COVID Fog? Study Links Smell Loss to Impulsivity and Brain Alterations

Study Links Smell Loss to Impulsivity and Brain Alterations
Study Links Smell Loss to Impulsivity and Brain Alterations. Credit | Getty images

United States: According to a new study of seventy-three adults who had stayed at the hospital, recovering from Covid, and lost their sense of smell, they seemed to have changes in their behaviors, their functions, and the structure of their brains.

More about the finding

Chilean scholars assessed cognition, decision-making on a test, functional abilities, and magnetic resonance imaging (MRI) with 73 individuals who contracted mild to moderate COVID-19 and 27 other COVID-naïve patients with infections from other pathogens.

Two follow-up sessions were held for a period of 15 days in between sessions.

The patients were convenience sampled from public and private hospitals, Santiago, enrolled in this study an average of nine months after diagnosis from February 2020 to May 2023.

The average age was 40.1 years. The team relied on loss of smell and the requirement of hospitalization as proxies of potential markers of neurologic involvement and disease severity.

These findings were reported late last week in the journal Scientific Reports.

The study author mentioned, “Given the significant global incidence of COVID-19, identifying factors that can distinguish individuals at risk of developing brain alterations is crucial for prioritizing follow-up care,” as cidrap.umn.edu reported.

Findings of the study

Among 73 COVID-19 patients, twenty-two (30.1 percent) said that they have differing degrees of attention and memory issues.

Seven of the patients stated that they had headaches, six said they were tired, and four had a persistently altered sense of smell that lasted, on average, 1.3 months.

Of these patients, 68.0 percent had anosmia, while the rest had a change in their olfactory sense.

Besides the self-administered change in smell, 6 out of 43 patients who lost their smell during the acute infection could only identify at most four of six odors by olfactory test, indicating ongoing impairment.

Thus, no significant differences in age or cognitive performance were found between the COVID and non-COVID groups, but patients with a loss of smell were more impulsive and were more likely to make a different choice when given a negative result when performing a behavioral task (a game), as cidrap.umn.edu reported.

In contrast, COVID inpatient participants displayed less strategic thinking and repeated the same wrong choice on the behavioral game delivered as a task.

According to the study authors, “Only six patients present indicators of persistent olfactory deficit; thus, our results are not due to actual deficit,” and “Hence, anosmia could serve as both a potential marker of virus-induced damage to neuronal tissues and a marker for individuals susceptible to brain damage.”