Patients with Long Covid and chronic fatigue tend to have swelling in an area of the brain associated with memory and concentration, according to a study published on Tuesday.

Researchers from Griffith University in Australia used an ultra-high-field magnetic resonance imaging (MRI) machine to analyse how long Covid and myalgic encephalomyelitis — also known as chronic fatigue syndrome (CFS) — similarly impact brain structure, Xinhua news agency reported.

The research involved 17 long Covid patients, 29 CFS patients, and 15 people with neither condition. The team identified significantly larger hippocampus volume in long Covid and CFS patients compared to healthy individuals.

The hippocampus is a small but important part of the brain that helps with learning and converting short-term memories into long-term memories, as well as verbal and spatial memory.

The research, published in the scientific journal PLOS ONE, found that hippocampal volume was similar among long Covid and CFS patients and that hippocampal swelling was linked to symptom severity in both groups.

Kiran Thapaliya, lead author of the new study, said that the findings show that hippocampal impairment in long Covid and CFS patients “may play a significant role in cognitive difficulties such as memory problems, difficulty concentrating, and delayed responses to questions or conversations.”

He said that the larger volume could be caused by neurogenesis — the process by which new cells are formed in the brain — or by a virus in the brain.

Further, the study also found the size of the hippocampus was associated with symptom severity in both patient groups.

People with high hippocampus volume had “impaired concentration, unrestorative sleep, pain, and fatigue,” Thapaliya said.

The researchers noted that the overlap between CFS and long Covid may pave the way for exploring potential treatments for both conditions.