Even though most of the press and general public have tuned out, the Covid-conscious have kept their eyes on research and news reports of long-term conditions and/or slow to be reversed damage. Some of these outcomes don’t show up in day-to-day living or in routine tests, but do in imaging. As we’ll discuss below, cognitive effects are harder to substantiate than others, but based on a teeny sample, we wonder if difficulty with checklists could be a Covid after effect.
Arguably, brain impacts have not been well studied, despite some efforts to do so. A big reason is the lack of a baseline. While most adults get regular bloodwork, perhaps an EKG, and quickly notice changes in their digestion, energy level, exercise performance, and pain levels, that’s not true for cognitive function, save for individuals being watched for dementia or other at-risk situations.
Nevertheless, studies have found post-Covid-era changes in behavior across the population, such as an increase in road rage. One study attributed that change not to the disease but the effects of lockdowns, work-from-home, greater substance abuse, and multitasking.
A later large-scale study using UK REACT participants, published in the New England Journal of Medicine, found small but measurable mental deficits among those who had suffered mild cases:
Participants were asked to perform an innovative online cognitive assessment on the Cognitron platform, which comprises tasks that can detect subtle changes in different aspects of their brain function, such as memory, reasoning, executive function, attention and impulsivity.
The study examined factors contributing to cognitive deficits in very fine detail while controlling for population variables such as age, demographics and pre-existing medical conditions.
Cognitive findingsThe study revealed small cognitive deficits that were still detectable a year or more after infection, even in people who had short duration illness. They were larger for people who had symptoms lasting 12 weeks or more (consistent with long Covid), those who had been to hospital for their illness or those who were infected with one of the early variants of the virus.
People who had longer lasting symptoms but whose symptoms had gone by the time they did the cognitive assessment showed small deficits that were similar to those of people who had a shorter duration illness.
The results showed that Covid‐19 was associated with deficits in multiple areas of cognition, most notably in memory, such as the ability to remember pictures of objects that were viewed a few minutes earlier. The researchers believe this may be due to problems forming new memories rather than accelerated forgetting. People also showed small deficits in some tasks testing executive and reasoning abilities, such as those that require spatial planning or verbal reasoning.
A 2023 Lancet study profiled “post-COVID cognitive dysfunction.” From its “Current status of epidemiology” section:
A recent two-year retrospective cohort study including over one million COVID-19 patients found that the risk of cognitive deficit was higher than that in matched controls at six months, with a hazard ratio of 1.36 (1.33–1.39), and that the risk remained higher at the end of the two-year follow-up period. Another longitudinal cohort study in China including 3233 COVID-19 survivors reported that severe COVID-19 was associated with higher risks of early-onset cognitive decline (six months after discharge), late-onset cognitive decline (12 months after discharge), and progressive cognitive decline than in controls, with an odds ratio (OR) of 4.87 (3.30–7.20), 7.58 (3.58–16.03) and 19.00 (9.14–39.51), respectively. Non-severe COVID-19 was associated with a higher risk of early onset cognitive decline, with an OR of 1.71 (1.30–2.27). The increased risk of cognitive impairment, seizures, dementia, psychosis, and other neurocognitive conditions persisted for at least two years.
Note that these studies did not seem to be testing for fine-grained changes as the REACT study did.
Some studies cited deterioration in spatial reasoning as a Covid effect; one found evidence of possible physical causes. From Molecular Psychiatry:
We aimed to investigate adults at least four months after recovering from mild COVID-19, which were assessed by neuropsychological, ocular and neurological tests, immune markers assay, and by structural MRI and 18FDG-PET neuroimaging to shed light on putative brain changes and clinical correlations. In approximately one-quarter of mild-COVID-19 individuals, we detected a specific visuoconstructive deficit, which was associated with changes in molecular and structural brain imaging, and correlated with upregulation of peripheral immune markers. Our findings provide evidence of neuroinflammatory burden causing cognitive deficit, in an already large and growing fraction of the world population.
With that as an introduction, I’ve been seeing enough of what I call “Covid brain” to be pretty confident it’s a real phenomenon. For instance, people with good general intelligence sometimes seem to have trouble processing what they have been told. There’s more “It goes in one ear and out the other” than usual.
One noteworthy example has been with three individuals, all with backgrounds that say they have had followed detailed protocols before, being given instructions (as in written documentation) for a small set of simple tasks. Each failed to do them, not once, not twice, but at least three times, even when given written correction (as in images of what was wrong and what needed to happen) and sometimes verbal on top of that. These instructions were not difficult yet the need for repeated correction was maddening. It was as if they were having difficulty processing the instructions. And I’ve given the same sort of instructions pre-Covid and never had this happen, not even once.
The procedure most resembles executing a short checklist, the sort of thing you might do when leaving your house in the morning (check you bag to make sure you have certain items, turn out the lights or turn off air con/fans, lock the door…), as in a brief and routine mental catalogue, as opposed to one so long as to be kept in written form.
Have any of you noticed difficulties in colleagues or family members in adapting to new checklists? And is this an issue of fresh memories (as one study above suggested) or might it apply to existing, checklist-driven routines (think flying airplanes or scuba diving as examples). Reader input appreciated.