Current practices in clinical gait analysis in Europe: A comprehensive survey-based study from the European society for movement analysis in adults and children (ESMAC) standard initiative.

BACKGROUND: Clinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. RESEARCH OBJECTIVE: This study aimed to review the current laboratory practices for CGA in Europe. METHODS: A comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. RESULTS: There was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. SIGNIFICANCE: The findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe.

Pre-treatment EMG can be used to model post-treatment muscle coordination during walking in children with cerebral palsy.

When treating children with Cerebral Palsy (CP), computational simulations based on musculoskeletal models have a great potential in assisting the clinical decision-making process towards the most promising treatments. In particular, predictive simulations could be used to predict and compare the functional outcome of a series of candidate interventions. In order to be able to benefit from these predictive simulations however, it is important to know how much information about the post-treatment patient's motor control could be gathered from data available before the intervention. Within this paper, we quantified how much of the muscle activity measured after a treatment could be explained by subject-specific muscle synergies computed from EMG data collected before the intervention. We also investigated whether generic synergies could be used, in case no EMG data is available when running predictive simulations, to reproduce both pre- and post-treatment muscle activity in children with CP. Subject-specific synergies proved to be a good indicator of the patient's post-treatment motor control, explaining on average more than 85% of the post-treatment muscle activity, compared to an average of 94% when applied to the original pre-treatment data. Generic synergies explained 84% of the pre-treatment and 83% of the post-treatment muscle activity on average, but performed relatively well for patients with low selective motor control and poorly in patients with more selectivity. Our results suggest that subject-specific muscle synergies computed from pre-treatment EMG data could be used with confidence to represent the post-treatment motor control of children with CP during walking. In addition, when performing simulations involving patients with a low selective motor control, generic synergies could be a valid alternative.

Role of femoral derotation on gait after selective dorsal rhizotomy in children with spastic cerebral palsy.

AIM: To evaluate the long-term outcome of selective dorsal rhizotomy (SDR) on gait and the influence of previous femoral derotation osteotomy (FDO). METHOD: In a retrospective cohort study of 29 children (16 females, 13 males) with spastic diplegic cerebral palsy, 14 children received FDO before SDR, whereas 15 children with moderate or near-normal internal femoral rotation during gait received only SDR. Three-dimensional gait data were obtained pre-FDO, pre-SDR, 1 year post-SDR, and 3 to 5 years post-SDR, to study the Gait Profile Score (GPS), pelvic tilt, and knee and hip kinematics. A mixed analysis of variance with the repeated measure 'time' was performed between different time points for each group. RESULTS: Children who first underwent FDO and then SDR started with a more complex gait pathology but showed fewer gait deviations 3 to 5 years post-SDR, compared to children who only underwent SDR. This was reflected by a lower GPS and pelvic tilt, as well as less knee flexion in stance. INTERPRETATION: The effect of SDR on gait is only significant in the mid- to long-term if the bony lever arms are also corrected. Thus, the clinical outcome after SDR is dependent on good proximal alignment. WHAT THIS PAPER ADDS: Pelvic tilt remains stable after femoral derotation osteotomy (FDO)+selective dorsal rhizotomy (SDR). But pelvic tilt deteriorates after SDR only. Hip and knee extension is better after FDO+SDR than after SDR only. Spasticity reduction (by SDR) combined with bony lever arm correction (by FDO) improves gait.

PAPEL DE LA DESROTACION FEMORAL EN LA MARCHA DESPUES DE UNA RIZOTOMIA SELECTIVE POSTERIOR EN NIÑOS CON PARÁLISIS CEREBRAL: OBJETIVO: Evaluar el resultado a largo plazo de la rizotomía selective posterior (RSP) sobre la marcha y la influencia de la osteotomía femoral desrotadora (OFD) previa. METODO: Estudio de cohorte retrospectivo de 29 niños (13 mujeres, 16 varones) con parálisis cerebral subtipo diplejia espástica, 14 niños recibieron OFD antes de la RSP, mientras que 15 niños con rotación femoral interna moderada o casi normal durante la marcha recibieron solo RSP. Se obtuvieron datos tridimensionales de la marcha pre-OFD, pre-RSP, 1 año post-RSP y 3 a 5 años post-RSP, para estudiar la puntuación del perfil de la marcha (Gait Profile Score. GPS, sigla en inglés), inclinación pélvica y cinemática de rodilla y cadera. Se realizó un análisis mixto de varianza con la medida repetida "tiempo" entre diferentes puntos de tiempo para cada grupo. RESULTADOS: Los niños que primero se sometieron a OFD y luego RSP comenzaron con una patología de la marcha más compleja, pero mostraron menos desviaciones de la marcha de 3 a 5 años después de la RSP, en comparación con los niños que solo se sometieron a RSP. Esto se reflejó por una menor GPS e inclinación pélvica, así como una menor flexión de la rodilla durante el apoyo. INTERPRETACIÓN: El efecto de la RSP en la marcha solo es significativo a medio o largo plazo si los brazos de palanca óseos también se corrigen. Por lo tanto, el resultado clínico después de la RSP depende de una buena alineación proximal.

PAPEL DA DERROTAÇÃO FEMORAL NA MARCHA APÓS RIZOTOMIA DORSAL SELETIVA EM CRIANÇAS COM PARALISIA CEREBRAL ESPÁSTICA: OBJETIVO: Avaliar o resultado em longo prazo da rizotomia dorsal seletiva (RDS) na marcha e a influência da osteotomia derrotativa femoral (ODF). MÉTODO: Em um estudo de coorte retrospectivo com 29 crianças (13 do sexo feminino, 16 do sexo masculino) com paralisia cerebral diplégica espástica, 14 crianças receberam ODF antes da RDS, enquanto 15 crianças com rotação femoral interna moderada ou quase normal durante a marcha receberam apenas RDS. Dados tridimensionais de marcha foram obtidos pré ODF, pré RDS, 1 ano pós RDS, e 3 a 5 anos após RDS, para estudar o Escore do Perfil da Marcha (EPM), inclinação pélvica, e cinemática de joelho e quadril. Uma análise mista de variância com a medida repetida 'tempo' foi realizada entre os diferentes pontos para cada grupo. RESULTADOS: Crianças que primeiro passaram por ODF e depois pela RDS começaram com patologia de marcha mais complexa, mas tiveram menos desvios na marcha 3 a 5 anos após RDS, comparadas com crianças que receberam apenas RDS. Isso foi refletido por menor escore EMG e inclinação pélvica, assim como menos flexão do joelho na fase de apoio. INTERPRETAÇÃO: O efeito da RDS na marcha apenas é significativo no médio a longo prazo se os braços de alavanca ósseos também são corrigidos. Assim, o resultado clínico após RDS depende de bom alinhamento proximal.

The influence of maximum isometric muscle force scaling on estimated muscle forces from musculoskeletal models of children with cerebral palsy.

BACKGROUND: Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance in order to represent each child's compensation mechanisms introduced through muscle weakness. RESEARCH AIM: The aims of this study were to (i) evaluate if maximum isometric muscle forces (MIMF) in musculoskeletal models of children with CP can be scaled based on strength measurements obtained with a hand-held-dynamometer (HHD), (ii) evaluate the impact of the HHD based scaling approach and previously published MIMF scaling methods on computed muscle forces during gait, and (iii) compare maximum muscle forces during gait between CP and typically developing (TD) children. METHODS: Strength and motion capture data of six CP and motion capture data of six TD children were collected. The HHD measurements to obtain hip, knee and ankle muscle strength were simulated in OpenSim and used to modify MIMF of the 2392-OpenSim model. These muscle forces were compared to the MIMF scaled on the child's body mass and a scaling approach, which included the body mass and muscle-tendon lengths. OpenSim was used to calculate peak muscle forces during gait. RESULTS: Ankle muscle strength was insufficient to reproduce joint moments during walking when MIMF were scaled based on HHD. During gait, peak hip and knee extensor muscle forces were higher and peak ankle dorsi-flexor forces were lower in CP compared to TD participants. SIGNIFICANCE: HHD measurements can be used to scale MIMF for the hip and knee muscle groups but underestimate the force capacity of the ankle muscle groups during walking. Muscle-tendon-length and mass based scaling methods affected muscle activations but had little influence on peak muscle forces during gait.

Gait deviations in Duchenne muscular dystrophy-Part 2. Statistical non-parametric mapping to analyze gait deviations in children with Duchenne muscular dystrophy.

BACKGROUND: Prolonged ambulation is considered important in children with Duchenne muscular dystrophy (DMD). However, previous studies analyzing DMD gait were sensitive to false positive outcomes, caused by uncorrected multiple comparisons, regional focus bias, and inter-component covariance bias. Also, while muscle weakness is often suggested to be the main cause for the altered gait pattern in DMD, this was never verified. RESEARCH QUESTION: Our research question was twofold: 1) are we able to confirm the sagittal kinematic and kinetic gait alterations described in a previous review with statistical non-parametric mapping (SnPM)? And 2) are these gait deviations related to lower limb weakness? METHODS: We compared gait kinematics and kinetics of 15 children with DMD and 15 typical developing (TD) children (5-17 years), with a two sample Hotelling's T2 test and post-hoc two-tailed, two-sample t-test. We used canonical correlation analyses to study the relationship between weakness and altered gait parameters. For all analyses, α-level was corrected for multiple comparisons, resulting in α = 0.005. RESULTS: We only found one of the previously reported kinematic deviations: the children with DMD had an increased knee flexion angle during swing (p = 0.0006). Observed gait deviations that were not reported in the review were an increased hip flexion angle during stance (p = 0.0009) and swing (p = 0.0001), altered combined knee and ankle torques (p = 0.0002), and decreased power absorption during stance (p = 0.0001). No relationships between weakness and these gait deviations were found. SIGNIFICANCE: We were not able to replicate the gait deviations in DMD previously reported in literature, thus DMD gait remains undefined. Further, weakness does not seem to be linearly related to altered gait features. The progressive nature of the disease requires larger study populations and longitudinal analyses to gain more insight into DMD gait and its underlying causes.

The Intra- and Inter-Rater Reliability of an Instrumented Spasticity Assessment in Children with Cerebral Palsy.

AIM: Despite the impact of spasticity, there is a lack of objective, clinically reliable and valid tools for its assessment. This study aims to evaluate the reliability of various performance- and spasticity-related parameters collected with a manually controlled instrumented spasticity assessment in four lower limb muscles in children with cerebral palsy (CP). METHOD: The lateral gastrocnemius, medial hamstrings, rectus femoris and hip adductors of 12 children with spastic CP (12.8 years, ±4.13 years, bilateral/unilateral involvement n=7/5) were passively stretched in the sagittal plane at incremental velocities. Muscle activity, joint motion, and torque were synchronously recorded using electromyography, inertial sensors, and a force/torque load-cell. Reliability was assessed on three levels: (1) intra- and (2) inter-rater within session, and (3) intra-rater between session. RESULTS: Parameters were found to be reliable in all three analyses, with 90% containing intra-class correlation coefficients >0.6, and 70% of standard error of measurement values <20% of the mean values. The most reliable analysis was intra-rater within session, followed by intra-rater between session, and then inter-rater within session. The Adds evaluation had a slightly lower level of reliability than that of the other muscles. CONCLUSIONS: Limited intrinsic/extrinsic errors were introduced by repeated stretch repetitions. The parameters were more reliable when the same rater, rather than different raters performed the evaluation. Standardisation and training should be further improved to reduce extrinsic error when different raters perform the measurement. Errors were also muscle specific, or related to the measurement set-up. They need to be accounted for, in particular when assessing pre-post interventions or longitudinal follow-up. The parameters of the instrumented spasticity assessment demonstrate a wide range of applications for both research and clinical environments in the quantification of spasticity.

Motor endplate-targeted botulinum toxin injections of the gracilis muscle in children with cerebral palsy.

AIM: Intramuscular botulinum toxin-A (BoNT-A) injections reduce spasticity by blocking neurotransmission at the motor endplate (MEP). The goal of this study was to assess the reduction in spasticity achieved by injecting BoNT-A at different sites of the gracilis muscle. METHOD: Thirty-four gracilis muscles, in 27 children (10 females and 17 males, mean age of 8.6y [SD 2.5y]) with spastic cerebral palsy (unilateral and bilateral, Gross Motor Function Classification System [GMFCS] levels I-IV), were randomly assigned to one of two groups. In one group BoNT-A was injected proximally (at a site 25% of the distance from the pubic tubercle and the medial epicondyle) and in the other it was injected at the MEP zones (half of the dose was administered at 30% of this distance and half at 60%). Spasticity was assessed before and after BoNT-A injection using simultaneous measurements of surface electromyography (sEMG) and angular velocity during passive muscle stretch applied at different velocities. The primary outcome measure included the velocity-dependent change in average root mean square electromyography (RMS-EMG). Secondary outcome was assessed with the Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS). RESULTS: Spasticity decreased more in MEP-targeted muscles than in proximally injected muscles, as demonstrated by a larger reduction in average RMS-EMG values (p=0.04), though this difference was not found with the MAS or MTS. INTERPRETATION: The results suggest that BoNT-A injection of the gracilis at sites with a high concentration of MEPs is effective at reducing spasticity. These preliminary findings should be confirmed by larger studies. In the case of long muscles, such as the gracilis, the injection site is important.

Can we unmask features of spasticity during gait in children with cerebral palsy by increasing their walking velocity?

BACKGROUND AND AIM: Spasticity is a velocity dependent feature present in most patients with cerebral palsy (CP). It is commonly measured in a passive condition. The aim of this study was to highlight markers of spasticity of gastrocnemius and hamstring muscles during gait by comparing the effect of increased walking velocity of CP and typical developing (TD) children. METHODS: 53 children with spastic CP and 17 TD children were instructed to walk at self-selected speed, faster and as fast as possible without running. Kinematics, kinetics and electromyography (EMG) were collected and muscle length and muscle lengthening velocity (MLV) were calculated. To compare the data of both groups, a linear regression model was created which resulted in two non-dimensional gait velocities. A difference score (DS) was calculated between the high and low velocity values for both groups. RESULTS: 103 gait parameters were analyzed of which 16 had a statistically significant DS between TD and CP groups. The spastic gastrocnemius muscle presented at high velocity with a higher ankle angular velocity, plantar flexion moment, power absorption and increased EMG signal during loading response. The spastic hamstrings demonstrated at high velocity a delayed maximum knee extension moment at mid-stance and increasing hip extension moment and hip power generation. The hamstrings also presented with a lower MLV during swing phase. CONCLUSIONS: A limited number of gait parameters differ between CP and TD children when increasing walking velocity, giving indirect insight on the effect of spasticity on gait.

Is an instrumented spasticity assessment an improvement over clinical spasticity scales in assessing and predicting the response to integrated botulinum toxin type a treatment in children with cerebral palsy?

OBJECTIVE: To compare responsiveness and predictive ability of clinical and instrumented spasticity assessments after botulinum toxin type A (BTX) treatment combined with casting in the medial hamstrings (MEHs) in children with spastic cerebral palsy (CP). DESIGN: Prospective cohort study. SETTING: Hospital. PARTICIPANTS: Consecutive sample of children (N=31; 40 MEH muscles) with CP requiring BTX injections. INTERVENTION: Clinical and instrumented spasticity assessments before and on average ± SD 53±14 days after BTX. MAIN OUTCOME MEASURES: Clinical spasticity scales included the Modified Ashworth Scale and the Modified Tardieu Scale. The instrumented spasticity assessment integrated biomechanical (position and torque) and electrophysiological (surface electromyography) signals during manually performed low- and high-velocity passive stretches of the MEHs. Signals were compared between both stretch velocities and were examined pre- and post-BTX. Responsiveness of clinical and instrumented assessments was compared by percentage exact agreement. Prediction ability was assessed with a logistic regression and the area under the receiver operating characteristic (ROC) curves of the baseline parameters of responders versus nonresponders. RESULTS: Both clinical and instrumented parameters improved post-BTX (P≤.005); however, they showed a low percentage exact agreement. The baseline Modified Tardieu Scale was the only clinical scale predictive for response (area under the ROC curve=0.7). For the instrumented assessment, baseline values of root mean square (RMS) electromyography and torque were better predictors for a positive response (area under the ROC curve=.82). Baseline RMS electromyography remained an important predictor in the logistic regression. CONCLUSIONS: The instrumented spasticity assessment showed higher responsiveness than the clinical scales. The amount of RMS electromyography is considered a promising parameter to predict treatment response.

Effect of dynamic orthoses on gait: a retrospective control study in children with hemiplegia.

Several positive influences of orthoses on gait in children with cerebral palsy have been documented, as well as some detrimental effects. Most importantly, push-off is decreased in orthoses, compromising a physiological third ankle rocker. The aim of this study was to evaluate the effect of three types of orthosis on gait in a homogeneous group of children. All orthoses aimed at improving push-off and normalizing the pathological plantarflexion-knee extension couple. Thirty-seven children (22 females, 15 males) with hemiplegia, aged 4 to 10 years (30 Gross Motor Function Classification System [GMFCS] Level I, six GMFCS Level II), walked barefoot and with orthoses being either Orteams (orthoses with the dorsal part containing 11 sleeves), posterior leafsprings (PLS), or Dual Carbon Fibre Spring ankle foot orthosis (AFOs; CFO: carbon fibre at the dorsal part of the orthosis). All orthoses were expected to prevent plantarflexion and allow dorsiflexion, thus improving first, second, and third rocker. The orthoses were compared through objective gait analysis, including 3D kinematics and kinetics. All orthoses successfully improved the gait pattern and only small differences were noted between the configurations of the different orthoses. The CFO, however, allowed a more physiological third ankle rocker compared with the Orteam/PLS. Although the PLS ensured the highest correction at the ankle around initial contact, the CFO created a significantly higher maximal hip flexion moment in stance. In general, the results of this study indicated a substantial functional flexibility of the CFO.

How can push-off be preserved during use of an ankle foot orthosis in children with hemiplegia? A prospective controlled study.

Several studies indicated that walking with an ankle foot orthosis (AFO) impaired third rocker. The purpose of this study was to evaluate the effects of two types of orthoses, with similar goal settings, on gait, in a homogeneous group of children, using both barefoot and shoe walking as control conditions. Fifteen children with hemiplegia, aged between 4 and 10 years, received two types of individually tuned AFOs: common posterior leaf-spring (PLS) and Dual Carbon Fiber Spring AFO (CFO) (with carbon fibre at the dorsal part of the orthosis). Both orthoses were expected to prevent plantar flexion, thus improving first rocker, allowing dorsiflexion to improve second rocker, absorbing energy during second rocker, and returning it during the third rocker. The effect of the AFOs was studied using objective gait analysis, including 3D kinematics, and kinetics in four conditions: barefoot, shoes without AFO, and PLS and CFO combined with shoes. Several gait parameters significantly changed in shoe walking compared to barefoot walking (cadence, ankle ROM and velocity, knee shock absorption, and knee angle in swing). The CFO produced a significantly larger ankle ROM and ankle velocity during push-off, and an increased plantar flexion moment and power generation at pre-swing compared to the PLS (<0.01). The results of this study further support the findings of previous studies indicating that orthoses improve specific gait parameters compared to barefoot walking (velocity, step length, first and second ankle rocker, sagittal knee and hip ROM). However, compared to shoes, not all improvements were statistically significant.

Do dynamic and static clinical measurements correlate with gait analysis parameters in children with cerebral palsy?

The present study documents the correlation between gait analysis data and clinical measurements and evaluates the combined predictive value of static and dynamic clinical measurements on gait data of children with cerebral palsy. Two hundred patients were evaluated using a set of measurements of range of motion (ROM), alignment, spasticity, strength and selectivity, and by three-dimensional gait analysis. Fair to moderate correlations were found between clinical measurements and gait data, the overall highest correlation being 0.60. Clinical data of strength and selectivity had the highest degree of significant correlations with gait data, compared to the ROM and spasticity. ROM, spasticity and strength measurements for the hip in the coronal plane and spasticity of rectus femoris most frequently showed fair to moderate correlations to gait data. Time and distance and EMG parameters mainly correlated with strength and selectivity parameters. Unexpectedly, alignment parameters only fairly correlated with hip rotation in stance. Multiple regression analysis revealed that adding dynamic clinical measurements (spasticity, strength and selectivity) to a static model (ROM) enhanced the link between clinical measurements and gait data. The variance of gait parameters was better explained by a combined model of static and dynamic clinical measurements, compared to a purely static model. However, R(2)-values were low. Gait analysis data cannot be sufficiently predicted by a combination of clinical measurements. The independence of the measurements supports the notion that both, clinical examination and gait analysis data provide important information for delineating the problems of children with CP.