By James Gamble via SWNS
The first-ever prosthetic limb that allows the wearer to sense temperature and feel the warmth of another person has been created.
The MiniTouch, a device that allows amputees to perceive and respond to temperature, is hoped to vastly improve their human connections.
The smart new device allows amputees to sense temperature by transmitting thermal information from the fingertip of the prosthetic hand to the wearer’s residual arm.
Using the device, an amputee of more than three decades was able to differentiate between hot and cold objects with 100 percent accuracy and even feel the warmth of another person’s hand through their prosthetic.
The clever piece of equipment was developed by scientists in Italy and Switzerland, and it’s hoped it could soon restore a full range of sensation to amputees.
Sensory feedback is one of the most important steps in allowing amputees to interact with their environment.
The MiniTouch, a sensorised prosthetic hand that provides realistic and real-time thermal feedback, intends to restore the sensory experiences of touch back to amputees.
Fabrizio, a 57-year-old man from Pistoia in Italy, is the first amputee to try the new device and was overcome with the emotions that resulted from feeling the warmth of another person again – 37 years after his hand was amputated from the wrist.
Using the MiniTouch, Fabrizio was also able to discriminate between and manually sort objects of different temperatures or materials.
“When one of the researchers placed the sensor on his own body, I could feel the warmth of another person with my phantom hand,” he said.
“It was a very strong emotion for me. It was like reactivating a connection with someone.”
The new technology, presented in a study published in the journal Med, marks the first time natural temperature sensations have been incorporated into a functional artificial limb.
Professor Silvestro Micera, a joint senior author of the study from the Sant’Anna School of Advanced Studies, explained: “Temperature is one of the last frontiers to restoring sensation to robotic hands.
“For the first time, we’re really close to restoring the full palette of sensations to amputees.
“This is a very simple idea that can be easily integrated into commercial prostheses.”
The collaborative team built on previous findings on phantom thermal sensations to develop the MiniTouch, which uses off-the-shelf electronics, can be integrated into commercially available prosthetic limbs and does not require any surgery.
The device is integrated into the wearer’s prosthesis and attached to a point on the same residual limb, producing thermal sensations in their phantom index finger.
In clinical tests at the Inail Prosthesis Centre in Vigorso di Budriothe in Bologna, Italy, the researchers discovered that Fabrizio was able to distinguish between three indistinguishable bottles containing cold (12°C), cool (24°C), or hot (40°C) water with 100 percent accuracy.
Without the device, his accuracy was just 33 percent.
The device also improved the Fabrizio’s ability to accurately and quickly classify metal cubes of differing temperatures and improved his ability to differentiate between human and prosthetic arms while blindfolded — from 60 percent without the device to 80 percent with it.
Dr. Solaiman Shokur, a joint senior author from the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, said: “When you reach a certain level of dexterity with robotic hands, you really need to have sensory feedback to really be able to use the robotic hand to its full potential.
“Adding temperature information makes the touch more human-like.
“We think having the ability to sense temperature will improve amputees’ embodiment – the feeling that ‘this hand is mine’.”
Jonathan Muheim, a doctoral student at EPFL and another co-first author of the study, added: “Up to now, thermal sensations have been very much neglected in neuroprosthetics research even if there is increasing evidence of their importance in our everyday life.
“We think that amputee individuals could benefit from regaining temperature sensations well beyond the detection of cold or warm objects.”
The MiniTouch is continuing to be tested in the lab, with the next step to ready the device for home use and to integrate thermal information from multiple points of an amputee’s limb.
For example, allowing wearers to differentiate thermal and tactile sensations on their finger and thumb might help them grasp a hot beverage, whilst enabling sensation in the back of the hand might improve the feeling of human connection by allowing amputees to sense when another person touches their hand.
“Our goal now is to develop a multimodal system that integrates touch, perception, and temperature sensations,” Dr Shokur says.
“With that type of system, people will be able to tell you ‘this is soft and hot’, or ‘this is hard and cold’.”
Prof Micera added: “This study paves the way for more natural hand prostheses that restore a full range of sensations, offering amputees a richer and more natural perception of the tactile world.”
