Collaboration across disciplines is an integral part of WashU, often yielding life-changing discoveries. In 2002, when Eric Leuthardt, MD, and Dan Moran were introduced to each other by their department chairs, no one could have predicted that it would lead to a collaboration that is reshaping the future of neuroscience.
Moran, a professor of biomedical engineering at the McKelvey School of Engineering, was then a new faculty member; and Leuthardt, now a professor of neurosurgery, was a resident at the School of Medicine. What started as a mentorship quickly turned into a research partnership and a lasting friendship.
“Collaboration is key,” says Moran. “Eric and I feed off each other, then you get a gestalt. It’s not like, ‘Oh, you’re gonna do XI will do there, and we’ll put those two things together. These are daily interactions and epiphanies.
Leuthardt says he learned engineering principles from Moran, such as bioelectrical phenomena in the brain and analytical analysis. “And as a neurosurgeon,” says Leuthardt, “I think I contribute to Dan’s ideas when we think about clinical applications.”
This shared learning led the two researchers to their big idea, the IpsiHand, which makes movement possible again for patients weakened by stroke. And that’s just the beginning. The device also opens up new possibilities in neurotechnology, including redesigning neural networks that were thought to be lost.
Developed by Neurolutions, the company that Leuthardt and Moran co-founded in 2008, the IpsiHand is the first brain-computer interface to receive FDA approval for stroke and the first FDA-approved thought-controlled device. “Other brain-computer interfaces can stimulate part of the brain,” says Leuthardt, “but this is the first to decode a patient’s intentions.”
The idea for the IpsiHand, which the FDA approved in April 2021, was born out of a groundbreaking discovery. The brain has long been known to function laterally, with one side of the brain controlling movement on the opposite side of the body. So when a stroke injures the left side of the brain, motor control can be lost on the right side of the body. Leuthardt’s laboratory was the first to demonstrate that ipsilateral movement, where the movement of one side of the body is controlled by the same side of the brain, could be affected.
The breakthrough came while Leuthardt and Moran were studying motor movement in patients. “Historically, if you have an electrode array on one side of the brain, subjects make opposing movements,” Leuthardt says. “But as a check, we said, ‘Let’s do some moves on the same side,’ not expecting anything very honestly. The first glimmer that something significant was there came when my grad student called and said: “We’re looking at this patient, but that’s the weirdest thing. We’re having them use the limb on the same side, and we’re seeing signal activations.
The discoveries followed from there. Leuthardt’s lab identified how these low-frequency, ipsilateral signals could be encoded. And at Neurolutions, the next leap was the development, in conjunction with Oak Ridge National Laboratory, of an exoskeletal device – the IpsiHand – that fits on a patient’s hand and activates when these ipsilateral signals occur.
How it works? The IpsiHand is not an aid for grasping or holding objects; instead, a bigger idea is at play. When a patient who has lost movement on one side of the body uses the uninjured part of the same side of the brain to think, for example, about moving a finger, low-level ipsilateral neural signals occur, instantly activating the IpsiHand to move the finger for them. This produces a neural response from the finger that connects to the brain’s original signal, forging a new neural network for movement. “When neurons fire together, they wire together,” Moran explains. “It’s a way to train the brain.”
The success of the invention was humbling, even poignant, for Leuthardt and Moran. An example is a firefighter who had lost movement due to a stroke. After four years, he was well past the six-month threshold where motor recovery was considered possible. “He used our system,” says Leuthardt, “and after four weeks he could put his pants back on by himself, which he hadn’t been able to do for four years. And he told me, and it still chokes me a little, that he wanted to hold his wife’s hand again – and now he can.
Leuthardt and Moran’s Big Idea can lead to greater discoveries in the future. They apply what they have learned to spinal cord injury and ALS. They also hope to move from motor function – the most decodable physiology – to brain-computer interfaces that treat psychiatric disorders such as depression. But even now, their discoveries are opening up a better future for all of us, one patient at a time.