Millions of people around the world have some form of sight or hearing loss, have no sense of smell or taste or have lost limbs, taking away their sense of touch. Fortunately, the science of senses is the most advanced it’s ever been. Biotech researchers are developing methods that merge humans and machines in ways that could restore human abilities to hear, see, taste, smell and touch. From neuro-prosthetic limbs that mimic touch to bionic eyes and smart glasses that restore sights, the innovations could drastically improve the quality of life of people around the world.
Some of the most advanced technology developed around the science of senses comes from the field of prosthetic limbs, where researchers are finding ways to connect tissue to metal. Systems called brain-machine interfaces literally wire robotic limbs to a person’s nervous system. Two of the latest achievements were reported in July 2019 in the journal “Science Robotics.”
In the first, a team from the University of Utah connected a robotic hand and partial forearm to the remaining nerves in the man’s arm. The man trained his brain to control the motion of the hand. At the same time, artificial zaps sent to the robotic hand were designed to mimic the skin’s natural response patterns to touch. Remarkably, the man could more easily discriminate between small and large objects as well as soft and hard items while blindfolded and wearing headphones. Another team, based at the National University of Singapore, engineered flexible, electronic skin that contains artificial nerves that transmit signals 1,000 times faster than nerves in human skin. The skin is able to sense temperature, pressure and humidity and is also durable enough to function even if it is scratched or damaged.
Since the mid-1980s, a tiny electronic device called a cochlear implant has been providing the sense of sound to hundreds of thousands of people worldwide, according to the National Institutes of Health. Part of the implant is surgically placed under the skin behind the ear, with another part attached in the same position externally. A third part is inserted inside the ear canal. Unlike a hearing aid that amplifies sound, a cochlear implant senses sounds and converts them into an electric signal that it uses to stimulate a person’s auditory nerve. Even people who are profoundly deaf can learn to discern sounds as long as some fraction of their nerve still functions.
But cochlear implants are not perfect. They are only capable of sensing and transmitting part of a sound wave’s full audio spectrum, producing a sound that has a metallic quality. That can make it difficult to filter out background noise, such as a crowd conversations or traffic. In 2019, a team from the University of Greenwich in England reported on new research that improves upon this technology, reports MedicalXpress. It deconstructs sounds from the environment and then reconstructs them with 90% to 100% percent efficiency. This means patients will be able to better distinguish noises from background sounds.
Oooh, That Smell
Smell loss, called anosmia, affects about 5% of the general population, according to the Massachusetts Eye and Ear Infirmary. The condition may be the result of something temporary, such as a sinus infection or swelling or polyps in the nasal cavity or it could be the result of damage to the sensory nerves. Permanent loss of smell can impact daily enjoyment of life and even affect safety. The inability of smelling smoke or natural gas could put someone in harm’s way.
Although there is no proven therapy, researchers at the Massachusetts Eye and Ear have, for the first time, invented a device that stimulates different smells. Their technology, which they reported in 2018 in the International Forum of Allergy & Rhinology, uses an array of tiny electrodes to send an electrical signal to the olfactory bulb, a structure in the brain involved in smell. In a small experiment, the scientists created different electrical stimulation in five patients, producing smells similar to onions and antiseptic as well as sour and fruity aromas. Although the innovation is still in the early stage, it demonstrates a possible path forward for a “cochlear implant for the nose,” the scientists say.
Although smell is connected to taste, it’s the receptor cells on the taste buds of a person’s tongue that discern sweet, salty, sour, bitter or savory flavors. Medical procedures inside the mouth or ear can alter a person’s taste, as can head trauma or ear infections, according to MedicineNet. Scientists have made a couple of attempts to solve the problem with technology. Back in 2013, a team from the National University of Singapore developed a taste simulator that used a kind of electronic tongue depressor to simulate taste sensations, New Scientist reported. Later, another team at City University of London invented a similar device called Taste Buddy that also stimulated taste buds to alter the flavor of foods, reported Digital Trends.
Unfortunately, neither gadget went beyond the research lab. For now, solutions may lie within human DNA. Lynnette McCluskey, a neurobiologist at the Medical College of Georgia at Augusta University, and her team are investigating whether a protein called interleukin-1, or IL-1, secreted during an injury could help rebuild a person’s sense of taste. The protein promotes inflammation and also helps regulate nerve growth. In 2018, she and her colleagues received grant money to study whether manipulating the proteins after an injury could help the nerves associated with taste recover faster, reports MedicalXpress. It could take a few more years to find out.
See You Soon
Worldwide, 36 million people are legally blind, according to Nature. Some biotechnological solutions, such as growing stem cells into those that can repair damage to the retina or using techniques from gene therapy to correct genetic defects, are showing promising results. But technology is also playing a big role.
A bionic eye, called the Argus II, is a retinal prosthesis system that, since its development in early 2000, has restored some vision capabilities to more than 300 people. It’s reserved for people who have no vision or almost no vision due to a genetic condition called retinitis pigmentosa. Patients undergo surgery, in which a tiny electronic device is attached to the person’s retina. It’s connected wirelessly to a pair of smart glasses that have a portable video-processing unit that project images from the outside world onto the person’s retina. Clinical trials done in 2015 showed that visual function improved in 90% of people wearing the prosthesis and that 80% of patients reported improved quality of life, according to the American Academy of Ophthalmology.
Advances in technology are allowing machines to merge with the human body. Coupled with our growing ability to correct genetic defects or repair cellular damage, the science of senses is moving into the future. One day all humans could move through the world with all five of their senses intact — seeing the unseen, hearing the unheard and tasting, touching and smelling new wonders that evoke all of the pleasures of being alive.
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