Losing one’s sense of smell, or anosmia, can be a devastating experience. It can affect not only the enjoyment of food but also our ability to detect danger and our emotional well-being. For many people, the loss of smell is permanent and can result from a variety of conditions, including brain injuries and diseases such as covid-19. Two researchers at the Virginia Commonwealth University School of Medicine are working on a bionic device that they hope will help millions of people struggling with anosmia.
Craig Jerome, a nurse practitioner in North Carolina, contracted covid two years ago and lost his sense of smell. He is one of the many people who continue to experience anosmia even after recovering from covid. Richard Costanzo and Daniel Coelho hope their neuroprosthetic, which they call a “bionic nose,” can help Jerome and others like him.
The bionic nose is a device that uses microelectronics and computer processing, including artificial intelligence, to bypass the damaged olfactory cells and stimulate the brain directly with an implanted electrode array. A small external odor sensing piece will send signals to a microprocessor chip which will generate “unique digital fingerprints for different smells.” The chip will then relay the information via special radio wave frequencies to a receiver inside the skull to stimulate specific brain areas that generate a particular smell sensation or perception.
It will take five to ten years for a fully developed prototype to be ready for implantation and testing in patients. The researchers are currently conducting human studies to map out specific regions of the brain that, if stimulated, could generate smell perceptions. They are also planning studies to build a clinical version of their prototype that is safe and effective.
Studies to understand smell perceptions
An early version of the neuroprosthetic was tested on rats. The researchers cut the olfactory nerves of the rodents and surgically placed an electrode array by the olfactory brain area. Costanzo said they were able to bypass the cut nerves and activate the olfactory brain cells.
“The rat could not tell us what they could smell, but we could record the electrical signals generated in the brain,” he said.
The researchers — collaborating with a former student of Costanzo, Mark Richardson — are now conducting human studies to map out specific regions of the brain that, if stimulated, could generate smell perceptions.
Richardson, director of functional neurosurgery at Massachusetts General Hospital, is studying epilepsy patients, who have electrodes placed in different regions of the brain to understand which areas are involved in seizures.
Those who agree to participate in the smell study are presented with different odors. Using recordings from the electrodes, the researchers are mapping brain areas associated with odor perceptions to determine the optimal sites for the olfactory electrode array.
“Figuring out how odor perception emerges from brain activity is a complex decoding problem,” Richardson said in an email, “but there may be multiple ways to re-create important aspects of smell for people with anosmia.”
The researchers also are planning studies to build a clinical version of their prototype that is safe and effective, they said.
The path to a commercial device
Across the Atlantic, the European Union is funding its own olfactory-implant project, called ROSE (Restoring Odorant detection and recognition in Smell dEficits). It launched in 2021 and involves seven institutions across Europe.
Thomas Hummel, head of the Smell & Taste Clinic at the Technical University of Dresden and a member of the consortium, says the ROSE researchers are partnering with Aryballe, a French company that makes a tiny sensor for odor analytics. The partners are currently experimenting with stimulating both the olfactory bulb and the prefrontal cortex. “All the parts that are needed for the device, they already exist,” he says. “The difficulty is to bring them together.” Hummel estimates that the consortium’s research could lead to a commercial product in 5 to 10 years. “It’s a question of effort and a question of funding,” he says.
Persaud, the e-nose expert, says the jury is out on whether a neuroprosthetic could be commercially viable. “Some people with anosmia would do anything to have that sense back to them,” he says. “It’s a question of whether there are enough of those people out there to make a market for this device,” he says, given that surgery and implants always carry some amount of risk.
The VCU researchers have already had an informal meeting with regulators from the U.S. Food and Drug Administration, and they’ve started the early steps of the process for approving an implanted medical device. But Moorehead, the investor who tends to focus on practical matters, says this dream team might not take the technology all the way to the finish line of an FDA-approved commercial system. He notes that there are plenty of existing medical-implant companies that have that expertise, such as the Australian company Cochlear, which dominates the cochlear-implant market. “If I can get [the project] to the stage where it’s attractive to one of those companies, if I can take some of the risk out of it for them, that will be my best effort,” Moorehead says.
Restoring people’s ability to smell and taste is the ultimate goal, Costanzo says. But until then, there’s something else he can give them. He often gets calls from desperate people with anosmia who have found out about his work. “They’re so appreciative that someone is working on a solution,” Costanzo says. “My goal is to provide hope for these people.”