In-Depth: COVID brain fog linked to changes in spinal fluid

Brain scans
Posted at 6:38 PM, Jan 21, 2022

SAN DIEGO (KGTV) – Scientists searching for ways to treat COVID long haulers have just made a discovery about those with brain fog.

Many people with cognitive symptoms have abnormalities in their spinal fluid, according to a new study led by researchers at the University of California San Francisco.

These anomalies can be detected months after the initial bout with the virus, even in patients who were never hospitalized for COVID, the study found.

Brain fog is one of the most common complaints in people with long COVID. By some estimates, 30 to 40 percent of all people infected with COVID develop cognitive symptoms.

“We want to identify what the mechanism is, what is the problem, so we can develop solutions or treatments for people with these issues,” said lead study author Dr. Joanna Hellmuth.

Hellmuth and her colleagues did spinal taps on 17 volunteers who recovered from mild COVID to examine the colorless fluid that surrounds the brain.

The researchers found noticeable imbalances in certain proteins in the fluid from 10 of the 13 patients complaining of COVID-related brain fog. The proteins are a sign of inflammation and overactivity of the immune system in the brain.

For comparison, they checked four samples from COVID survivors who were not experiencing cognitive issues. Their spinal fluid had no imbalances.

It’s not clear if the anomalies in the spinal fluid are causing the cognitive issues directly or are some kind of associated consequence, Dr. Hellmuth said.

It’s also unclear why the issues persist for months. Did the virus trick the body into attacking itself? Or are bits of the virus hiding somewhere in the brain?

“If there was a virus in the brains of these individuals, we’d expect to see a slightly elevated white blood cell count and we’re not seeing that,” Dr. Hellmuth said. “So really, the data that we see now are suggesting that maybe this is kind of a misdirected immune system.”

While the researchers work to figure out the why, the study offers clues about who is most likely to develop COVID-related brain fog.

The study participants tended to have two or more risk factors like diabetes, high blood pressure, or heavy alcohol use; conditions that can harm blood vessels in the brain. Other risk factors included anxiety, depression, and a history of learning disabilities or ADHD.

Dr. Hellmuth theorizes that structural differences in the brains of people with learning disabilities and ADHD may make them more vulnerable.

People with ADHD have trouble with their executive functioning regions of the brain, Hellmuth said. “Those are the same networks in the brain that we see impacted by these COVID-related cognitive changes.”

COVID isn’t the only virus that can cause cognitive issues; so can SARS, MERS, hepatitis C, and HIV. But Hellmuth is optimistic that researchers will find a treatment for the cognitive problems from long haul COVID.

Over time, she says some of her patients have recovered on their own.