The cognitive impact of COVID-19

Written by: Dr Dennis Chan
Edited by: Robert Smith

A significant proportion of people with long covid have neurological problems including headache, autonomic dysfunction and peripheral nerve symptoms. However, the most prominent of all is cognitive impairment, referred to colloquially as “brain fog”.


In this latest article with Dr Dennis Chan, we discuss the evaluation of cognitive impairment in long Covid. Dr Chan leads the £1.3 million national research project studying then treating “cognitive Covid” named CICERO (see the NIHR website for more details).

How much does COVID-19 affect cognitive function?

There is increasing evidence that cognition is affected in the majority of people with long covid, with some studies suggesting 80% of people are affected. The main aspects of cognitive function affected are: attention, speed of information processing, executive function (organisational ability, decision making, planning) and memory. The resulting problems can impact heavily on everyday life, including the ability to return to normal working.

Why might COVID-19 affect cognitive function?

The SARS-CoV-2 virus can attack the brain in a number of ways, leading to cognitive impairment. First, the virus can travel directly into the brain along neural pathways, such as those originating in the nose. Second, viral infection results in downstream inflammation and also damage to blood vessels, both of which can cause brain dysfunction. Finally, it is possible (though yet to be established) that a COVID-19 infection may increase the risk of developing dementia in later life.

How can cognitive problems in long Covid be treated?

Cognitive problems often co-exist with other long covid symptoms such as fatigue, poor sleep, anxiety and depression. While fatigue can be hard to treat, the other symptoms can respond to drug treatment and if they improve then cognition can improve too. Beyond that, my team and I are looking at the possibility that neuropsychology-based rehabilitation may also help a return to normal function, and this is something that will be assessed in our CICERO study.

For more information on COVID-19 and its impact on our cognitive health, you may like to get in contact with the highly regarded neurologist, Dr Dennis Chan. Click here to visit his Top Doctors profile today.

By Dr Dennis Chan

Dr Dennis Chan is a highly qualified neurologist with vast experience treating a range of neurological disorders including headache, Parkinson's disease, epilepsy, and multiple sclerosis. He is an internationally recognised expert in dementia, specialising in the diagnosis of Alzheimer's disease, mild cognitive impairment, and other memory disorders. His private clinics are located at Spire Gatwick Park Hospital, Spire Montefiore Hospital in Hove and The North Downs Hospital in Caterham. Dr Chan's NHS clinics in memory disorders and general neurology are held in Cambridge and Sussex.

Dr Chan qualified in medicine from the University of Cambridge. In addition to his medical degree, he holds two research doctorates. He obtained a PhD under the supervision of Professor John O'Keefe (University College London), who was later awarded the 2014 Nobel Prize in Physiology or Medicine, and an MD under Professor Rossor, Institute of Neurology, London. From 2014 - 2019 he was based at the University of Cambridge and in 2019 he moved his NHS work back to Sussex, and his academic work back to UCL.

Dr Chan's research into Alzheimer's disease has received extensive media coverage, with articles in all the leading national newspapers (including The Times, Independent, Guardian, Daily Mail, Daily Telegraph) as well as interviews on BBC national TV, the BBC Radio 4 Today programme and CBS TV in the USA. His work has been published in the top research journals including Nature and The Lancet. Dr Chan receives research grant funding from the Medical Research Council, Wellcome Trust, Alzheimer's Research UK, Alzheimer's Society, Innovate UK, and the Alan Turing Institute. His research has been extensively covered by the national and international news media. 

Dr Chan is also leading UK research into cognitive impairment (brain fog) as part of long Covid. In July 2021 he was awarded £1.2 million by the National Institute of Health Research to study and treat this problem.

Dr Dennis Chan is happy to offer virtual consultations. To request an appointment, please click the blue eConsultation button on the profile. 

For more information about Dr Chan, go to: 

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