Thread by @DrEricDing

📍HUGE—Covid may cause greater loss of gray matter and tissue damage in the brain 🧠 than naturally occurs in people who have not been infected with the virus, a new study finds—the first study with both brain scans before and after #COVID19 infection. 🧵
nytimes.com/2022/03/07/hea…

2) The study, involving people aged 51 to 81, found shrinkage and tissue damage primarily in brain areas related to sense of smell; some of those areas are also involved in other brain functions, the researchers said.

3) “To me, this is pretty convincing evidence that something changes in brains of this overall group of people with Covid,” said Dr. Serena Spudich, chief of neurological infections and global neurology at the Yale School of Medicine,

4) The study involved 785 participants in UK Biobank, a repository of medical and other data from about half a million people in Britain. The participants each underwent two brain scans roughly three years apart, plus some basic cognitive

5) testing. In between their two scans, 401 participants tested positive for the coronavirus, all infected between March 2020 and April 2021.
The other 384 participants formed a control group because they had not been infected with the coronavirus and had similar characteristics.

6) With normal aging, people lose a tiny fraction of gray matter each year. For example, in regions related to memory, the typical annual loss is between 0.2 percent and 0.3 percent, the researchers said.

7) But Covid patients in the study — who underwent their second brain scan ~4.5 months after their infection — lost more than noninfected participants, experiencing between 0.2% and 2% **additional gray matter** loss in different brain regions over the three years between scans.

8) They also lost more overall brain volume and showed more tissue damage. 👀

“I find it surprising how much more was lost and how generalized it is,” said Dr. Spudich, who has studied COVID neurological effects, “I wouldn’t have expected to see quite so much % change.” ⚠️

9) The effects may be particularly notable because the study involved mostly people who — like the majority of Covid patients in the general population — were **mildly affected by their initial Covid infection**, ➡️ not becoming sick enough to need hospitalization. 👀

10) The main cognitive assessment where Covid patients showed a deficit was the trail-making test, a connect-the-dots type of exercise. “Covid patients took longer to complete the task, which might suggest weaknesses in focus, processing speed & other skills.” ⚠️

11) Sidenote— be sure to order second round of free COVID home tests if you’re in the Us.

https://twitter.com/DrEricDing/status/1500916481764343812

12) The study—“ The infected participants also showed on average larger cognitive decline between the two timepoints. Importantly, these imaging and cognitive longitudinal effects were still seen after excluding the 15 cases who had been hospitalised.”

13) “These mainly limbic brain imaging results may be the in vivo hallmarks of a degenerative spread of the disease via olfactory pathways, of neuroinflammatory events, or of the loss of sensory input due to anosmia.” Wow.

nature.com/articles/s4158…

14) We also know there’s huge IQ drops in both severe and MILD COVID patients. This study is peer reviewed too—comes from a major national UK 🇬🇧 testing data of COVID and non-Covid people. Even -2 point drop is huge—that’s ~lead poisoning IQ drop! And we see that in mild cases.👀

https://twitter.com/DrEricDing/status/1419873294023602176

15) In case anyone think that’s sensationalized that… it is NOT. Just read the lay Sky News article yourself. The study wasn’t small - it was a huge 81,000 study of folks who were assessed cognitive decline, 13,000 who had COVID. IQ drop in mild cases! news.sky.com/story/covid-19…

16) Covid’s long term effects on “brain fog” is notorious. Lots of data on this even last year, including increased risk of mental illness and major psychiatric diagnoses. See detailed thread 🧵 below. So much data doesn’t lie 👇

https://twitter.com/drericding/status/1326038189971288064

17) Why didn’t CDC or other govts warn us about brain damage and IQ declines??? I honestly don’t know. But we epidemiologists have known and highlighted this #LongCovid brain issue since 2020! 👇

https://twitter.com/drericding/status/1326294302155214866

18) Don’t look up… hospitalizations rising in England 🏴󠁧󠁢󠁥󠁮󠁧󠁿 and deaths spiking in Hong Kong 🇭🇰 — due to BA2. But I’m sure if @CDCDirector just puts her head down into the sand, it won’t surge in the US, right? Right?!

https://twitter.com/DrEricDing/status/1500983875207680006