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Wits researchers interpret brainwaves to give amputees a hand

By University of Witwatersrand 26 November 2019

Top marks are due for a bionic hand engineered by Wits University postgraduates, who have made mobility more accessible to the 1 million amputees in South Africa. Their 3D-printed hand is not only light in weight, but light on the pocket, as it drops the cost of this prosthetic from around R500 000 to R20 000.

ENGINEERING PIVOTAL MOVES 

Biomedical engineers at Wits have researched how brainwaves can be used to control a robotic prosthetic hand. The impact is far reaching as such a Brain Computer Interface (BCI) will enable amputees and people with motor impairments to regain some hand mobility. 

“In South Africa, stroke victims may benefit significantly from this technology,” says Abdul-Khaallq Mohamed, Lecturer and PhD candidate in the School of Electrical and Information Engineering at Wits. “Stroke afflicts an estimated 132 000 South Africans per year.” 

Currently, a prosthetic hand costs around R500 000, an investment out of reach for most South Africans. This research will use 3D-printing to create a prosthetic hand for R20 000, thereby increasing access to such healthcare for many.

Mohamed coordinates a research group of students studying different aspects of potentially controlling a robotic hand. Most BCI experiments to date have centered on basic hand movements such as finger taps, button presses or simple finger grasps.

BIOTECH OF INTERPRETING BRAINWAVES 

“I envisage a BCI capable of controlling a robotic prosthetic hand that will enable people with motor disabilities to write, hold a glass or shake hands,” he explains. The Wits-based research

group focuses uniquely on a combination of hand movements including wrist extension, wrist flexion, finger flexion, finger extension and the tripod pinch. 

BCls can use electroencephalograms (EEGs) brainwaves to interpret human intentions from electrical signals in the brain and use these to control an external device such as a prosthetic hand, computer, or speech synthesizer. 

The prosthetic robotic hand relies on EEGs extracted via electrodes on the skull, or electromyography (EMG) obtained from electrodes recording muscle signals, for information. A BCI will interpret these signals and translate them to instruct the movements of the artificial hand. 

Other life-changing research within biotech and engineering is being done at the globally ranked university, which has over 97% of its graduates employed within six months of graduation. This includes engineering advancement by Wits biomedical engineer Adam Pantanowitz and his teams. 

THE BRAIN AS A NETWORK DEVICE 

Pantanowitz discovered he had a neuromuscular condition as a teenager and since then, the Lecturer in the School of Electrical and Information Engineering has researched the potential of technology to empower people with disabilities. In particular, he has explored the untapped potential of the brain through Brain Computer Interfaces (BCIs).

In February 2019, in an experiment believed to be a world first, Pantanowitz and colleagues incorporated the human brain as a computer network. Dubbed ‘BrainConnect’, the researchers connected two computers through the human brain and successfully transmitted words like ‘hello’ and ‘apple’, passively, without the user being aware that a message was present. 

MORSE CODE VIA LIGHT SIGNALS 

BrainConnect links light, signal transmission, the visual cortex of the human brain, and two computers. 

It works by attaching a device to a person’s head, which links the two computers. The person passively stares at a flashing light whilst a word, for example, ‘apple’, is encoded in the light signal. The flashing light stimulates the visual cortex in the brain and an electroencephalogram (EEG) – a measurement that detects electrical activity in the brain, wirelessly transmits information to a second computer, which decodes the signals to appear on the second computer. 

“You can think of it like Morse Code via light signals,” says Pantanowitz. BrainConnect can decipher up to 17 symbols at a rate of four seconds per symbol. The more relaxed the person is, the greater the possibility of invoking a response through this ‘steady state visually evoked potential’.

SEEING VISIONARY ASSISTIVE TECH 

Although BrainConnect is fledgling research, Pantanowitz says this BCI may have applications in eye-gaze devices, which allow for the control of the environment by detecting where the gaze is focused. DM

Join one of the leading postgraduate teams of researchers at Wits University and position yourself at the top of engineering and biotech fields. For more information about the world-changing work being done by Witsies, go to www.wits.ac.za/future/ and www.wits.ac.za/news/latest-news/research-news/

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