Reliability and minimum detectable change of the gait profile score for post-stroke patients

Gait pattern after electromechanically-assisted gait training with the Hybrid Assistive Limb and conventional gait training in sub-acute stroke rehabilitation-A subsample from a randomized controlled trial

Introduction

Electromechanically-assisted gait training has been introduced in stroke rehabilitation as a means to enable gait training with a large number of reproducible and symmetrical task repetitions, i.e. steps. However, few studies have evaluated its impact on gait pattern functions. This study includes persons with no independent ambulation function at the start of a 4-week neurorehabilitation period in the sub-acute phase after stroke. The primary aim of the study was to evaluate whether the addition of electromechanically-assisted gait training to conventional training resulted in better gait pattern function than conventional training alone. The secondary aim was to identify correlations between overall gait quality and standardized clinical assessments.

Participants and methods

Seventeen patients with no independent ambulation function who participated in a Prospective Randomized Open Blinded End-point study in the sub-acute phase after stroke were randomized into two groups; one group (n = 7) to undergo conventional training only (CONV group) and the other group (n = 10) to undergo conventional training with additional electromechanically-assisted gait training (HAL group). All patients were assessed with 3D gait analysis and clinical assessments after the 4-week intervention period. Overall gait quality as per the Gait Profile Score (GPS), as well as kinematic, and kinetic and other spatiotemporal metrics were collected and compared between intervention groups. Correlations between biomechanical and clinical outcomes were evaluated.

Results

Both the CONV and HAL groups exhibited similar gait patterns with no significant differences between groups in any kinematic, kinetic parameters or other spatiotemporal metrics. The GPS for the paretic limb had a median (IQR) of 12.9° (7.8°) and 13.4° (4.3°) for the CONV and HAL groups, respectively (p = 0.887). Overall gait quality was correlated with independence in walking, walking speed, movement function and balance. We found no added benefit in gait pattern function from the electromechanically-assisted gait training compared to the conventional training alone.

Discussion

This finding raises new questions about how to best design effective and optimal post-stroke rehabilitation programs in patients with moderate to severe gait impairments to achieve both independent walking and optimal gait pattern function, and about which patients should be in focus in further studies on the efficacy of electromechanically-assisted gait training.

Clinical trial registration

The study was retrospectively registered at ClinicalTrials.gov, identifier (NCT02410915) on April 2015.

Time profile of kinematic synergies of stroke gait

BACKGROUND

In stroke subjects, the motor skills differ between sides and among subjects with different levels of motor recovery, impacting inter-joint coordination. How these factors can affect the kinematic synergies over time during gait has not been investigated yet. This work aimed to determine the time profile of kinematic synergies of stroke patients throughout the single support phase of gait.

METHODS

Kinematic data from 17 stroke and 11 healthy individuals was recorded using a Vicon System. The Uncontrolled Manifold approach was employed to determine the distribution of components of variability and the synergy index. To analyze the time profile of kinematic synergies, we applied the statistical parametric mapping method. Comparisons were made within the stroke group (paretic and non-paretic limbs) and between groups (stroke and healthy). The stroke group was also subdivided into subgroups with worse and better motor recovery.

FINDINGS

There are significant differences in synergy index at the end of the single support phase between stroke and healthy subjects; paretic and non-paretic limbs; and paretic limb according to the motor recovery. Comparisons of mean values showed significantly larger values of synergy index for the paretic limb compared to the non-paretic and healthy.

INTERPRETATION

Despite the sensory-motor deficits and the atypical kinematic behavior, stroke patients can produce joint covariations to control the center of mass trajectory in the forward progression plane, but the modulation of the synergy is impaired, reflecting altered adjustments, especially in the paretic limb of subjects with worse levels of motor recovery.

Synchronized Cyclograms to Assess Inter-Limb Symmetry during Gait in Post-Stroke Patients

The aim of this study was to assess the inter-limb symmetry during gait in post-stroke patients using the synchronized cyclograms technique. In total, 41 individuals with stroke (21 left and 20 right hemiplegic patients; age: 57.9 ± 12.8 years; time stroke event 4.6 ± 1.8 years) and 48 age-, sex-, and height-matched individuals (control group: CG; age: 54.4 ± 12.5 years) were assessed via 3D gait analysis. Raw kinematic data were processed to compute spatio-temporal parameters (speed, stride length, cadence, stance, swing, and double support phases duration) and angle–angle diagrams (synchronized cyclograms), which were characterized in terms of area, orientation, and trend symmetry indices. The results reveal that all spatio-temporal parameters are characterized by abnormal values, with reduced speed, stride length, cadence, and swing phase duration and increased stance and double support phases duration. With respect to inter-limb symmetry, higher values were found in post-stroke individuals for all the considered parameters as patients generally exhibited a cyclogram characterized by larger areas, higher orientation, and trend symmetry parameters with respect to CG. The described alterations of gait asymmetry are important from a clinical point of view as the achievement of symmetry in gait represents a crucial objective in the rehabilitation of hemiplegic people.

Brain Asymmetry and Its Effects on Gait Strategies in Hemiplegic Patients: New Rehabilitative Conceptions

Brain asymmetry is connected with motor performance, suggesting that hemiparetic patients have different gait patterns depending on the side of the lesion. This retrospective cohort study aims to further investigate the difference between right and left hemiplegia in order to assess whether the injured side can influence the patient’s clinical characteristics concerning gait, thus providing insights for new personalized rehabilitation strategies. The data from 33 stroke patients (17 with left and 16 with right hemiplegia) were retrospectively compared with each other and with a control group composed of 20 unaffected age-matched individuals. The 3D gait analysis was used to assess kinematic data and spatio-temporal parameters. Compared to left hemiplegic patients, right hemiplegic patients showed worse spatio-temporal parameters (p < 0.05) and better kinematic parameters (p < 0.05). Both pathological groups were characterized by abnormal gait parameters in comparison with the control group (p < 0.05). These findings show an association between the side of the lesion—right or left—and the different stroke patients’ gait patterns: left hemiplegic patients show better spatio-temporal parameters, whereas right hemiplegic patients show better segmentary motor performances. Therefore, further studies may develop and assess new personalized rehabilitation strategies considering the injured hemisphere and brain asymmetry.

The gait profile score characterises walking performance impairments in young stroke survivors

BACKGROUND

The Gait Profile Score (GPS) provides a composite measure of the quality of joint movement during walking, but the relationship between this measure and metabolic cost, temporal (e.g. walking speed) and spatial (e.g. stride length) parameters in stroke survivors has not been reported.

RESEARCH QUESTION

The aims of this study were to compare the GPS (paretic, non-paretic, and overall score) of young stroke survivors to the healthy able-bodied control and determine the relationship between the GPS and metabolic cost, temporal (walking speed, stance time asymmetry) and spatial (stride length, stride width, step length asymmetry) parameters in young stroke survivors to understand whether the quality of walking affects walking performance in stroke survivors.

METHODS

Thirty-nine young stroke survivors aged between 18 and 65years and 15 healthy age-matched able-bodied controls were recruited from six hospital sites in Wales, UK. Joint range of motion at the pelvis, hip, knee and ankle, and temporal and spatial parameters were measured during walking on level ground at self-selected speed with calculation of the Gait Variable Score and then the GPS.

RESULTS

GPS for the paretic leg (9.40° (8.60-10.21) p < 0.001), non-paretic leg (11.42° (10.20-12.63) p < 0.001) and overall score (11.18° (10.26-12.09) p < 0.001)) for stroke survivors were significantly higher than the control (4.25° (3.40-5.10), 5.92° (5.11 (6.73)). All parameters with the exception of step length symmetry ratio correlated moderate to highly with the GPS for the paretic, non-paretic, and/or overall score (ρ = <-0.732 (p < 0.001)).

SIGNIFICANCE

The quality of joint movement during walking measured via the GPS is directly related to the speed and efficiency of walking, temporal (stance time symmetry) and spatial (stride length, stride width) parameters in young stroke survivors.

Accuracy of Temporo-Spatial and Lower Limb Joint Kinematics Parameters Using OpenPose for Various Gait Patterns With Orthosis

A cost-effective gait analysis system without attachments and specialized large environments can provide useful information to determine effective treatment in clinical sites. This study investigates the capability of a single camera-based pose estimation system using OpenPose (OP) to measure the temporo-spatial and joint kinematics parameters during gait with orthosis. Eleven healthy adult males walked under different conditions of speed and foot progression angle (FPA). Temporo-spatial and joint kinematics parameters were measured using a single camera-based system with OP and a three-dimensional motion capture system. The limit of agreement, mean absolute error, absolute agreement (ICC_{2, 1}), and relative consistency (ICC_{3, 1}) between the systems under each condition were assessed for reliability and validity. The results demonstrated that most of the ICC for temporo-spatial parameters and hip and knee kinematics parameters were good to excellent (0.60 - 0.98). Conversely, most of the ICC for ankle kinematics in all conditions were poor to fair (< 0.60). Thus, the gait analysis using OP can be used as a clinical assessment tool for determining the temporo-spatial, hip, and knee sagittal plane angles during gait.

Assessment of the Kinematic Adaptations in Parkinson's Disease Using the Gait Profile Score: Influences of Trunk Posture, a Pilot Study

INTRODUCTION

Postural abnormalities are common in patients with Parkinson's disease (PD) and lead to gait abnormalities. Relationships between changes in the trunk posture of PD patients and gait profile score (GPS) and gait spatiotemporal parameters are poorly investigated. The aim of the current study was to investigate the relationships between trunk posture, GPS, and gait spatiotemporal parameters, in patients with PD.

MATERIALS AND METHODS

Twenty-three people with PD and nineteen age-matched healthy people participated in this study. A 3D gait kinematical analysis was applied to all participants using the Plug-In Gait Full BodyTM tool. Trunk and limb kinematics patterns and gait spatio-temporal parameters of patients with PD and the control group were compared. Additionally, correlations between trunk kinematics patterns, gait spatio-temporal parameters, and GPS of the PD group were tested.

RESULTS

Cadence, opposite foot off, step time, single support, double support, foot off, gait speed, trunk kinematics, and GPS showed significant differences between the two groups (p ≤ 0.05). Posture of the trunk during gait was not related to the spatio-temporal parameters and gait profile score in the PD group. The trunk flexor pattern influenced GPS domains, mainly of the ankle and the knee.

DISCUSSION AND CONCLUSIONS

Flexed posture of the trunk in patients with PD seems to influence both ankle and knee movement patterns during the gait. The GPS analysis provided direct and simplified kinematic information for the PD group. These results may have implications for understanding the importance of considering the positioning of the trunk during gait.

Are there common walking gait characteristics in patients diagnosed with late-onset Pompe disease?

Late-onset Pompe disease (LOPD) is a rare disease, defined as a progressive accumulation of lysosomal glycogen resulting in muscle weakness and respiratory problems. Anecdotally, individuals often have difficulties walking, yet, there is no three-dimensional data supporting these claims. We aimed to assess walking patterns in individuals with LOPD and compare with healthy individuals. Kinematic, kinetic and spatiotemporal data were compared during walking at a self-selected speed between individuals with LOPD (n = 12) and healthy controls (n = 12). Gait profile scores and movement analysis profiles were also determined to indicate gait quality. In comparison with healthy individuals, the LOPD group demonstrated greater thoracic sway (96%), hip adduction angles (56%) and pelvic range of motion (77%) and reduced hip extensor moments (36%). Greater group variance for the LOPD group were also observed. Individuals with LOPD had a slower (15%) walking speed and reduced cadence (7%). Gait profile scores were 37% greater in the LOPD group compared to the healthy group. Proximal muscular weakness associated with LOPD disease is likely to have resulted in a myopathic gait pattern, slower selected walking speeds and deviations in gait patterns. Although individuals with LOPD presented with some common characteristics, greater variability in gait patterns is likely to be a result of wide variability in phenotype spectrum observed with LOPD. This is the first study to examine walking in individuals with LOPD using instrumented gait analysis and provides an understanding of LOPD on walking function which can help orientate physiotherapy treatment for individuals with LOPD.

Hallux rigidus affects lower limb kinematics assessed with the Gait Profile Score

BACKGROUND

Previous research showed that hallux rigidus (HR) affects foot and ankle kinematics during gait. It is unclear if HR affects lower limb kinematics as well.

RESEARCH QUESTION

Does HR affect lower limb kinematics, and if so, is gait deviation correlated with patient-reported outcome?

METHODS

This was a retrospective case-control study, including 15 HR patients and 15 healthy controls who underwent three-dimensional gait analysis by using the Plug-in Gait lower body model. The Gait Profile Score (GPS), a gait index score describing gait deviation and composed out of nine Gait Variable Scores (GVS), and intersegmental range of motion of lower limb joints were assessed. Patient-reported outcome was assessed with the Foot Function Index (FFI) and Manchester-Oxford Foot Questionnaire (MOXFQ). Data were analysed with Student t-tests and Spearman rank correlations.

RESULTS

HR significantly affects gait, reflected by a higher GPS in HR subjects as compared to healthy controls. Gait deviation was seen in ankle flexion (GVS_{ankle flexion}) and to a lesser extent in pelvic rotation (GVS_{pelvic rotation}). Interestingly, these differences were not detected when lower limb kinematics were evaluated by comparing the intersegmental ranges of motion of these joints. Positive correlations were present between patient-reported outcomes and GPS, especially functional subdomains, were positively correlated with GPS and GVS_{ankle flexion}.

SIGNIFICANCE

This study demonstrated that HR, next to foot kinematics, additionally affects lower limb kinematics evaluated with an objective gait index score, i.e. GPS. The positive correlation between the GPS and patient-reported outcome can be seen as the first step in defining whether objectively measured gait indices can be used in considering surgery since most of the benefit of surgery will be expected in the patients with most gait deviation.

RESULTS OF ORTHOSES USED ON AMBULATORY PATIENTS WITH BILATERAL CEREBRAL PALSY

Objective:

To investigate the impact of ankle-foot orthoses (AFO) on subjects diagnosed with bilateral cerebral palsy (CP) using the gait index and temporal data parameters.

Methods:

Twenty-four subjects, 14 male and 10 female, with a mean age of 11 (5-17 years old), underwent a comprehensive gait analysis under both barefoot (BF) and braced walking conditions. All children had been wearing the orthoses for at least 2 months before the gait analysis.

Results:

The overall values for the left and right Gait Profile Scores (GPS) did not show statistically significant variations when comparing the same individuals with and without orthoses. Gait velocity increased by 19.5% (p < 0.001), while the cadence decreased by 4% with use of orthosis, although it was not statistically significant (p > 0.05). The stride and the step lengths on both the right and left sides, however, resulted in statistically significant increases, when wearing AFO.

Conclusion:

AFO, prescribed for assistance by professionals without using gait data, did not significantly affect the gait index (GPS), but improved temporal data. The determination of quantitative clinical parameters for the prescription of orthotics in patients with bilateral CP, as well as orthotics that meet the specific requirements are points to be addressed in the future to obtain more significant effects. Level of evidence III, Case control study.

Test-retest reliability and minimal detectable change of ankle kinematics and spatiotemporal parameters in MS population

BACKGROUND

Many people with multiple sclerosis (pwMS) experience walking impairments often including foot drop, evident as either reduced dorsiflexion at initial contact and/or at the swing phase of the gait cycle. To measure even subtle differences in ankle kinematics, 3D gait analysis is considered a 'gold' standard. However, the psychometric properties of ankle kinematics in the MS population have not yet been examined.

OBJECTIVE

The aim of the study was to examine test-retest relative and absolute reliability of sagittal ankle kinematics and spatiotemporal parameters in two groups of pwMS with different levels of walking impairment.

METHODS

Two groups of pwMS underwent 3D gait analysis on two occasions 7-14 days apart. Group A consisted of 21 (14 female) people with Expanded Disability Status Scale (EDSS) 1-3.5 and group B consisted of 28 participants (14 female) with EDSS 4-6. The Intraclass Correlation Coefficient (ICC_2,2), standard error of measurement (SEM) and minimal detectable change (MDC_95%) were calculated for peak dorsiflexion (DF) in swing, ankle angle at initial contact (IC), gait profile score (GPS), walking speed, cadence and step length.

RESULTS

Both groups presented 'excellent' ICC values (>0.75) for DF in swing, IC and step length of most and least affected limbs, walking speed and cadence, with GPS for both limbs exhibiting 'fair' to 'good' ICCs (0.489-0.698). The MDC_95% values for all ankle kinematic parameters in group A were lower (1.9°-4.2°) than those in group B (2.2°-7.7°).

CONCLUSION

The present results suggest that ankle kinematic and spatiotemporal parameters derived from 3D gait analysis are reliable outcome measures to be used in the MS population. Further, this study provides indices of reliability that can be applied to both clinical decision making and in the design of studies aimed at treating foot drop in people with MS.

Gait profile score identifies changes in gait kinematics in nonfaller, faller and recurrent faller older adults women

BACKGROUND

Quantification of differences in gait kinematics between young and older adults provides insight on age-related gait changes and can contribute to the investigation of risk of falls. Gait Profile Score (GPS) is an index that indicates gait quality, using kinematic gait data, but so far it has not been used in an elderly population without neurological conditions.

RESEARCH QUESTION

Is the Gait Profile Score (GPS) an index that shows reliability for use in old adults? Does this index detect changes in gait quality observed by kinematic data between nonfaller, faller and recurrent faller older adults?

METHODS

Forty-nine women (mean age 72,43 ± 6,44; 27 faller and 22 nonfaller) were included in the study. Intra-session reliability was obtained from the intraclass correlation coefficient (ICC) between the five strides of each session.

RESULTS

Overall value of GPS shows no difference between nonfaller (6.65 ± 1.59º), faller (6.67 ± 2.05º) and recurrent faller (6.62 ± 0.86º) older adult. In all groups larger values of Gait Variable Scores (GVS) were observed in the hip and knee joints. Intra-session ICC values the GVS and GPS presented high stability, ranging from 0.80 to 0.99. MDC lower values in GPS were observed in the faller (0.39; ICC - 0.97) and recurrent faller (0.69; ICC - 0.90).

SIGNIFICANCE

Due to the high reliability, GPS has proven to be a valid method to analyze the gait quality of faller and nonfaller older woman. The most sensitive indexes (GPS and GVS) are the gear changes in fallers and recurrent fallers.

Center of mass in analysis of dynamic stability during gait following stroke: A systematic review

BACKGROUND

The Center of mass (CoM) analysis reveals important aspects of gait dynamic stability of stroke patients, but the variety of methods and measures represents a challenge for planning new studies.

RESEARCH QUESTION

How have the CoM measures been calculated and employed to investigate gait stability after a stroke? Three issues were addressed: (i) the methodological aspects of the calculation of CoM measures; (ii) the purposes and (iii) the conclusions of the studies on gait stability that employed those measures.

METHODS

PubMed and Science Direct databases have been searched to collect original articles produced until July 2017. A set of 26 studies were selected according to criteria involving their methodological quality.

RESULTS

A compromise between accuracy and feasibility in CoM calculation could be reached using the segmental method with 7-9 segments. Regarding their purposes, two types of studies were identified: clinical and research oriented. From the first ones, we highlighted: the margin of stability (MoS) in the mediolateral (ML) direction, and the angular momentum in the frontal plane could be indicators of dynamical stability; the MoS in the anteroposterior (AP) direction might be able to detect the risk of falls and the symmetry of vertical CoM displacement could be used to analyze energy expenditure during gait. These and other CoM measures are potentially useful in clinical settings, but their psychometric properties are still to be determined. The research oriented studies allowed to clarify that stability is not improved by widening the step in stroke patients and that the impaired control of the non-paretic limb might be the main source of instability.

SIGNIFICANCE

This review provides recommendations on the methods for estimating CoM and its measures, identifies the potential usefulness of CoM parameters and indicates issues that could be addressed in future studies.

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.

Gait Profile Score in able-bodied and post-stroke individuals adjusted for the effect of gait speed

BACKGROUND

The Gait Profile Score (GPS) measures the quality of an individual's walking by calculating the difference between the kinematic pattern and the average walking pattern of healthy individuals.

RESEARCH QUESTIONS

The purposes of this study were to quantify the effect of speed on the GPS and to determine whether the prediction of gait patterns at a specific speed would make the GPS outcome insensitive to gait speed in the evaluation of post-stroke individuals.

METHODS

The GPS was calculated for able-bodied individuals walking at different speeds and for the comparison of post-stroke individuals with able-bodied individuals using the original experimental data (standard GPS) and the predicted gait patterns at a given speed (GPS velocity, GPS^v). We employed standard gait analysis for data collection of the subjects. Sixteen participants with a stroke history were recruited for the post-stroke group, and 15 age-matched, able-bodied participants formed the control group.

RESULTS

Gait speed significantly affects the GPS and the method to predict the gait patterns at any speed is able to mitigate the effects of gait speed on the GPS. Overall, the gap between the GPS and GPS^v values across the post-stroke individuals was small (0.5° on average, range from 0.0° to 1.4°) and not statistically significant. However, there was a significant negative linear relationship in the absolute difference between the GPS and GPS^v values for the participants of the post-stroke group with gait speed, indicating that a larger difference between the speeds of the post-stroke participant and the reference dataset resulted in a larger difference between the GPS and GPS^v.

SIGNIFICANCE

The modified version of the GPS, the GPS^v, is effective in reducing the impact of gait speed on GPS; however, the observed difference between the two methods was only around 1° for the slowest individuals in comparison to the reference dataset.

Reliable sagittal plane kinematic gait assessments are feasible using low-cost webcam technology

Three-dimensional (3-D) motion capture systems are commonly used for gait analysis because they provide reliable and accurate measurements. However, the downside of this approach is that it is expensive and requires technical expertise; thus making it less feasible in the clinic. To address this limitation, we recently developed and validated (using a high-precision walking robot) a low-cost, two-dimensional (2-D) real-time motion tracking approach using a simple webcam and LabVIEW Vision Assistant. The purpose of this study was to establish the repeatability and minimal detectable change values of hip and knee sagittal plane gait kinematics recorded using this system. Twenty-one healthy subjects underwent two kinematic assessments while walking on a treadmill at a range of gait velocities. Intraclass correlation coefficients (ICC) and minimal detectable change (MDC) values were calculated for commonly used hip and knee kinematic parameters to demonstrate the reliability of the system. Additionally, Bland-Altman plots were generated to examine the agreement between the measurements recorded on two different days. The system demonstrated good to excellent reliability (ICC>0.75) for all the gait parameters tested on this study. The MDC values were typically low (<5°) for most of the parameters. The Bland-Altman plots indicated that there was no systematic error or bias in kinematic measurements and showed good agreement between measurements obtained on two different days. These results indicate that kinematic gait assessments using webcam technology can be reliably used for clinical and research purposes.

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.