Researchers from TU Delft, University of Twente, VUmc and the Radboud umc, have developed a robotic arm that can support the daily activities of people suffering the muscular disease Duchenne Muscular Dystrophy.
The researchers recently put the final touches on the first prototype for a discreet, body-connected support aid that can be worn under the clothing and that can support independent operation of the arm during important daily activities.
Gerard Dunning, PhD candidate in the Precision & Microsystems Engineering and BioMechanical Engineering departments in the Faculty of Mechanical, Maritime and Materials Engineering was one of the participating researchers. He will be awarded a PhD on Friday 22 April for his thesis entitled ‘Wearable arm orthosis for Duchenne patients’.
Duchenne Muscular Dystrophy occurs in approximately 1 in 5,000 live born boys. The muscles of Duchenne Muscular Dystrophy patients become weaker during their life. As a result, boys with Duchenne lose the ability to use their arms until, eventually, they are unable to use them at all. Medicines can slow the progress of the disease and increase the life expectancy of boys with Duchenne, which means preserving the functionality of their arms becomes even more important.
There are a few support aids that can recapture the loss of muscle function in the arms, but these support aids do not compensate for the entire loss of function and can result in stigmatisation.
The robotic arm, called the A-gear arm support, that the consortium worked on was developed in answer to a request made by young Duchenne patients. Most of the robotic aids available to this group are too heavy and obtrusive, precisely the kind of thing that teenage boys do not want to be seen wearing. Their greatest wish was for a robotic arm that does not stand out, but works efficiently.
The researchers spent four years developing two arm-support aids: one is a passive arm support, powered by the user but without a motor, and the other is an active arm support, powered by motors and controlled by the user. The active arm support is powered by electric (EMG) muscle signals or minimal muscle power from the arm, creating a movement that looks as intuitive and natural as possible.
Dunning was responsible for the passive arm support and developed spring systems that give adequate support, allow the arm to be brought closer to the body and are more comfortable.
In order to assess their design, the researchers compared the arm functionality of boys with Duchenne with and without A-Gear arm support. During the research, there were a number of participants who had been unable to independently move their arms for between three and five years and they were able to complete the tests set out in the tasks. The freedom of movement and the functionality of the arm increased when the subjects used the prototype. In addition, the movements required less energy.
The researchers not only looked into a technical solution, they also obtained more insight into the development of arm function in boys and men with Duchenne Muscular Dystrophy. By measuring the arm function of patients of different ages, they were able to obtain an impression of how the arm function changes over the course of the illness and, accordingly, how to adjust the arm support over time.
Although the results of the A-Gear project have provided new insights into the appearance of support aids such as these, much work is yet to be done in various areas. At the moment, a review is being carried out to work out what the next steps should be to convert the prototype into a product that can be used effectively.
The A-Gear project is an initiative of the Stichting Flextension (Flextension Foundation), which was initiated by the Duchenne Parent Project. Flextension started in 2007 as a result of questions from the Duchenne community about what engineering and technology could do to improve the quality of life for boys with Duchenne.
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