As per studies, Covid harms the brain in the same way that Alzheimer’s and Parkinson’s do.

According to a study, people who died from Covid-19 had brains that looked similar to those who died from neurodegenerative conditions like Alzheimer’s and Parkinson’s disease.

According to researchers from Stanford School of Medicine and Saarland University in Germany, both groups showed similar inflammation and impairment in brain circuits.

The findings, which were published in the journal Nature, may help explain why one-third of people hospitalised for Covid have symptoms of neurological problems such as fuzzy thinking, forgetfulness, difficulty concentrating, and depression.

The researchers examined brain tissues from eight people who died from the disease, as well as brain samples from 14 people who died from other causes.

“The brains of patients who died from severe Covid-19 showed profound molecular markers of inflammation, despite the absence of clinical signs of neurological impairment,” said Tony Wyss-Coray, Professor of Neurology and Neurological Sciences at Stanford.

“Viral infection appears to trigger inflammatory responses throughout the body, which may cause inflammatory signalling across the blood-brain barrier, potentially triggering neuroinflammation in the brain,” he added.

Furthermore, the team discovered that the activation levels of many genes associated with inflammatory processes differed in the brains of Covid-19 patients versus the control group.

There were also signs of stress in neurons in the cerebral cortex, a brain region important for decision-making, memory, and mathematical reasoning.

The outermost layers of the cerebral cortex of Covid-19 patients showed molecular changes indicating suppressed excitatory neuron signalling as well as increased signalling by inhibitory neurons, which act as brakes on excitatory neurons. According to the researchers, this type of signalling imbalance has been linked to cognitive deficits and neurodegenerative conditions such as Alzheimer’s disease.

Furthermore, T cells, a type of peripheral immune cell, were significantly more abundant in brain tissue from deceased Covid-19 patients. These immune cells are few and far between in healthy brains.

“It’s likely that many Covid-19 patients, particularly those reporting or exhibiting neurological problems or those hospitalised, have these neuroinflammatory markers we saw in the people who died from the disease,” Wyss-Coray said. It may be possible to find out by analysing the cerebrospinal fluid of these patients, the contents of which are similar to those of the living brain.

“Our findings may help explain brain fog, fatigue, and other neurological and psychiatric symptoms associated with long Covid,” he said.