[Cognitive disorders and sleep disturbances in long COVID]

During the last 2 years of the coronavirus disease 2019 (COVID-19) pandemic, knowledge about the long-term effects of the disease, the so-called long COVID, has rapidly grown; however, many questions remain unanswered, especially regarding the causes of persistent symptoms and their prognosis. Cognitive disorders and sleep disturbances are among the most frequent complaints. Both are associated with severe suffering and significant impairment in everyday functioning.

What is known about the occurrence of cognitive disorders and sleep disturbances in long COVID? What are the influencing factors and what is known about the course over time and possible underlying mechanisms? What treatment options are available?

In a narrative review, the most important findings on cognitive disorders and sleep disturbances in long COVID are presented. An overview of cohort studies with data on the prevalence and influencing factors of both symptom complexes is given. Current knowledge and hypotheses on pathophysiological mechanisms are presented and an outlook on treatment approaches is given.

About one in five of those affected report cognitive impairment more than 3 months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and about one third report sleep disturbances. The latter comprise symptoms of insomnia as well as hypersomnia. Cognitive impairment and sleep disturbances occur in patients with all levels of initial disease severity. There are indications of an improvement of cognitive deficits over time but further longitudinal studies are needed.

In addition to the prognosis, the underlying disease mechanisms are still insufficiently understood. Furthermore, there is a great need for research on the efficacy and specific effective factors of therapeutic interventions.