Brain-activated muscle stimulation restores monkeys' hand movement after paralysis
An artificial connection between the brain and muscles can restore complex hand movements in monkeys following paralysis, according to a study funded by the National Institutes of Health.
In a report in the journal Nature, researchers describe how they combined two pieces of technology to create a neuroprosthesis a device that replaces lost or impaired nervous system function. One piece is a multi-electrode array implanted directly into the brain which serves as a brain-computer interface (BCI). The array allows researchers to detect the activity of about 100 brain cells and decipher the signals that generate arm and hand movements. The second piece is a functional electrical stimulation (FES) device that delivers electrical current to the paralyzed muscles, causing them to contract. The brain array activates the FES device directly, bypassing the spinal cord to allow intentional, brain-controlled muscle contractions and restore movement.
The research team was led by Lee E. Miller, Ph.D., professor of physiology at Northwestern University's Feinberg School of Medicine in Chicago. Prior to testing the neuroprosthesis, Dr. Miller's group recorded the brain and muscle activity of two healthy monkeys as the animals performed a task requiring them to reach out, grasp a ball, and release it. The researchers then used the data from the brain-controlled FES device to determine the patterns of muscle activity predicted by the brain activity.
To test the device, the researchers gave monkeys an anesthetic to locally block nerve activity at the elbow, causing temporary paralysis of the hand. With the aid of the neuroprosthesis, both monkeys regained movement in the paralyzed hand, could pick up and move the ball in a nearly routine manner and complete the task as before.
Dr. Miller's research team also performed grip strength tests, and found that their system restored precision grasping ability. The device allowed voluntary and intentional adjustments in force and grip strength, which are keys to performing everyday tasks naturally and successfully.
This new research moves beyond earlier work from Dr. Miller's group showing that a similar neuroprosthesis restores monkeys' ability to flex or extend the wrist despite paralysis. "With these neural engineering methods, we can take some of the important basic physiology that we know about the brain, and use it to connect the brain directly to muscles," Dr. Miller said. "This connection from brain to muscles might someday be used to help patients paralyzed due to spinal cord injury perform activities of daily living and achieve greater independence."
In 2008, a team led by Eberhard Fetz, Ph.D. at the University of Washington in Seattle coupled the activity of single neurons to an FES device similar to the one used for Miller's study. Monkeys learned to activate individual neurons to control the FES device and move a joystick, and could adapt neurons previously unassociated with wrist movement to complete the task. (See "Scientists Restore Movement to Paralyzed Limbs through Artificial Brain-Muscle Connections") The investigators suggest that this process of learning and adaption plays an important role in how the BCI translates the brain's activity patterns into adaptive control of the FES device.
The unique design of the ball grasp-and-release task used with the animals in this study is a further contribution to advanced neuroprosthetic testing and development. Daofen Chen, Ph.D., a program director at NIH's National Institute of Neurological Disorders and Stroke (NINDS), described how researchers in the field are striving toward devices that will go beyond simple arm movements and allow fine hand and finger movements. "We've learned a lot from non-human primate studies focused on understanding neural control of arm and wrist movements," said Dr. Chen. "Dr. Miller's study builds on those efforts and focuses on the complex hand and finger movements needed to grasp an object."
FES devices are currently used for foot drop, a clinical condition seen in patients with stroke or partial spinal cord injury where weak or paralyzed muscles cause the toes to catch on the ground while walking, leading to trips and falls. FES can be activated with shoe sensors, or coordinated with walking movements, to stimulate muscles and lift the toes at the appropriate time during a step.
Other FES devices in current clinical use take advantage of the patient's residual muscle activity. For example, a prosthetic arm can use sensors built into the shoulder, sensing a shrugging motion that is used to stimulate muscles to open or close the hand. However, this is a less precise and less natural method of control, and it is not an option for patients with higher level spinal cord injuries and little or no shoulder and arm movement. For these patients, the creation of a brain-controlled FES device that connects brain activity directly to muscle stimulation would provide an opportunity to restore hand function.
The temporary nerve block used in the current study is a useful model of paralysis, but it does not replicate the chronic changes that occur after prolonged brain and spinal cord injuries, Dr. Miller cautioned. He said the next steps include testing this system in primate models of long-term paralysis, and studying how the brain changes as it continues to use this neuroprosthesis.
More information: Ethier C et al. "Restoration of grasp following paralysis through brain-controlled stimulation of muscles." Nature, published online April 18, 2012. DOI: 10.1038/nature10987
Journal reference: Nature
Provided by National Institutes of Health
- 'Smart' prosthetics: restoring independence to people with disabilities Feb 16, 2007 | not rated yet | 0
- Researchers are developing devices that can help restore bodily movement Jun 17, 2009 | not rated yet | 0
- Study shows benefits of electrical stimulation therapy for people paralyzed by spinal cord injury Feb 17, 2011 | not rated yet | 0
- Robot arm improves performance of brain-controlled device Dec 14, 2010 | not rated yet | 0
- Thinking makes it so: Science extends reach of prosthetic arms Nov 11, 2007 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
How can there be a term called "intestinal metaplasia" of stomach
4 hours ago Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
- More from Physics Forums - Medical Sciences
More news stories
Researchers at the University of Illinois at Chicago College of Medicine will study gender differences in how the heart uses and stores fat—its main energy source—and how changes in fat metabolism play ...
Medical research 2 hours ago | not rated yet | 0
Nearly 20 percent of kidneys that are recovered from deceased donors in the U.S. are refused for transplant due to factors ranging from scarring in small blood vessels of the kidney's filtering units to the organ going too ...
Medical research 19 hours ago | 5 / 5 (2) | 0 |
Discovery of circadian clock in mice hair reveals period of time when damage from radiotherapy can be quickly repaired
Discovering that mouse hair has a circadian clock - a 24-hour cycle of growth followed by restorative repair - researchers suspect that hair loss in humans from toxic cancer radiotherapy and chemotherapy ...
Medical research 19 hours ago | 5 / 5 (2) | 1 |
Salamanders' immune systems are key to their remarkable ability to regrow limbs, and could also underpin their ability to regenerate spinal cords, brain tissue and even parts of their hearts, scientists have ...
Medical research 20 hours ago | 4.9 / 5 (7) | 4 |
New research from the University of Southampton has shown that blind and visually impaired people have the potential to use echolocation, similar to that used by bats and dolphins, to determine the location of an object.
Medical research 23 hours ago | not rated yet | 1 |
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
13 minutes ago | not rated yet | 0 |
In a remote fishing community in Venezuela, a lone fisherman sits on a cliff overlooking the southern Caribbean Sea. This man –– the lookout –– is responsible for directing his comrades on the water, ...
2 hours ago | not rated yet | 0 |
(Medical Xpress)—A research team, led by Jeremy Barr, a biology post-doctoral fellow, unveils a new immune system that protects humans and animals from infection.
16 hours ago | 4.7 / 5 (16) | 7 |
Johns Hopkins researchers say they have discovered specific chemical alterations in two genes that, when present during pregnancy, reliably predict whether a woman will develop postpartum depression.
7 hours ago | not rated yet | 0 |
A novel approach to obstructing the runaway inflammatory response implicated in some types of asthma has shown promise in a Phase IIa clinical trial, according to U. S. researchers.
2 hours ago | not rated yet | 0