Neuropsychological profiles and cerebral glucose metabolism in neurocognitive Long COVID-syndrome, 2021, Dressing et al

Abstract

During the Corona Virus Disease 2019 (COVID-19) pandemic, Long COVID-syndrome, which impairs patients through cognitive deficits, fatigue, and exhaustion, has become increasingly relevant. Its underlying pathophysiology, however, is unknown. In this study, we assessed cognitive profiles and regional cerebral glucose metabolism as a biomarker of neuronal function in outpatients suffering from long-term neurocognitive symptoms after COVID-19.

Methods: Outpatients seeking neurological counseling with neurocognitive symptoms persisting for more than three months after polymerase chain reaction (PCR)-confirmed COVID-19 were included prospectively between June 16, 2020, and January 29, 2021. Patients (n = 31, 54±2.0 years) in the long-term phase after COVID-19 (202±58 days after positive PCR) were assessed with a neuropsychological test battery. Cerebral 18F-FDG PET imaging was performed in 14/31 patients.

Results: Patients self-reported impaired attention, memory, and multitasking abilities (31/31), word-finding difficulties (27/31), and fatigue (24/31). Twelve of 31 patients could not return to the previous level of independence/employment. For all cognitive domains, average group results of the neuropsychological test-battery showed no impairment, but deficits (z-score<-1.5) were present on single-patient level mainly in the domain of visual memory (in 7/31; other domains ≤2/31). Mean MoCA performance (27/30 points) was above the cutoff-value for detection of cognitive impairment (< 26 points), although 9/31 patients performed slightly below this level (23-25 points). In the subgroup of patients who underwent 18F-FDG PET, we found no significant changes of regional cerebral glucose metabolism.

Conclusion: Long COVID patients self-report uniform symptoms hampering their ability to work in a relevant fraction. However, cognitive testing showed minor impairments only on single-patient level approximately six months after the infection, whereas functional imaging revealed no distinct pathological changes. This clearly deviates from previous findings in subacute COVID-19 patients, suggesting that underlying neuronal causes are different and possibly related to the high prevalence of fatigue.

Open access, https://jnm.snmjournals.org/content/early/2021/10/14/jnumed.121.262677

 

Uh? Odd choice of words.

The ongoing "all our tests are normal but we can't possibly imagine that we just don't have tests for that" is getting way more than annoying at this point. Of course if you keep administering the wrong tests it's not going to tell you anything. It's the most basic thing in the world for a professional to understand that just because you have a toolbox doesn't mean it contains every tool for every problem. Ugh.

 

Yeah the classic "lets use 40+ year old technologies and tests with laughable sensitivity, if nothing comes up well it's just the fatigue" as if that means anything..

 

I haven't read the paper, so only general comments.

Neuropsycological testing batteries, such as WAIS, are about assessing difficulties in neurodevelpmentral disorders, not necessarily terribly good at picking up issues with acquired problems. That gers missed a lot.

Impairment in neuropsychology testing has a specific meaning. Below 5th percentile compared to appropriate functioning in HC. Having lower than expected, but not necessarily bad enough to be impaired is a find.

Choice of testing vital to criterion validity otherwise real world issues to the patient can get lost in the noise.

From memory, PET scan studies in pwME are few and far between. This is perhaps first study of Long Covid using this method. Not clear how they have established if it even can measure anything meaningful. Appears they start from the assumption that it would be valid tech to identify issues and proceed. And then they find that PET doesn't find much and making sweeping conclusions. Ugh.