A team of researchers from the University of Houston (UH) has developed an algorithm that enabled a man whose right hand had been amputated to grasp objects using a bionic hand controlled by his thoughts. While we've seen similar accomplishments in recent years, the new technique is non-invasive, capturing brain activity via a scalp EEG.
Research developments in recent years have given amputees much cause for hope with various thought-controlled prosthetic devices. Some have relied on surgically implanted electrodes, while others make use of electrical signals from muscles (known as myoelectric control).
But Jose Luis Contreras-Vidal, a neuroscientist and engineer at UH points out that such methods have their disadvantages. Surgery, particularly neurosurgery, is a risky business, while myoelectric systems require the brain activity from muscles related to the missing limb still be intact.
In an effort to avoid these problems, UH researchers attached electrodes of a 64-channel active EEG (electroencephalogram) to the scalps of five able-bodied, right-handed men and women in their 20s. These volunteers were then tasked with picking up five different objects – a soda can, a compact disc, a credit card, a small coin and a screwdriver – each intended to illustrate a different type of grasp. The data collected data was then used to create software to decode neural activity into motor signals that reconstructed the grasping movements.
The scalp EEG was then fitted to a 56-year-old man whose right hand had been amputated and a high-tech bionic hand fitted to the remaining stump. After being told to observe and visualize himself controlling the hand, he was able to grasp the various objects using his thoughts with an 80 percent success rate.
Contreras-Vidal says a delay of 50 to 90 milliseconds between the time the signals were recorded by the EEG and when the bionic hand began to grasp indicated that the brain predicted the movement, rather than reflected it.
The researchers claim this is the first time grasping has been demonstrated using EEG-based brain-machine interface (BMI) control of a multi-fingered prosthetic hand, with Contreras-Vidal saying it could lead to the development of better prosthetic devices.
Three Austrian men have become the first in the world to undergo a new technique called "bionic reconstruction", enabling them to use a robotic prosthetic hand controlled by their mind, according to new research published in The Lancet. All three men suffered for many years with brachial plexus injuries [1] and poor hand function as a result of motor vehicle and climbing accidents.
The new technique was developed by Professor Oskar Aszmann, Director of the Christian Doppler Laboratory for Restoration of Extremity Function at the Medical University of Vienna, together with engineers from the Department of Neurorehabilitation Engineering of the University Medical Center Goettingen. It combines selective nerve and muscle transfers, elective amputation, and replacement with an advanced robotic prosthesis (using sensors that respond to electrical impulses in the muscles). Following comprehensive rehabilitation, the technique restored a high level of function, in all three recipients, aiding in activities of daily living.
"In effect, brachial plexus avulsion injuries represent an inner amputation, irreversibly separating the hand from neural control. Existing surgical techniques for such injuries are crude and ineffective and result in poor hand function", explains Professor Aszmann. "The scientific advance here was that we were able to create and extract new neural signals via nerve transfers amplified by muscle transplantation. These signals were then decoded and translated into solid mechatronic hand function" [2]
Before amputation, all three patients spent an average of 9 months undergoing cognitive training, firstly to activate the muscles, and then to use the electrical signals to control a virtual hand. Once they had mastered the virtual environment, they practiced using a hybrid hand--a prosthetic hand attached to a splint-like device fixed to their non-functioning hand (Figure 1 page 3 and video).
Three months after amputation, robotic prostheses gave all three recipients substantially better functional movement in their hands, improved quality of life, and less pain. For the first time since their accidents all three men were able to accomplish various everyday tasks such as picking up a ball, pouring water from a jug, using a key, cutting food with a knife, or using two hands to undo buttons.
