Work by Dr. Steele and Ben Shuman featured in The Daily news post

The team found that of the 473 children who had undergone surgery in their current study, those with higher Walk-DMC scores prior to surgery had better treatment outcomes, even after factoring in age and prior treatment.

The Daily, of the University of Washington, posted an article about Dr. Steele and Ben Shuman’s recent work on predicting cerebral palsy treatment outcomes based on motor modules, or muscle synergies. This work is in partnership with Michael Schwartz at Gillette Children’s Specialty Healthcare.  An excerpt from the article is below. To read the article in full, click here.

Ben Shuman, a PhD student in the Steele Lab, smiles while working with electromyography equipment (EMG). Photo credit: Liam Brozik

 

Walk-DMC – Kat Steele and Michael Schwartz are featured in GeekWire

A staff member of a gait lab kneels next to a child to apply additional motion detecting markers at Gillette Children's Specialty Healthcare. Another staff member sits behind a desk, observing the instrumentation on the lab computer. Photo taken by Michael Schwartz.

GeekWire, a national technology news resource, has featured Dr. Steele and Dr. Schwartz‘s Walk-DMC in a special series focused on community issues and innovative solutions to societal challenges. Lisa Stiffler reports on the analysis that is used to create Walk-DMC, an assessment tool that uses routinely collected electromyography (EMG) data to identify which kids are the strongest candidates for surgery — and to help develop alternative treatments for children needing a different solution.

“It’s a very complex problem,” said Steele, who is a co-author of a paper explaining the Walk DMC metric published this month in the journal Developmental Medicine & Child Neurology. “You can have two individuals who are walking visually nearly identically,” she said, “but how they’re controlling that motion can be very different.”

To read the full article, click HERE.

EE Bulter, KM Steele, L Torburn, JG Gamble, J Rose (2016) “Clinical motion analyses over eight consecutive years in a child with crouch gait: a case report.” Journal of Medical Case Reports

Sagittal-plane images of child from 6-13 years of age.

Journal article in the Journal of Medical Case Reports:

A case study of crouch gait over 8-years in a child with no surgical interventions.

Sagittal-plane images of child from 6-13 years of age.

Background: This case report provides a unique look at the progression of crouch gait in a child with cerebral palsy over an 8-year time period, through annual physical examinations, three-dimensional gait analyses, and evaluation of postural balance. Our patient received regular botulinum toxin-A injections, casting, and physical therapy but no surgical interventions.

Case presentation: A white American boy with spastic diplegic cerebral palsy was evaluated annually by clinical motion analyses, including physical examination, joint kinematics, electromyography, energy expenditure, and standing postural balance tests, from 6 to 13 years of age. These analyses revealed that the biomechanical factors contributing to our patient’s crouch gait were weak plantar flexors, short and spastic hamstrings, moderately short hip flexors, and external rotation of the tibiae. Despite annual recommendations for surgical lengthening of the hamstrings, the family opted for non-surgical treatment through botulinum toxin-A injections, casting, and exercise. Our patient’s crouch gait improved between ages 6 and 9, then worsened at age 10, concurrent with his greatest body mass index, increased plantar flexor weakness, increased standing postural sway, slowest normalized walking speed, and greatest walking energy expenditure. Although our patient’s maximum knee extension in stance improved by 14 degrees at 13 years of age compared to 6 years of age, peak knee flexion in swing declined, his ankles became more dorsiflexed, his hips became more internally rotated, and his tibiae became more externally rotated. From 6 to 9 years of age, our patient’s minimum stance-phase knee flexion varied in an inverse relationship with his body mass index; from 10 to 13 years of age, changes in his minimum stance-phase knee flexion paralleled changes in his body mass index.

Conclusions: The motor deficits of weakness, spasticity, shortened muscle-tendon lengths, and impaired selective motor control were highlighted by our patient’s clinical motion analyses. Overall, our patient’s crouch gait improved mildly with aggressive non-operative management and a supportive family dedicated to regular home exercise. The annual clinical motion analyses identified changes in motor deficits that were associated with changes in the child’s walking pattern, suggesting that these analyses can serve to track the progression of children with spastic cerebral palsy.

Featured in UWToday: Michael Schwartz and Kat Steele have developed a quantitative assessment of motor control in children with cerebral palsy

A child walking in the motion analysis lab at Gillette Children's Specialty Healthcare. Photo by Michael Schwartz.

Our lab’s director, Dr. Kat Steele, and Dr. Michael Schwartz, from Gillette Children’s Specialty Healthcare, have developed a quantitative assessment of motor control in children with cerebral palsy called Walk-DMC, which could be used to help determine whether or not patients would benefit from aggressive, invasive surgeries to assist in walking and motion. Jennifer Langston reports on the new technique within UWToday. An exert from the article is posted below, but for the full article, read HERE.

“Only about 50 percent of children have significant improvement in their movement after these highly invasive surgeries,” said Kat Steele, a UW assistant professor of mechanical engineering. “Our motivation has really been to figure out how we can push up these success rates.”

BR Shuman, M Goudriaan, L Bar-On, MH Schwartz, K Desloovere, KM Steele (2016) “Repeatability of muscle synergies within and between days for typically developing children and children with cerebral palsy.” Gait & Posture.

BR Shuman, M Goudriaan, L Bar-On, MH Schwartz, K Desloovere, KM Steele (2016) “Repeatability of muscle synergies within and between days for typically developing children and children with cerebral palsy.” Gait & Posture.

Journal article in Gait and Posture:

Filtering parameters impact the results from muscle synergy analyses.

Top: Average tVAF for day 1 and day 2 in TD and CP calculated from all measured gait cycles. The LME model identified a significant difference in synergy complexity between TD and CP for n = 1–5 synergies. Bottom: Average tVAF for each of the three walking speeds in TD and CP from both days. Walking speed had a significant effect on synergy complexity for tVAF of 1–5 synergiesAbstract: Muscle synergies are typically calculated from electromyographic (EMG) signals using nonnegative matrix factorization. Synergies identify weighted groups of muscles that are commonly activated together during a task, such as walking. Synergy analysis has become an emerging tool to evaluate neuromuscular control; however, the repeatability of synergies between trials and days has not been evaluated. The goal of this study was to evaluate the repeatability of synergy complexity and structure in unimpaired individuals and individuals with cerebral palsy (CP). EMG data were collected from eight lower-limb muscles during gait for six typically developing (TD) children and five children with CP on two separate days, over three walking speeds. To evaluate synergy complexity, we calculated the total variance accounted for by one synergy (tVAF1). On a given day, the average range in tVAF1 between gait cycles was 18.2% for TD and 19.1% for CP. The average standard deviation in tVAF1 between gait cycles was 4.9% for TD and 5.0% for CP. Average tVAF1 calculated across gait cycles was not significantly different between days for TD or CP participants. Comparing synergy structure, the average (standard deviation) within day correlation coefficients of synergy weights for two or more synergies were 0.89 (0.15) for TD and 0.88 (0.15) for CP. Between days, the average correlation coefficient of synergy weights for two or more synergies was greater than 0.89 for TD and 0.74 for CP. These results demonstrate that synergy complexity and structure averaged over multiple gait cycles are repeatable between days in both TD and CP groups.