Made to help amputees feel again from their missing limbs, SENSY from SensArs is a interesting prosthetic device available worldwide, made to restore life-like sensory feedback from the prosthesis of amputees or from the limb of patients with damages to the peripheral nerves. The neuroprosthetic is implanted within the residual nerves of the amputees, or the healthy part of their nerves to restore the natural flow of the neural sensory information.
Those who have lost their limbs in unfortunate events would thus be able to return a bit more to their previous way of living, perhaps easing them slightly from the mental and body fatigue of their accidents. This also helps subjects feel more natural again, tackling the problem of the phantom limb syndrome that may possibly arise. Over the course of a one-month therapy program with neurostimulation, scientists managed to considerably reduce phantom limb pain in one of the patients who complained of having it and in the other, the pain disappeared completely.
The prosthetic leg device, SENSY, is able to sense various parts such as foot touch, pressure, and knee joint angle with its external sensors. These sensed signals are then transmitted back to the nervous system using a set of stimulation electrodes implanted into the tibial nerve.
SENSY consists of an implantable intraneural electrode for sensory nerve stimulation, an implantable stimulator and an external smart controller. This smart controller, which is the “brain of the system” can be connected to the sensors embedded in the prosthesis or to a sensorized glove or sock, and receives information from the prosthesis and transduces it in the language of the nervous system, instructions of stimulation, which it sends to the implantable stimulator.
In other words, Artificial sensors are implanted to connect to intact nerves, stimulating response in the brain as if there was an intact nerve in a limb. The sensors are connect to wires simulating an actual nerve, and those wires are implanted and connected to actual nerves within the body. Between the artificial sensors and the residual nerve is an implantable neurostimulator which is bidirectional, sending and receiving signals from both the intact nerve and the artificial sensors.
The device was created with several options of usage:
- Being simply a sort of neural sensory pacemaker if the user does not have prosthetics
- an excitable device like a sensor which also sends a signal to the nerve.
- Being a sensorized prosthetic
- Being a sensorized glove or sock over intact limbs but with nerve damage
- These socks and gloves contain sensors within the fabric which act essentially as sensitized skin, also sending signals to an implanted device which communicates with the intact nerves
To make this device, the scientists tested attached tactile sensors to the sole of commercially available prosthetic feet, and collected knee movement data. They then placed tiny electrodes in volunteers’ thighs, connecting them to residual leg nerves, trying to introduce eletrodes inside the nerve to allow the restoration of a more natural sensory feedback.
The research team then made algorithms to translate information from their sensors into current impulses that the nervous system reads, delivering them to the residual nerve. The signals from the residual nerves are conveyed to the person’s brain, which is thus able to sense the prosthesis and helps the user to adjust their manner of walking accordingly.
From the test they received positive feedback from volunteers of the device, with many mentioning it was less mentally strenuous to use and also gave patients more confidence in themselves.
I think the device is good as it gives those who have unfortunately lost a limb a chance to return to the way of living before their accident. Those who have lost their limbs in accidents most probably face the stress of losing a limb they were previously reliant on, and now, instead of having to change their entire lifestyle, they could still continue the path they were moving on. Usual prosthetics may help in providing some comfort by helping the users in feeling whole again but it may also go so far, as the senses in the lost limb are not felt by the user. This device helps users to come close to feeling as though they had never lost their limb, easing their pain.
I think SENSY is also incredible as it works in various ways. The adaptability of the device ensures a large range of users reap the benefits from their products, as those with varying problems from having nerve damage to missing an entire limb are all covered with SENSY.
Perhaps SENSY can go one step further and work with researchers studying how to make more human-like artificial skin to make the prosthetic even more similar to an actual limb. One example of an interesting skin made is by RMIT, that can electronically replicate the way human skin senses pain. The device mimics the body’s near-instant feedback response and can react to painful sensations with the same lighting speed that nerve signals travel to the brain.
Features of the electronic skin:
- Stretchable electronics: combining oxide materials with biocompatible silicone to deliver transparent, unbreakable and wearable electronics as thin as a sticker.
- Temperature-reactive coatings: self-modifying coatings 1,000 times thinner than a human hair based on a material that transforms in response to heat.
- Brain-mimicking memory: electronic memory cells that imitate the way the brain uses long-term memory to recall and retain previous information.
“It means our artificial skin knows the difference between gently touching a pin with your finger or accidentally stabbing yourself with it – a critical distinction that has never been achieved before electronically.”
Hence, if they are able to work with RMIT, they could most probably create an artificial limb akin to a real one, allowing amputees get back their limbs and feel no difference.
All in all, SENSY is amazing as it is able to in a way replicate an actual human body part using technology and allow users’ neural signals to work with this artificially made device. Considering this, it feels as though advances in technology is bringing us one step closer to a world of cyborgs. Perhaps in the near future, one can easily replace damaged limbs for better artificial ones.