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Thursday, May 23, 2024

This Device Helps Paralyzed People Breathe—and Sing

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In his early twenties, Lee Nam-hyun was an avid swimmer. But in 2004 he broke his neck in a pool, which left him paralyzed from the shoulders down. Recovery from his injuries required years of rehabilitation.

The accident also temporarily halted his lifelong passion for singing. Opera and K-pop songs are his favorites, and being able to sing again became one of his top goals in recovery. But a lack of core muscles and limited lung capacity meant he couldn’t even cough. When he tried singing, he says, it sounded like whining, or little more than a whisper.

“The singing I did before and after was completely different,” he says. “The tones, the sounds, the beats—I couldn't make it anymore after I was injured. It was a sound that was unlistenable.”

About two years after the accident, a health care professional forced him to cough by pushing against his diaphragm. He learned that applying pressure to his abdomen could help him produce a larger sound.

Nearly a decade later, he learned through therapists about a prototype device being built for just this purpose, and Lee began to work with a biorobotics lab at Seoul National University. The device would eventually be named Exo-Abs. Its creators call it the first robotic device of its kind to help people breathe, cough, speak, and sing by automatically applying pressure to their abdomen.

Creators of the device, which began as a class project, hope to someday make it a commercial product. Researchers at the robotics lab first began work on the prototype device after popular singer Kim Hyuk-gun was hit by a car and paralyzed in 2012. Kim was lead vocalist for the Cross, a band whose songs are still a popular choice in South Korean karaoke bars. He’s known for a style of singing that can sound more like shouting, and two years after his injury he began to work with the biorobotics lab on a device that allows him to sing with similar volume. It wasn’t until later that the researchers learned that spinal cord injury patients often need help not just to move their limbs again but with respiratory therapy.

“When you breathe out, you're basically pushing the belly and narrowing down the volume of the lungs, so we’re trying to mimic that process,” says Seoul National University professor Cho Kyu-jin.

Cho is director of the Soft Robotics Research Center at the university, a biorobotics lab that takes inspiration from the natural world, including the human body. Aside from Exo-Abs, Cho has also created a robotic hand called Exo-Glove, a glider with wings like a ladybug, and a robot that simulates water skimmers, also called Jesus bugs because of their ability to walk on water.

“All wearable robots today are about moving the limbs, like the arms, the shoulders, and legs,” he says. Exo-Abs is different because “it's basically changing the whole volume of your body.” But he says the device’s potential is largely unexplored because it is not well known.

People who suffer strokes or neurological disorders often need ongoing care, including respiratory therapy. Failure to clear breathing passages can lead to ailments such as pneumonia and premature death. Today people use equipment like a ventilator mask to assist them with breathing, but the creators of Exo-Abs think their device could someday replace ventilators for some people.

Unlike existing devices that may require use of a face mask or ventilator, Exo-Abs can be concealed under a shirt. Machines for operating the device fit inside a backpack that can strap to the back of a wheelchair. The current iteration of Exo-Abs involves bands placed across the chest and midsection for measuring breathing and pressing against the diaphragm.


This is the third version of Exo-Abs. The first was manually controlled by the user with a joystick and had to be plugged into a power outlet. The second was a backpack version for people with ailments like COPD who may not need assistance all the time but may have trouble, for example, climbing stairs without running out of breath.

The latest version of Exo-Abs uses artificial intelligence to regulate the pressure applied to a person’s midsection. The AI is fed by sensors that include a microphone that detects when a person is talking and an elastic tube laced through a belt around the midsection to monitor breathing levels. It also factors in a person’s physical fitness, body shape, the stiffness of the user’s abdominal cavity, and the user’s activity. Singing that requires a lot of effort like opera, for example, may require more pressure than sitting calmly and having a conversation.

Lee Sang-yoep, a PhD candidate at Seoul National University working with Cho, envisions other uses for Exo-Abs, such as syncing the artificial abs to music or singing puzzle games like One Hand Clapping.

“I download a song file, then the robot can interpret the beats per minute and know how much effort is needed so someone can practice singing a song,” he says. “I think it could develop into a whole new robotics scheme so it can be just attached to anyone.”

Singing, he says, is not just a way to bring joy to people’s lives but also one of the most complicated versions of speech and breathing, offering engineers a compelling technical challenge. In other words, refining AI with the sensitivity to automatically recognize a person’s breathing patterns when singing should help advance the technical understanding required to meet the needs of people using the device to breathe, cough, or speak.


Creators of Exo-Abs have patents in the US and South Korea and hope for FDA approval someday. Getting it right could also enable people in wheelchairs with respiratory challenges to consider occupations associated with public speaking or performance arts.

For Lee Nam-hyun, respiratory therapy that included Exo-Abs helped him major in opera at Seoul National University. He initially struggled to finish songs, leading to discrimination and self doubt, but he says his quality of life improved when he was singing opera. He went on to perform with the KBS Symphony Orchestra in South Korea, travel to shows in the US, and sing for fans on YouTube. “You Raise Me Up” has been a favorite during the pandemic.

Today, Lee says he no longer requires Exo-Abs or the four or five other medical devices he used to recover from his swimming injury. Use of the device helped restore muscle memory for his abdominal muscles, but it was not without issues. In 2014 when he used the first prototype version, Exo-Abs was too slow to keep up with some song tempos; he also worried about the side effects of continually placing pressure on his midsection. Opera singers, he says, typically breathe by ballooning air into their entire midsection, but Exo-Abs only applied pressure to his front and back.

“If you keep doing that for a long period of time, there can be an issue of problems with your intestines pushing out or blood in your urine or your stool,” he says.

Kim, the singer in the Cross, said in a 2014 YouTube video that the device did cause him some bleeding—though he also said it was worth it to sing again. Kim was unable to respond to questions about his experience with the device due to health complications.

Lee Sang-yoep says that as the first users of the device, Lee Nam-hyun and Kim had the harshest feedback. The early version allowed excessive force to be placed on a patient’s midsection. The latest version distributes force more evenly, does away with manual control, and limits the amount of force that can be applied by the robot to an amount on par with the amount a therapist can apply. The latest version of Exo-Abs is also lighter, at 7.5 pounds, down from 10 pounds earlier.

Ongoing experiments at Seoul National University Hospital focus on allowing people in need of mild respiratory therapy to use Exo-Abs four to six hours a day for three weeks at a time under the supervision of health professionals.

Despite some bad experiences, Lee Nam-hyun says he recognizes that he was one of the first users of the device, and he hopes to see Exo-Abs improve over time so it can help more people.

“As this technology develops, perhaps it will become like self-driving cars where it gets better and better,” he says. “As with many prototype devices, I'm hoping this device as well becomes lighter, portable, and beautifully designed in the future.”

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