Engineering to enhance human mobility, play, and exploration
Brianna Goodwin, a Master’s student in our lab, presented her collaborative 
abstract on monitoring Constraint-Induced Movement Therapy (CIMT), a therapy for children with hemiplegic cerebral palsy (CP), at the Seattle Children’s Hospital (SCH) Grand Rounds this past week. The Grand Rounds are a time to present research, new ideas, and translational science to medical personnel of varied background.
To read Brianna’s abstract in full, download her PDF here: SCH Grand Rounds, CIMT abstract
Journal article in PLOSOne: In collaboration with the University of Washington Prosthetics and Orthotics Division, a user-centered design approach was used to improve the design and wearability of a passive, wrist-driven orthosis. To read the article in full, click HERE. To access the open-source print files, click HERE.
Background: Assistive technology, such as wrist-driven orthoses (WDOs), can be used by individuals with spinal cord injury to improve hand function. A lack of innovation and challenges in obtaining WDOs have limited their use. These orthoses can be heavy and uncomfortable for users and also time-consuming for orthotists to fabricate.
Purpose/Methods: The goal of this research was to design a WDO with user (N = 3) and orthotist (N = 6) feedback to improve the accessibility, customizability, and function of WDOs by harnessing advancements in 3D-printing.
Results: The 3D-printed WDO reduced hands-on assembly time to approximately 1.5 hours and the material costs to $15 compared to current fabrication methods. Varying improvements in users’ hand function were observed during functional tests, such as the Jebsen Taylor Hand Function Test. For example, one participant’s ability on the small object task improved by 29 seconds with the WDO, while another participant took 25 seconds longer to complete this task with the WDO. Two users had a significant increase in grasp strength with the WDO (13–122% increase), while the other participant was able to perform a pinching grasp for the first time.
The WDO designs are available open-source to increase accessibility and encourage future innovation.
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.
Journal article in Journal of Electromyography and Kinesiology:
In collaboration with Rehabilitation Medicine here at the University of Washington, we evaluated muscle use of 20 unimpaired participants during three upper-extremity functional tests. An interactive supplement can be found HERE.
Background: Performance-based tests, such as the Jebsen Taylor Hand Function Test or Chedoke Arm and Hand Activity Inventory, are commonly used to assess functional performance after neurologic injury. However, the muscle activity required to execute these tasks is not well understood, even for unimpaired individuals. The purpose of this study was to evaluate unimpaired muscle recruitment and coordination of the dominant and non-dominant limbs during common clinical tests.
Methods: Electromyography (EMG) recordings from eight arm muscles were monitored bilaterally for twenty unimpaired participants while completing these tests. Average signal magnitudes, activation times, and cocontraction levels were calculated from the filtered EMG data, normalized by maximum voluntary isometric contractions (MVICs).
Results: Overall, performance of these functional tests required low levels of muscle activity, with average EMG magnitudes less than 6.5% MVIC for all tests and muscles, except the extensor digitorum, which had higher activations across all tasks (11.7 ± 2.7% MVIC, dominant arm). When averaged across participants, cocontraction was between 25 and 62% for all tests and muscle pairs.
Conclusion: Tasks evaluated by speed of completion, rather than functional quality of movement demonstrated higher levels of muscle recruitment. These results provide baseline measurements that can be used to evaluate muscle-specific deficits after neurologic injury and track recovery using common clinical tests.
Momona Yamagami and Karley Benoff attended the Society of Women Engineers (SWE) 2017 conference in Austin, TX. Momona presented on her work with assessing a flexible electrode for long-term electromyography measurements and placed among the top 10 finalists in the graduate research poster competition for SWE. Congratulations Momona!
Karley said that SWE 17 was an incredible experience filled with opportunities for professional growth and networking. Here are some of her impressions:
“My favorite guest talk was titled “TECHing While Women and with Disability” where five panelists shared their experiences navigating the engineering world with a disability and/or as an advocate for those with disabilities. Dr. Richard Ladner of the University or Washington CSE department (pictured with Karley below) was one of the panelists. His research on accessible technology, especially technology for the blind, deaf, deaf-blind, and hard-of-hearing, was truly inspiring. The panelists’ presentations provided a unique perspective for approaching user-centered design. I hope to use the lessons learned from the panelists, as well as from all of the SWE 17 attendees I met, to better inform the development of my orthosis project this year. By targeting accessibility and user-centered design, I aspire to develop a universal elbow-driven orthosis that will improve function for users with a wide variety of abilities.
The panelist idea is something HuskyADAPT wants to organize for its club members. Since I am an officer in the club, we are currently trying to plan such an event to better inform design teams and members alike about peoples’ experiences living with disabilities. By understanding what each individual needs, we can better design devices and technology to address what the user wants.”
