A soft robotic wearable restores arm function to people with ALS

It is comfortable, safe and easy to use.

Amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease, is a neurodegenerative condition that damages nerve cells in the brain and spinal cord. Approximately 30,000 Americans are affected by it.

A team of Harvard John A Paulson School of Engineering and Applied Sciences (SEAS) and Massachusetts General Hospital (MGH) researchers has developed a soft robotic wearable that can significantly assist people with ALS in moving their upper arm and shoulder [1]. According to senior author Conor Walsh, this study gives hope to developing new devices capable of restoring function to people with ALS and other diseases that impair mobility. He leads the Harvard Biodesign Lab at SEAS as the Paul A Maeder Professor of Engineering and Applied Sciences.

Powered by a battery, the assistive prototype is soft, fabric-based and cordless. The technology behind this wearable is quite simple, says Tommaso Proietti, first author and a former postdoctoral research fellow in Walsh’s lab.

Essentially, it’s a shirt with an inflatable, balloon-like actuator under the armpit. The pressurised balloon helps the wearer combat gravity and move their upper arm and shoulder.

A sensor system was developed to assist patients with ALS in moving their arms naturally and smoothly with a balloon actuator by detecting residual movement of the arm. The researchers recruited ten ALS patients to determine how well the device might prolong or restore people’s quality of life and activity [2].

The team found that the soft robotic wearable, after a 30-second calibration procedure, to detect each wearer’s unique level of mobility and strength, improved participants’ range of motion, reduced muscle fatigue and enhanced task performance such as holding or reaching for objects. Participants learned how to use the device in less than 15 minutes.

Fabric and inflatable balloons make these systems very safe, according to Proietti. As opposed to rigid robots, soft robots stop inflating when they fail. However, they do not pose any danger to the wearer.

According to Walsh, the soft wearable feels like clothing on the body. The goal is to create comfortable robots that function like apparel for long periods. David Lin, director of MGH’s Neurorecovery Clinic, works with his team on stroke rehabilitation applications. The team also sees broader applications of the technology, especially for those with spinal cord injuries or muscular dystrophy.

The development of new disease-modifying treatments that will extend life expectancy must be accompanied by the development of tools that will improve patients’ independence with daily activities, says co-author Sabrina Paganoni, a physician-scientist at MGH’s Healey & AMG Center for ALS and Harvard Medical School associate professor. ALS prototypes could only function on study participants with some residual shoulder movements. However, ALS typically progresses quickly within two to five years, leaving patients unable to move and eventually unable to speak or swallow. 

Researchers are exploring possible versions of assistive wearables controlled by brain signals in cooperation with MGH neurologist Leigh Hochberg, principal investigator of the BrainGate Neural Interface System. One day, they hope, such a device might aid patients whose muscles are no longer active.

Proietti says the feedback from ALS study participants was inspirational, moving and motivating. Seeing people’s eyes light up while performing tasks and experiencing movement with the wearable, hearing them express overjoy at being able to move their arms as they had not been able to for years, was a bittersweet feeling.

The team is eager to see this technology begin enhancing people’s lives, but they caution that they are still in the development phase, several years away from commercialisation. For ALS patients, soft robotic wearables are an essential step on the path to restoring their function. Thanking people living with ALS who took part in this study, Paganoni said it is only through their selfless efforts that advancements can be made and new technology developed.

Patents arising from this study have been protected by Harvard’s Office of Technology Development [3]. In 2022, the Cullen Education and Research Fund (CERF) Medical Engineering Prize for ALS Research was awarded to team members.

[1] https://seas.harvard.edu/
[2] https://seas.harvard.edu/news/2023/02/soft-robotic-wearable-restores-arm-function-people-als
[3] https://otd.harvard.edu/

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