Cyber arm for the paralyzed
An artificial hand can be controlled with the help of thought
Kirill Stasevich, Compulenta
Neurophysiologists have managed to establish a connection between the neurons of the human brain and a cybernetic prosthesis.
Researchers from Brown University report the biggest success they have achieved in creating prosthetics controlled by human thought. Two elderly people who had been paralyzed for many years had the opportunity to drink coffee themselves, without assistance – they did it with the help of a mechanical arm that received signals directly from the human brain.
A paralyzed woman drinks coffee with a mechanical hand (photo by the authors of the article).
Neurophysiologists have been trying for quite some time to create cybernetic devices that would move according to neural commands. And periodically there are messages about the next successes and the transition to clinical trials. However, just at this crucial stage, more or less impressive results have not yet been achieved. But in a new article published in Nature (Hochberg et al., Reach and grasp by people with tetraplegia using a neurologically controlled robotic arm), scientists report exactly about a successful clinical trial of a "mentally controlled" prosthesis. The main problem here, as you can easily guess, is the translation of the language of neural impulses into electronic machine language. Previously, it was already possible to make a person move the cursor with the power of thought. The transition from two-dimensional motion on the monitor screen to three-dimensional space took several years: neural coding of movements in three-dimensional space is still much more complicated. In addition, the researchers wanted to recreate a full-fledged limb that would not just move back and forth and right and left, but which could, for example, take an object from the table so as not to break it, and purposefully move it.
In order to transmit neural signals to a mechanical arm, a chip implant was created, measuring 4x4 millimeters and with 96 thinnest electrodes.
The chip was placed on the surface of the motor cortex of the brain, which is responsible for the movements of the hand; at the same time, the electrodes were immersed in the brain tissue by a millimeter. The computer was engaged in the conversion of neural impulses into mechanical commands.
The study involved a 66-year-old man and a 58-year-old woman. The stroke paralyzed their limbs and made them unable to speak. A man had a brain chip implanted five months ago, a woman – more than five years ago.
The participants of the experiment had to touch or grab an object within 30 seconds; the latter required particularly careful control over the movements of the prosthesis.
Of course, not all attempts ended successfully, but in general, the probability of correct completion of the task ranged from 43 to 95 percent, depending on the complexity of the movements and the model of the prosthesis (two models of the cybernetic arm were used in the experiment).
The participants in the experiment reported that they simply tried to imagine the movement of a mechanical arm as their own, and the device moved according to their desires. (To avoid confusion, let us clarify that the conversation with the paralyzed and mute participants of the experiment was carried out through visual signals: they looked at the letters and words they had in mind).
There is no need to explain how important this result is, what kind of future opens up in this regard for bioengineering, etc., Just as there is no need to remember about "Robocop" – it is already remembered whenever it comes to combining the human brain and a cybernetic device. It is much more important to present the problems that scientists need to solve in order to provide this technology with a real triumph. Firstly, although the brain implant has proven its ability to work for a long period of time, it is still necessary to find out exactly how long it can decode neural signals. Our body is wary of any foreign body, and it is possible that the brain is slowly but surely trying to get rid of the chip. Secondly, it would be good to replace wired chips with wireless ones that would use radio signals to control a mechanical arm. And finally, the decoding algorithm itself requires further improvement in order to deal with neural impulses of any complexity.
Prepared based on the materials of Brown University: People with paralysis control robotic arms using brain-computer interface.
Portal "Eternal youth" http://vechnayamolodost.ru17.05.2012