0.001; bCP: r_pb = 0.357, p ≤ 0.05; uCP: r_pb = 0.641, p ≤ 0.001). The global total hemispheric and laterality of the hemispheres scores differentiated between the minor and both the extension (p ≤ 0.001 and p ≤ 0.001) and flexion (p = 0.016 and p = 0.013, respectively) MJ patterns in the total group. Maximal periventricular involvement and CC intactness were associated with extension patterns (p ≤ 0.05 and p ≤ 0.001, respectively). Current findings demonstrated relationships between brain structure and motor function as well as pathological gait, in this cohort of children with CP. These results might facilitate the timely identification of gait pathology and, ultimately, guide individualized treatment planning of gait impairments in children with CP.

Gait deficits and dynamic stability in children and adolescents with cerebral palsy: A systematic review and meta-analysis

BACKGROUND

Studies have demonstrated that ambulatory children and adolescents with cerebral palsy demonstrate atypical gait patterns. Out of numerous gait variables, identification of the most deteriorated gait parameters is important for targeted and effective gait rehabilitation. Therefore, this study aimed to identify the gait parameters with the most discriminating nature to distinguish cerebral palsy gait from normal gait.

METHODS

Multiple databases were searched to include studies on ambulatory children and adolescents with cerebral palsy that included gait (spatio-temporal, kinematic, and kinetic) and dynamic stability variables.

FINDINGS

Of 68 studies that met the inclusion criteria, 35 studies were included in the meta analysis. Effect size was used to assess the discriminative strength of each variable. A large effect (≥ 0.8) of cerebral palsy on double limb support time (Standardized Mean Difference = 0.98), step length (Standardized Mean Difference = 1.65), step width (Standardized Mean Difference = 1.21), stride length (Standardized Mean Difference = 1.75), and velocity (Standardized Mean Difference = 1.42) was observed at preferred-walking speed. At fast-walking speed, some gait variables (i.e. velocity and stride length) exhibited larger effect size compared to preferred-walking speed. For some kinematic variables (e.g. range of motion of pelvis), the effect size varied across the body planes.

INTERPRETATION

Our systematic review detects the most discriminative features of cerebral palsy gait. Non-uniform effects on joint kinematics across the anatomical planes support the importance of 3D gait analysis. Differential effects at fast versus preferred speeds emphasize the importance of measuring gait at a range of speeds.

Association between Gait Deviation Index and Physical Function in Children with Bilateral Spastic Cerebral Palsy: A Cross-Sectional Study

This study examined the association between Gait Deviation Index (GDI) and the five-times-sit-to-stand test (FTSST) or gait speed results, which represent mobility and muscle strength of the lower extremities in ambulatory children with Gross Motor Function Classification System (GMFCS) level I and II spastic cerebral palsy. In this cross-sectional, observational study, three-dimensional gait analysis data were obtained during gait trials to evaluate the GDI in 35 children (age 5–16 years) with spastic palsy. Motor function was evaluated using FTSST and gait speed. Gross motor function was evaluated using GMFCS. Children with GMFCS level II spastic cerebral palsy demonstrated lower GDI (p < 0.001) and poorer FTSST (p = 0.031) than those with GMFCS level I spastic cerebral palsy. Correlation analysis showed that FTSST results were significantly correlated with GDI (r = −0.624; p < 0.001). Motor function may be important for the maintenance of gait quality in patients with GMFCS level I and II spastic cerebral palsy and should not be ignored. In conclusion, reduction in gait impairment may affect the values of FTSST and GDI in patients with spastic cerebral palsy who can ambulate without an assistive device.

Application of the Gait Deviation Index in the analysis of post-stroke hemiparetic gait

Due to the complexity and volume of kinematic data from 3-dimensional gait analysis, the Gait Deviation Index (GDI) was introduced as a summary measure providing a global picture of gait kinematic data, however previously it was not validated as an outcome measure in individuals after stroke. The present study investigated the concurrent validity of the GDI as an outcome measure of gait defects at a chronic stage of recovery post-stroke, through comparisons with conventional measures of gait. Those enrolled included 65 individuals after stroke and 65 healthy individuals without gait disorders, matched for age and gender. The kinematic gait parameters were measured using a movement analysis system. Walking speed, walking distance, number of steps, self-reliant mobility, cadence, step length, and single support time were evaluated. Strong correlation was found between cadence and mGDI as well as GDI for the affected leg (0.7 ≤ |R| < 0.9; p < 0.001). Moderate correlations were found between walking speed, number of steps, step length affected leg and mGDI as well as GDI for the affected leg (0.5 ≤ |R| < 0.7; p < 0.001). Low correlations were found between walking distance, self-reliant mobility, single support time affected leg and mGDI as well as GDI for the affected leg (0.3 ≤ |R| < 0.5; p < 0.001; p < 0.005). The findings confirm the concurrent validity of the GDI, but only for the affected leg and mGDI in post-stroke patients. On the other hand, the GDI for unaffected leg may be useful in efforts to identify any compensatory mechanisms developing in post-stroke gait patterns. Trial registration: anzctr.org.au, ID:ACTRN12617000436370. Registered 24 March 2017.

Individuals with knee osteoarthritis present increased gait pattern deviations as measured by a knee-specific gait deviation index

BACKGROUND

A biomechanical analysis can provide valuable information on osteoarthritis (OA) gait, but important multidimensional interactions are often ignored. The Gait Deviation Index (GDI) was designed to address the issue of data complexity in gait analyses by providing a single, encompassing, value for one's deviation from a normative reference group.

RESEARCH QUESTION

The primary aim of this study was to examine differences in a knee-specific GDI among young adults, and older individuals with and without knee OA. Secondarily, we aimed to examine these differences while controlling for gait speed.

METHOD

Sagittal and frontal plane knee joint angles and moments were used in the computation of a GDI among young adults, and older individuals with and without knee OA. The GDI was calculated such that scores ≥100% were considered typical young-healthy gait and a 10% decrease below 100 equated to 1 standard deviation from typical gait. Scores were first examined using a one-way analysis of variance, and examined again after correcting for gait speed.

RESULTS

The GDI was calculated for three groups: young-healthy adults (n = 52), older individuals without knee OA (n = 56), and individuals with knee OA (n = 191). Those with knee osteoarthritis exhibited a mean GDI of 87.2 (11.1), which was significantly lower than young adults (99.6 (10.6); p < 0.001) and older individuals without knee OA (94.3 (11.0); p < 0.001). Differences in GDI remained consistent after controlling for gait speed. Knee OA gait waveforms displayed significant variability across similar GDIs, specifically in frontal plane patterns.

CONCLUSION

Those with knee osteoarthritis exhibited lower (worse) GDIs compared to those without knee osteoarthritis and young, healthy individuals. After correcting for gait speed, these findings did not change. The GDI highlighted the significant variability in gait waveforms within individuals with knee OA, but the clinical utility of the GDI score itself remains limited.

Correlations between the Gait Profile Score and standard clinical outcome measures in children with idiopathic clubfoot

BACKGROUND

Measures of overall gait deviations such as the Gait Profile Score (GPS) and the Gait Variable Score (GVS) are used to evaluate gait in clinical practice and for research purposes. In the clinical setting, gait deviations are often visually assessed and classified using structured protocols such as the Clubfoot Assessment Protocol (CAP).

RESEARCH QUESTION

Determine the relationship between measures of overall gait deviations and clinical assessments.

METHODS

This cross-sectional study evaluated the usability of GPS and GVS in children with idiopathic clubfoot. Twenty consecutively born children with idiopathic clubfoot participated in this study. At 7 years of age, the children were referred for three-dimensional gait analysis and, on the same day, they also underwent a clinical examination according to the CAP.

RESULTS

The overall gait deviations, expressed as the GPS (overall and affected side) and the GVS for nine key variables were calculated. The correlations between the GPS and values from CAP, its domains, and a single item called walking and between the item walking and the GVS values were analyzed using the Spearman's rank correlation coefficient (r_s). The item walking correlated significantly with the GPS (r_s = -0.62), and the GVS for foot progression (r_s = -0.61) and foot dorsiflexion/plantarflexion (r_s = -0.50). The domain "morphology" correlated with the GPS (r_s = 0.64).

SIGNIFICANCE

These findings indicate that the GPS index along with the GVS reflects gait deviations observed clinically in children with clubfoot.

An Analysis of Relative Gait Impairment in Commonly Diagnosed Pediatric Conditions

BACKGROUND

Gait indices were developed to represent the magnitude of impairment extracted from a gait analysis with a single value. The Gillette Gait Index (GGI), and the Gait Deviation Index (GDI) are 2 widely used indices that represent gait impairment differently based on their statistical properties. Our purpose was to (1) report on the results of gait analysis for a broad spectrum of pediatric conditions using the GGI and GDI, and (2) identify the parameters that dominate impairment.

METHODS

A total of 1439 children with 13 different diagnoses with a complete, baseline gait analysis were identified. The GGI and its 16 parameters were calculated in all cases, and the GDI was calculated from a smaller subset. T tests, and z-scores were used to compare each of these values to typically developing children for each diagnosis. A separate linear regression controlling for age, sex, and use of an orthosis, or assistive device was performed for the GGI.

RESULTS

In our series, there were 71 typically developing children with a GGI of 31. We qualify relative gait impairment as severe, mild, or moderate as based on the GGI, and propose that values <100 represent mild, 100 to 200 represent moderate, and >200 represents severe impairment. On the basis of strong correlation between the GGI and GDI, we suggest that GDI values >80 represent mild, and values <70 represent severe impairment. T tests and z-scores demonstrated that both the number and magnitude of abnormal parameters increase the GGI. These tests also identified the most clinically relevant parameters contributing to functional impairment for each diagnosis. Multivariate linear regression showed that all diagnoses except flatfoot and scoliosis demonstrated statistically significant differences in GGI scores.

CONCLUSIONS

This is the first study to apply these gait indices to a large population of diverse pediatric conditions. We propose GGI and GDI values to qualify gait impairment among these conditions as severe, moderate, or mild. Furthermore, impairment in gait reflects both the number and magnitude of abnormal parameters within each condition.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Influence of normative data's walking speed on the computation of conventional gait indices

The pathology's impact on gait pattern may be overestimated by conventional gait indices (Gillette Gait Index - GGI, Gait Deviation Index - GDI, Gait Profile Score - GPS), since impairments' consequences on kinematics may be amplified by a change in walking speed. The objectives of this study were to evaluate the influence of walking speed on the computation of gait indices and to propose a corrective method to cancel the effects of walking speed. Spatiotemporal parameters and kinematics of fifty-four asymptomatic participants (30 M/24 W, 37.9 ± 13.7 years, 72.8 ± 13.3 kg, 1.74 ± 0.10 m) were collected at four speed conditions (C₁:[0,0.4] m s^-1, C₂:[0.4,0.8] m s^-1, C₃:[0.8,1.2] m s^-1, C₄:spontaneous). Four values of each index were computed for each trial using successively the four conditions as normative data repository. Mean values over all participants were statistically compared (paired t-tests, 95% confidence level). Indices values computed with normative at equivalent walking speed were not statistically different from reference values. Meanwhile, deviations appeared when the walking speed discrepancy between conditions and normative increased. These drifts related to walking speed mismatch have been quantified and fitting functions proposed. A correction was applied to indices. GGI was efficiently adjusted while GDI and GPS remain different from their reference values for C₁ and C₂. Gait indices must be interpreted cautiously in function of the normative data repository's walking speed used for computation. Furthermore, a coupled use of conventional and corrected gait indices could lead to a better comprehension of the contribution of impairments and walking speed on gait deviations and overall gait quality.

An index to quantify deviations from normal trunk mobility: Clinical correlation and initial test of validity

BACKGROUND

In case of people suffering from chronic low back pain, specific movements of the hip, pelvis, and trunk are associated with pain. Comparing range of motion measurements for multiple planes and from different segments and lines in reference to those of healthy individuals seems interesting but present interpretations challenge in relation to important number of variables and correlation with clinical data.

METHODS

The proposed index is based on using principal component analysis to quantify differences in trunk mobility between patients with chronic low back pain and a control group. Kinematic data were recorded for the cervical and thoracic vertebrae, the lumbar spine, and the pelvic and scapular belts during repeated trials (hip flexion and extension, hip bending, and trunk twists). Angular motion values were calculated. Principal component analysis was used to convert 10 discrete variables (kinematical data) extracted from control data into 10 independent variables.

FINDINGS

The proposed index comprises the sum of the variables. Initial demonstration of its clinical utility and statistical tests of this index validity were revealed. It establishes correlations between the psychosocial impact of chronic low back pain, trunk mobility (as summarized by the index) and the positive effects of functional restoration program.

INTERPRETATION

This index let to assess the absolute potential benefits of rehabilitation in term of kinematic motion. Functional restoration program promotes the physical functioning of patients by increasing their range of motion. This index uses kinematic motion to assess the potential benefits of such rehabilitation program.

Psychometric properties of measures of gait quality and walking performance in young people with Cerebral Palsy: A systematic review

Availability of outcome measures (OMs) with robust psychometric properties is an essential prerequisite for the evaluation of interventions designed to address gait deterioration in young people with Cerebral Palsy (CP). This review evaluates evidence for the reliability, validity and responsiveness of outcome measures of gait quality and walking performance in young people with CP. A systematic search was performed in MEDLINE, CINAHL, PubMed and Scopus. Articles that met the eligibility criteria were selected. Methodological quality of studies was independently rated by two raters using the modified COnsensus-based Standard for the selection of health status Measurement INstruments checklist. Strength of evidence was rated using standardised guidelines. Best evidence synthesis was scored according to Cochrane criteria. Fifty-one articles reporting on 18 distinct OMs were included for review. Best evidence synthesis indicated a moderate to strong evidence for the reliability for OMs of walking performance but conflicting evidence for the reliability of OMs of gait quality. The evidence for responsiveness for all OMs included in this review was rated as 'unknown'. The limitations of using the modified COSMIN scoring for small sample sizes are acknowledged. Future studies of high methodological quality are needed to explore the responsiveness of OMs assessing gait quality and walking performance in young people with CP.

Analysis of gait patterns pre- and post- Single Event Multilevel Surgery in children with Cerebral Palsy by means of Offset-Wise Movement Analysis Profile and Linear Fit Method

Gait analysis is used for the assessment of walking ability of children with cerebral palsy (CP), to inform clinical decision making and to quantify changes after treatment. To simplify gait analysis interpretation and to quantify deviations from normality, some quantitative synthetic descriptors were developed over the years, such as the Movement Analysis Profile (MAP) and the Linear Fit Method (LFM), but their interpretation is not always straightforward. The aims of this work were to: (i) study gait changes, by means of synthetic descriptors, in children with CP that underwent Single Event Multilevel Surgery; (ii) compare the MAP and the LFM on these patients; (iii) design a new index that may overcome the limitations of the previous methods, i.e. the lack of information about the direction of deviation or its source. Gait analysis exams of 10 children with CP, pre- and post-surgery, were collected and MAP and LFM were computed. A new index was designed asa modified version of the MAP by separating out changes in offset (named OC-MAP). MAP documented an improvement in the gait pattern after surgery. The highest effect was observed for the knee flexion/extension angle. However, a worsening was observed as an increase in anterior pelvic tilt. An important source of gait deviation was recognized in the offset between observed tracks and reference. OC-MAP allowed the assessment of the offset component versus the shape component of deviation. LFM provided results similar to OC-MAP offset analysis but could not be considered reliable due to intrinsic limitations. As offset in gait features played an important role in gait deviation, OC-MAP synthetic analysis was proposed as a novel approach to a meaningful parameterisation of global deviations in gait patterns of subjects with CP and gait changes after treatment.

The analysis of three-dimensional ground reaction forces during gait in children with autism spectrum disorders

Minimal information is known about the three-dimensional (3D) ground reaction forces (GRF) on the gait patterns of individuals with autism spectrum disorders (ASD). The purpose of this study was to investigate whether the 3D GRF components differ significantly between children with ASD and the peer controls. 15 children with ASD and 25 typically developing (TD) children had participated in the study. Two force plates were used to measure the 3D GRF data during walking. Time-series parameterization techniques were employed to extract 17 discrete features from the 3D GRF waveforms. By using independent t-test and Mann-Whitney U test, significant differences (p<0.05) between the ASD and TD groups were found for four GRF features. Children with ASD demonstrated higher maximum braking force, lower relative time to maximum braking force, and lower relative time to zero force during mid-stance. Children with ASD were also found to have reduced the second peak of vertical GRF in the terminal stance. These major findings suggest that children with ASD experience significant difficulties in supporting their body weight and endure gait instability during the stance phase. The findings of this research are useful to both clinicians and parents who wish to provide these children with appropriate treatments and rehabilitation programs.

Reliability and Minimum Detectable Change of the Gait Deviation Index (GDI) in post-stroke patients

The Gait Deviation Index (GDI) is a summary measure that provides a global picture of gait kinematic data. Since the ability to walk is critical for post-stroke patients, the aim of this study was to determine the reliability and Minimum Detectable Change (MDC) of the GDI in this patient population. Twenty post-stroke patients (11 males, 9 females; mean age, 55.2±9.9years) participated in this study. Patients presented with either right- (n=14) or left-sided (n=6) hemiparesis. Kinematic gait data were collected in two sessions (test and retest) that were 2 to 7days apart. GDI values in the first and second sessions were, respectively, 59.0±8.1 and 60.2±9.4 for the paretic limb and 53.3±8.3 and 53.4±8.3 for the non-paretic limb. The reliability in each session was determined by the intra-class correlation coefficient (ICC) of three strides and, in the test session, their values were 0.91 and 0.97 for the paretic and non-paretic limbs, respectively. Between-session reliability and MDC were determined using the average GDI of three strides from each session. For the paretic limb, between-session ICC, standard error of measurement (SEM), and MDC were 0.84, 3.4 and 9.4, respectively. Non paretic lower limb exhibited between-session ICC, standard error of measurement (SEM), and MDC of 0.89, 2.7 and 7.5, respectively. These MDC values indicate that very large changes in GDI are required to identify gait improvement. Therefore, the clinical usefulness of GDI with stroke patients is questionable.

Correlation between the Gait Deviation Index and gross motor function (GMFCS level) in children with cerebral palsy

AIM

The Gait Deviation Index (GDI) is a score derived from three-dimensional gait analysis (3DGA). The GDI provides a numerical value that expresses overall gait pathology (ranging from 0 to 100, where 100 indicates the absence of gait pathology). The aim of this study was to investigate the association between the GDI and different levels of gross motor function [defined as the Gross Motor Function Classification System (GMFCS)] and to explore if age, height, weight, gender and cerebral palsy (CP) subclass (bilateral and unilateral CP) exert any influence on the GDI in children with unilateral and bilateral spastic CP.

METHODS

We calculated the GDI of 109 children [73 % boys, mean age 9.7 years (standard deviation, SD 3.5)] with spastic CP, classified at GMFCS levels I, II and III. Twenty-three normally developing children were used as controls [61 % boys, mean age 9.9 years (SD 2.6)]. Multiple linear regression analysis was performed.

RESULTS

The mean GDI in the control group was 100 (SD 7.5). The mean GDI in the GMFCS level I group was 81 (SD 11), in the GMFCS level II group 71 (SD 11) and in the GMFCS level III group 60 (SD 9). Multiple linear regression analysis showed that gender, age and CP subclass had no significant correlation with the GDI, whereas height and weight had a slight impact.

CONCLUSION

This study showed a strong correlation between the GDI and GMFCS levels. The present data indicate that calculation of the GDI is a useful tool to characterise walking difficulties in children with spastic CP.

The Gait Deviation Index Is Associated with Hip Muscle Strength and Patient-Reported Outcome in Patients with Severe Hip Osteoarthritis-A Cross-Sectional Study

Background

The Gait Deviation Index summarizes overall gait ‘quality’, based on kinematic data from a 3-dimensional gait analysis. However, it is unknown which clinical outcomes may affect the Gait Deviation Index in patients with primary hip osteoarthritis. The aim of this study was to investigate associations between Gait Deviation Index as a measure of gait ‘quality’ and hip muscle strength and between Gait Deviation Index and patient-reported outcomes in patients with primary hip osteoarthritis.

Method

Forty-seven patients (34 males), aged 61.1 ± 6.7 years, with BMI 27.3 ± 3.4 (kg/m²) and with severe primary hip osteoarthritis underwent 3-dimensional gait analysis. Mean Gait Deviation Index, pain after walking and maximal isometric hip muscle strength (flexor, extensor, and abductor) were recorded. All patients completed the ‘Physical Function Short-form of the Hip disability and Osteoarthritis Outcome Score (HOOS-Physical Function) and the Hip disability and Osteoarthritis Outcome Score subscales for pain (HOOS-Pain) and quality-of-life (HOOS-QOL).

Results

Mean Gait Deviation Index was positively associated with hip abduction strength (p<0.01, r = 0.40), hip flexion strength (p = 0.01, r = 0.37), HOOS-Physical Function (p<0.01, r = 0.41) HOOS-QOL (p<0.01, r = 0.41), and negatively associated with HOOS-Pain after walking (p<0.01, r = -0.45). Adjusting the analysis for walking speed did not affect the association.

Conclusion

Patients with the strongest hip abductor and hip flexor muscles had the best gait ‘quality’. Furthermore, patients with higher physical function, quality of life scores and lower pain levels demonstrated better gait ‘quality’. These findings indicate that interventions aimed at improving hip muscle strength and pain management may to a moderate degree improve the overall gait ‘quality’ in patients with primary hip OA.

Quantifying Gait Quality in Patients with Large-Head and Conventional Total Hip Arthroplasty--A Prospective Cohort Study

We used the Gait Deviation Index (GDI) as method to compare preoperative to postoperative gait changes after uncemented 50 mm (median) large-head and 28/32 mm total hip arthroplasty (THA). We also identified predictors of improvements in GDI. Gait analysis and patient-reported (WOMAC) data were recorded in 35 patients before, 2 and 6-months after treatment. Twenty age-matched adults provided normative gait data. Contrary to our hypothesis, patients who received large-head THA had less improvement in GDI compared with patients who received 28/32 mm THA. The preoperative GDI score was identified as a predictor of postoperative GDI improvement, while WOMAC, age, gender and walking speed were not. This study provides useful information for clinicians and rehabilitation specialists about gait improvement that can be expected after THA.

Multi-scale complexity analysis of muscle coactivation during gait in children with cerebral palsy

The objective of this study is to characterize complexity of lower-extremity muscle coactivation and coordination during gait in children with cerebral palsy (CP), children with typical development (TD) and healthy adults, by applying recently developed multivariate multi-scale entropy (MMSE) analysis to surface electromyographic (EMG) signals. Eleven CP children (CP group), eight TD children and seven healthy adults (considered as an entire control group) were asked to walk while surface EMG signals were collected from five thigh muscles and three lower leg muscles on each leg (16 EMG channels in total). The 16-channel surface EMG data, recorded during a series of consecutive gait cycles, were simultaneously processed by multivariate empirical mode decomposition (MEMD), to generate fully aligned data scales for subsequent MMSE analysis. In order to conduct extensive examination of muscle coactivation complexity using the MEMD-enhanced MMSE, 14 data analysis schemes were designed by varying partial muscle combinations and time durations of data segments. Both TD children and healthy adults showed almost consistent MMSE curves over multiple scales for all the 14 schemes, without any significant difference (p > 0.09). However, distinct diversity in MMSE curve was observed in the CP group when compared with the control group. There appears to be diverse neuropathological processes in CP that may affect dynamical complexity of muscle coactivation and coordination during gait. The abnormal complexity patterns emerging in the CP group can be attributed to different factors such as motor control impairments, loss of muscle couplings, and spasticity or paralysis in individual muscles. This study expands our knowledge of neuropathology of CP from a novel point of view of muscle co-activation complexity, which might be useful to derive a quantitative index for assessing muscle activation characteristics as well as motor function in CP.

Gait Deviation Index, Gait Profile Score and Gait Variable Score in children with spastic cerebral palsy: Intra-rater reliability and agreement across two repeated sessions

The Gait Deviation Index (GDI) and Gait Profile Score (GPS) are the most used summary measures of gait in children with cerebral palsy (CP). However, the reliability and agreement of these indices have not been investigated, limiting their clinimetric quality for research and clinical practice. The aim of this study was to investigate the intra-rater reliability and agreement of summary measures of gait (GDI; GPS; and the Gait Variable Score (GVS) derived from the GPS). The intra-rater reliability and agreement were investigated across two repeated sessions in 18 children aged 5-12 years diagnosed with spastic CP. No systematic bias was observed between the sessions and no heteroscedasticity was observed in Bland-Altman plots. For the GDI and GPS, excellent reliability with intraclass correlation coefficient (ICC) values of 0.8-0.9 was found, while the GVS was found to have fair to good reliability with ICCs of 0.4-0.7. The agreement for the GDI and the logarithmically transformed GPS, in terms of the standard error of measurement as a percentage of the grand mean (SEM%) varied from 4.1 to 6.7%, whilst the smallest detectable change in percent (SDC%) ranged from 11.3 to 18.5%. For the logarithmically transformed GVS, we found a fair to large variation in SEM% from 7 to 29% and in SDC% from 18 to 81%. The GDI and GPS demonstrated excellent reliability and acceptable agreement proving that they can both be used in research and clinical practice. However, the observed large variability for some of the GVS requires cautious consideration when selecting outcome measures.

The use of the Gait Deviation Index for the evaluation of participants following total hip arthroplasty: An explorative randomized trial

INTRODUCTION

In this paper, the Gait Deviation Index (GDI) was used as a convenient method to evaluate pre-to-postoperative gait pattern changes after total hip arthroplasty and identify factors which might be predictive of outcome.

DESIGN

Three-dimensional gait data from a randomized clinical trial was used to determine changes in gait quality in participants walking at self-selected speed. Upon completion of the first assessment, the participants were randomly assigned to either resurfacing hip arthroplasty or conventional hip arthroplasty. The outcome was changes in overall gait 'quality' measured with GDI during the 6-month post-surgery follow-up period.

RESULTS

38 participants with severe unilateral primary hip osteoarthritis took part in the trial. We found no difference in change scores between the two treatment groups; 1.9 [95%CI: -0.3 to 4.0] or between change scores for the non-operated and the operated limbs; 0.3 [95%CI: -2.3 to 1.7]. However, the score for the two groups (pooled data) improved after surgery by 4.4 [95%CI: 1.8-7.0]. The single level regression analysis identified the preoperative GDI score as a strong predictor of outcome (p<0.001).

CONCLUSION

Six months after surgery, there was no additional effect of resurfacing hip arthroplasty on GDI scores compared with conventional hip arthroplasty. Participants with the most pathological preoperative gait pattern improved the most. The GDI increased, which indicates an overall improvement in gait pathology after surgery.

TRIAL REGISTRATION

NCT01229293.

Application of the Gillette Gait Index, Gait Deviation Index and Gait Profile Score to multiple clinical pediatric populations

Gait indices are now commonly used to assess overall pathology and outcomes from studies with instrumented gait analyses. There are differences in how these indices are calculated and therefore inherent differences in their sensitivities to detect changes or differences between groups. The purpose of the current study was to examine the three most commonly used gait indices, Gillette Gait Index (GGI), Gait Deviation Index (GDI), and Gait Profile Score (GPS), comparing the statistical sensitivity and the ability to make meaningful interpretations of the clinical results. In addition, the GDI*, a log transformed and scaled version of the GPS score which closely matches the GDI was examined. For seven previous or ongoing studies representing varying gait pathologies seen in clinical laboratories, the GGI, GDI, and GPS/GDI* were calculated retrospectively. The GDI and GPS/GDI* proved to be the most sensitive measures in assessing differences pre/post-treatment or from a control population. A power analysis revealed the GDI and GDI* to be the most sensitive statistical measures (lowest sample sizes required). Subjectively, the GDI and GDI* interpretation seemed to be the most intuitive measure for assessing clinical changes. However, the gait variable sub-scores of the GPS determined several statistical differences which were not previously noted and was the only index tool for quantifying the relative contributions of specific joints or planes of motion. The GGI did not offer any advantages over the other two indices.

Walking dynamic similarity induced by a combination of Froude and Strouhal dimensionless numbers: Modela-w

The aim of this study was to assess the accuracy of a new dimensionless number associating Froude (Nfr) and Strouhal (Str) called Modela-w to induce walking dynamic similarity among humans of different sizes. Nineteen subjects walked in three experimental conditions: (i) constant speed, (ii) similar speed (Nfr) and (iii) similar speed and similar step frequency (Modela-w). The dynamic similarity was evaluated from scale factors computed with anthropometric, temporal, kinematic and kinetic data and from the decrease of the variability of the parameters expressed in their dimensionless form. Over a total of 36 dynamic parameters, dynamic similarity from scale factors was met for 11 (mean r = 0.51), 22 (mean r = 0.52) and 30 (mean r = 0.69) parameters in the first, the second and the third experimental conditions, respectively. Modela-w also reduced the variability of the dimensionless preceding parameters compared to the other experimental conditions. This study shows that the combination of Nfr and Str called Modela-w ensures dynamic similarity between different-sized subjects and allows scientists to impose similar experimental conditions removing all anthropometric effects.

Assessment of bioethanol yield by S. cerevisiae grown on oil palm residues: Monte Carlo simulation and sensitivity analysis

Oil palm trunk (OPT) sap was utilized for growth and bioethanol production by Saccharomycescerevisiae with addition of palm oil mill effluent (POME) as nutrients supplier. Maximum yield (YP/S) was attained at 0.464g bioethanol/g glucose presence in the OPT sap-POME-based media. However, OPT sap and POME are heterogeneous in properties and fermentation performance might change if it is repeated. Contribution of parametric uncertainty analysis on bioethanol fermentation performance was then assessed using Monte Carlo simulation (stochastic variable) to determine probability distributions due to fluctuation and variation of kinetic model parameters. Results showed that based on 100,000 samples tested, the yield (YP/S) ranged 0.423-0.501g/g. Sensitivity analysis was also done to evaluate the impact of each kinetic parameter on the fermentation performance. It is found that bioethanol fermentation highly depend on growth of the tested yeast.