Passing the Sniff Test

It has been estimated that about one-fifth of the global population experiences some type of loss of the sense of smell. This is certainly not a new problem, but it was significantly exacerbated in recent years by the emergence of COVID-19, which is known to cause some individuals to permanently lose their ability to smell. Those impacted by this condition not only have to deal with the loss of enjoyment of food, but they also face challenges when it comes to noticing fire, gas, or smoke.

That is a serious safety concern, so many people suffering from olfactory dysfunction seek out treatment to restore as much function as they possibly can. Most people are not aware of this fact, but olfactory training can reverse dysfunction in many cases. However, the training process is very time-consuming, and it is repetitive and uninteresting to boot. For this reason, patients commonly do not stay the course and leave treatment programs before the full benefits can be attained.

A researcher at the Imperial College London and the Royal College of Art has developed a creative device that is meant to make olfactory training more interesting and engaging. The device, called Seent, looks like a miniature arcade cabinet, and it gamifies the olfactory training process.

The hardware includes a panel with four buttons, a five-inch display, and a Raspberry Pi 4 Model B, which controls an array of piezoelectric atomizers. These atomizers each contain a distinct scent solution — phenylethyl alcohol, eucalyptol, citronella, or eugenol. When activated, the atomizers convert the liquid scents into a fine mist that is released through holes on the panel, allowing users to sniff specific odors. This digital delivery method ensures consistency and precision in scent release, automating the timing and amount of each odor for a reliable experience.

Seent’s gamified interface includes three interactive games designed to improve olfactory abilities. The first game is a simple "press and play" mode, where participants press a button to release a scent while a visual icon of the odor appears on the screen. This process helps users associate each scent with its corresponding visual cue. The second game is an odor identification exercise, where one of the four scents is released randomly, and participants must guess which scent it is by pressing the corresponding button. Finally, in the odor differentiation game, users smell three consecutive scent releases, two of which are identical, while one differs, and they must identify the odd one out. Instant feedback is provided during these games, adding an engaging, playful element that enhances olfactory rehabilitation by encouraging regular participation and progress tracking.

The system has not yet been evaluated in user studies, so its potential effectiveness is purely theoretical. There are future plans to evaluate Seent formally to assess its utility, however. Moving forward, the device will also be improved such that it can additionally be used to carry out olfactory testing procedures, which medical professionals use to assess one’s sense of smell. Such tests may also help to uncover cases of Parkinson’s Disease and Alzheimer’s Disease in the earlier stages.