Long-term loss of smell due to Covid-19 may predict onset of cognitive decline, study finds.
- According to the Ministry of Health, “we speak of ‘long Covid’ when, after being infected, a patient still suffers from initial symptoms or symptoms that have occurred secondarily for more than 3 months, without these being linked to another pathology” .
- The researchers noticed that the volunteers suffering from severe cognitive disorders also suffered… from a loss of smell. And that the more severe and persistent the anosmia, the more significantly brain disorders could be predicted.
If it persists over time, anosmia, in other words a loss of smell, could predict an increased risk of “long-term brain decline”according to a study presented at the end of July during the Alzheimer’s Association International Conference (AAIC) and relayed by the scientific journal Medscape Medical News.
Three distinct smells
To reach this conclusion, Argentinian researchers examined for a year the cases of 766 patients, aged 55 to 95, almost all (88.4%) infected with Covid-19. The participants underwent regular physical, neuropsychiatric and cognitive tests, one of which involved identifying three distinct smells, which was used to assess their degree of loss of smell. At the same time, the scientists analyzed the volunteers’ attention, language, executive function and memory.
As a result, the scientists found that two-thirds of the infected participants had functional memory disorders, which were particularly serious in half of them. In detail, 11.7% suffered from a failing memory, 8.3% from a deficiency in attention and executive functions, and 11.6% from combined problems (memory, learning, attention, execution of tasks, etc.).
“Whatever the severity” of the Covid
However, the researchers noticed that the volunteers suffering from severe cognitive disorders also suffered… from a loss of smell in the long term. And that the more severe and persistent the anosmia, the more significantly brain disorders could be predicted.
“Our data strongly suggest that adults over 60 are more vulnerable to post-Covid cognitive impairment if they have smell dysfunction, regardless of Covid severity”, explains Dr. Gabriela Gonzalez-Aleman, the lead author of the study, quoted by Medscape. In other words, more than the severity of the disease itself, it would be the severity of the anosmia that would best predict the onset of cognitive disorders.
Participants with impaired sense of smell had a “predominance of memory impairment, as would be seen in Alzheimer’s disease”, adds the researcher. Anosmia, scientists say, is indeed a signal of an inflammatory response in the brain – inflammation that is part of the neurodegenerative process associated with Alzheimer’s.
