People struck by debilitating long Covid have unique changes to their brains which makes it harder to think and speak.

A new study found they have fewer protective proteins in their brains and higher levels of inflammation, both of which are linked to dementia.

Long Covid patients also perform worse in language tests, such as finding the right word or understanding what certain words mean, which can be signs of brain fog.

The study suggests, for the first time, that damage to the brain, rather than a ramped up immune system, causes the symptoms of long Covid.

Though the study included just 17 people, the researchers plan to use the findings to launch larger-scale studies to find the causes of Long Covid. 

Dr Michael Lawrence, lead study author and neuropsychologist at Corewell Health in Michigan, said: ‘To our knowledge, this is the first controlled study that shows specific self-reported neurocognitive and central nervous systems changes in long COVID patients which validates the symptoms they’ve been experiencing.’ 

Long Covid is an amorphous condition made up of a constellation of symptoms from brain fog and fatigue to heart inflammation and joint pain.

An estimated 17 million Americans have it.

Researchers in MIchigan found Long Covid may be caused by decreased protective proteins in the brain and higher levels of damaging inflammation (stock image)

Some people may only experience shortness of breath and fatigue, while others may only experience brain fog and difficulty concentrating.

Because of this, diagnosing long Covid is challenging.

The study, published in the journal PLOS One, looked at 17 patients aged 25 to 60 who were previously infected with Covid at least six months prior. 

The participants included 10 people diagnosed with Long Covid and seven who healthy controls.

All but one patient were female, and the average age was 42. 

Participants completed interviews about their lingering symptoms, which could have included brain fog, memory issues, fatigue, anxiety or depression. 

Researchers also performed cognitive tests to evaluate processing speed, language, learning and memory, problem solving, multitasking and concentration. 

The researchers also drew blood samples from each participant to test elevated levels of the stress hormone cortisol and inflammation.

The experts found Long Covid patients had 33 percent lower levels of nerve growth factor (NGF) in their brains, a protein that helps maintain neurons in the brain and central nervous system.

Low NGF levels have been associated with neurocognitive conditions like Alzheimer’s disease and multiple sclerosis. 

Long Covid patients also had 50 percent more interleukin 10, a protein that helps regulate inflammation and immune responses in the body.

Though interleukin 10 normally controls inflammation, high levels can have the opposite effect and create more inflammation in the central nervous system. 

Nine in 10 participants in the Long Covid group had elevated inflammatory markers like interleukin 10 compared to one of out the seven healthy controls. 

Additionally, Long Covid patients scored 30 percent lower on tests of language processing, suggesting Long Covid triggers inflammation in the brain’s language centers.

The team also found Long Covid patients were 75 percent more likely than healthy patients to suffer a worsened quality of life overall. They also had a 61 percent increased risk of suffering general pain or discomfort.

Dr Alison Cohen, an epidemiologist and long Covid researcher at the University of California San Francisco, never imagined Long Covid would upend her life. But three years after getting Covid, she can hardly run or make a long drive before feeling ill

Violet Affleck — seen with father Ben Affleck and stepmother Jennifer Lopez — has been outspoken about contracting ‘a post-viral condition’ in 2019. She has called on local governments ‘ to confront the long Covid crisis’

The findings suggest Long Covid symptoms are caused by increased inflammatory markers in the brain and lower levels of NGF, which would normally protect neurons and reduce inflammation. 

This increased inflammation may damage parts of the brain responsible for language processing, as well as those that regulate pain and depression.  

Dr Lawrence said: ‘Additional services such as speech therapy, psychotherapy for stress reduction and incorporating medications that target fatigue and mental fogginess could all be elements of creating a successful treatment plan as well.’ 

The team noted while the study is small and has several limitations, including most participants being female and white, they hope to conduct larger studies to confirm the findings.  

Dr Judith Arnetz, corresponding study author and professor emerita at Michigan State University College of Human Medicine, said: ‘Although this is a small study and more work needs to be done, from a clinical application standpoint, physicians potentially can identify individuals who are struggling sooner and provide wrap-around care that could be helpful to them.’