Persistent cognitive slowing in post-COVID patients: longitudinal study over 6 months, 2023, Martin et al

[EndME]

Persistent cognitive slowing in post-COVID patients: longitudinal study over 6 months

Abstract

Background
Fatigue is a frequent and one of the most debilitating symptoms in post-COVID syndrome (PCS). Recently, we proposed that fatigue is caused by hypoactivity of the brain’s arousal network and reflected by a reduction of cognitive processing speed. However, it is unclear whether cognitive slowing is revealed by standard neuropsychological tests, represents a selective deficit, and how it develops over time.

Objectives
This prospective study assesses whether PCS patients show deficits particularly in tests relying on processing speed and provides the first longitudinal assessment focusing on processing speed in PCS patients.

Methods
Eighty-eight PCS patients with cognitive complaints and 50 matched healthy controls underwent neuropsychological assessment. Seventy-seven patients were subsequently assessed at 6-month follow-up. The Test for Attentional Performance measured tonic alertness as primary study outcome and additional attentional functions. The Neuropsychological Assessment Battery evaluated all key cognitive domains.

Results
Patients showed cognitive slowing indicated by longer reaction times compared to control participants (r = 0.51, p < 0.001) in a simple-response tonic alertness task and in all more complex tasks requiring speeded performance. Reduced alertness correlated with higher fatigue (r =  − 0.408, p < 0.001). Alertness dysfunction remained unchanged at 6-month follow-up (p = 0.240) and the same was true for most attention tasks and cognitive domains.

Conclusion
Hypoarousal is a core deficit in PCS which becomes evident as a selective decrease of processing speed observed in standard neuropsychological tests. This core deficit persists without any signs of amelioration over a 6-month period of time.

https://link.springer.com/article/10.1007/s00415-023-12069-3

 

[Hutan]

Jena, Germany

At baseline assessment, on average 13.5 (8.07–25.85) months had passed since acute SARS-CoV-2 infection and 18.2% of patients had been treated at the hospital during acute COVID-19 disease.

Notably, the reported results were also found when the 16 hospitalized PCS patients were excluded from the analyses

Clear differences in reaction time and in many tests affected by reaction time.

 

[Hutan]

Blue is healthy controls, pink is post-covid syndrome at baseline (an average of 13.5 months after onset) and red is post-covid syndrome 6 months later (with some attrition).

Reasons for the attrition from baseline to 6 months are given as

The 11 dropouts (12.5%) were due to the following reasons: No access granted to the hospital because of failing pandemic access criteria (n = 1), inpatient rehabilitation stay (n = 4), move to another state (n = 1), acute viral infection (n = 2), a family emergency (n = 1) and unknown reasons (n = 2).

Given people who are doing an 'inpatient rehabilitation stay' are unlikely to be cured, it looks like the cognitive dysfunction present in most PCS participants at baseline persisted in most 6 months later.