Acute flaccid myelitis (AFM) is a rare condition that affects the nervous system and has about a 2% recovery rate. The starkness of a medical statistic like this is brutal, and even more so when it relates to the health of your own children, but this was what Bodo Hoenen and his family were facing in the summer of 2016 when their five-year-old daughter, Lorelei, was diagnosed with AFM. The condition particularly affects the spinal column and in Lorelei’s case it had paralysed her left shoulder and left arm. “The prognosis was that the only thing that would help was occupational therapy and physiotherapy,” says Hoenen, “but looking at the results, back then, there were only two kids that had had any significant recovery” Hope was needed and it was sparked by a project the family saw in the hospital: “Researchers were strapping on an exoskeleton suit to paraplegic individuals and providing them the biofeedback with the suit,” recalls Hoenen.

“They also provided visual feedback by adding a VR headset showing them the actual movement of the arms. With the headset, you would see yourself walking and then feel your body walking as the exoskeleton suit was moving your body and this would force the brain to think ‘Okay, I’m going to walk now’ and they would pick up those signals from the brain and translate them into messages to control the exosuit and VR.” After consulting specialists, Hoenen theorised that instead of hooking sensors to the brain they needed to hook sensors directly to the biceps muscle in Lorelei’s arm: “We knew there were at least very weak signals going to the muscle and we were hoping to pick those up and hoping that forcing her to continue sending signals to her muscles would help that rehabilitation process.” Hoenen knew that probably the best way to do this was to build some kind of robotic prosthetic arm, but he had a problem: he had no idea how to do it. That’s when he and Lorelei decided to ask the world.

“We decided to leverage the collective intelligence of everyone around us,” says Hoenen. So, after sifting through all the information they could find and talking to other parents with children that had AFM, Bodo and Lorelei got to work with a simple first design – they wanted to 3D-print the braces and somehow acquire an actuator motor to help pull the arm up and down.

But before they got too far into the project, they decided to record some videos to ask experts for help. The response was “pleasantly surprising”, says Hoenen.

Within a couple of weeks they’d had Actuonix donating actuators while, among many helpers, they’d received assistance from experts in battery tech and electronics from South Africa and Germany respectively, and had a full scan of Lorelei’s arm done. It wasn’t long before a prototype was made, followed by a 3D-printed sleeve in PLA. Read more from…

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