People who lost their sense of smell during Covid are now experiencing a temporary change in their personality

A brand new investigation into the consequences of Covid In the long term it shows that people who lost their sense of smell During the acute phase of the infection, the brain now suffers structural alterations, which is particularly evident in a specific behavior: being more prone to impulses in decision making.

Since the beginning of the pandemic caused by SARS-CoV-2, evidence has accumulated that some recovered patients present cognitive impairment and brain disorders. Studies have found that even months after recovery, some people continue to experience neurological, psychiatric and cognitive effects. Other studies suggest that vaccination remains a weapon to cushion these consequences.

“Despite the growing body of evidence, specific clinical factors associated with brain alterations remain elusive, presenting challenges in identifying populations at risk of developing long-term brain and cognitive impairment after SARS-CoV-2 infection,” says a paper published in the journal Scientific Report, which has given one step forward in that sense.

The work, whose evidence is based on a “laboratory game” in which participants had to perform a series of elections under certain premises, was carried out by researchers from the Center for Studies in Human Neuroscience and Neuropsychology at Diego Portales University, Chile, and published in Nature.

“The severity of acute infection It is the most studied clinical factor leading to brain and cognitive impairment. A longitudinal cohort study has revealed that the severity of the acute episode correlates with cognitive impairment in long-term follow-up,” the research adds.

Digital model of the human brain showing, in red-yellow, brain regions damaged by Covid. Photo: NYT

Patients who experienced a severe episode and exhibited neurological symptoms during the infection showed cognitive impairment and brain alterations. one year after infectionEven patients with mild Covid also show subtle brain changes, experts say.

Consequences of loss of smell

As for the loss of smellthe researchers note that “Anosmia is a commonly reported symptom in patients with Covid-19 that frequently occurs early in the course of the disease and may persist as a long-term symptom. It has been suggested that SARS-CoV-2 infection causes the death of supporting cells in the olfactory epithelium, with consequences for neuronal function. This mechanism aligns with the rapid onset of anosmia in Covid-19 and its rapid recovery after the regeneration of support cells.”

“Our findings indicated that both hospitalization and anosmia had differential impacts on behavior in a cognitive flexibility task. However, only anosmia was consistently correlated with alterations in brain function on several parameters including the functional activityhe cortical thickness and the white matter integrity (fibers of the neurons that connect them and transmit impulses to others”, alterations associated with changes in character, more impulsive behavior and deficits in decision-making.

“While no differences were observed in our cognitive screening assessment, differences did emerge intriguing patterns in the performance of the behavioral task. All participants showed adaptive behavior during the game. In particular, the distinctive decision-making strategy observed in patients with anosmia was characterized by more impulsive option changes“, they concluded.

Neurologist Conrado Estol, consulted on the subject, framed this picture within what is called long Covid or “Long Covid”: “Long Covid is a great challenge for the worldfor human health, for health systems and the global economy. There are about 400 million people affected in the world and the cost of treating these people would be one trillion dollars (1% of the global economy). These patients can have any organ of the body affected. We are still far from having a biomarker. Several have been evaluated and none define who specifically has this form of long Covid, and there is no approved treatment either, although there are several under evaluation.”

The Covid vaccine remains the best tool to avoid short- and long-term complications.

He then focused on the object of study of the published work: “The brain is one of the most affected organsThe mechanism is complex because inflammatory cells and substances are activated, which alter the function of brain tissue and cause damage with inflammation of the neurons and activation of the cells located between the neurons, which injures the neurons. In addition, a relationship is activated between the adrenal gland and the cortisol generated by that gland, with an effect on the brain.”

In the research they observed that patients who had loss of smell during Covid “have altered responses and this is manifested by impulsivity and difficulty in decision makingfunctions that belong to the frontal lobe in what is called executive function, which is what allows us to organize and carry out actions,” Estol explained.

Finally, the expert added that “patients, whether they had moderate or severe disease, when they presented loss of smell – confirming that the virus had entered the brain and affected this sense – evidently by performing more sensitive cognitive studies, the researchers detected that Not only had they lost their sense of smellbut they had altered behaviors, reflecting that the brain damage had been more extensive.”