Publications

Choi, H. Evaluation of Gait and Muscle Function with Ankle Foot Orthoses. PhD Dissertation.

Keshia OtherPublication, Publications

 

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, University of Washington, 2016. To download and read in full, CLICK HERE. to access through the University of Washington’s ResearchWorks Archive.

A methods figure is shown depicting an Ultrasound Coordinate System. The figure depicts how the Achilles tendon length is quantified by using an ultrasound, participant, and modeling system with motion capture markers. [In photo text: Global Coordinate System; Ultrasound Coordinate System; Figure 19 Quantification of Achilles tendon length. On left, AFO, ultrasound, and position of experimental markers. On right, scaled musculoskeletal model and schematic of coordinate systems for ultrasound to define AT length.Background: Many individuals with cerebral palsy (CP) and stroke are prescribed ankle foot orthoses
(AFOs) for use during daily life. AFOs have been shown to improve pathologic gait and walking
speed in CP and stroke by providing support and alignment. There are many different types of
AFOs available such as posterior leaf spring AFOs, rigid AFOs, and articulated AFOs. Further,
there are many parameters that can be customized or tuned for each type of AFO, such as
stiffness, heel height, shank to vertical angle, and foot plate length. However, how different types
of AFOs and the customization of specific parameters impact muscle function remains unclear.

Purpose: The goals of this dissertation were to evaluate how different types of AFOs and different
tuning parameters impact gait kinematics and muscle function. Of particular interest is the
gastrocnemius, a key muscle that crosses the knee and ankle joints and is commonly tight among
individuals with CP or stroke. Gastrocnemius operating length, defined as the total muscle and
tendon length during a functional activity, influences ankle and knee kinematics during gait.

Results/Discussion: This dissertation provides important evidence for how humans adapt to various AFO
properties and suggests important implications for the design and prescription of AFOs. This
work provides a quantitative evaluation of how AFOs impact musculotendon dynamics among
individuals with stroke (Aim 1) and cerebral palsy (Aim 2). The fabrication methods in Aim 3
creates a powerful and flexible research platform for evaluating AFO design, which may be
extended to fabrication of AFOs for daily use with further improvements in additive
manufacturing materials and methods. The final study (Aim 4), provides the first experimental
evidence combining ultrasound and musculoskeletal modeling to understand how muscle and
tendon length are impacted by AFO design. These evaluations provide guidance for future AFO
design and prescription that can not only augment human mobility for unimpaired individuals,
but also provide improve metrics for improving function and guiding rehabilitation for
individuals with neurologic impairments.

Michael MacConnell, Bradley Wachter, CJ Smith, and Sasha Portnova Present at the Undergraduate Research Symposium

Keshia Orthoses, Presentation, Projects, Publications , ,
Undergraduate Research Symposium graphic displaying May 20th in Mary Gates Hall.

Our undergraduate researchers presented in Mary Gates Hall today, presenting their research from 11am-1pm. Member of the community, faculty, and staff stopped by to hear about Bradley and CJ’s work developing an open-source proximal control orthosis, Sasha’s wrist-driven, wrist-hand orthosis, and Michael’s work on ankle foot orthoses as a rehabilitation tool. Great job, everyone!

 

 

CJ and Bradley, members of our research team, discuss the outcome measures of their proximal control device with interested community members. Michael MacConnell, a member of our research team, shares his research with members of the community. Sasha Portnova, a member of our research team, fields questions from an interested member of the community about her wrist-driven, wrist-hand orthosis.

CL Bennett, K Cen, KM Steele, DK Rosner, (2016) “An intimate laboratory? Prostheses as a tool for experimenting with identity and normalcy.” CHI Human Factors in Computing Systems, ACM

Dr. Steele Handathon, JournalArticle, Orthoses, UbiquitousRehabilitation , , , , , ,
Prostheses from the 15th century (medieval metal hand) to the 21st century (3D-printed enable hand).

Peer-review paper at CHI Human Factors in Computing Systems Annual Conference:

Prostheses are more than just a tool to enhance function – they strongly influence perceptions of identity and normalcy.

Prostheses from the 15th century (medieval metal hand) to the 21st century (3D-printed enable hand).Abstract: This paper is about the aspects of ability, selfhood, and normalcy embodied in people’s relationships with prostheses. Drawing on interviews with 14 individuals with upper-limb loss and diverse experiences with prostheses, we find people not only choose to use and not use prosthesis throughout their lives but also form close and complex relationships with them. The design of “assistive” technology often focuses on enhancing function; however, we found that prostheses played important roles in people’s development of identity and sense of normalcy. Even when a prosthesis failed functionally, such as was the case with 3D-printed prostheses created by an on-line open-source maker community (e-NABLE), we found people still praised the design and initiative because of the positive impacts on popular culture, identity, and community building. This work surfaces crucial questions about the role of design interventions in identity production, the promise of maker communities for accelerating innovation, and a broader definition of “assistive” technology.

View the video for more information on this work.

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

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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

Dr. Steele JournalArticle, MotorControl , ,
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.