For Chrissi Kelly, losing her sense of smell was a catastrophic event that changed her life forever. After catching a virus while traveling to the Czech Republic 14 years ago, she began experiencing complete smell loss, which lasted for months. Despite visiting doctors and trying to find answers, she was told she’d have to learn to live with it.
However, Kelly’s experience is not unique – researchers estimate that up to 22% of the population lives with smell impairments, like hyposmia (partial smell loss) or anosmia (complete smell loss).
The pandemic brought unprecedented attention and research interest to the sense of smell. With Covid-19 causing millions of noses worldwide to malfunction at roughly the same time, scientists began to study this critical sense in greater detail.
As they learn more about how the sense of smell operates, evidence is mounting that it’s deeply tied not only to quality of life but also to brain health.
Smell enriches life and directs our behavior, helping parents and children bond, warning us of environmental dangers, and anchoring emotional memory. ‘Humans are actually quite good at smelling,’ says Swedish psychologist Jonas Olofsson, author of The Forgotten Sense: The New Science of Smell and the Extraordinary Power of the Nose.
The sense of smell works by detecting airborne molecules that bind to specialized receptors in the nasal cavity. Millions of olfactory neurons in the upper nose detect these odorants, then send electrical impulses via the olfactory bulbs, which create a sensory map in the brain – basically, a system to identify, distinguish, and remember scents.
Unlike vision or hearing, smell directly signals brain areas responsible for emotion (the amygdala) and memory (the hippocampus), which could be why smells can strongly trigger memories. Furthermore, the olfactory bulbs are now known to be among the few brain regions that create new neurons during adulthood, helping the brain deal with constantly changing environments.
After losing her sense of smell, Kelly searched for insight and commiseration but found neither. She then founded two nonprofit patient groups and became a community scientist, co-publishing more than 30 academic papers with researchers. Her experience highlights the need for greater understanding and support for those affected by smell loss.
Smell loss can be caused by various factors, including viruses that attack olfactory support cells, head injuries that damage the olfactory nerves, allergies, and sinus infections. In some cases, the problem clears when the inflammation does, but in others, lasting damage is done to the olfactory nerves.
Dave, a wine lover who lost his sense of smell 20 years ago, managed to fake it on wine tours and cruises. However, he later experienced a slowed gait and tremors, leading to a diagnosis of Parkinson’s disease. There are many unknowns about the earliest stages of this disorder, but researchers believe that smell loss can be an early indicator.
As scientists continue to study the sense of smell, they’re uncovering its complexities and importance in our lives. By shedding light on this often-overlooked aspect of human experience, we may gain a deeper understanding of ourselves and the world around us.
Source: Original article