Imaging techniques reveal brain abnormalities from post-treatment Lyme disease
COURTESY OF MATT HAUGHEY / CC BY-NC-SA 2.0
Brain imaging techniques can help scientists understand what is going on inside the heads of patient populations.
In their recent study published in PLOS ONE, Dr. John Aucott and Cherie Marvel found that unexpected white matter activity in the brain, a symptom normally considered pathological, was found to be correlated with better outcomes in patients with post-treatment Lyme disease (PTLD).
PTLD occurs in patients who have received treatments for Lyme disease but have yet to fully recover. Persistent complaints about cognitive difficulty are one of the symptoms.
Aucott is an associate professor in the Division of Rheumatology at the School of Medicine. He is also the director of the Lyme Disease Clinical Research Center and a clinical-translational researcher in Lyme disease with a focus on PTLD.
He stressed that PTLD affects 10% to 20% of patients who were previously diagnosed with and treated for Lyme disease in an interview with The News-Letter.
“Post-treatment Lyme disease is not a trivial problem. It is a problem that should be noticed,” he said.
Marvel is a cognitive neuroscientist and an associate professor of Neurology at the School of Medicine. She has been using brain imaging methods to look at different cognitive and motor functions, primarily in clinical populations.
In an interview with The News-Letter, Marvel noted that the complaints of PTLD patients did not align well with the standard cognitive or neuro-psychological testing.
“So we thought we should look inside the brain. The way we can do that non-invasively is through functional MRI,”she said.
Participants were asked to perform working memory tasks while their brain activity was recorded by functional magnetic resonance imaging (fMRI). fMRI measures brain activity by detecting increased oxygen level in areas of activation.
Aucott highlighted that the decision to use an fMRI test for the study was intentional.
“The mystery behind post-treatment Lyme disease is whether there is something biological going on. Tests that are normally available to clinicians, such as regular MRI or CT, scans can’t identify these,“ he said. “So we hypothesized that stress tests under fMRI would be more sensitive to any biological changes.”
All participants performed two tasks. The easier task, which was the control condition, required participants to remember two letters for a short duration. After, the screen would show a new letter, and the participant would need to evaluate whether it was one of the two letters previously shown.
The harder task, which was the experimental condition, required participants to count two alphabetical letters forward of the same two letters and remember the new letters. Then, they were asked if a newly-appeared letter was one of the two new letters. (See link for article)
It is disingenuous to use the PTLD moniker for many reasons:
- It denies persistent infection
- It only includes the smaller subset of patients that have bee diagnosed and treated early and omits the larger subset of patients that are diagnosed and treated late
- Those with persistent symptoms may develop secondary psychosomatic & psychiatric disorders. By using the PTLD moniker, treatment will only address the secondary conditions, but continue to deny life-saving antimicrobials
This is crucial because ignoring these facts will only propagate the continuing under-treatment (or denying treatment altogether) of severely ill patients
- The researchers found expected brain activity in the gray matter but also in the white matter, which wasn’t expected.
- White matter cells communicate signals between gray matter.
- The finding caused the researchers to look more closely at the phenomenon.
- Axial diffusivity (water leaking along the axon) is how the neurons relay electrical signals to each other and increased axial diffusivity was correlated with better outcomes and few symptoms.
- Aucott states this response appears to be the body’s compensatory response to slower cognitive functions and is similar to a positive response to injury.
- The researchers want to follow patients longitudinally as well as look for inflammatory markers through cerebral fluid samples.