Quantitative parameters to define the angle and severity of the catch in children with spastic cerebral palsy (original) (raw)
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Comprehensive quantification of the spastic catch in children with cerebral palsy
Research in Developmental Disabilities, 2013
In clinical settings, the spastic catch is judged subjectively. This study assessed the psychometric properties of objective parameters that define and quantify the severity of the spastic catch in children with cerebral palsy (CP). A convenience sample of children with spastic CP (N=46; age range: 4-16 years) underwent objective spasticity assessments. High velocity, passive stretches were applied to the gastrocnemius (GAS) and medial hamstrings (MEH). Muscle activity was measured with surface electromyography (sEMG), joint angle characteristics using inertial sensors and reactive torque using a force sensor. To test reliability, a group of 12 children were retested after an average of 13 ± 9 days. The angle of spastic catch (AOC) was estimated by three biomechanical definitions: joint angle at (1) maximum angular deceleration; (2) maximum change in torque; and (3) minimum power. Each definition was checked for reliability and validity. Construct and clinical validity were evaluated by correlating each AOC definition to the averaged root mean square envelope of EMG (RMS-EMG) and the Modified Tardieu Scale (MTS). Severity categories were created based on selected parameters to establish face validity. All definitions showed moderate to high reliability. Significant correlations were found between AOC3 and the MTS of both muscles and the RMS-EMG of the MEH, though coefficients were only weak. AOC3 further distinguished between mild, moderate and severe catches. Objective parameters can define and quantify the severity of the spastic catch in children with CP. However, a comprehensive understanding requires the integration of both biomechanical and RMS-EMG data.
PLoS ONE, 2014
The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP) these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.863.8 yrs; bilateral/unilateral involvement n = 32/22; Gross Motor Functional Classification Score I-IV) of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG) from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG) compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle-and subject-specific (p,0.01). The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between incremental position zones during low velocity stretches was found to be the most sensitive in categorizing muscles into activation patterns (p,0.01). Future studies should investigate whether muscles with different patterns react differently to treatment.
A method for quantifying dynamic muscle dysfunction in children and young adults with cerebral palsy
Gait & Posture, 2007
Cerebral palsy (CP) is caused by a lesion to the brain resulting in adaptations to the structure and function of the muscles and compromised mobility. Spastic cerebral palsy is commonly assessed by the limb kinematics and kinetics measured in a gait laboratory. However, these measures do not directly quantify the patterns of muscle dysfunction that occur during movements. Recent studies have shown that electromyographic (EMG) signals from children with CP have abnormal magnitude, timing and frequency content. Here we demonstrate how wavelet decomposition of the EMG signals into time-frequency space coupled to principal component analysis of the EMG spectra can be used as a powerful tool to quantify the patterns of muscle dysfunction. Data were compared between 17 children with spastic diplegic CP and 36 asymptomatic controls for the rectus femoris, semimembranosus, medial gastrocnemius and tibialis anterior muscles. CP muscle generated higher mean EMG frequencies. Imbalances in activity between the tibialis anterior and medial gatrocnemius contributed to equinus ankle during the swing phase. Patterns of co-activations between antagonistic muscles differed between CP and asymptomatic patients and were EMG frequency dependent. Muscle dysfunction was greater in the distal compared to the proximal lower limb. Muscle dysfunction between the tibialis anterior and medial gastrocnemius was distinguished with 96% sensitivity at 95% specificity. #
Validation of a New Biomechanical Model to Measure Muscle Tone in Spastic Muscles
Neurorehabilitation and Neural Repair, 2011
Background. There is no easy and reliable method to measure spasticity, although it is a common and important symptom after a brain injury. Objective. The aim of this study was to develop and validate a new method to measure spasticity that can be easily used in clinical practice. Methods. A biomechanical model was created to estimate the components of the force resisting passive hand extension, namely ( a) inertia (IC), ( b) elasticity (EC), ( c) viscosity (VC), and ( d) neural components (NC). The model was validated in chronic stroke patients with varying degree of hand spasticity. Electromyography (EMG) was recorded to measure the muscle activity induced by the passive stretch. Results. The model was validated in 3 ways: ( a) NC was reduced after an ischemic nerve block, ( b) NC correlated with the integrated EMG across subjects and in the same subject during the ischemic nerve block, and ( c) NC was velocity dependent. In addition, the total resisting force and NC correlated wi...
INTRODUCTION. Due to the heterogeneous clinical presentation of spastic cerebral palsy (SCP), which makes spasticity treatment challenging, more insight into the complex interaction between spasticity and altered muscle morphology is warranted. AIMS. We studied associations between spasticity and muscle morphology and compared muscle morphology between commonly observed spasticity patterns (i.e. different muscle activation patterns during passive stretches). METHODS. Spasticity and muscle morphology of the medial gastrocnemius (MG) and semitendinosus (ST) were defined in 74 children with SCP (median age 8 years 2 months, GMFCS I/II/III: 31/25/18, bilateral/unilateral: 46/27). Using an instrumented assessment, spasticity was quantified as the difference in muscle activation recorded during passive stretches at low and high velocities and was classified in mixed length-/velocity-dependent or pure velocity-dependent activation patterns. Three-dimensional freehand ultrasound was used to assess muscle morphology (volume and length) and echogenicity intensity (as a proxy for muscle quality). Spearman correlations and Mann-Whitney-U tests defined associations and group differences, respectively. RESULTS. A moderate negative association (r=-0.624, p<0.001) was found between spasticity and MG muscle volume, while other significant associations between spasticity and muscle morphology parameters were weak. Smaller normalized muscle volume (MG p=0.004, ST p=<0.001) and reduced muscle belly length (ST p=0.015) were found in muscles with mixed length-/velocity-dependent patterns compared to muscles with pure velocity-dependent patterns. DISCUSSION. Higher spasticity levels were associated with smaller MG and ST volumes and shorter MG muscles. These muscle morphology alterations were more pronounced in muscles that activated during low-velocity stretches compared to muscles that only activated during high-velocity stretches.
Relationship of spasticity to knee angular velocity and motion during gait in cerebral palsy
Gait & Posture, 2006
This study investigated the effects of spasticity in the hamstrings and quadriceps muscles on gait parameters including temporal spatial measures, knee position, excursion and angular velocity in 25 children with spastic diplegic cerebral palsy (CP) as compared to 17 agematched peers. While subjects were instructed to relax, an isokinetic device alternately flexed and extended the left knee at one of the three constant velocities 308/s, 608/s and 1208/s, while surface electromyography (EMG) electrodes over the biceps femoris and the rectus femoris recorded muscle activity. Patients then participated in 3D gait analysis at a self-selected speed. Results showed that, those with CP who exhibited heightened stretch responses (spasticity) in both muscles, had significantly slower knee angular velocities during the swing phase of gait as compared to those with and without CP who did not exhibit stretch responses at the joint and the tested speeds. The measured amount (torque) of the resistance to passive flexion or extension was not related to gait parameters in subjects with CP; however, the rate of change in resistance torque per unit angle change (stiffness) at the fastest test speed of 1208/s showed weak to moderate relationships with knee angular velocity and motion during gait. For the subset of seven patients with CP who subsequently underwent a selective dorsal rhizotomy, knee angular extension and flexion velocity increased post-operatively, suggesting some degree of causality between spasticity and movement speed. # . Mean stiffness in the hamstrings muscles, calculated as the slope of the torque  angle curve, at the isokinetic velocity of 1208/s plotted for the subgoups with hamstring + quadriceps spasticity, hamstring spasticity only, the CP group with no hamstring or quadriceps spasticity, and the non-CP comparison group.
Characterization of spasticity in cerebral palsy: dependence of catch angle on velocity
Developmental Medicine & Child Neurology, 2010
Modified Ashworth scale MSE Manual spasticity evaluator ROM Range of motion AIM To evaluate spasticity under controlled velocities and torques in children with cerebral palsy (CP) using a manual spasticity evaluator. METHOD The study involved 10 children with spastic CP (six males, four females; mean age 10y 1mo, SD 2y 9mo, range 7-16y; one with quadriplegia, six with right hemiplegia, three with left hemiplegia; Gross Motor Function Classification System levels I [n=2], II [n=3], III [n=2], IV [n=2], and V [n=1]; Manual Ability Classification System levels II [n=5], III [n=4], and V [n=1]
Musculoskeletal Science and Practice, 2017
Background Normalizing to a reference signal is essential when analysing and comparing electromyography signals across or within individuals. However, studies have shown that MVC testing may not be as reliable in persons with acute and chronic pain. Objectives The purpose of this study was to compare the test-retest reliability of the muscle activity in the biceps femoris and gluteus maximus between a novel sub-MVC and standard MVC protocols. Methods This study utilised a single individual repeated measures design with 12 participants performing multiple trials of both the sub-MVC and MVC tasks on two separate days. The participant position in the prone leg raise task was standardised with an ultrasonic sensor to improve task precession between trials/days. Dayto-day and trial-to-trial reliability of the maximal muscle activity was examined using ICC and SEM. Findings Day-today and trial-to-trial reliability of the EMG activity in the BF and GM were high (0.70-0.89) to very high (≥0.90) for both test procedures. %SEM was <5-10% for both tests on a given day but higher in the day-today comparisons. The lower amplitude of the sub-MVC is a likely contributor to increased %SEM (8-13%) in the day-today comparison. Conclusions The findings show that the sub-MVC modified prone double leg raise results in GM and BF EMG measures similar in reliability and precision to the standard MVC tasks. Therefore, the modified prone double leg raise may be a useful substitute for traditional MVC testing for normalizing EMG signals of the BF and GM.
Neurorehabilitation
The aim of this study was to investigate the intra-rater reliability of the Modified Modified Ashworth Scale (MMAS) in the upper limb of patients with hemiparesis and to determine the effect of pain and contracture presence on the reliability of the MMAS. For this test-retest study 30 patients with hemiparesis were included. One physiotherapist using the MMAS, randomly rated the spasticity of shoulder adductors, elbow flexors, and wrist flexors in the affected upper limb of each patient with hemiparesis twice with at least a 1 week interval between testing sessions. The presence of pain and contracture during passive stretch was recorded. The magnitude of the contracture was measured by a goniometer. The quadratic weighted kappa statistics was very good for the upper limb spasticity (κw= 0.84). Intra-rater reliability was good for shoulder adductors (κw=0.75), and very good for elbow flexors and wrist flexors (κw 0.86 and 0.90, respectively). There were no differences between the we...