What Lyme Disease Does to the Brain: Brain Fog, MRI, and White Matter
Brain fog is common.
Standard tests may appear normal.
But the brain may still be affected.
Lyme disease can affect the brain, particularly in individuals with persistent symptoms after treatment.
Patients may experience brain fog, memory problems, slowed thinking, and difficulty concentrating.
This helps explain what Lyme disease does to the brain—even when routine testing appears normal.
Start here: Lyme disease symptoms guide
Does Lyme Disease Affect the Brain?
Yes, Lyme disease can affect the brain—especially in patients with persistent symptoms after treatment.
It may cause brain fog, slowed thinking, memory problems, and changes in attention.
Imaging studies show that these symptoms can be linked to changes in brain function and white matter structure.
What Brain Imaging Shows in Lyme Disease
Marvel and colleagues evaluated working memory in patients with post-treatment Lyme disease (PTLD) using functional MRI.
They found altered brain activation patterns in specific brain regions compared to healthy controls.
In several regions, individuals with PTLD showed reduced blood flow.
Despite these changes, patients performed tasks accurately—but more slowly.
This suggests the brain is working differently, not necessarily failing.
White Matter Changes in Lyme Disease
The study also identified changes in white matter within the frontal lobe.
White matter is critical for communication between different parts of the brain.
Changes in white matter may affect how brain regions communicate, contributing to symptoms like brain fog.
Some areas showed increased activity, which may reflect compensatory mechanisms.
The authors suggest that higher axial diffusivity could indicate repair and healing over time.
This supports the idea that the brain adapts in response to Lyme-related changes.
Why Patients Feel Brain Fog
Patients with Lyme disease may feel cognitively impaired—even when standard tests appear normal.
This may reflect subtle changes in brain function rather than obvious structural damage.
The brain may rely on alternative pathways to maintain performance, which can lead to slower processing and fatigue.
This may explain why patients feel impaired even when routine testing appears normal.
Does Lyme Disease Cause Brain Damage?
Most evidence suggests these changes are functional rather than permanent brain damage.
Instead of widespread destruction of brain tissue, Lyme disease appears to alter how the brain functions and communicates.
In some cases, imaging findings may reflect adaptation or repair rather than irreversible injury.
How Lyme Disease Affects the Brain Over Time
These findings suggest that cognitive symptoms may evolve over time.
The brain may undergo periods of dysfunction, adaptation, and possible repair.
This dynamic process may explain why symptoms fluctuate.
Learn more: why Lyme tests can be negative
Clinical Takeaway
Lyme disease can affect the brain in ways that are not always visible on standard testing.
Changes in brain function and white matter may contribute to symptoms like brain fog and slowed thinking.
Understanding these changes can help explain why patients feel impaired—even when routine tests appear normal.
Related Articles
- Lyme disease triggers inflammation in the hindbrain
- Could cytokines contribute to brain fog in Lyme disease?
- Lyme disease causes a “false brain tumor” in a child
References
- Marvel CL, Alm KH, Bhattacharya D, et al. A multimodal neuroimaging study of brain abnormalities and clinical correlates in post-treatment Lyme disease. PLOS ONE. 2022.
- Fallon BA, Keilp JG, Corbera KM, et al. A randomized, placebo-controlled trial of repeated IV antibiotic therapy for Lyme encephalopathy. Neurology. 2008.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
my daughter began having seizures about a year after being treated for lyme arthritis. Is there any other similar situations?
I have Lyme disease patients in my practice whose develop neurologic problems after resolution of their rheumatologic condition. Their seizures persist despite a thorough neurologic assessment. The seizures are often atypical. There are usually other symptoms between seizures. I have found treatment for Lyme disease helpful for some of these cases.
I have been treated for lymes in early May and late October I started having pain in my index finger main joints. Recently one index finger had turned a purplish color. Is there any correlation between the two?
I have had Lyme disease patients with bluish extremities associated with dysautonomia.
I have had Lyme disease for almost ten years, and have been on and off antibiotics throughout this period. About eight months ago I started having a lot of eye pain, and a feeling of something in my eye. Im now starting to have occasional blurry vision. Would this mean that I was possibly on the wrong antibiotics?
Did you test positive for Babesia? If so, were you treated for that along with the Lyme?
Dr Rawls book Unlocking Lyme explains a lot. You can put Lyme in a test tube and pulse it with antibiotics and it still will not kill all the Lyme so how are antibiotics going to? Only time I would take antibiotics is if my symptoms were so bad I had to lower my load so my immune system can kick in.
His supplements did wonders for me.
Blurry vision can be caused by ocular infections with Bartonella and Borrelia pathogens. Borrelia treatment with Doxy or Amoxil antibiotics is a must. Ocular Bartonella is treated with Doxycycline + Rifampin for four to six weeks for complete resolution of the symptoms.
I have very slurred speech which has caused me a lot of distress. I tested positive for Lyme, Bartonella and Babesia in 2021. I have had all the treatment I can afford, various antibiotics, IV and oral. Overall I am well but no significant improvement to the speech so I am now assuming irreversible damage?
52 year old chronic Lyme psychiatric symptoms confusionhearing sensitivity no treatment Paralysed by tick at 4 yrs old Is there any help at all None in Australia
Hi I had Lyme back in 2002, by 2003 Dr I was finally treated. Now on 3/7/24 test was done and came back 1.09 high is like positive Dr send me for more tests hopefully comes back negative. But when I was sick I had alot of bruises fast heart beat brain fog weakness in my legs insomnia neurological problem dizziness vomiting it was getting so bad,but Dr only treated with pills and I think it wasn’t enough for me.