Muscle Stiffness In Children Research Articles

Impact of lower muscle stiffness on ankle dorsiflexion restriction in children with cerebral palsy evaluated using ultrasound elastography

BackgroundPlantar flexor muscles always contribute to limiting the range of motion of ankle dorsiflexion in children with spastic cerebral palsy, but the individual contributions of these muscles are not well defined. This study aimed to identify which muscles' stiffness impacts the dorsiflexion range of motion in children with cerebral palsy. MethodsTwenty-five children with cerebral palsy were included. The maximum passive dorsiflexion range of motion was measured in two positions: hip and knee joints in flexion, and both joints in full extension. Strain ratios indicating muscle stiffness were measured using strain elastography of the lateral and medial gastrocnemius, soleus, flexor hallucis longus, peroneus longus, peroneus brevis, and tibialis posterior muscles. To analyze which muscles impact the limitation of the dorsiflexion range, multiple regression analyses were conducted. The values of muscle stiffness were included as independent valuables, and the values of the dorsiflexion range were included as dependent valuables. A p-value <0.05 was considered statistically significant. FindingsIn the analyses, the soleus and flexor hallucis longus muscle stiffness were significant independent factors for the dorsiflexion range of motion of hip and knee flexion (adjusted R2: 0.50). The lateral gastrocnemius muscle stiffness was a significant independent factor for the dorsiflexion range of motion with both joints in full extension (adjusted R2: 0.61). InterpretationFlexor hallucis longus muscle stiffness, in addition to triceps surae muscle stiffness, was shown to impact dorsiflexion range; attention should be paid to muscle stiffness in children with cerebral palsy.

Functional level and its relationship to upper extremity function, pain, and muscle stiffness in children with Duchenne muscular dystrophy.

The progressive symptoms of Duchenne muscular dystrophy (DMD) negatively affect upper extremity skills, and this may have an effect that reduces the independence of daily life. The purpose of this study is to investigate the relationship between functional level and upper extremity function, pain, and stiffness in children with DMD. A total of 38 children with DMD were participated. The functional level of the upper and lower extremities was assessed using Brooke scale and Vignos scale. Upper extremity function, pain and stiffness were assessed using Upper Limb Short Questionnaire (ULSQ). The correlation between ULSQ and Brooke and Vignos scales was calculated. A moderate positive correlation was calculated between ULSQ total scores and Vignos scale (r = 0.52, p < 0.001) and Brooke scale (r = 0.65, p < 0.001). There was a moderate positive correlation between Vignos scale scores and ULSQ subscores of function (r = 0.42, p < 0.05) and stiffness (r = 0.56, p < 0.001); no significant correlation was found between pain scores and Vignos scale (p = 0.053). There was a moderate positive correlation between the function (r = 0.54, p < 0.001), pain (r = 0.40, p < 0.05), and stiffness (r = 0.62, p < 0.001) subscores of the ULSQ with the Brooke scale. In our study, there was a significant relationship between the functional level of patients with DMD and upper extremity function, pain, and muscle stiffness.

Muscle stiffness of the rectus femoris and vastus lateralis in children with Osgood–Schlatter disease

BackgroundThe relevance of the mechanical properties of muscles in relation to Osgood–Schlatter disease (OSD) remains unclear. The present study aimed to examine rectus femoris (RF) and vastus lateralis (VL) muscle stiffness in children with OSD. MethodsA total of 28 legs affected by OSD and 26 legs without OSD were assessed. The shear-wave velocity (SWV) of the RF and VL (in m/s) during passive knee flexion (0° (i.e., fully extended position), 45°, and 90° knee joint flexion) and isometric contraction (50% of maximal voluntary contraction) was measured using shear-wave elastography. ResultsThe SWV of the RF was higher in subjects with OSD than in those without OSD at 45° and 90° flexion (P = 0.033 and P = 0.035, respectively); however, the SWV of the RF did not significantly differ at 0° flexion (P = 0.469). Similarly, the SWV of the VL exhibited no significant difference between the tested groups (P > 0.05). No significant difference in the SWV of both muscles during isometric contraction was observed between the two groups (P > 0.05). ConclusionsThe results suggest that a stiffer RF under stretched conditions (45° and 90° flexion) is related to the presence of OSD. Furthermore, both muscles under unstretched and contracted conditions and the VL under stretched conditions have limited association with the presence of OSD. These results have important implications for understanding the association between the mechanical properties of muscles and OSD.

Effects of tDCS on Muscle Stiffness in Children with Cerebral Palsy Measured by Myotonometry: A Preliminary Study

Background: The aim of this study was to investigate the influence of transcranial direct current stimulation (tDCS) on the biceps brachii and flexor carpi radialis stiffness in children with cerebral palsy (CP). The authors also aimed to verify the relationship between spasticity and muscle stiffness. Methods: Twelve children with CP (mean ± SD; age, 8 ± 1.3 years; height, 118.7 ± 4.1 cm; weight, 23.0 ± 2.2 kg) were involved in the study. Muscle stiffness was estimated using a MyotonPRO device in a MultiScan pattern of five measurements. Simultaneously, the tDCS stimulation was performed. Spasticity was assessed by a neurologist using the Ashworth Scale. Results: Stiffness of the flexor carpi radialis muscle decreased significantly after tDCS therapy (p = 0.04). There was no significant change in stiffness of the biceps brachii. For all participants, the Spearman rank correlation showed statistically significant and positive relationships between muscle stiffness and the Ashworth Scale (p = 0.04). Conclusions: Transcranial direct current stimulation has a decreasing effect on stiffness and spasticity of the flexor carpi radialis in children with CP. The MyotonPRO device provides objective data and correlates with spasticity measurements.

Use of ultrasound shear wave to measure muscle stiffness in children with cerebral palsy.

Cerebral palsy (CP) is a disorder characterized by an increased muscle stiffness that can be contingent on both neurological and biomechanical factors. The neurological aspects are related to hyper-excitability of the stretch reflex, while the biomechanical factors are related to modifications in muscle structure. We used smart-shear wave elastography (S-SWE) to analyze muscle properties and to compare shear wave speed in soleus muscles of patients affected by CP and typically developing children. We enrolled 21 children (15 males and 6 females; age range 3-16) with spastic hemiplegia CP and 21 healthy children (11 males and 10 females; age range 3-14). Measurements of soleus S-SWE were performed using a Samsung RS80A ultrasound scanner with Prestige equipment (Samsung Medison Co. Ltd., Seoul, Korea), with a convex array transducer (CA1-7; Samsung Medison Co. Ltd., Seoul, Korea). For each CP child clinical assessment included Modified Ashworth Scale (MAS) score. Children with CP showed greater S-SWE values than the healthy ones (p < 0.001). Our data suggest a significant correlation between the S-SWE values and the MAS scores (Spearman correlation coefficient 0.74; p < 0.001 at Kruskal-Wallis test) in children with CP. Measuring muscle properties with SWE, a non-invasive and real-time technique, may integrate the physical exam. SWE may be a reliable clinical tool for diagnosis and longitudinal monitoring of muscle stiffness, as well as particularly suitable for grading and for assessing the response to treatments.

Quantifying Effect of Onabotulinum Toxin A on Passive Muscle Stiffness in Children with Cerebral Palsy Using Ultrasound Shear Wave Elastography.

A pilot study was conducted to longitudinally quantify effect of onabotulinum toxin A (BoNT-A) on passive muscle properties in children with cerebral palsy using ultrasound shear wave elastography. This was a prospective longitudinal cohort study. Between 1 and 3 mos post-BoNT-A, a significant improvement in the shear modulus of the lateral gastrocnemius was found at 10-degrees plantar flexion (PF) (-7.57 [-10.98, -5.07], P = 0.02) and 0-degrees PF (-14.74 [-18.21, -9.38], P = 0.03). There was a notable, but nonsignificant, difference in shear modulus at 20-degrees PF, 10-degrees PF, and 0-degrees PF between pre-BoNT-A and 1 mo post-BoNT-A. Pre-BoNT-A shear modulus was not significantly different from 3 mos post-BoNT-A at all foot positions. No significant differences in ankle passive range of motion or spasticity were found. Despite no significant change in ankle range of motion or spasticity, shear wave elastography was able to detect a difference in lateral gastrocnemius passive muscle properties in children with cerebral palsy after BoNT-A injections. The difference in passive muscle properties resolved by 3 mos post-BoNT-A.

Therapeutic effects of anti-gravity treadmill (AlterG) training on reflex hyper-excitability, corticospinal tract activities, and muscle stiffness in children with cerebral palsy.

We aimed to study therapeutic effects of antigravity treadmill (AlterG) training on reflex hyper-excitability, muscle stiffness, and corticospinal tract (CST) function in children with spastic hemiplegic cerebral palsy (CP). Three children received AlterG training 3 days per week for 8 weeks as experimental group. Each session lasted 45 minutes. One child as control group received typical occupational therapy for the same amount of time. We evaluated hyper-excitability of lower limb muscles by H-reflex response. We quantified muscle stiffness by sonoelastography images of the affected muscles. We quantified CST activity by transcranial magnetic stimulation (TMS). We performed the evaluations before and after training for both groups. H response latency and maximum M-wave amplitude were improved in experimental group after training compared to control group. Two children of experimental group had TMS response. Major parameters of TMS (i.e. peak-to-peak amplitude of motor evoked potential (MEP), latency of MEP, cortical silent period, and intensity of pulse) improved for both of them. Three parameters of texture analysis of sonoelastography images were improved for experimental group (i.e. contrast, entropy, and shear wave velocity). These findings indicate that AlterG training can improve reflexes, muscle stiffness, and CST activity in children with spastic hemiplegic CP and can be considered as a therapeutic tool to improve neuromuscular abnormalities occurring secondary to CP.

Shear wave elastography for the assessment of muscle stiffness in children with CP: insights and challenges.

This commentary is on the original article by Brandenburg et al. on pages 1288–1294 of this issue.

Quantifying passive muscle stiffness in children with and without cerebral palsy using ultrasound shear wave elastography.

The aim of this study was to compare passive muscle stiffness in children with cerebral palsy (CP) and children with typical development using a novel ultrasound technique: ultrasound shear wave elastography (SWE). We conducted a prospective study of 13 children with CP (six females and seven males, median age 5y 1mo [interquartile range 4y 4mo-7y 8mo]) and 13 children with typical development (six females and seven males, median age 5y 3mo [interquartile range 4y 4mo-9y 4mo]). Demographic information and physical exam measurements were obtained in addition to shear modulus measurements (passive muscle stiffness) of the lateral gastrocnemius muscle at 20° plantar flexion, 10° plantar flexion, and 0° plantar flexion using SWE. Children with CP had significantly greater shear modulus measurements at all three foot positions (p<0.050). When the shear modulus values were normalized to the baseline value for each child, there was no significant difference between the two groups. Passive muscle stiffness, measured without the influence of spasticity, is greater in children with CP than in children with typical development when a muscle is at slack and at stretch. When shear modulus was normalized, the results indicate that muscle in children in both groups responds similarly to passive stretch. Further work includes evaluating effect of botulinum toxin on passive muscle properties.

Feasibility and reliability of quantifying passive muscle stiffness in young children by using shear wave ultrasound elastography.

The purpose of this study was to investigate the feasibility and reliability of passive muscle stiffness measurements in children by shear wave ultrasound elastography. We conducted a prospective cross-sectional study quantifying the passive stiffness of bilateral lateral gastrocnemius muscles during passive stretching in 20 typically developing children (age range, 2.0-12.6 years). Data collected included passive stiffness of the lateral gastrocnemius muscle (shear modulus in kilopascals) at 4 positions of progressive passive foot dorsiflexion, demographic characteristics of the participants, and comparison of demographic characteristics with the shear modulus. Passive stiffness increased with increasing stretching (mean [SD] range of stiffness, 7.1 [2.0] to 36.2 [22.0] kPa). For all 4 foot positions, no significant difference was found between right and left legs (range, P = .42 to P = .98) or between the sexes (range, P = .28 to P > .99). No correlation of passive muscle stiffness with age, body mass index, or ankle range of motion was found. The reliability of measurements was good to excellent (mean [95% confidence interval] range of reliability, 0.67 [0.44-0.83] to 0.80 [0.63-0.90]). Measurements of passive stiffness of the lateral gastrocnemius muscle are feasible and reliable in children as young as 2 years. Because this study found no significant difference between sex and the side tested in this age group, future studies involving children of this age range may not need to be stratified on the basis of these parameters. Defining normal passive muscle stiffness in children is critical for identifying and understanding the implications of abnormal passive muscle stiffness in children with neuromuscular disorders.

Measurement of Muscle Stiffness in Children with Spastic Cerebral Palsy

Editor: We read with great interest the article in the June 2012 issue of Radiology by Kwon and colleagues (1), who used sonoelastography to demonstrate a difference in stiffness of the medial gastrocnemius muscle between healthy children and those with spastic cerebral palsy. The authors provided a new insight about biomechanical assessment of spasticity in addition to the neurophysiologic aspect. Measurement of muscle stiffness may be more complicated than measurements of the tendons or the plantar fascia (2) because more factors must be controlled. We note that the authors performed sonoelastography while subjects were in a prone position with feet hanging from the edge, but no information was provided regarding the angle of the ankle when performing the measurement. Stiffness of the biarticular gastrocnemius muscle may be increased when the ankle is in dorsiflexion and decreased when the ankle is in plantar flexion. Furthermore, although the authors discontinued scanning whenever reflexive or voluntary contraction of the lower limbs muscle was apparently visualized, application of surface electromyography can provide the solid evidence of muscle relaxation. Spasticity was not defined clearly in the article (1). The definition of spasticity has been widened to “disordered sensorimotor control, resulting from an upper motor neuron lesion, presenting as intermittent or sustained involuntary activations of muscles” (3). Because the modified Ashworth scale (MAS) simply measures muscle resistance to passive movement, which has been described as a grading of muscle stiffness (4), it is reasonable that the authors found significant correlations between the MAS scores and sonoelastographic parameters. However, the MAS is unable to help differentiate between the neural and peripheral contributions. The stiffer gastrocnemius muscle in these children with cerebral palsy may indicate muscle atrophy or fibrosis but has nothing to do with spasticity.

Measurement of muscle stiffness using robotic assisted gait orthosis in children with cerebral palsy: a proof of concept

Purpose. To evaluate the feasibility and reliability of a novel stiffness assessment tool implemented in the driven gait orthosis Paediatric Lokomat; to investigate the influence of single robotic-assisted gait training (RAGT) on muscle stiffness in children with cerebral palsy (CP).Methods. Ten children with spastic CP conducted a single standard RAGT session and stiffness was assessed before and after the RAGT. Nine of the ten subjects were tested twice on the same day to investigate test–retest reliability, intraclass correlation coefficients (ICCs), standard error of measurement (SEM), coefficient of variation of the method error (CVME) and resistive torques during passive leg movements (stiffness in Nm/°) were calculated.Results. ICCs showed high reliability (0.83–0.97) for hip and knee movements. SEM and CVME indicated 0.028–0.085 Nm/°, 9.5–23.0% of test–retest variability in hip and 0.018–0.064 Nm/°, 13.3–43.5% in knee measures. Using the assessment tool, a significant decrease in muscle stiffness in participants, especially in children with high levels of muscle tone, could be shown after a single session of RAGT.Conclusions. The assessment tool L-STIFF is a feasible tool for automated measurement of stiffness in children with CP, but it is not sensitive enough to record small changes in muscle tone.