Researchers seeking better measures of cognitive fatigue

Summary

Near the end of his first series of chess matches against IBM’s Deep Blue computer in 1996, the Russian grandmaster Garry Kasparov lamented what he saw as an unfair disadvantage: “I’m really tired. These games took a lot of energy. But if I play a normal human match, my opponent would also be exhausted.”Why thinking hard makes us feel tiredWhereas machine intelligence can keep running as long as it has a power supply, a human brain will become fatigued — and you don’t have to be a chess grandmaster to understand the feeling. Anyone can end up drained after a long day of work, at school or juggling the countless decisions of daily life. This mental exhaustion can sap motivation, dull focus and erode judgement. It can raise the odds of careless mistakes. Especially when combined with sleep loss or circadian disruption, cognitive fatigue can also contribute to deadly medical errors and road traffic accidents.It was partly Kasparov’s weary comments that inspired Mathias Pessiglione, a cognitive neuroscientist and research director at the Paris Brain Institute, to study the tired brain. He wanted to know: “Why is this cognitive system prone to fatigue?”Researchers and clinicians have long struggled to define, measure and treat cognitive fatigue — relying mostly on self-reports of how tired someone says they feel. Now, however, scientists from across disciplines are enlisting innovative experimental approaches and biological markers to probe the metabolic roots and consequences of cognitive fatigue.The efforts are getting a boost in attention and funding in large part because of long COVID, which afflicts roughly 6 in every 100 people after infection with the coronavirus SARS-CoV-2, says Vikram Chib, a biomedical engineer at Johns Hopkins University in Baltimore, Maryland. “The primary symptom of long COVID is fatigue,” says Chib. “I think that has opened a lot of people’s eyes.”Chib and others hope that a fundamental understanding of cognitive fatigue will help the billi...