Cerebral Palsy Archives - Page 10 of 17 - Neuromechanics & Mobility Lab

BR Shuman, MH Schwartz, KM Steele (2017) “Electromyography Data Processing Impacts Muscle Synergies during Gait for Unimpaired Children and Children with Cerebral Palsy.” Frontiers in Computational Neuroscience

Dr. Steele JournalArticle, MotorControl, Projects, Publications May 19, 2017October 12, 2021Cerebral Palsy, EMG, Gillette, Synergy, UWIN, Walk-DMC

Journal article in Frontiers in Computational Neuroscience:

Filtering parameters impact the results from muscle synergy analyses.

Abstract: Muscle synergies calculated from electromyography (EMG) data identify weighted groups of muscles activated together during functional tasks. Research has shown that fewer synergies are required to describe EMG data of individuals with neurologic impairments. When considering potential clinical applications of synergies, understanding how EMG data processing impacts results and clinical interpretation is important. The aim of this study was to evaluate how EMG signal processing impacts synergy outputs during gait. We evaluated the impacts of two common processing steps for synergy analyses: low pass (LP) filtering and unit variance scaling. We evaluated EMG data collected during barefoot walking from five muscles of 113 children with cerebral palsy (CP) and 73 typically-developing (TD) children. We applied LP filters to the EMG data with cutoff frequencies ranging from 4 to 40 Hz (reflecting the range reported in prior synergy research). We also evaluated the impact of normalizing EMG amplitude by unit variance. We found that the total variance accounted for (tVAF) by a given number of synergies was sensitive to LP filter choice and decreased in both TD and CP groups with increasing LP cutoff frequency (e.g., 9.3 percentage points change for one synergy between 4 and 40 Hz). This change in tVAF can alter the number of synergies selected for further analyses. Normalizing tVAF to a z-score (e.g., dynamic motor control index during walking, walk-DMC) reduced sensitivity to LP cutoff. Unit variance scaling caused comparatively small changes in tVAF. Synergy weights and activations were impacted less than tVAF by LP filter choice and unit variance normalization. These results demonstrate that EMG signal processing methods impact outputs of synergy analysis and z-score based measures can assist in reporting and comparing results across studies and clinical centers.

NIH cerebral palsy strategic plan – our comments

Dr. Steele MotorControl, UbiquitousRehabilitation April 10, 2017October 12, 2021AccessEngineering, Cerebral Palsy

The National Institutes of Health recently released the “Strategic Plan for Cerebral Palsy Research” which outlines challenges and priorities to guide future research to improve the lives of people with cerebral palsy.

Our diverse research group enjoyed reading and discussing this plan, which will likely influence our future research goals and support. We’ve shared our group’s comments, organized and prepared by Dr. Heather Feldner, below:

“Our research group appreciated the committee’s focus on creating a centralized data source for CP, attention to the needs and perspectives of adults with CP, their childhood experiences, and their transition from pediatric to adult healthcare providers, and the call for greater caregiver support services and patient-reported outcomes. However, we also had concerns. First, the terminology is inconsistent and often inappropriate. “Cure”, “damage”, and the implication that people with CP cannot be “healthy” is not empowering language in supporting the lives, unique contributions, and perspectives of people with CP as diverse and valued individuals in our society. Further, while advocates of people with CP were included in this stakeholder group, there is a concerning lack of people who actually have a diagnosis of CP, when these should be the primary stakeholders setting a research agenda about their own lives and needs. Finally, given the uncertainty of government funding agencies like the NIH under the current administration’s budget proposal, and the speed of science of translating research from bench to bedside, it appears that too little priority has been placed on interventions or programs that could have an influence right now for the people living with CP in the US dealing with self-identified participation issues such as access to employment and education, as well as impairment-related needs such as pain management, access to technology, and functional mobility.“

We are excited that NIH is engaged to set a national research agenda for cerebral palsy and we look forward to continuing to serve this community.

H Choi, TL Wren, KM Steele (2016) “Gastrocnemius operating length with ankle foot orthoses in cerebral palsy.” Prosthetics & Orthotics International

Dr. Steele JournalArticle, Orthoses July 16, 2016October 12, 2021AFO, Cerebral Palsy, Modeling, Simulation

Example of gastrocnemius operating length from one subject with different AFOs.

Journal article in Prosthetics & Orthotics International:

How does the operating length of the gastrocnemius vary with different common AFOs in children with cerebral palsy?

Background: Many individuals with cerebral palsy wear ankle foot orthoses during daily life. Orthoses influence joint motion, but how they impact muscle remains unclear. In particular, the gastrocnemius is commonly stiff in cerebral palsy. Understanding whether orthoses stretch or shorten this muscle during daily life may inform orthosis design and rehabilitation.

Objectives: This study investigated the impact of different ankle foot orthoses on gastrocnemius operating length during walking in children with cerebral palsy.

Study design: Case series, within subject comparison of gastrocnemius operating length while walking barefoot and with two types of ankle foot orthoses.

Methods: We performed gait analyses for 11 children with cerebral palsy. Each child was fit with two types of orthoses: a dynamic ankle foot orthosis (Cascade dynamic ankle foot orthosis) and an adjustable dynamic response ankle foot orthosis (Ultraflex ankle foot orthosis). Musculoskeletal modeling was used to quantify gastrocnemius musculotendon operating length and velocity with each orthosis.

Results: Walking with ankle foot orthoses could stretch the gastrocnemius more than barefoot walking for some individuals; however, there was significant variability between participants and orthoses. At least one type of orthosis stretched the gastrocnemius during walking for 4/6 and 3/5 of the Gross Motor Functional Classification System Level I and III participants, respectively. AFOs also reduced peak gastrocnemius lengthening velocity compared to barefoot walking for some participants, with greater reductions among the Gross Motor Functional Classification System Level III participants. Changes in gastrocnemius operating length and lengthening velocity were related to changes in ankle and knee kinematics during gait.

Conclusion: Ankle foot orthoses impact gastrocnemius operating length during walking and, with proper design, may assist with stretching tight muscles in daily life.

Clinical relevance: Determining whether ankle foot orthoses stretch tight muscles can inform future orthotic design and potentially provide a platform for integrating therapy into daily life. However, stretching tight muscles must be balanced with other goals of orthoses such as improving gait and preventing bone deformities.

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

Keshia Media, MotorControl, News, Projects May 27, 2016October 12, 2021Cerebral Palsy

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.

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

Keshia Media, News, Publications April 29, 2016October 12, 2021Cerebral Palsy, Gillette, Walk-DMC

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.