Olfactory implants: Several projects are working on solutions

The covid pandemic has brought a great deal of attention to many issues that were previously largely under the public radar. In addition to chronic fatigue syndrome, the loss of the sense of smell in particular has been the subject of much discussion, since it affects a considerable proportion of sufferers. For some time now – and independently of the pandemic – implants have been developed in several projects that are intended to restore the sense of smell and thus a large part of the quality of life.

Project at Virginia Commonwealth University

Richard Costanzo and Daniel Coelho have been leading a project at Virginia Commonwealth University for several years aimed at developing an olfactory implant. The implant is based on a system that closely resembles that of the long-established cochlear implants that allow the deaf to hear. Costanzo and Coelho filed a patent application back in 2016.

At the heart of the implant is a sensor that is designed to detect odors and recode them into electrical signals, which in turn are relayed to a transmitter. This transmitter sends the signals to an implanted stimulator, which is supposed to trigger an olfactory sensation via electrical stimuli. A prototype has already been built – but only from the external elements of the prosthesis, i.e., without a stimulator. In a demonstration for IEEE Spectrum magazine, the prototype was instead connected to a smartphone that signaled what kind of smell it was. Various liquids held in front of the sensor were tested.

Smell stimuli trigger complex response

Costanzo and Coelho were able to show in animal experiments that the sense of smell is far more complex than commonly thought. For example, stimulation of the olfactory bulb not only triggered an odor sensation, but also led to the activation of other brain areas. The two researchers suspect that, to a certain extent, this involves mapping of different olfactory sensations. Among other things, brain areas responsible for processing emotions, memories and abstract information are involved. Accordingly, odors are not simply isolated pieces of information, but are closely linked to memories and emotions – which explains why they are of central importance for quality of life.

This aspect of quality of life was lost by many people in a short period of time during the pandemic. Studies suggest that the occasional loss of smell associated with Covid-19 remains permanent in 7.5 percent of cases. However, not only Covid-19, but also other infectious diseases can cause loss of the sense of smell. In addition, accidents can cause it.

Other projects are working on olfactory implants

In addition to Costanzo and Coelho, other researchers are also working on olfactory implants. For example, research by the ROSE team, which is funded by the EU, is particularly promising. This project will develop, implant and test implants. It is an interdisciplinary collaboration involving specialized teams from France, Italy, Germany and Greece.

Meanwhile, working to commercialize Virginia Commonwealth University’s technology is a startup founded by wireless entrepreneur Scott Moorehead. Moorehead himself has been affected by the loss of his sense of smell. The cause in this case was a skateboarding accident.

Despite all efforts, however, it will probably be several years before a corresponding product is ready for the market. In addition, it is to be expected that the scope of detectable odors will be significantly limited in the first models. In the long term, however, it should be possible to detect several hundred odors.

The research is part of the efforts to overcome physical limitations of humans by technical means. In addition to cochlear implants, vision implants have already been developed and used. Even electrodes that are inserted into the spinal cord and allow paraplegics to walk again have already been developed.