An early survey of 153 COVID-19 patients in the U.K. and a more recent preprint study of people hospitalized with the disease in Italy both found that about a third had neurological symptoms of some kind. Other estimates have trended even higher.
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Increasingly common symptoms include fatigue and memory problems—and, at times, new cases of psychosis or mania. Some neurological manifestations of post-COVID, such as stuttering, are more bizarre than others.
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Soo-Eun Chang, a neuroscientist at the University of Michigan, is among the few researchers investigating stutter. “While stress and anxiety are not the cause of stutter, they do exacerbate it,” Chang says… But she says the origins of the disorder lie in complex circuits of the brain that coordinate the millions of neuronal connections needed for human speech.
Having the virus, she says, could lead to conditions that disrupt speech. “Speech is one of the more complex movement behaviors that humans perform,” Chang says. “There are literally 100 muscles involved that have to coordinate on a millisecond time scale, so it’s a significant feat. And it depends on a well-functioning brain.” COVID’s inflammatory response could undermine the efficiency of these circuits. “An immune-mediated attack on synaptic connections could lead to a change in brain function,” she says.
