I didn’t read the Lancet paper. Are they able to rule out selection biases? It’s possible that people who got mild Covid will score slightly lower on the cognitive tests (even if you adjust for observable demographic differences). It also seems plausible that this very small measured difference (for non-respiratory Covid) will further diminish over time. (Also the mean age is ~47 and so a 30yo should expect smaller effects and better recovery in any case).
It’s not a great study. It’s observational, and the best it can show is correlation. It’s just as likely that people with that score lower on cognitive tests are more likely to get covid, which doesn’t seem unrealistic. A bit of armchair analysis (with only a little bit of ax-grinding): https://sebastianrushworth.com/2021/07/26/does-covid-cause-brain-damage/
I edited the section to include some more thoughts on the paper’s quality. In brief, I expect a 2x diminishment over time (though this was conservative and it could easily be larger); I expect the selection bias is definitely real, though there’s a countervailing effect from most of the COVID cases being self-reports which I expect means higher conscientiousness and many missed cases from the group otherwise being selected for; I also think the ventilator impairment matches well with other evidence we have about ventilator impairment and is probably not a large overestimate, though this may not shed much light on the smaller disease burden impairment integrity; and I hadn’t noticed the age difference, thanks a lot for pointing that out!
I didn’t read the Lancet paper. Are they able to rule out selection biases? It’s possible that people who got mild Covid will score slightly lower on the cognitive tests (even if you adjust for observable demographic differences). It also seems plausible that this very small measured difference (for non-respiratory Covid) will further diminish over time. (Also the mean age is ~47 and so a 30yo should expect smaller effects and better recovery in any case).
It’s not a great study. It’s observational, and the best it can show is correlation. It’s just as likely that people with that score lower on cognitive tests are more likely to get covid, which doesn’t seem unrealistic. A bit of armchair analysis (with only a little bit of ax-grinding): https://sebastianrushworth.com/2021/07/26/does-covid-cause-brain-damage/
In another comment, I discuss what seems like a big limitation of the paper.
I edited the section to include some more thoughts on the paper’s quality. In brief, I expect a 2x diminishment over time (though this was conservative and it could easily be larger); I expect the selection bias is definitely real, though there’s a countervailing effect from most of the COVID cases being self-reports which I expect means higher conscientiousness and many missed cases from the group otherwise being selected for; I also think the ventilator impairment matches well with other evidence we have about ventilator impairment and is probably not a large overestimate, though this may not shed much light on the smaller disease burden impairment integrity; and I hadn’t noticed the age difference, thanks a lot for pointing that out!