Studies have found that patients with Lyme disease experience exaggerated responses to pain and non-painful stimuli despite antibiotic treatment.

Lopez-Sola and colleagues describe those same responses in patients with fibromyalgia, a condition associated with widespread musculoskeletal pain and tenderness accompanied by fatigue, cognitive, emotional and sleep-related symptoms.

In addition to pain-related changes, fibromyalgia patients show reduced tolerance to non-painful sensory stimulation—visual, auditory, olfactory and tactile—along with abnormal brain processing of non-painful sensory stimuli, making this an important consideration for Lyme disease symptoms.

Measuring the Brain’s Pain Response with fMRI

Lopez-Sola’s team used Functional Magnetic Resonance Imaging (fMRI) to demonstrate an exaggerated response to pain and non-painful stimuli in fibromyalgia patients.

fMRI has previously been used to measure regional, time-varying changes in the brain’s metabolism as a biomarker for disease and to monitor therapy, or for studying pharmacological efficacy. PET and SPECT scans are also used to measure brain function.

The team exposed 37 fibromyalgia patients and 35 control patients to painful pressure and non-painful visual, auditory, and tactile stimuli. When the people with fibromyalgia were exposed to painful stimuli, they had greater Neurologic Pain Signature (NPS) responses than those without the condition.

Greater responses were also described for non-painful visual, auditory, and tactile stimuli.

In fibromyalgia, the misfiring and irregular engagement of different parts of the brain to process normal sensory stimuli like light, sound, pressure, temperature and odor, results in pain, flu-like sensations or other symptoms. This extra brain work can be exhausting, explains Jan Chambers, founder of the National Fibromyalgia & Chronic Pain Association.

Clinical Applications of fMRI

The potential for brain measures is that they can tell us something about the particular brain abnormalities that drive an individual’s suffering, according to Wager.

The fMRI can provide clinicians with insight into the neural pathology underlying fibromyalgia pain symptoms. The novelty of this study is that it provides potential neuroimaging-based tools that can be used with new patients to inform about the degree of certain neural pathology underlying their pain symptoms, states Lopez-Sola.

The fMRI results may also help predict treatment responses in fibromyalgia by establishing a framework for assessing therapeutic mechanisms and predicting treatment response at the individual level.

Brain Changes in Pain Processing

The brain changes due to pain consisted of augmented responses in sensory integration and self-referential regions in fibromyalgia, and reduced responses in the lateral frontal cortex, describes Lopez-Sola.

The brain changes due to non-painful sensory stimulation consisted of augmented responses in insula, posterior cingulate, and medial prefrontal regions, and reduced responses in primary and secondary sensory cortices, basal ganglia and cerebellum.

Why This Matters for Lyme Disease

The authors cautioned that exaggerated responses to pain and non-painful stimuli are not unique to fibromyalgia. Though this is taken as a provisional signature for fibromyalgia, these patterns are not unique to fibromyalgia or differentiate it from other conditions.

Multifocal pain and widespread mechanical hypersensitivity are common features of multiple chronic pain conditions.

In fact, exaggerated responses to pain and non-painful stimuli, frequently described in Lyme disease, could possibly be measured by fMRI to help assess therapeutic approaches and predict treatment response for individual Lyme disease patients.

Pain Characteristics in Lyme Disease

Acute and chronic pain associated with Lyme borreliosis has been characterized as having qualities of neuropathic pain—radicular, deep aching, or lancinating pain, often worse at night, and associated with both sensory and motor findings, according to Zimering.

Chronic pain despite adequate antibiotic treatment of neuroborreliosis was reported by a substantial number of patients described by various investigators.

Sensory Hyperarousal in Lyme Disease

Lyme disease patients frequently report central sensitization or sensory hyperarousal. In patients with post-treatment Lyme syndrome, sensory hyperarousal was reported by a majority of patients after acquiring Lyme disease, most often affecting hearing and vision.

Hypersensitivity to sound may be limited to louder sounds, but in some individuals even the volume fluctuations in a normal conversation can be noxious, according to Batheja from the Department of Psychiatry, Columbia University.

These patients might be seen wearing earplugs or sound-protectors when in situations normally tolerable to others.

The individual’s life may be quite altered by this hypersensitivity: wearing sunglasses indoors and avoidance of being outside during daylight, which in turn limits the ability to sustain a normal work and social life.

Hypersensitivity in other sensory modalities, such as olfactory, tactile, gustatory, and temperature have been described. This pattern of sensory amplification overlaps significantly with what patients report as allodynia.

Clinical Takeaway

Research using fMRI demonstrates measurable, exaggerated brain responses to both painful and non-painful stimuli in fibromyalgia and Lyme disease—augmented responses in sensory integration regions with reduced lateral frontal cortex responses create central sensitization where the brain amplifies sensory input. Multifocal pain and widespread mechanical hypersensitivity are common features across multiple chronic pain conditions, and exaggerated responses could potentially be measured by fMRI to assess therapeutic approaches and predict treatment response for individual Lyme disease patients. Chronic pain despite adequate antibiotic treatment has been documented, and sensory hyperarousal affecting hearing, vision, smell, touch, taste, and temperature is frequently reported in post-treatment Lyme syndrome.

Frequently Asked Questions

Can the brain’s pain response be measured in Lyme disease?
Research using fMRI has demonstrated measurable, exaggerated brain responses to both painful and non-painful stimuli in conditions like fibromyalgia that share features with Lyme disease pain.

Why are Lyme disease patients sensitive to light and sound?
Central sensitization causes the brain to amplify sensory input. This can make normal levels of light, sound, touch, and smell feel overwhelming or painful.

What is central sensitization?
Central sensitization is a state in which the brain and spinal cord become hyper-responsive to both painful and non-painful stimuli, amplifying sensory signals beyond what the stimulus warrants.

Related Reading

Lyme Disease Symptoms: What Patients Need to Know
Chronic Pain in Lyme Disease: Why It Moves and What Helps
Allodynia: When Normal Touch Becomes Painful
Burning Pain With Normal EMG: Understanding the Disconnect
Autonomic Dysfunction in Lyme Disease
Medical Dismissal in Lyme Disease

References

1. Batheja S, et al. Post-treatment Lyme syndrome and central sensitization. J Neuropsychiatry Clin Neurosci. 2013;25(3):176-86.
2. Zimering JH, et al. Acute and chronic pain associated with Lyme borreliosis: clinical characteristics and pathophysiologic mechanisms. Pain. 2014;155(8):1435-8.
3. Lopez-Sola M, et al. Towards a neurophysiological signature for fibromyalgia. Pain. 2017;158(1):34-47.
4. Glover GH. Overview of functional magnetic resonance imaging. Neurosurg Clin N Am. 2011;22(2):133-9.