Severe Covid can cause brain impacts equivalent to ageing 20 years, study finds
Even patients who weren't sick enough to be hospitalised could have signs of impairment.
People who suffer with severe Covid infections could experience lasting mental impact that may be the equivalent to 20 years of ageing, a new study has revealed.
According to scientists from the University of Cambridge and Imperial College London who led the study, these long-term impacts could be the same as losing 10 IQ points and are similar to the cognitive decline experienced by those aged between 50 and 70 years old.
The research – which was recently published in the journal eClinicalMedicine – indicates that the effects of severe Covid are still detectable more than six months after being ill, a time period where any recovery is gradual at best. It is the first time such rigorous assessment and comparison relating to the after-effects of severe Covid has been carried out, according to the researchers behind the project.
Professor Adam Hampshire from the Department of Brain Sciences at Imperial College London and first author of the study, said:
"Tens of thousands of people have been through intensive care with Covid-19 in England alone and many more will have been very sick, but not admitted to hospital.
"This means there are a large number of people out there still experiencing problems with cognition many months later. We urgently need to look at what can be done to help these people."
Fatigue, 'brain fog', problems recalling words, sleep disturbances, anxiety and even post-traumatic stress disorder (PTSD) are some of the lasting cognitive and mental health problems that scientists in the study said Covid patients can potentially experience months after infection.
They found this information by analysing data from 46 people who received in-hospital care – either on the ward or in intensive care units - for Covid, 16 of whom experienced enough viral infection that they had to be placed on mechanical ventilation.
Patients underwent "detailed computerised cognitive assessment alongside scales measuring anxiety, depression and post-traumatic stress disorder under supervised conditions," the research article stated.
Analysis revealed that Covid survivors were less accurate and had slower response times when compared with the general population – a difference which was still detectable six months later.
The impacts were strongest amongst those who required mechanical ventilation but even patients who weren't sick enough to be hospitalised could have tell-tale signs of mild impairment.
Verbal analogical reasoning is an area that those who had overcome severe Covid illness scored especially poorly on when completing tasks. In addition, survivors also found it difficult to find the right words and experienced slower processing speeds.
The study's senior author, Professor David Menon from the Division of Anaesthesia at the University of Cambridge explained:
"Cognitive impairment is common to a wide range of neurological disorders, including dementia, and even routine ageing, but the patterns we saw – the cognitive 'fingerprint' of Covid-19 – was distinct from all of these."
There are several factors that could cause the cognitive deficits, researchers said.
Direct viral infection is a possible culprit however it's unlikely to be a major cause. In fact, researchers found that it is more likely that a combination of factors result in this impact – these include inadequate oxygen or blood supply to the brain, blockage of large or small blood vessels due to clotting and microscopic bleeds.
That said, emerging evidence reveals that the body's own inflammatory response and immune system could cause key damage.
Patient improvement was gradual at best – and for some, researchers predict that they might never properly recover.
Professor Menon said:
"We followed some patients up as late as 10 months after acute infection, so we were able to see a very slow improvement. While this was not statistically significant, it is at least heading in the right direction, but it is very possible that some of these individuals will never fully recover."