Cognitive abilities refer to the mental processes and skills used in thinking, learning, remembering, and problem solving.
The study used a special device called the olfactory action meter to test how well people smell and remember different smells. Covid patients and recovered were part of the study.
The IISER scientist Dr. Nixon M. Abraham told TOI, “We found that symptomatic patients and recovered participants had significant difficulties in learning to match different odors during and after infection (up to 4-18 months post-Covid) compared to their healthy peers. The study therefore suggested that Covid could cause long-term problems with thinking and memory.”
The study assessed neurocognitive impairments (difficulty distinguishing and retaining olfactory information in working memory or thought processes related to sensory mapping) in these groups. Such impairments can include problems with memory, attention, language, and other cognitive functions.
Previously, LNCB had used the smell meter to identify asymptomatic Covid-19 carriers, a study published in the Lancet eClinical Medicine.
“Now we look forward to developing the olfactory meter as a diagnostic tool to quantify olfactory abilities in health and disease conditions, since people with neurodegenerative diseases often have problems with such abilities. Therefore, recognizing these problems at an early stage would be important to help better treatment strategies. We also expect financial support from the private sector,” said Dr. Abraham.
“As part of the study, participants were given one stimulus or odor to smell, followed by another. They were then asked to retain the information about the first smell in their working memory. When given the second stimulus (second smell), they were asked to compare it to the first and judge whether both smells were the same or different. We also asked the post-Covid participants, as well as the healthy ones, to come back on consecutive days for the same test. The test was conducted periodically for five days to assess whether their performance had improved,” said Dr. Abraham.
The team observed that healthy participants showed a marked improvement in their ability to identify different smells, but there was no improvement in Covid patients or those who had recovered from the infection many months ago.
“This was a clear indication that a person’s cognitive abilities can be impaired even up to 6-8 months after recovery from infection with Covid. However, this can be subjective depending on several factors,” added Dr. added to Abraham.