Wits researchers interpret brainwaves to give amputees a hand
360° of progress engineered for real, life-changing solutions
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 SA, stroke victims may benefit significantly from this technology,” says Abdul-Khaaliq Mohamed, lecturer and PhD candidate in the School of Electrical and Information Engineering at Wits. “Strokes afflict 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, increasing access to such healthcare for many.
Mohamed co-ordinates a research group of six students studying different aspects of potentially controlling a robotic hand. Most BCI experiments to date have centred 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 says. 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 more than 97% of its graduates employed within six months of graduation. This includes engineering advancement by Wits biomedical engineer Adam Pantanowitz and his teams.
Top marks are due for a bionic hand engineered by Wits University postgraduates, who have made mobility more accessible to the 1m amputees in SA. The 3D-printed hand is light in weight and light on the pocket, as it drops the cost of this prosthetic from around R500,000 to R20,000.
THE BRAIN AS A NETWORK DEVICE
Pantanowitz discovered he had a neuromuscular condition as a teenager and since then, the lecturer in the Wits 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 while 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
Though 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 gaze is focused.
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This article was paid for by the University of the Witwatersrand.