Japanese man struggles with memory loss as research shows COVID's long-term brain effects

OSAKA -- "I have a hard time typing emails for work," said a 60-year-old man in west Japan with COVID-19 aftereffects while reading aloud a memo to his doctor. Besides headaches and fatigue, the man has also become forgetful, and needs to keep records to accurately convey his symptoms.

It has gradually come to light that anyone infected with the coronavirus can suffer from a decline in memory and cognitive abilities. There is no established treatment, and a U.S. team's study which found that COVID-19 patients had increased risks of developing Alzheimer's disease one year after infection sent shockwaves across the medical community.

The 60-year-old man is an office worker living in Hyogo Prefecture. His daily routine is to make memos on his smartphone of difficulties he faces, such as "After getting up in the morning, I couldn't even sit on the bedding," and "I can't do anything because of fatigue." He cannot do without these memos, which he uses to convey his symptoms to Satoshi Marumo, a doctor at Medical Research Institute Kitano Hospital in the city of Osaka.

"In the past, I could explain things while arranging them in order from my memory effortlessly. My ability to concentrate and think has declined, and even with the memos, there are times when it's hard to follow the letters," the man revealed.

It was around September 2022 when he became aware of the symptoms. He could not escape from these struggles during family gatherings when he got home from work, and sometimes forgot why he went into the kitchen. He also finds that he needs to search for misplaced items more often. He lost interest in everything, and said, "It's become bothersome for me when my family comes to me for advice."

The man was infected with the coronavirus in late July 2022. He had a fever of 38.6 degrees Celsius, but he recovered from mild symptoms in a few days. The abnormalities occurred from around 10 days after the onset of the initial symptoms. He could not stop coughing and struggled with severe fatigue, and could not return to work. Though he eventually returned to his job in late August, as he worked from home, the man said that he could barely complete tasks due to headaches and other symptoms. Apparent memory impairment also began appearing around this time.

Marumo, who examines patients with aftereffects, explained, "It is possible that a brain inflammation caused by the infection is continuing and impacting cognition and memory."

A U.S. study has revealed astonishing findings regarding brain-related aftereffects, which are known as symptoms that remain after COVID-19, besides impairments in taste and smell.

A team, including a researcher from the Institute for Public Health at Washington University in St. Louis, published a paper in the medical journal Nature Medicine in September 2022. The team used national health care databases of military veterans to primarily analyze data on 154,068 individuals with COVID-19, whose average age was 61.4 years, and 5,638,795 individuals who were not infected, whose average age was 63.4 years.

The study found that risks of memory problems developing in COVID-19 patients one year after infection was 1.77 times higher compared with people who were not infected. This risk was particularly high among people aged in their 40s and 50s. Furthermore, risks of developing Alzheimer's disease -- a form of dementia -- in COVID-19 patients rose to 2.03 times that of their non-infected counterparts.

The team concluded, "The risks and burdens were elevated even in people who did not require hospitalization during acute COVID-19. Limitations include a cohort comprising mostly White males. Taken together, our results provide evidence of increased risk of long-term neurologic disorders in people who had COVID-19."

(Japanese original by Ryo Watanabe, Science & Environment News Department)