Projects

M Yamagami, KM Peters, I Milovanovic, I Kuang, Z Yang, N Lu, KM Steele (2018) “Assessment of Dry Epidermal Electrodes for Long-Term Electromyography Measurements.” Sensors

Keshia JournalArticle, Projects, Publications, UbiquitousRehabilitation
Sample sEMG signal from one subject’s FCU for (left) MVIC; (middle) dynamic and (right) functional tests indicate that there were no significant differences between the Delsys (lighter grey) and ESS electrodes (darker grey) based on raw sEMG amplitude, linear envelope amplitude, or power spectral density.

Journal article in Sensors:

In collaboration with University of Texas – Austin, we evaluated a new flexible, gold-based epidermal electrode for sensing muscle activity.

Sample sEMG signal from one subject’s FCU for (left) MVIC; (middle) dynamic and (right) functional tests indicate that there were no significant differences between the Delsys (lighter grey) and ESS electrodes (darker grey) based on raw sEMG amplitude, linear envelope amplitude, or power spectral density.Background: Commercially available electrodes can only provide quality surface electromyography (sEMG) measurements for a limited duration due to user discomfort and signal degradation, but in many applications, collecting sEMG data for a full day or longer is desirable to enhance clinical care. Few studies for long-term sEMG have assessed signal quality of electrodes using clinically relevant tests. The goal of this research was to evaluate flexible, gold-based epidermal sensor system (ESS) electrodes for long-term sEMG recordings.

Methods: We collected sEMG and impedance data from eight subjects from ESS and standard clinical electrodes on upper extremity muscles during maximum voluntary isometric contraction tests, dynamic range of motion tests, the Jebsen Taylor Hand Function Test, and the Box & Block Test. Four additional subjects were recruited to test the stability of ESS signals over four days.

Results: Signals from the ESS and traditional electrodes were strongly correlated across tasks. Measures of signal quality, such as signal-to-noise ratio and signal-to-motion ratio, were also similar for both electrodes.

Conclusions: Over the four-day trial, no significant decrease in signal quality was observed in the ESS electrodes, suggesting that thin, flexible electrodes may provide a robust tool that does not inhibit movement or irritate the skin for long-term measurements of muscle activity in rehabilitation and other applications.

Karley Benoff named in the Husky 100!

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We are honored to have a 2018 Husky 100 member in our lab! The Husky 100 recognizes 100 UW undergraduate and graduate students from Bothell, Seattle, and Tacoma in all areas of study who are making the most of their time at the UW. Read an excerpt of Karley’s application packet below to learn more about her involvement with HuskyADAPT, her research with orthotic design, outreach, and her studies. Congratulations, Karley!

Students lead toy hack at Expanding Your Horizons Conference

Keshia HuskyADAPT, News, Outreach, Projects

Expanding Your Horizons (EYH website) is a non-profit organization dedicated to providing gateway opportunities for female middle and high school students to become more involved in STEM activities and careers. Two of our Steele Lab teams participated. Michael Rosenberg and Momona Yamagami created a remote control car you can control using muscle activity, and engaged in hands-on learning with the young women. Members of the University of Washington’s HuskyADAPT (Accessible Design & Play Technology) team, including lab members Brianna Goodwin, Brandon Nguyen, and Karley Benoff, led a workshop yesterday on accessible design and adaptation of toys for children with varying abilities.

A total of 12 toys were adapted to incorporate a new switch mechanism to facilitate play, and 26 high school women learned about toy adaptation, soldering, and circuitry. Thank you to our HuskyADAPT team and our lab members for their dedication to outreach events!

M Goudriaan, BR Shuman, KM Steele, M Van den Hauwe, N Goemans, G Molenaers, K Desloovere (2018) “Non-neural Muscle Weakness Has Limited Influence on Complexity of Motor Control during Gait.” Frontiers in Human Neuroscience

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Journal Article in Frontiers in Human Neuroscience:

Despite significant differences in kinematics children with Duchenne muscular dystrophy have similar control complexity to typically developing children.

Abstract: Cerebral palsy (CP) and Duchenne muscular dystrophy (DMD) are neuromuscular disorders characterized by muscle weakness. Weakness in CP has neural and non-neural components, whereas in DMD, weakness can be considered as a predominantly non-neural problem. Despite the different underlying causes, weakness is a constraint for the central nervous system when controlling gait. CP demonstrates decreased complexity of motor control during gait from muscle synergy analysis, which is reflected by a higher total variance accounted for by one synergy (tVAF1). However, it remains unclear if weakness directly contributes to higher tVAF1 in CP, or whether altered tVAF1 reflects mainly neural impairments. If muscle weakness directly contributes to higher tVAF1, then tVAF1 should also be increased in DMD. To examine the etiology of increased tVAF1, muscle activity data of gluteus medius, rectus femoris, medial hamstrings, medial gastrocnemius, and tibialis anterior were measured at self-selected walking speed, and strength data from knee extensors, knee flexors, dorsiflexors and plantar flexors, were analyzed in 15 children with CP [median (IQR) age: 8.9 (2.2)], 15 boys with DMD [8.7 (3.1)], and 15 typical developing (TD) children [8.6 (2.7)]. We computed tVAF1 from 10 concatenated steps with non-negative matrix factorization, and compared tVAF1between the three groups with a Mann-Whiney U-test. Spearman’s rank correlation coefficients were used to determine if weakness in specific muscle groups contributed to altered tVAF1. No significant differences in tVAF1 were found between DMD [tVAF1: 0.60 (0.07)] and TD children [0.65 (0.07)], while tVAF1 was significantly higher in CP [(0.74 (0.09)] than in the other groups (both p < 0.005). In CP, weakness in the plantar flexors was related to higher tVAF1 (r = −0.72). In DMD, knee extensor weakness related to increased tVAF1 (r = −0.50). These results suggest that the non-neural weakness in DMD had limited influence on complexity of motor control during gait and that the higher tVAF1 in children with CP is mainly related to neural impairments caused by the brain lesion.

AccessEngineering featured on UW College of Engineering’s website

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Thanks to AccessEngineering and other DO-IT programs, I don’t feel like I’m pursuing my education alone, or that I have to figure out how to overcome obstacles that others don’t have to by myself.

AccessEngineering, an interdisciplinary universal design program co-led by Dr. Kat Steele at the University of Washington, was featured on the College of Engineering’s news webpage.

Since it’s launch in 2014, AccessEngineering has sought to champion the development of a diverse, well-prepared workforce of engineering graduates and university faculty. One of the key ways that this program seeks to promote this agenda is by increasing general participation of individuals with disabilities in engineering. AccessEngineering also aims to promote their core goals by improving engineering education. The primary means by which this group seeks to enrich the curriculum is by integrating disability-related and universal design content into engineering courses.

Dr. Kat Steele coordinates AccessEngineering at the UW with Dr. Maya Cakmak, an assistant professor in the Paul G. Allen School of Computer Science & Engineering, and Dr. Sheryl Burgstahler, director of UW Access Technology and the DO-IT Center.

To read about AccessEngineering program as posted on College of Engineering website, follow this LINK, or visit the program’s website.