Categories

Archive for the ‘PROTHESIS’ Category

BIONIC EYE READY FOR HUMAN TRIALS SAY RESEARCHERS Arthur Lowery and Jeffrey Rosenfeld

Tuesday, May 5th, 2015

Arthur Lowery and Jeffrey Rosenfeld with a 9mm ceramic tile central to their bionic eye project image www.newcures.info

Arthur Lowery and Jeffrey Rosenfeld with a 9mm ceramic tile central to their bionic eye project. Photo: Simon Schluter

Researchers working on the ambitious project led by Monash University to build a bionic eye have revealed they are ready to start human trials next year.

“We have gone past the point of no return, where the device has been manufactured in prototype form and it is working in the laboratory,” said Jeffrey Rosenfeld​, director of the Monash Institute of Medical Engineering.

Professor Rosenfeld​ outlined the group’s progress in Washington DC on Monday, at the American Association for Neurology Surgeons’ annual scientific meeting.

The human trial will involve patients who have lost their sight having tiny “ceramic tiles” the size of a small fingernail implanted into their brain’s visual cortex at the Alfred Hospital, where Professor Rosenfeld​ is director of neurosurgery.

Up to five patients will participate in the trial. All will have lost their sight but Professor Rosenfeld​ said this could be due to a range of reasons.

This is because the device bypasses the normal visual pathway, unlike the other bionic eye being developed by Bionic Vision Australia which relies on an implant in the retina.

Developed by a multidisciplinary team at Monash Vision Group, the bionic eye uses a digital camera mounted on glasses to capture images before transferring them to a vision processing device about the size of a mobile phone.

Once processed, the image is transferred to an antenna attached to the back of a glasses frame.

The image is then wirelessly transmitted to the brain, where it is received by the small ceramic tiles implanted during surgery. The tiny tiles, each containing 43 microelectrodes​, measure 9mm by 9mm.

bionicEye schematic diagram image www.newcures.info

“The tiles are like a little pin cushion that pierce the brain,” Professor Rosenfeld​ said. “And we can put multiple tiles in so we can have several hundred electrodes.”

The more electrodes, the more detailed the image will be. However Monash Vision Group director Arthur Lowery said a maximum of 11 tiles, giving 473 electrodes, could be implanted. Fully-sighted people use over a million electrodes.

Working with a limited number of electrodes to carry information means the device has to be programmed to select which information it gathers and transmits.

To do this, researchers recreated what they believed people would see when they had the electrodes in the brain. They developed a computer program which takes a camera image and selects the important information before translating it into a “dot pattern” the brain would experience when excited by electrodes.

The dot patterns were then tested on sighted people using virtual reality goggles.

“That allowed us to test different visual processing algorithms,” Professor Lowery said. “The idea really is to cut out the clutter in an image and present the information that is important to people.”

More than 500,000 Australians are considered clinically blind. Many of them have damaged optical nerves, which prevent signals from reaching the brain.

The Monash Vision Group, a collaboration between Monash University, Alfred Health, MiniFAB and Grey Innovation, is building a bionic eye that bypasses the eye. Bionic Vision Australia, is taking a different approach and developing a microchip to be inserted into the retina of vision-impaired patients.

OOO

Henry Sapiecha

NEUROPROSTHESIS GIVES MONKEY FEELINGS BACK INTO PARALYSED HAND

Wednesday, May 2nd, 2012

NEUROPROSTHESIS AND RESTORATION OF MOVEMENT IN PARALYZED HAND

Researchers at Northwestern University have developed a neuroprosthesis that restores complex movement in the paralyzed hands of monkeys. By implanting a multi-electrode array directly into the brain of the monkeys, they were able to detect the signals that generate arm and hand movements. These signals were deciphered by a computer and relayed to a functional electrical stimulation (FES) device, bypassing the spinal cord to deliver an electrical current to the paralyzed muscles. With a lag time of just 40 milliseconds, the system enabled voluntary and complex movement of a paralyzed hand.

The experiments were carried out on two healthy monkeys, whose electrical brain and muscle signals were recorded by the implanted electrodes when they grasped, lifted and released a ball into a small tube. Using these recordings, the researchers developed an algorithm to decode the monkeys’ brain signals and predict the patterns of muscle activity that occurred when they wanted to move the ball.

The monkeys were then given an anesthetic to locally block nerve activity at the elbow, resulting in temporary paralysis of the hand. The multi-electrode array and FES device – which combine to form the neuroprosthesis – allowed the monkeys to regain movement in the paralyzed hand and pick up and move the ball with almost the same level of dexterity as they did before the paralysis.

“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 Lee E. Miller, the Edgar C. Stuntz Distinguished Professor in Neuroscience at Northwestern University Feinberg School of Medicine and the lead investigator of the study.

Dr. Miller’s team also performed grip strength tests, and found that the neuroprosthesis enabled voluntary and intentional adjustments in force and grip strength – key factors in successfully performing everyday tasks naturally.

The multi-electrode array implant detects the activity of about 100 neurons in the brain, which is just a fraction of the millions of neurons involved in making the hand movements. However, Miller points out that the neurons they are detecting are output neurons normally responsible for sending 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.

Miller added that, while the temporary nerve block used in the study is a useful model of paralysis, it doesn’t replicate the chronic changes that occur after prolonged brain and spinal cord injuries. For this reason, the next test for the system will be in primates suffering long-term paralysis to study how the brain changes as it continues to use the device.

However, the ultimate aim for the team is for the system to restore movement in human paralysis sufferers. “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,” said Miller.

The results of the Northwestern University team’s study, which was funded by the National Institutes of Health (NIH), appears in the journal Nature.

Sourced & published by Henry Sapiecha

EYE DISEASE & THE BIONIC EYE CONCEPT ACCELERATES IN A POSITIVE WAY IN AUSTRALIA

Wednesday, May 2nd, 2012

FIFTEEN years ago, the bid to create Australia’s first bionic eye relied on university researchers pillaging old stereos for parts.

However today, 154 researchers led by biomedical engineers from the University of NSW could be less than a year away from their goal of saving the vision of degenerative eye disease sufferers.

In 1997, when the work began, Gregg Suaning and Nigel Lovell were unfunded, but dogged, researchers ripping old stereos asunder for spare parts in their attempts to build a bionic eye.

Their work today is a $42 million joint project involving the university, the Bionics Institute, the Centre for Eye Research Australia, NICTA and the University of Melbourne.

Researchers say they could be months away from offering hope to people with macular degeneration and retinitis pigmentosa, the leading causes of sight loss in industrial countries.

The technology centres on an intricate and minuscule implant containing 98 electrodes, which is designed to stimulate nerve cells in the retina.

Images taken by an external camera implanted in glasses worn by the patient would be processed and relayed via an external wire to a receiver implanted behind the ear, from which signals will be sent to the retina processing chip. If all goes to plan the retina, having been stimulated with the signals, will send information to vision processing centres in the brain.

Human trials will begin next year. But people with any vestiges of sight will not be accepted. ”Because they have so much to lose, people who even see light won’t be able to qualify,” Professor Suaning said.

These trials will be the researchers’ first in Australia, fulfilling a dream held for decades.

The team began producing the implants last week, and will make about 25 before they know whether they’re ready to proceed.

It is envisaged that the technology, and follow-up treatment, will cost more than $60,000 per patient

Sourced & published  Henry Sapiecha

PHANTOM HAND SYNDRONE NOW OVERCOME BY TRICKING BRAIN

Monday, August 16th, 2010

New ‘hand’ may alleviate phantom pain


JENA, Germany (UPI) — Amputees suffering from “phantom pain” may get relief from a modified prosthetic that can convince the brain the body part still exists, researchers say.

Scientists at the University of Jena in Germany say phantom pain often lasts for years, and sometimes for a lifetime, often putting amputees at risk of mediation addiction from high dosages of painkillers, a university release said Friday.

Researchers say they’ve produced a modified prosthetic hand than can reduce phantom pain following amputation by using a stimulation unit in the hand’s cuff connected to the remaining part of the upper arm.

Modern prosthetic hands have pressure sensors meant to regulate the strength of grip of the artificial hand depending on what the wearer is trying to pick up, such as a raw egg or a hammer.

The stimulation unit in the modified hand takes feedback from the sensors and “talks” to the wearer’s brain, Dr. Gunther Hofmann of the Jena Department for Trauma, Hand and Reconstructive Surgery says.

“Our system is now able to transmit this sensory information from the hand to the upper arm,” Hofmann says.

Brain structures responsible for processing sensory information coming from the lost body part are “out of work” following an amputation and try to reorganize themselves, often leading to sensations of pain in a “phantom” hand, the Jena researchers say. By giving the appropriate brain structure sensory input from the “hand” it is meant to control, the reorganization can be prevented or reversed, thus eliminated phantom pain, they say.

Copyright 2010 by United Press International

Sourced & published by Henry Sapiecha