Brain-computer interface reverses paralysis in stroke victims

St. Louis, Missouri - After three strokes that left the right side of his body paralyzed, Rick Arnold told his wife Kim that he had just one wish.

“All I really wanted to do was to be able to hold her hand. In the very beginning, it was to hold her hand,” said Arnold, a paramedic firefighter from Missouri who suffered the first of three paralyzing strokes in 2009.

These days Arnold can hold his wife’s hand again thanks in part to a new device that could potentially change the rules on how well stroke victims recover. Arnold is using brain-machine interface technology developed by Eric Leuthardt, a neurosurgeon at Washington University in St. Louis.

After years of research, Leuthardt discovered that the rule that one side of the brain controls the opposite side of the body isn’t set in stone and that a thought or intention to move could be derived from other parts of the brain.

“In a stroke patient they have had an injury to one side of their brain that causes their hand to be paralyzed. So we are taking a signal from the uninjured side of the brain and decoding that intention to move,” said Leuthardt.

That thought of wanting to move is then converted into a machine command which is sent to a computerized exoskeleton device that moves Arnold’s hand. Leuthardt says that by using the device, the brain can be re-wired and re-trained to compensate for its injured parts.

“We are using external circuitry, meaning that we are using this brain-computer interface and this exoskeleton which gets controlled by your brain to alter the internal circuitry,” he said.

Arnold has recovered better than anyone expected and continues to improve every day. That, says Leuthardt, confounds the other classic notion that the body’s ability to recover declines six months after a stroke.

“Rick was three to four years out from his stroke and we can still recharge his plasticity for him to change his brain circuitry to functional improvement,” said Leuthardt.

“Every day is Christmas. It’s all working, it’s just falling into place the way you want it to be. .I am going way beyond what anyone thought including myself, much better,” added Arnold.

Arnold says that every day presents a new obstacle, but now that his wish came true and he’s holding his wife’s hand again, he’s up for any challenge.