Paralyzed Man Uses Thoughts to Move Hand, Fingers

Pauline Anderson

April 14, 2016

A young man who just 2 years ago couldn't move his hands or fingers is now holding cups, stirring sticks, and and even playing video games, using his thoughts to bypass his spinal cord injury and take command of his hands.

Ian Burkhart sustained nonspastic C5/C6 quadriplegia from a cervical spinal cord injury (SCI) during a diving accident almost 6 years ago. Although technically paralyzed from his midchest down, he retained some residual movement in his shoulders and elbows.

He was selected as the first participant to test an investigational device called NeuroLife, developed at Batelle Memorial Institute.

Surgeons at Ohio State University Wexner Medical Center implanted a tiny chip (4 mm by 4 mm) on the hand area of the primary motor cortex of Burkhart's brain. The chip has 96 electrodes that penetrate into the neuronal layer.

Dr Gaurav Sharma

As Burkhart thinks about doing a task, computer algorithms decode the neurostimulus. A high-resolution neuromuscular electrical stimulator delivers electrical stimulation to his paralyzed right forearm muscles using an array of 130 electrodes embedded in a custom-made flexible sleeve.

Ian Burkhart, seated, with research team (from left) Dr. Ali Rezai, Dr. Marcie Bockbrader, and Nick Annetta. OSU Wexner Medical Center

"Once we decode the signals, or decode the thoughts, we re-encode them back into electrical pulses, which are sent to the sleeve, which can be wrapped around his arm," explained study author Gaurav Sharma, PhD, a mechanical engineer and principal research scientist at Battelle.

"So Ian will think about a task, the machine algorithms will decode it, and then our stimulation sleeve will get the right muscle to evoke that movement." The algorithms are running on a computer in real time, added Dr Sharma.

The researchers reported their promising results of their tests in a letter published online April 13 in Nature.

Re-encoded Signals

Burkhart was chosen for the project partly because his injury was relatively recent. "The longer you wait after the injury, the more muscle atrophy there is, and the more difficult it becomes to restore movement," Dr Sharma explained. Burkhart was undergoing physiotherapy, which helps to stave off complete muscle atrophy.

Of course, Burkhart had to be trained on using the technology. At first, "even to do a very simple task like opening or closing his hand took awhile because he had to think differently; he had to think about opening each individual finger," he said.

But over time, he has progressively mastered the technology "and algorithms have learned to better decode his intent," said Dr Sharma.

In the article, Dr Sharma and his colleagues described the accuracy of several tasks, including thumb extension, wrist flexion, wrist extension, middle flexion, thumb flexion and hand opening.

Using the system, his accuracy of performing individual movements ranged from 93.1% for wrist flexion (P < .01) to 97.3% for thumb flexion (P < .01). Sensitivity (percentage during cued movement where correct movement was observed) ranged between 32.9% for thumb extension and 81.9% for wrist extension, and specificity (percentage correctly identified during rest or nontarget movement cues) ranged between 94.8% for wrist flexion and 99.8% for thumb flexion.

To test tasks used in daily living, researchers asked Burkhart to perform a complex functional movement. The task required him to grasp a bottle, maintain his grasp while pouring the contents into a jar, open his hand to release the bottle, and pick up and use a stick to stir the jar's contents.

During the task, Burkhart used his residual shoulder and elbow movements to guide his hand while he performed the task. Initially, he had difficulty in maintaining his grasp of the objects, particularly during transfer, and he often dropped them.

But after training, he was able to do the grasp-pour-and-stir task three out of five times within 10 minutes.

This is a complex task not only because it's a combination of different movements, but also because it involves using both his paralyzed muscles and the "able" muscles in his shoulder, said Dr Sharma.

Using this investigational system, Burkhart "gained wrist and hand function consistent with a C7–T1 level of injury," write the authors. "This improvement in function is meaningful for reducing the burden of care in patients with SCI as most C5 and C6 patients require assistance for activities of daily living, while C7–T1 level patients can live more independently."

Thanks to neural bypass technology, Ian Burkhart can now swipe a credit card again. OSU Wexner Medical Center

Burkhart "has been a great participant" and has come up with his own useful ideas for living more independently, said Dr Sharma. For example, he can now pull a credit card out of his wallet with pinch-type of grip and swipe it in a credit card reader. This type of skill would enable him to, for example, pay his restaurant or hotel bill.

It's still difficult, however, to do tasks involving fine motor movements, such as picking up a coin from a table. "Our focus in this past 2 years of study has been to help Ian do tasks that are more functional for him, that can help him in activities of daily living," said Dr Sharma.

Although he can't take this technology home with him yet, Burkhart is "very excited" about it and says it "has given him hope" about future possibilities, said Dr Sharma.

It might even eventually be possible to create a version of the technology to stimulate muscles in his leg to facilitate walking, said Dr Sharma.

Portable Version

But the next step is to test the system in a second participant, which should begin next summer. The researchers also want to perfect the device.

"The next biggest goal is to miniaturize or shrink the system down into a portable belt-worn system," said Dr Sharma.

For a comment, Medscape Medical News approached An Do, MD, assistant professor, Department of Neurology, University of California, Irvine. Dr Do coauthored a paper on a brain-computer interface that allowed a spinal cord injured man to walk.

Dr Do pointed out that another study (EURASIP J Adv Signal Process. 2005:3152-3155) showing that brain-computer interfaces can help tetraplegic individuals regain control of hand grip.

This new study, he said, "shows that brain-implanted electrodes can enable brain-computer interfaces to restore higher levels of dexterous movements in the hand."

In conjunction with other brain-computer interface studies, "this research suggests that it may ultimately be possible to use neuro-technologies to restore movement in the hand, arm, and legs after spinal cord injury," said Dr Do.

However, he cautioned that "many technical challenges still lay ahead for this to be realized."

"It should be noted that the system presented in this study was only tested in one subject," he added. "Future studies will need to be performed to establish whether this experimental technique can generalize to larger population of individuals with SCI."

Dr Sharma is an employee of Batelle Memorial Institute, Columbus, Ohio. The custom neuromuscular stimulation sleeve and computer algorithms described in the study are covered by one or more patent applications. Dr Sharma is among the authors associated with these patents.

Nature. Published online April 13, 2016. Abstract


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