Study Confirms Memory, Concentration Issues After Lyme Disease

Nov. 15, 2022 – People who have been treated for Lyme disease, but continue to have symptoms, have changes in their brains that confirm the memory and concentration problems many of them have reported, a new study has found. 

Many people with what’s known as post-treatment Lyme disease – or PTLD – complain about problems with memory and concentration, which sometimes come with fatigue, muscle pain, insomnia, and depression. 

To understand potential changes in brain function that might explain these cognitive difficulties, researchers used specialized imaging techniques to compare the brains of 12 adults with PTLD and 18 adults with no history of Lyme disease. 

The researchers found changes in the white matter of the brains of those with PTLD. White matter is found in the deeper brain tissues and contains nerve fibers that are extensions of nerve cells.

“We found that … white matter function increased while participants with PTLD were performing a cognitive task,” says lead investigator Cheri Marvel, PhD, an associate professor of neurology and psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine in Baltimore.

It seemed logical “that if there were cognitive and neurological symptoms involved, then the brain may reveal something about this. Then we could begin to connect the dots between the patient experience and the underlying mechanisms driving them,” she says.

To investigate, Marvel’s team used functional magnetic resonance (fMRI), an imaging technique that measures blood flow to areas of the brain, often while specific tasks are performed — in this case, short-term memory tasks that involved memorizing and recalling capital and lowercase letters as well as the alphabetical order of multiple letters.

Those with PTLD performed more slowly on some of the memory tasks, although their slower speed did not affect the accuracy of their performance.

The researchers found unusual activity in the white matter of the frontal lobe — an area of the brain involved in cognitive tasks, such as memory recall and concentration — in the PTLD group. 

Typically, this type of tissue sees less blood flow, compared to gray matter in the brain, and is responsible for moving information around the brain and “delivering” it to the gray matter. The amount of activity they saw “is unusual to observe with the MRI methods we used, and we did not see such activity in the healthy control group,” Marvel says. 

In the meantime, the researchers want to work with other experts to answer their remaining questions, she says. 

“It is important for clinicians to know that PTLD leads to real, quantifiable brain changes and that patients’ cognitive complaints may be a direct consequence of these brain changes, rather than a side effect of other symptoms, such as fatigue, for example,” Marvel said. 

Commenting on the study for this report, John Keilp, PhD, an associate professor of clinical psychology at Columbia University in New York City, says it is an “important, carefully executed study that expands upon earlier brain imaging studies of patients with PTLD” using “state-of-the-art brain imaging and analysis methods.”

The researchers “have shown us a way forward to examine these patients and this disorder in greater detail as we attempt to unlock the uncertainties surrounding the physiological basis of these patients’ symptoms,” says Keilp, who heads the neuropsychology laboratory in the division of Molecular Imaging and Neuropathology at the New York State Psychiatric Institute.