New cyborg technology offers hope for paralysis

New "cyborg" technology has been developed that can bypass the spinal cord and bring signals from the brain directly to the muscles, allowing the movement of paralyzed limbs.

 

The Northwestern University Feinberg School of Medicine in Chicago said the technology, once perfected, could eventually help paralyzed patients. 'Eavesdropping on the body's natural signals'

 

“We are eavesdropping on the natural electrical signals from the brain that tell the arm and hand how to move, and sending those signals directly to the muscles,” said lead investigator Lee Miller, who also holds the Edgar C. Stuntz Distinguished Professorship in Neuroscience at Northwestern University Feinberg School of Medicine.

 

He added this connection from brain to muscles might be used to help patients paralyzed due to spinal cord injury “perform activities of daily living and achieve greater independence.”

 

Miller is also a professor of physiology and physical medicine and rehabilitation at Feinberg and a Sensory Motor Performance Program lab chief at the Rehabilitation Institute of Chicago.

 

Other members of the team that performed the experiments were Christian Ethier, a post-doctoral fellow, and Emily Oby, a graduate student in neuroscience, both at the Feinberg School of Medicine.

 

The study, published in Nature, was done on monkeys: implanted electrodes picked up the electrical brain and muscle signals as they grasped a ball, lifted it, and released it into a small tube.

 

Such recordings allowed the researchers to develop an algorithm or “decoder” that let them process the brain signals and predict the patterns of muscle activity when the monkeys wanted to move the ball, according to a news release by the university.

 

Experimental 'neuroprosthesis'

 

In the experiment, the researchers gave the monkeys a local anesthetic to block nerve activity at the elbow, causing temporary, painless paralysis of the hand.

 

They then used special devices in the brain and the arm called a neuroprosthesis, which used the monkeys’ brain signals to control tiny electric currents delivered in less than 40 milliseconds to their muscles.

 

These currents caused the muscles to contract, allowing the monkeys to pick up the ball and complete the task nearly as well as they did before.

 

“The monkey won’t use his hand perfectly, but there is a process of motor learning that we think is very similar to the process you go through when you learn to use a new computer mouse or a different tennis racquet. Things are different and you learn to adjust to them,” said Miller.

 

Since the researchers computed the relationship between brain and muscle activity, the neuroprosthesis senses and interprets a variety of movements a monkey may want to make.

 

In theory this allows the neuroprosthesis to make a range of voluntary hand movements.

 

“This gives the monkey voluntary control of his hand that is not possible with the current clinical prostheses,” Miller said.

 

Restoring the ability to grasp

 

The university said the Freehand prosthesis is one of several prostheses available to spinal cord injury patients that can restore the ability to grasp.

 

“Provided these patients can still move their shoulders, an upward shrug stimulates the electrodes to make the hand close, a shrug down stimulates the muscles to make the hand open. The patient also is able to select whether the prosthesis provides a power grasp in which all the fingers are curled around an object like a drinking glass, or a key grasp in which a thin object like a key is grasped between the thumb and curled index finger,” it said.

 

In the new system developed by Miller and his team, a tiny implant called a multi-electrode array detects the activity of about 100 neurons in the brain.

 

It serves as the interface between the brain and a computer that deciphers the signals that generate hand movements.

 

“We can extract a remarkable amount of information from only 100 neurons, even though there are literally a million neurons involved in making that movement. One reason is that these are output neurons that normally send signals to the muscles. Behind these neurons are many others that are making the calculations the brain needs in order to control movement. We are looking at the end result from all those calculations,” Miller said. — TJD, GMA News