Many folks over this past year experienced the loss of their senses of smell during the Covid pandemic. Anosmia, as it’s called in medical speak, is when foreign invaders mess with the parts in your brain that are responsible for your ability to detect scents. But anosmia might not just come about when you’ve got a respiratory infection. In fact, it may be an early sign of dementia.
Anosmia and Dementia
A growing body of research suggests that anosmia could be an early sign of dementia, and that’s because the condition has been linked to the olfactory system. The olfactory system refers to the communication pathways between our nose and our brain that allows us to perceive smell. In our nasal cavities, we have olfactory neurons, and each one has an odor receptor. Substances in our environments, like a cup of coffee or cookies baking in the oven, release tiny molecules into the air that stimulate these receptors. When the neurons detect these molecules, they send a message to your brain, allowing you to smell that specific scent.
According to one specific study published in the Journal of the American Geriatrics Society, an early decline in our olfactory abilities is linked with dementia. The researchers recruited 2,906 men and women between the ages of 57 and 85 for their sample. Each participant was asked to do a verbal interview and a smell test which asked them to identify five scents: peppermint, fish, orange, rose, and leather. They sniffed the scents and were then given four answers to choose from, and the scientists recorded how many they answered right and wrong.
The researchers conducted a follow-up interview five years later. According to their data, the folks who were unable to identify at least four out of the five odors during the initial smell test were found to be more than twice as likely to have developed dementia over those five years. “These results show that the sense of smell is closely connected with brain function and health,” Jayant M. Pinto, MD, senior author of the study, said in a press release. “We think a decline in the ability to smell, specifically, but also sensory function more broadly, may be an important early sign, marking people at greater risk for dementia.”
The team suggests that the link is probably a signal that dementia may cause an impairment in the olfactory cortex in the left hemisphere of the brain, which is responsible for other functions like language and calculation.
All this being said, there are other possible causes of anosmia, including sinus infections, allergies, covid-19 infection, side effects from some medications, and Parkinson’s disease. Make sure to your doctor about any new or recurring symptoms you’ve noticed (did you know that increases in body pain might signal dementia?). It’s truly your best bet when it comes to making determinations about your long-term health.