Locked-In Syndrome

A speech prosthetic developed by a collaborative team of neuroscientists, neurosurgeons and engineers can translate a person's brain signals into what they're trying to say. The new technology might one day help people unable to talk due to neurological disorders regain the ability to communicate through a brain-computer interface. A speech prosthetic developed by a collaborative team of Duke neuroscientists, neurosurgeons, and engineers can translate a person's brain signals into what they're trying to say. Appearing Nov. 6 in the journal Nature Communications, the new technology might one day help people unable to talk due to neurological disorders regain the ability to communicate through a brain-computer interface. "There are many patients who suffer from debilitating motor disorders, like ALS (amyotrophic lateral sclerosis) or locked-in syndrome, that can impair their ability to speak," said Gregory Cogan, Ph.D., a professor of neurology at Duke University's School of Medicine and one of the lead researchers involved in the project. "But the current tools available to allow them to communicate are generally very slow and cumbersome." Imagine listening to an audiobook at half-speed. That's the best speech decoding rate currently available, which clocks in at about 78 words per minute. People, however, speak around 150 words per minute. The lag between spoken and decoded speech rates is partially due the relatively few brain activity sensors that can be fused onto a paper-thin piece of material that lays atop the surface of the brain. Fewer sensors provide less decipherable information to decode. To improve on past limitations, Cogan teamed up with fellow Duke Institute for Brain Sciences faculty member Jonathan Viventi, Ph.D., whose biomedical engineering lab specializes in making high-density, ultra-thin, and flexible brain sensors. For this project, Viventi and his team packed an impressive 256 microscopic brain sensors onto a postage stamp-sized piece of flexible, medical-grade plastic. Neurons just a grain of sand apart can have wildly different activity patterns when coordinating speech, so it's necessary to distinguish signals from neighboring brain cells to help make accurate predictions about intended speech. After fabricating the new implant, Cogan and Viventi teamed up with several Duke University Hospital neurosurgeons, including Derek Southwell, M.D., Ph.D., Nandan Lad, M.D., Ph.D., and Allan Friedman, M.D., who helped recruit four patients to test the implants. The experiment required the researchers to place the device temporarily in patients who were undergoing brain surgery for some other condition, such as treating Parkinson's disease or having a tumor removed. Time was limited for Cogan and his team to test drive their device in the OR. "I like to compare it to a NASCAR pit crew," Cogan said. "We don't want to add any extra time to the operating procedure, so we had to be in and out within 15 minutes. As soon as the surgeon and the medical team said 'Go!' we rushed into action and the patient performed the task." The task was a simple listen-and-repeat activity. Participants heard a series of nonsense words, like "ava," "kug," or "vip," and then spoke each one aloud. The device recorded activity from each patient's speech motor cortex as it coordinated nearly 100 muscles that move the lips, tongue, jaw, and larynx. Afterwards, Suseendrakumar Duraivel, the first author of the new report and a biomedical engineering graduate student at Duke, took the neural and speech data from the surgery suite and fed it into a machine learning algorithm to see how accurately it could predict what sound was being made, based only on the brain activity recordings. For some sounds and participants, like /g/ in the word "gak," the decoder got it right 84% of the time when it was the first sound in a string of three that made up a given nonsense word. Accuracy dropped, though, as the decoder parsed out sounds in the middle or at the end of a nonsense word. It also struggled if two sounds were similar, like /p/ and /b/. Overall, the decoder was accurate 40% of the time. That may seem like a humble test score, but it was quite impressive given that similar brain-to-speech technical feats require hours or days-worth of data to draw from. The speech decoding algorithm Duraivel used, however, was working with only 90 seconds of spoken data from the 15-minute test. Duraivel and his mentors are excited about making a cordless version of the device with a recent $2.4M grant from the National Institutes of Health. "We're now developing the same kind of recording devices, but without any wires," Cogan said. "You'd be able to move around, and you wouldn't have to be tied to an electrical outlet, which is really exciting." While their work is encouraging, there's still a long way to go for Viventi and Cogan's speech prosthetic to hit the shelves anytime soon. "We're at the point where it's still much slower than natural speech," Viventi said in a recent Duke Magazine piece about the technology, "but you can see the trajectory where you might be able to get there." This work was supported by grants from the National Institutes for Health (R01DC019498, UL1TR002553), Department of Defense (W81XWH-21-0538), Klingenstein-Simons Foundation, and an Incubator Award from the Duke Institute for Brain Sciences.

THURSDAY, May 18, 2023 (American Heart Association News) -- Kate Adamson liked exercising so much, her goal was to become a fitness trainer. She grew up in New Zealand playing golf and later, living in California, she worked out often while raising her two young daughters. Although she was healthy and ate well, she had occasional migraines. At age 33, they were getting worse and more frequent. One week, she had the worst headache of her life. It went on for days. She wasn't sleeping well and got up early to take a shower. She felt a wave of dizziness. Her left side seemed to collapse. Adamson made her way down to the edge of the tub to rest. She was able to return to bed, where she woke up her husband, Steven Klugman. "I need help now," she said. Her next memory was seeing paramedics rushing into the house while her 3-year-old daughter, Stephanie, was in the arms of a neighbor. Rachel, her other daughter, then 18 months old, was still asleep. When she woke up in the hospital, Adamson found herself surrounded by doctors. Klugman was by her side. She could see them, hear them and understand them. But she could not move or react. Doctors told Klugman that his wife had experienced a massive brain stem stroke. It was later thought to be related to neck manipulations she had received from a chiropractor for the migraines. The stroke resulted in what's known as locked-in syndrome, a disorder of the nervous system. She was paralyzed except for the muscles that control eye movement. Adamson realized she could answer yes-or-no questions by blinking her eyes. Klugman was told that Adamson had a very minimal chance of recovery. She was put on a ventilator to breathe, given nutrition through a feeding tube and had to use a catheter. She learned to coordinate eye movements to an alphabet chart. This enabled her to make short sentences. "Am I going to die?" she asked one of her doctors. "No, we're going to get you into rehab," he said. Adamson stayed in the ICU on life support for 70 days before being transferred to an acute rehabilitation facility. She could barely move a finger, but that small bit of progress gave her hope. In rehab, she slowly started to regain use of her right side; her left side remained paralyzed. Therapists taught her to swallow and to speak. She had to relearn to blow her nose, use a toilet and tie her shoes. She was particularly fond of a social worker named Amy who would incorporate therapy exercises into visits with her children, such as bubble blowing to help her breathing. Amy, who Adamson became friends with, also helped the children adjust to seeing their mother in a wheelchair. Adamson changed her dream job from fitness trainer to hospital social worker. She left rehab three and a half months later, still in a wheelchair but able to breathe, eat and use the toilet on her own. She continued outpatient rehab for another year. She assumed her left side would improve as her right side did. But it remained paralyzed. She would need to use a brace on her left leg to walk and couldn't use her left arm and hand. Still, two years after the stroke, which happened in 1995, Adamson was able to drive with a few equipment modifications. After her recovery, she spent many years doing advocacy work while raising Rachel and Stephanie. She founded a stroke caregiver support group, volunteered with the American Heart Association and lobbied for stroke research funding. She became a motivational speaker and wrote a book about her journey from locked-in syndrome to recovery. She also traveled, including visiting family in New Zealand. In 2010, she even went tandem paragliding with an instructor. In 2018, Adamson reached another milestone. She graduated with a master's degree in social work; she'd started college in 2011 at age 49. "It wasn't easy going to school. I just had to take it a day at a time, a semester at a time," she said. "The stroke has taught me I can walk through anything." In 2020, Stephanie, who had moved to Nashville, Tennessee, convinced her mother, who was by then divorced, to move east. Her other daughter, Rachel, was already living there. Last year, Adamson fulfilled her goal of working as a licensed social worker at a hospital. Now 60, she works with renal transplant and pulmonary patients, helping coordinate their services and care with the rest of the medical team at Vanderbilt University Medical Center. "Knowing that you're making a difference in somebody's life is very satisfying. It takes me back to when I was a patient – I'm always looking at how I would want to be treated," she said. "I've really come full circle." Adamson has adapted to doing things one-handed in a two-handed world, such as cooking and tying her shoes. She also walks with a cane. To stay in shape, she works with a trainer doing functional exercises and strength training. She has a special glove that pulls her left hand into a fist, allowing her to use a rowing machine and stationary bike. She also uses her muscles to pick up her two grandchildren, 15 and 16 months old. "It's really special seeing her be a grandma," said her daughter, Stephanie Gaveck. "When my daughter was first born, she was hesitant to hold her with one arm. But she quickly made modifications and became more confident." Now that Stephanie is the same age her mother was when she had the stroke, she understands more of what her mom went through. "I've always been proud of her and I use her as an inspiration," she said. "She's a very, very determined person." Adamson is especially determined when it comes to helping her patients. "I work really hard to be an example to them, to show that we are all capable of going through difficult life challenges while still maintaining a positive attitude and making a difference in the world." American Heart Association News covers heart and brain health. Not all views expressed in this story reflect the official position of the American Heart Association. Copyright is owned or held by the American Heart Association, Inc., and all rights are reserved. By Diane Daniel, American Heart Association News Posted May 2023

Under the direction of Woon-Hong Yeo at the Georgia Institute of Technology, a multi-institutional research team has developed a wireless wearable brain-machine interface (BMI) system using soft scalp electronics. The new system could make BMI technology more comfortable and easier to use while improving the accuracy of brain signal capture. A brain-machine interface offers enhanced rehabilitation for neuromuscular conditions that cause motor dysfunction. Currently, most BMI systems use wired electroencephalography (EEG) brain mapping technology that requires hard electrodes, gels, pastes, and a tight skullcap to secure electrodes to the scalp. In a departure from these cumbersome BMI systems, the international team built a portable EEG system that combines virtually imperceptible microneedle electrodes with soft wireless electrical circuits. The EEG wearable could allow a user to operate a wireless robotic arm or wheelchair by imagining the action in their mind. Standard BMI systems require a tangle of multiple wires; they are time consuming to set up and require gels or pastes to affix the hard electrode sensor to the skin. Maintaining proper electrode contact is an ongoing challenge, and displaced electrodes degrade signal acquisition, leading to reduced accuracy. In contrast, the new BMI is easier and faster to apply, requires no gels, and offers a more comfortable experience because the electrodes and circuitry are soft and flexible. There’s also less chance of signal noise because the electrodes don’t shift around so easily, leading to improved accuracy. The researchers further improved accuracy by using VR technology and powerful AI algorithms to train the BMI. In preliminary tests, four non-disabled human subjects successfully controlled movements in a VR environment using imagined motor actions, such as grasping. Although still in the early stages, the new BMI holds promise for individuals with severe paralysis and locked-in syndrome, a condition in which a fully conscious individual cannot move or communicate. Further development and testing is planned with subjects across a range of motor dysfunction conditions. The researchers published their findings in the journal Advanced Science.