A new study has found that COVID-19 may cause deadly neurological problems, including inflammation of the brain, delirium, stroke and nerve damage.

According to the authors of the study, there's been an increase in patients with a rare and sometimes deadly neurological condition called acute disseminated encephalomyelitis (ADEM). Patients with ADEM tested posted with the coronavirus, suggesting that the disease its causes may be leading to a spike in this neurological disorder.

What the research team discovered adds to a growing body of evidence linking COVID-19 to brain defects. For this reason, doctors need to be more "vigilant and look out for these complications" in coronavirus-positive patients, study co-senior author Dr. Michael Zandi, a neurologist at the National Hospital for Neurology and Neurosurgery in London, said in a statement.

It's unknown how frequent complications of the brain occur in COVID-19 patients, but the study largely focused on already hospitalized patients, who were then referred to the neurology department.

The study authors gathered information on 43 patients at the National Hospital for Neurology and Neurosurgery, ranging from 16 to 85 years of age. 29 of them tested positive of the virus, and the remaining number were suspected or probable cases of COVID-19.

The team found eight patients who suffered strokes. This coincides with previous research that tied COVID-19 to an increase in blood clots. Most of these patients don't recover well, with none making it back to full health. One patient succumbs to death after their stroke.

There were 10 patients found with temporary brain dysfunction or transient encephalopathies, accompanied by symptoms of disorientation, confusion, and delirium. One had auditory and visual hallucinations.

Twelve were found to have brain inflammation. Usually, ADEM is seen in children, but the patients with ADEM in this study were all adults. In this group, one patient died, 8 more developed nerve damage, which is usually due to Guillain-Barre syndrome.

The research team found no trace of the coronavirus in cerebrospinal fluid samples taken from patients, which suggests that SARS-CoV-2 had not attacked the brain directly. In some patients, the researchers found evidence that the brain inflammation was likely caused by an immune response to the disease, suggesting that some neurological complications of Covid-19 might come from the immune response rather than the virus itself.

More studies are needed in order to better understand what causes these brain disorders and whether they will lead to long-term health complications, concluded the authors.