Cerebral Palsy

SSM Lee, D Gaebler-Spira, LQ Zhang, WZ Rymer, KM Steele, (2016) “Use of shear wave ultrasound elastography to quantify muscle properties in cerebral palsy.” Clinical Biomechanics

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Sample ultrasound images from gastrocnemius and tibialis anterior showing greater shear wave velocity on more affected limb.

Journal article in Clinical Biomechanics:

Kat Steele partnered with Sabrina Lee from Northwestern University and the Rehabilitation Institute of Chicago to investigate shearwave ultrasound elastography as a new tool to quantify changes in muscle properties in cerebral palsy.

Sample ultrasound images from gastrocnemius and tibialis anterior showing greater shear wave velocity on more affected limb.Abstract: Individuals with cerebral palsy tend to have altered muscle architecture and composition, but little is known about the muscle material properties, specifically stiffness. Shear wave ultrasound elastography allows shear wave speed, which is related to stiffness, to be measured in vivo in individual muscles. Our aim was to evaluate the material properties, specifically stiffness, as measured by shear wave speed of the medial gastrocnemius and tibialis anterior muscles in children with hemiplegic cerebral palsy across a range of ankle torques and positions, and fascicle strains. Shear wave speed was measured bilaterally in the medial gastrocnemius and tibialis anterior over a range of ankle positions and torques using shear wave ultrasound elastography in eight individuals with hemiplegic cerebral palsy. B-mode ultrasound was used to measure muscle thickness and fascicle strain. Shear waves traveled faster in the medial gastrocnemius and tibialis anterior of the more-affected limb by 14% (P = 0.024) and 20% (P = 0.03), respectively, when the ankle was at 90°. Shear wave speed in the medial gastrocnemius increased as the ankle moved from plantarflexion to dorsiflexion (less affected: r2 = 0.82, P < 0.001; more-affected: r2 = 0.69, P < 0.001) and as ankle torque increased (less affected: r2 = 0.56,P < 0.001; more-affected: r2 = 0.45, P < 0.001). In addition, shear wave speed was strongly correlated with fascicle strain (less affected: r2 = 0.63, P < 0.001; more-affected: r2 = 0.53, P < 0.001). The higher shear wave speed in the more-affected limb of individuals with cerebral palsy indicates greater muscle stiffness, and demonstrates the clinical potential of shear wave elastography as a non-invasive tool for investigating mechanisms of altered muscle properties and informing diagnosis and treatment.

Two NIH R01 Grants Funded

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NIH logoThe Ability & Innovation Lab is excited to announce that two of our recent grant proposals have been funded! This funding will help to accelerate our mission to improve movement for individuals with neurologic disorders.

Quantifying patient-specific changes in neuromuscular control in cerebral palsy: Funded by the National Institute of Neurological Disorders and Stroke, this research will examine how new measures of neuromuscular control can be used to better predict outcomes after multi-level orthopaedic surgery for individuals with cerebral palsy. We will be working in close partnership with Gillette Children’s Specialty Healthcare, one of the leading institutions in the management of pediatric neurological disorders. This research will address the challenge of identifying the best treatment for each individual. Cerebral palsy is caused by a brain injury and every brain injury is unique. We will be using new measures from muscle synergy analysis (see prior work here) to determine how patient-specific measures of control can be used to predict outcomes after surgery.

Ubiquitous rehabilitation to improve movement after neurologic injury: Funded by the joint NSF-NIH Smart & Connected Health Initiative, this research will work in partnership with the University of Texas at Austin to use flexible electrodes to track and train muscle activity after stroke and other neurologic injuries. We know that more practice and use after brain injury increases long-term recovery and function. This research will investigate new pathways for both motivating patients to re-learn to use their muscle and providing doctors and therapists with the data and insight needed to guide and customize therapy.

KM Steele, A Rozumalski, MH Schwartz (2015) “Muscle synergies and complexity of neuromuscular control during gait in cerebral palsy.” Developmental Medicine & Child Neurology

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WalkDMC decreased with GMFCS level among individuals with cerebral palsy.

Journal article accepted in Developmental Medicine & Child Neurology:

Kat Steele partnered with Mike Schwartz and Adam Rozumalski of Gillette Children’s Specialty Healthcare to complete one of the largest studies to date of individuals with cerebral palsy. They quantified how neuromuscular control is altered among individuals with cerebral palsy and how this altered control can contribute to impaired function.

WalkDMC decreased with GMFCS level among individuals with cerebral palsy.

Abstract: Individuals with cerebral palsy (CP) have impaired movement due to a brain injury near birth. Understanding how neuromuscular control is altered in CP can provide insight into pathological movement. We sought to determine if individuals with CP demonstrate reduced complexity of neuromuscular control during gait compared with unimpaired individuals and if changes in control are related to functional ability. Muscle synergies during gait were retrospectively analyzed for 633 individuals (age range 3.9–70y): 549 with CP (hemiplegia, n=122; diplegia, n=266; triplegia, n=73; quadriplegia, n=88) and 84 unimpaired individuals. Synergies were calculated using non-negative matrix factorization from surface electromyography collected during previous clinical gait analyses. Synergy complexity during gait was compared with diagnosis subtype, functional ability, and clinical examination measures. Fewer synergies were required to describe muscle activity during gait in individuals with CP compared with unimpaired individuals. Changes in synergies were related to functional impairment and clinical examination measures including selective motor control, strength, and spasticity. Interpretation: Individuals with CP use a simplified control strategy during gait compared with unimpaired individuals. These results were similar to synergies during walking among adult stroke survivors, suggesting similar neuromuscular control strategies between these clinical populations. PDF

Also, make sure you look at the commentary from Diane Damiano. She provides perspective about the utility of synergies for evaluating neuromuscular control in children with cerebral palsy and future challenges.

KM Steele, A Rozumalski, MH Schwartz, “Altered muscle synergies during gait in cerebral palsy are not due to altered kinematics or kinetics.” International Society of Biomechanics (Glasgow, UK) July 15, 2015.

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International Society of Biomechanics LogoKat Steele presented our recent work on altered synergies during gait in cerebral palsy and the impact of altered gait patterns at the International Society of Biomechanics conference on July 15, 2015 in Glasgow, Ireland.

MH Schwartz, A Rozumalski, KM Steele, “Dynamic motor control during walking predicts treatment outcomes in cerebral palsy.” International Society of Biomechanics (Glasgow, UK) July 13, 2015.

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International Society of Biomechanics LogoKat Steele & Mike Schwartz presented their research demonstrating that synergies measured from EMG are predictive of post-operative outcomes after botulinum toxin injections, selective dorsal rhizotomy, and multi-level orthopaedic surgery. These results will support future research to determine if synergies can be used clinically to quantify patient-specific changes in control and guide treatment planning.

International Society of Biomechanics conference on July 13, 2015 in Glasgow, Ireland.