'I feel like I have dementia': Thousands experiencing 'brain fog' after bout with COVID

After contracting the coronavirus in March, Michael Reagan lost all memory of his 12-day vacation in Paris, even though the trip was just a few weeks earlier.

Several weeks after Erica Taylor recovered from her COVID-19 symptoms of nausea and cough, she became confused and forgetful, failing to even recognize her own car, the only Toyota Prius in her apartment complex's parking lot.

Lisa Mizelle, a veteran nurse practitioner at an urgent care clinic who fell ill with the virus in July, finds herself forgetting routine treatments and lab tests and has to ask colleagues about terminology she used to know automatically.

"I leave the room, and I can't remember what the patient just said," she said, adding that if she hadn't exhausted her medical leave she'd take more time off.

"It scares me to think I'm working," Mizelle, 53, said. "I feel like I have dementia."

It's becoming known as COVID brain fog: troubling cognitive symptoms that can include memory loss, confusion, difficulty focusing, dizziness and grasping for everyday words. Increasingly, COVID survivors say brain fog is impairing their ability to work and function normally.

"There are thousands of people who have that," said Dr. Igor Koralnik, chief of neuro-infectious disease at Northwestern Medicine in Chicago, who has already seen hundreds of survivors at a post-COVID clinic he leads. The impact on the workforce that is affected is going to be significant, he added.

Confusion, delirium and other types of altered mental function, called encephalopathy, have occurred during hospitalization for COVID-19 respiratory problems, and a study found such patients needed longer hospitalizations, had higher mortality rates and often couldn't manage daily activities right after hospitalization.

But research on long-lasting brain fog is just beginning. A French report in August on 120 patients who had been hospitalized found that 34% had memory loss and 27% had concentration problems months later.

In a soon-to-be-published survey of 3,930 members of Survivor Corps, a group of people who have connected to discuss life after COVID, more than half reported difficulty concentrating or focusing, said Natalie Lambert, an associate research professor at Indiana University School of Medicine, who helped lead the study. It was the fourth most common symptom out of the 101 long-term and short-term physical, neurological and psychological conditions that survivors reported. Memory problems, dizziness or confusion were reported by one-third or more respondents.