ANN ARBOR, Mich. — If you find yourself lacking alertness or overall mental sharpness, you may be at a higher risk of suffering from viral infections, a new study reveals.
A team from the University of Michigan, Duke University School of Medicine, and the University of Virginia say that when a person’s cognitive functioning starts to fluctuate, they’re likely to be more infectious and experience more symptoms from respiratory viruses.
“We all know that if we’re stressed, or haven’t slept enough, that predisposes us to have a less resilient immune system,” says Alfred Hero, the John H. Holland Distinguished University Professor of Electrical Engineering and Computer Science at U-M, in a university release.
“This is the first exposure study in humans to show that one’s cognitive performance before exposure to a respiratory virus can predict the severity of the infection,” the researcher adds.
Small changes in typical daily cognitive performance can lead to changes in brain states that can increase risk of illness, such as stress, fatigue, and poor sleep. The team measured cognitive variability in order to determine how cognitive function may serve as an indicator of immune health after exposure to a respiratory virus.
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To do this, they recruited a group of 18 healthy volunteers who took brain performance tests three times per day for three days using a digital self-test at home.
Study authors then exposed them to a human rhinovirus — which is a cold virus. The game tested 18 measures of cognitive function, such as reaction time, attention, and rapid switching between numbers and symbols. The researchers combined the results to create an index of variability.
“In the beginning, we didn’t find that cognitive function had a significant association with susceptibility to illness because we used the raw scores. But later, when we looked at change over time, we found that variation in cognitive function is closely related to immunity and susceptibility,” says first author Yaya Zhai, a recent PhD graduate in bioinformatics at U-M, who led the variability index study alongside Prof. Hero.
The team was able to assess viral shedding using a saline solution to wash out the nasal passages of the participants. They examined the presence of viral infection and viral quantity in the fluid by growing the virus in a cell culture. To keep track of symptoms, the participants rated themselves on a scale of one to three on eight common cold symptoms.
The team is hopeful that their findings open doors to improving public health, especially when it comes to the brain’s role in immune health.
“Traditional clinical cognitive assessments that look at raw scores in a single time point often do not provide a true picture of brain health,” concludes P. Murali Dorwaiswamy, director of the Neurocognitive Disorders Program at the Duke University School of Medicine.
“At home, periodic cognitive monitoring, through self-test digital platforms, is the future of brain health assessment.”
The findings are published in the journal Scientific Reports.