Browsing by Person "Balzer, Julia"

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Construct validity and reliability of the Selective Control Assessment of the Lower Extremity in children with cerebral palsy
(Blackwell, 2016-02) Balzer, Julia; Marsico, P.; Mitteregger, E.; van der Linden, Marietta; Mercer, Tom; van Hedel, H.
AIM: Assessing impaired selective voluntary movement control in children with cerebral palsy (CP) has gained increasing interest. We investigated construct validity and intra- and interrater reliability of the Selective Control Assessment of the Lower Extremity (SCALE). METHOD: Thirty-nine children (21 males, 18 females) with spastic CP, mean age 12 years 6 months [range 6y 11mo-19y 9mo], Gross Motor Function Classification System (GMFCS) levels I to IV, participated. Differences in SCALE scores were determined on joint levels and between patients categorized according to their limb distribution and GMFCS levels. SCALE scores were correlated with the Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale. To determine reliability, the SCALE was applied once and recorded on video. RESULTS: SCALE scores differed significantly between the less and more affected leg (p<0.001) and between most leg joints. Total SCALE scores differed significantly between GMFCS levels I and II. Correlations with Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale were 0.88, 0.88, and -0.55 respectively. Intraclass correlation coefficients were all above 0.9, with the minimal detectable change below 2 points. INTERPRETATION: The SCALE appears to be a valid and reliable tool to assess selective voluntary movement control of the legs in children with spastic CP.
DETERMINING SELECTIVE VOLUNTARY MOTOR CONTROL OF THE LOWER EXTREMITY IN CHILDREN WITH CEREBRAL PALSY
(2018) Balzer, Julia
For physiotherapists working in neuro-paediatric gait-rehabilitation, improving motor control of the lower extremity is a major focus. Nevertheless, our understanding of selective voluntary motor control (SVMC) is in its infancy. This PhD project aimed to contribute to close this gap by investigating the nature of SVMC of the lower extremity in children with cerebral palsy (CP) and providing a psychometric robust yet sensitive measurement instrument for quantifying SVMC. The first study investigated the influence of SVMC and other lower extremity and trunk motor impairments on gait capacity using multiple regression-analyses. Although SVMC was not kept within the final model, these study results revealed the importance of SVMC in relation to muscle strength, trunk control and gait capacity. The aim of the second study was to establish validity and reliability of the German version of the ‘Selective Control Assessment of the Lower Extremity’ (SCALE). Although the psychometric properties of the German SCALE were good, information about its responsiveness is lacking. Accordingly, a systematic review was carried out to identify a SVMC measurement instrument with the highest level of evidence for its psychometric properties and best clinical utility. As the findings showed the absence of appropriate, responsive SVMC measures, the aim of the last study was to modify the existing SCALE to make it more sensitive. Due to the positive findings in relation to the psychometric properties of the SCALE, its procedure was combined with a surface electromyography Similarity Index (SI). The first validity and reliability results of the SCALE-SI are promising and serve as benchmarks when applying the SCALE-SI in future clinical and scientific practice. However, to use the SCALE-SI as an outcome measure for detecting therapy-induced changes of SVMC in children with CP, its responsiveness needs to be evaluated in future studies. Key Words: cerebral palsy, selective voluntary motor control, psychometric properties, lower extremity, gait rehabilitation
Effects of simulated crouch gait on foot kinematics and kinetics in healthy children
(2013-09) Balzer, Julia; Schelldorfer, S.; Bauer, C.; van der Linden, Marietta
Identification of secondary and tertiary impairments in neurologically induced gait deviations, such as crouch gait, is not always straightforward, but essential in order to decide upon the most efficient medical treatment in patients with cerebral palsy (CP). Until now, exact intersegmental dependency of the development of foot deformities has not been investigated. Therefore, the aim of this study was to explore if an artificially induced bilateral knee flexion contracture causes compensatory mechanisms in foot motion during gait in healthy children. Three-dimensional kinematic and kinetic data from 30 healthy children (mean age 10.6 years) were derived from the Oxford Foot model (OFM). Participants walked first in an artificially induced crouch gait (limitation of knee extension to 40) and then normally. Walking speed was kept the same in both conditions. Analysis revealed small but significant (p < 0.05) differences between the two conditions in hindfoot and forefoot kinematics in all three planes during the stance phase as well as for all peak internal moments within the foot. In general the foot tended to compensate for an artificial knee flexion contracture with an increase in maximal dorsiflexion, eversion and external rotation of the hindfoot, which also allowed increased foot motion in other foot segments. The results of this study showed that an isolated proximal joint contracture had an influence on foot position during stance in healthy children. Further interpretation of the data in relation to CP children will be possible as soon as comparable OFM data of pathological crouch gait is available. 2013 Elsevier B.V. All rights reserved.
First validation of a novel assessgame quantifying selective voluntary motor control in children with upper motor neuron lesions
(SpringerNature, 2019-12-30) Keller, Jeffrey W.; Balzer, Julia; Fahr, Annina; Lieber, Jan; Keller, Urs; van Hedel, Hubertus J. A.
The question whether novel rehabilitation interventions can exploit restorative rather than compensatory mechanisms has gained momentum in recent years. Assessments measuring selective voluntary motor control could answer this question. However, while current clinical assessments are ordinal-scaled, which could affect their sensitivity, lab-based assessments are costly and time-consuming. We propose a novel, interval-scaled, computer-based assessment game using low-cost accelerometers to evaluate selective voluntary motor control. Participants steer an avatar owl on a star-studded path by moving the targeted joint of the upper or lower extremities. We calculate a target joint accuracy metric, and an outcome score for the frequency and amplitude of involuntary movements of adjacent and contralateral joints as well as the trunk. We detail the methods and, as a first proof of concept, relate the results of select children with upper motor neuron lesions (n = 48) to reference groups of neurologically intact children (n = 62) and adults (n = 64). Linear mixed models indicated that the cumulative therapist score, rating the degree of selectivity, was a good predictor of the involuntary movements outcome score. This highlights the validity of this assessgame approach to quantify selective voluntary motor control and warrants a more thorough exploration to quantify changes induced by restorative interventions.
Influence of trunk control and lower extremity impairments on gait capacity in children with cerebral palsy
(Taylor & Francis, 2017-09-24) Balzer, Julia; Marsico, Petra; Mitteregger, Elena; van der Linden, Marietta; Mercer, Tom; van Hedel, Hubertus J. A.
Purpose: We investigated the combined impact of trunk control and lower extremities impairments on predicting gait capacity in children with cerebral palsy (CP) and evaluated relationships between trunk control and lower extremities impairments. Methods: Data of 52 children with CP [29 boys, mean age 11 years 9 months (±4 years 6 months)] were included in this observational study. Gait capacity was measured by the “modified Time Up and Go test”. Experienced therapists performed the “Modified Ashworth Scale”, “Manual Muscle Test”, the “Selective Control Assessment of the Lower Extremity”, and the “Trunk Control Measurement Scale”. We calculated Spearman correlations coefficients (ρ) and performed regression analyses. Results: Trunk control was the strongest predictor (β = –0.624, p < 0.001) when explaining the variance of gait capacity and remained in the model together with spasticity (R2 = 0.67). Muscle strength and selectivity correlated moderately to strongly with the trunk control and gait capacity (–0.68 ≤ ρ ≤ –0.78), but correlations for the spasticity were low (ρ<–0.3). Conclusions: The interconnection between trunk control, leg muscle strength and selectivity for gait capacity in children with CP was shown. It indicates the significance of these impairments in gait assessment and, potentially, rehabilitation.Implications for RehabilitationTrunk control was the strongest predictor for gait capacity in a regression model with lower extremity spasticity, muscle strength and selectivity and age as independent variables.Lower extremity muscle strength, selectivity, and trunk control explained a similar amount of gait capacity variance which is higher than that explained by lower extremity spasticity.Lower extremity muscle strength and selectivity correlated strongly with trunk control.Therefore, we cautiously suggest that a combined trunk control and lower extremity training might be promising for improving gait capacity in children with CP (Gross Motor Function Classification System level I–III), which needed to be tested in future intervention-studies. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Selective voluntary motor control measures of the lower extremity in children with upper motor neuron lesions: a systematic review
(Wiley, 2017-03-08) Balzer, Julia; van der Linden, Marietta; Mercer, Tom; van Hedel, Hubertus J. A.
Aim: Recovery and trainability of impaired selective voluntary motor control (SVMC) of the lower extremity in children with upper motor neuron lesions has received little attention. To facilitate an evidence-based debate about this topic, this review evaluates the evidence level of the psychometric properties of SVMC measures. Method: MEDLINE, Embase, CINAHL, PsycINFO, Scopus, Cochrane and PEDro databases were systematically searched up to July 2016. Two independent raters scored the methodological quality in accordance to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. The overall level of evidence was scored according to Cochrane criteria. Results: We identified 3590 studies, of which 17 were included. COSMIN scores ranged from 'poor' to 'excellent' for studies investigating measurement properties of the Selective Motor Control test, modified Trost test, Gillette's Selective Motor Control test, Selective Control Assessment of the Lower Extremity (SCALE), kinematic measures, electromyography, and torque steadiness. Studies assessing the SCALE scored highest on COSMIN items. Evidence levels for SCALE's validity and reliability properties were moderate, while for the other SVMC measures these ranged from unknown to moderate. Responsiveness was not assessed. Interpretation: Further psychometric studies of SVMC measures are needed to provide a scientific contribution to the ongoing debate of SVMC trainability. 2017 Mac Keith Press.
Validity and reliability of an accelerometer-based assessgame to quantify upper limb selective voluntary motor control
(BioMed Central, 2020-07-13) Keller, Jeffrey W.; Fahr, Annina; Balzer, Julia; Lieber, Jan; van Hedel, Hubertus J. A.; The Swiss National Science Foundation supported this work (grant numbers 32003B_156646 und 32003B_179471). The funding body did not have a role in designing the study, analyzing or interpreting the data, or writing the manuscript.
Introduction: Current clinical assessments measure selective voluntary motor control (SVMC) on an ordinal scale. We introduce a playful, interval-scaled method to assess SVMC in children with brain lesions and evaluate its validity and reliability. Methods: Thirty-one neurologically intact children (median [1st-3rd quartile]: 11.6 years [8.5–13.9]) and 33 patients (12.2 years [8.8–14.9]) affected by upper motor neuron lesions with mild to moderate impairments participated. Using accelerometers, they played a movement tracking game (assessgame) with isolated joint movements (shoulder, elbow, lower arm [pro−/supination], wrist, and fingers), yielding an accuracy score. Involuntary movements were recorded simultaneously and resulted in an involuntary movement score. Both scores were normalized to the performance of 33 neurologically intact adults (32.5 years [27.9; 38.3]), which represented physiological movement patterns. We correlated the assessgame outcomes with the Manual Ability Classification System, Selective Control of the Upper Extremity Scale, and a therapist rating of involuntary movements. Furthermore, a robust ANCOVA was performed with age as covariate, comparing patients to their healthy peers at the age levels of 7.5, 9, 10.5, 12, and 15 years. Intraclass correlation coefficients and smallest real differences indicated relative and absolute reliability. Results: Correlations (Kendall/Spearman) for the accuracy score were τ = 0.29 (p = 0.035; Manual Ability Classification System), ρ = − 0.37 (p = 0.035; Selective Control of the Upper Extremity Scale), and ρ = 0.64 (p < 0.001; therapist rating). Correlations for the involuntary movement metric were τ = 0.37 (p = 0.008), ρ = − 0.55 (p = 0.001), and ρ = 0.79 (p < 0.001), respectively. The robust ANCOVAs revealed that patients performed significantly poorer than their healthy peers in both outcomes and at all age levels except for the dominant/less affected arm, where the youngest age group did not differ significantly. Robust intraclass correlation coefficients and smallest real differences were 0.80 and 1.02 (46% of median patient score) for the accuracy and 0.92 and 2.55 (58%) for involuntary movements, respectively. Conclusion: While this novel assessgame is valid, the reliability might need to be improved. Further studies are needed to determine whether the assessgame is sensitive enough to detect changes in SVMC after a surgical or therapeutic intervention.
Validity and reliability of an electromyography-based similarity index to quantify lower extremity selective voluntary motor control in children with cerebral palsy
(Elsevier, 2022-03-28) Balzer, Julia; Fahr, Annina; Keller, Jeffrey W.; van der Linden, Marietta; Mercer, Tom; van Hedel, Hubertus J. A.
OBJECTIVE To quantify selective voluntary motor control (SVMC) objectively and more precisely, we combined the “Selective Control Assessment of the Lower Extremity” (SCALE) with surface electromyography. The resulting Similarity Index (SI) measures the similarity of muscle activation patterns. This study evaluated the preliminary validity and reliability of this novel SISCALE measure in children with cerebral palsy (CP).
Validity and reliability of an electromyography-based upper limb assessment quantifying selective voluntary motor control in children with upper motor neuron lesions
(SAGE, 2021-04-19) Keller, Jeffrey W.; Fahr, Annina; Balzer, Julia; Lieber, Jan; van Hedel, Hubertus J. A.
Current clinical assessments evaluating selective voluntary motor control are measured on an ordinal scale. We combined the Selective Control of the Upper Extremity Scale (SCUES) with surface electromyography to develop a more objective and interval-scaled assessment of selective voluntary motor control. The resulting Similarity Index (SI) quantifies the similarity of muscle activation patterns. We aimed to evaluate the validity and reliability of this new assessment named SISCUES (Similarity Index of the SCUES) in children with upper motor neuron lesions. Thirty-three patients (12.2 years [8.8;14.9]) affected by upper motor neuron lesions with mild to moderate impairments and 31 typically developing children (11.6 years [8.5;13.9]) participated. We calculated reference muscle activation patterns for the SISCUES using data of 33 neurologically healthy adults (median [1st; 3rd quantile]: 32.5 [27.9; 38.3]). We calculated Spearman correlations (ρ) between the SISCUES and the SCUES and the Manual Ability Classification System (MACS) to establish concurrent validity. Discriminative validity was tested by comparing scores of patients and healthy peers with a robust ANCOVA. Intraclass correlation coefficients2,1 and minimal detectable changes indicated relative and absolute reliability. The SISCUES correlates strongly with SCUES (ρ = 0.76, p < 0.001) and moderately with the MACS (ρ = −0.58, p < 0.001). The average SISCUES can discriminate between patients and peers. The intraclass correlation coefficient2,1 was 0.90 and the minimal detectable change was 0.07 (8% of patients’ median score). Concurrent validity, discriminative validity, and reliability of the SISCUES were established. Further studies are needed to evaluate whether it is responsive enough to detect changes from therapeutic interventions.