If your alertness and reaction time are higher than usual, you may be at higher risk of contracting a viral illness. This is the main finding of an experiment conducted by researchers from the University of Michigan, Duke University School of Medicine and the University of Virginia reported in the review Scientific Reports. Their study reveals that poor immune performance tends to go hand in hand with periods of fluctuating cognitive performance. They thus hypothesize that when a person’s cognitive functioning begins to fluctuate, the latter is more likely to present more symptoms related to respiratory infections. As a reminder, cognitive functioning corresponds to the capacities of the brain which make it possible to interact with the environment: they make it possible to perceive, concentrate, acquire knowledge, reason, adapt and interact with others.
« We all know that if we are stressed or if we have not slept enough, it predisposes us to have a less resistant immune system. says Alfred Hero, professor emeritus of electrical engineering and computer science and corresponding author of the study. “ This is the first exposure study in humans to show that cognitive performance before exposure to a respiratory virus can predict the severity of infection. Small changes in typical daily cognitive performance can lead to changes in brain states that can increase disease risk, such as stress, fatigue, and poor sleep. Based on this observation, the scientific team wanted to measure cognitive function and determine whether it was predictive of immune performance after exposure to a respiratory virus. It turns out that cognitive variability, measured using a digital home self-test, was found to be highly predictive.
“Variation in cognitive function is closely linked to immunity”
To do this, the researchers recruited 18 healthy volunteers who agreed to take brain performance tests three times a day for three days using a digital home self-test. The goal: to obtain 18 measures of cognitive function, including reaction time, and attention which were then combined to give scientists an index of variability. They were then exposed to the human rhinovirus (HRV), usually responsible for the common cold. During the remaining days, they were self-administered with a nose wash to measure the presence and volume of excreted viral cells. The volunteers were also asked to rate their experience of eight symptoms, including chills, cough, headache, stuffy nose, runny nose, sneezing, sore throat and fatigue. The results showed that those who shed the most virus and had the worst symptoms tended to show inconsistent cognitive scores in the days leading up to their illness.
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« At first, we did not find that cognitive function had a significant association with disease susceptibility because we used raw scores. But later, when we looked at change over time, we found that variation in cognitive function is closely related to immunity. underlines Pr Yaya Zhai, first author of the study. In other words, one single test is probably not enough to determine the state of a person’s immune system. Cognitive performance measured over days could be the answer, however, although the study authors acknowledge that most people are unlikely to take a cognitive test three times a day for the rest of their lives. Another difficulty encountered in applying this method is that in the “real” world, a person does not know when they will next be exposed to a virus, making it difficult to predict future immune responses through brain tests: regularity remains to be determined.
While further studies with a larger sample of participants are needed, the science team says they hope this finding will pave the way for more research regarding the role of the brain in immune health. She also says she is optimistic about the possibility that smartphone use could help identify periods of increased susceptibility to infection, by monitoring cognitive indicators such as speed and accuracy of use as well as the time user goes to sleep. This data would then be combined with attention and memory tests to better predict an increased risk of serious illness and precautionary measures could then be taken to reduce their exposure, or secure their body’s defenses. ” Traditional clinical cognitive assessments do not provide an accurate picture of brain health. », notes Fr. Murali Doraiswamy of Duke University School of Medicine, who designed the study’s neurocognitive test. ” At home, periodic cognitive monitoring, via digital self-testing platforms, is the future of brain health assessment. »he concludes.