Do olfactory illusions exist, similar to optical and audio illusions?

There are optical illusions and audio illusions. Is there such a thing as an olfactory illusion? Philip Martin Tintwistle, Derbyshire, UK I can personally testify that there is. After contracting the omicron variant of the covid-19 coronavirus, I lost my sense of smell almost completely. Advertisement After several years hoping in vain that I would recover naturally, I was advised by my family doctor to try “smell retraining therapy”, developed by Thomas Hummel at the University of Dresden in Germany. This involves trying to teach your brain to relearn the range of core smell types: menthol, citrus, rose, etc. Although initially dubious, since consistently inhaling essential oils over the past few months, I have once again begun to detect many odours, such as perfume and various foodstuffs. However, during this period, I have also experienced some episodes where strong smells have appeared randomly out of nowhere with no obvious link to anything in the surrounding environment. Interestingly, at the same time, I experience intense memories of places associated with those smells. It seems as if, during the process of relearning, my brain is mixing up sensations and generating phantom smells. I have experienced episodes where strong smells have appeared randomly with no obvious link to the surroundings Joe Oldaker Nuneaton, Warwickshire, UK Almost certainly. I heard of someone who constantly smelled the scent of daffodils, although there were no daffodils present. It turned out he had a brain tumour. To answer this question – or ask a new one – email [email protected]. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address. The use of AI tools (e.g. ChatGPT, Claude) to write either questions or answers is forbidden, and any submissions found to have been written using AI tools will be withdrawn.