Post by Nadica (She/Her) on Jul 4, 2024 7:23:08 GMT
Cognitive dysfunction after covid-19 - Published Feb 1, 2024
What you need to know
As of March 2023, when the Office for National Statistics stopped collecting data on this condition, 1.879 million individuals had self-assessed as having long covid—symptoms lasting more than 12 weeks following acute covid-19 infection. Of these, the proportion of individuals with symptoms lasting two years or more is around 42%, suggesting a decline in new cases of long covid but a persistence of those with ongoing symptoms.1 Some systematic reviews and meta-analyses have reported that up to a third of such individuals have persistent symptoms of cognitive impairment,23 but estimates vary widely and are complicated by methodological heterogeneity—eg, study size, assessment approach, follow-up duration, and different sampling frames (from self-reported surveys4 to large retrospective matched cohort studies of health records5), as discussed in a recent meta-analysis.6
The pathological underpinnings and potential therapeutic possibilities for cognitive impairment in long covid are also uncertain. The bulk of evidence to date is mechanistic (using basic science, animal models, or human tissue), observational (using longitudinal cohort studies), or hypothetical (reasoning from basic principles); this literature has been well summarised by the RECOVER Consortium.7 Because of the methodological heterogeneity, even when individual studies have been rigorously conducted, it is difficult to know to what extent their findings can be extrapolated and generalised across those with long covid. A few randomised controlled trials of potential treatments (pharmacological and non-pharmacological) have been completed, and others are under way.7
Cognitive performance is typically conceptualised in terms of functional domains depending upon the task at hand. Domains are hierarchical and inter-related, ranging from more basic sensory and perceptual processes to executive functioning and cognitive control.8 Both psychometric studies and qualitative studies of the patient experience identify problems across one or more of these domains. The most frequent symptoms seem to affect memory, attention, and concentration9 but discrete impairments are also seen in attentional and executive processing,1011 different types of memory,1012 visuospatial processing,13 and language.12 Many patients show deficits in multiple domains,1214 which may or may not correlate with self-reported symptoms.15 Moreover, linked systemic symptoms such as fatigue, insomnia, and a general befuddled state frequently termed “brain fog” are commonly reported. This seems to wax and wane with physical fatigue.16 A higher symptom burden is often associated with concomitant mood disorders or post-traumatic stress disorder, regardless of illness severity.1
What you need to know
-Cognitive problems are common after acute SARS-CoV-2 infection and can be disabling and frightening
-Symptoms tend to improve, but this may take up to a year. Those with chronically persistent symptoms lasting more than 12 months have a lower chance of improving
-Symptoms usually fluctuate
-Assessment should be directed to documenting the nature and trajectory of the impairment and excluding alternative diagnoses
-Self-management techniques may help patients manage their condition
-Symptoms tend to improve, but this may take up to a year. Those with chronically persistent symptoms lasting more than 12 months have a lower chance of improving
-Symptoms usually fluctuate
-Assessment should be directed to documenting the nature and trajectory of the impairment and excluding alternative diagnoses
-Self-management techniques may help patients manage their condition
As of March 2023, when the Office for National Statistics stopped collecting data on this condition, 1.879 million individuals had self-assessed as having long covid—symptoms lasting more than 12 weeks following acute covid-19 infection. Of these, the proportion of individuals with symptoms lasting two years or more is around 42%, suggesting a decline in new cases of long covid but a persistence of those with ongoing symptoms.1 Some systematic reviews and meta-analyses have reported that up to a third of such individuals have persistent symptoms of cognitive impairment,23 but estimates vary widely and are complicated by methodological heterogeneity—eg, study size, assessment approach, follow-up duration, and different sampling frames (from self-reported surveys4 to large retrospective matched cohort studies of health records5), as discussed in a recent meta-analysis.6
The pathological underpinnings and potential therapeutic possibilities for cognitive impairment in long covid are also uncertain. The bulk of evidence to date is mechanistic (using basic science, animal models, or human tissue), observational (using longitudinal cohort studies), or hypothetical (reasoning from basic principles); this literature has been well summarised by the RECOVER Consortium.7 Because of the methodological heterogeneity, even when individual studies have been rigorously conducted, it is difficult to know to what extent their findings can be extrapolated and generalised across those with long covid. A few randomised controlled trials of potential treatments (pharmacological and non-pharmacological) have been completed, and others are under way.7
Cognitive performance is typically conceptualised in terms of functional domains depending upon the task at hand. Domains are hierarchical and inter-related, ranging from more basic sensory and perceptual processes to executive functioning and cognitive control.8 Both psychometric studies and qualitative studies of the patient experience identify problems across one or more of these domains. The most frequent symptoms seem to affect memory, attention, and concentration9 but discrete impairments are also seen in attentional and executive processing,1011 different types of memory,1012 visuospatial processing,13 and language.12 Many patients show deficits in multiple domains,1214 which may or may not correlate with self-reported symptoms.15 Moreover, linked systemic symptoms such as fatigue, insomnia, and a general befuddled state frequently termed “brain fog” are commonly reported. This seems to wax and wane with physical fatigue.16 A higher symptom burden is often associated with concomitant mood disorders or post-traumatic stress disorder, regardless of illness severity.1