Clinic evaluation of cognitive impairment in post-COVID syndrome: Performance on legacy pen-and-paper and new digital cognitive tests 2025 Patel et al

Highlights

• Post-Covid cognitive impairment affects daily function and quality of life.
• ACE-III fails to detect cognitive impairment in most post-Covid patients.
• 89% of patients have impaired attention, executive function, processing speed on novel tests.
• New tests are needed for post-Covid cognitive assessment in clinical practice.

Abstract

Background
Cognitive impairment, colloquially termed “brain fog”, is one of the most prevalent manifestations of post-Covid syndrome and a major contributor to impaired daily function and reduced quality of life. However, despite the high numbers of affected individuals presenting to clinical services with cognitive impairment, little work has been undertaken to date on the suitability of current memory clinic tests for identifying the cognitive deficits in this new acquired cognitive disorder.

The aim of this study was therefore to determine the performance of people with post-Covid syndrome presenting with cognitive impairment on the Addenbrooke's Cognitive Examination-III (ACE-III), a cognitive test used widely in memory clinics. A subset of individuals also underwent testing on a novel battery of short digital tests assessing attention, speed of information processing and executive function, representing the domains primarily implicated in post-Covid cognitive dysfunction.

Methods
102 individuals with post-Covid syndrome presenting with subjective cognitive complaints were recruited from a specialist cognitive long Covid clinic at University Hospitals Sussex NHS Trust. All participants completed self-report questionnaires on depression, anxiety, sleep and fatigue. Cognitive performance was assessed using the ACE-III, with 20 participants also being tested on the digital Long COVID Assessment Battery (LCCAB) (N = 20).

Results
The overall sample had a mean ACE-III score of 91/100 (SD 6) with 15.7% (16/102) scoring at or below the cut-off score considered to represent objective cognitive impairment. Of the 20 individuals who also completed the LCCAB, 89.47% were impaired on at least one task, primarily in the domains of attention, executive function and processing speed. Cognitive performance was not associated with depression, anxiety, sleep quality or fatigue.

Conclusion
The vast majority of individuals with post-Covid syndrome presenting with subjective cognitive complaints do not exhibit impaired performance on the ACE-III. This likely reflects the historical use of ACE-III and other pen and paper cognitive tests to detect cognitive impairment in diseases causing dementia, but they are ill-equipped to identify impairment in those cognitive domains affected in post-Covid syndrome. The LCCAB detected cognitive impairments in nearly 90% of participants, primarily affecting attention, executive function, and processing speed. These observations highlight the need for alternative cognitive tests for use in routine clinical practice to detect the impairments in new acquired cognitive disorders that are not adequately captured by legacy tests.

Open access, https://www.sciencedirect.com/science/article/pii/S2666354624001959

 

It's seriously baffling to me that no one has yet managed to come up with a single valid test for this. I knew they were inept when it comes to this but this is just extreme. It shows how they're incapable of coming up with the tools and methods that they need to come up with useful stuff. Makes me wonder how the profession even managed to produce anything, other than I guess it was mostly easy stuff and anything half-complicated is just too much for a brute force approach. As soon as they're outside of biology and physiology, it just dies, they don't perform at all.

For many years I was completely single-tasking, I could not possibly handle even doing simple things that a child can easily do. And that's just one component. This should be easy to test for, they just don't seem to be working the problem as it is, instead are focused on solving different problems in their toolbox. It's just so exactly like the main problem of LLMs, where they perform well on problems they saw thousands of times, but as soon as they step out of those and have to generalize it fails more often than not. Except here it almost always fails.

I don't know if it's simply an effect that those impaired are simply not able to participate, so they only ever get a mix of people with no such problem and others with various other things that they can't tell apart.

At least here they are on the right track:

Those are definitely the domains most affected. But after 5 years this is very little to show for it, and years away until anything filters through practice, and it may not even be useful given all the blockers on the way. I truly don't understand the horrible performance of those systems. Even by random chance they should be able to achieve more than this.