Summary: The results reveal how a person’s cognitive performance before viral exposure can predict the severity of symptoms once the virus develops.
Source: University of Michigan
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 working closely with researchers from Duke University School of Medicine and the University of Virginia.
“We all know that if we’re stressed or haven’t had enough sleep, it predisposes us to have a less resilient immune system,” says Alfred HeroJohn H. Holland Professor Emeritus of Electrical Engineering and Computer Science at UM and corresponding author of the study in Scientific reports.
“This is the first human exposure study to show that a person’s cognitive performance before exposure to a respiratory virus can predict the severity of infection,” he said. .
Subtle variations in daily cognitive performance can signal changes in brain states known to increase the risk of diseases such as stress, fatigue and lack of sleep. The team wanted to measure cognitive function and determine if it was predictive of immune performance after exposure to a respiratory virus. Cognitive variability, measured using a digital home self-test, was found to be highly predictive.
The team studied a cohort of 18 healthy volunteers who took brain performance tests three times a day for three days and then were exposed to a common cold virus called human rhinovirus. The software provided 18 measures of cognitive function, including reaction time, attention, and rapid switching between numbers and symbols, which were combined to derive an index of variability.
“At first, we didn’t find that cognitive function had a significant association with disease susceptibility because we used raw scores. But later, when we looked at the changes over time, we found that the variation in cognitive function is closely related to immunity and susceptibility,” said Yaya Zhai, a recent Ph.D. graduate in bioinformatics at UM and first author of the study. She and Hero led the development of the Cognitive Variability Index.
The team assessed viral shedding by using saline solution to wash out the participants’ nasal passages. They determined the presence of viral infection and the amount of virus in the fluid by growing the virus in cell culture. For symptoms, the team used the Jackson Score, in which participants rated themselves from one to three out of eight cold symptoms.
“This is an interesting observation in a relatively small study. Hopefully there will be a chance to confirm these findings in a larger, more definitive study,” said Ronald Turner, professor emeritus of pediatrics at the University. of Virginia, who conducted the experiment.
The team is optimistic that smartphone use could eventually help identify periods of heightened susceptibility to the disease, by monitoring cognitive indicators such as typing speed and accuracy as well as the time the user goes to sleep.
“Traditional clinical cognitive assessments that look at raw scores at a given time often don’t provide a true picture of brain health,” said P. Murali Doraiswamydirector of the neurocognitive disorders program at Duke University School of Medicine, who designed the neurocognitive testing portion of the study.
“At home, periodic cognitive monitoring, via digital self-testing platforms, is the future of brain health assessment,” Doraiswamy said.
The study was part of a project funded by the Defense Advanced Research Projects Agency to find out if it was possible to predict disease susceptibility in soldiers. This project was led by Geoffrey Ginsburg, then a professor at the Duke Center for Applied Genomics and Precision Medicine, and he led the contingent of the team analyzing blood samples for biomarkers that could indicate susceptibility to the disease.
The experiment also uncovered a few genetic markers that may indicate reduced immune function, which the team could explore further in future studies.
Lumos Laboratories provided access to their line Neurocognitive performance tests but was not involved in the process of conducting the study or publishing the report.
Hero is also the R. Jamison Professor of Engineering and Betty Williams Professor of Biomedical Engineering and Professor of Statistics at UM. Zhai is now a data scientist at VivoSense Inc. Ginsburg is now the medical and scientific director of the All of Us research program at the National Institutes of Health. Doraiswamy is also a professor of psychiatry and medicine at Duke University School of Medicine and an advisor to Lumos Labs.
UM and Duke have filed for patent protection for the Cognitive Variability Index.
About this infection and current neuroscience research
Author: Katherine McAlpine
Source: University of Michigan
Contact: Katherine McAlpine – University of Michigan
Image: Image is in public domain
Original research: Free access.
“Pre-exposure cognitive performance variability is associated with respiratory infection severity” by Alfred Hero et al. Scientific reports
Pre-exposure cognitive performance variability is associated with respiratory infection severity
Using data from a longitudinal viral challenge study, we find that post-exposure viral shedding and symptom severity are associated with a new measure of pre-exposure cognitive performance variability (CPV), defined before viral exposure does not occur.
Each individual’s CPV score is calculated from data collected from a repeated neurocognitive performance test (NCPT) over a 3-day pre-exposure period. Of the 18 NCPT measures reported by the tests, 6 contribute materially to the CPV score, prospectively differentiating highs from lows.
Among these 6 are the 4 clinical measures digSym-time, digSym-correct, trail-time and reaction-time, commonly used to assess executive cognitive functioning. CPV is found to be correlated with stress and also with several genes previously reported to be associated with cognitive development and dysfunction.
A perturbation study on the number and timing of NCPT sessions indicates that as few as 5 sessions are sufficient to maintain a high association between CPV score and viral shedding, as long as the timing of these sessions is balanced over the three days pre-exposure.
Our results suggest that variations in cognitive function are closely related to immunity and susceptibility to serious infections.
Further study of these relationships can help us better understand the connections between neurocognitive and neuroimmune systems, which is timely in this era of the COVID-19 pandemic.