Brain Fog

What Is Brain Fog?

“Brain fog” is a term used to describe a constellation of cognitive difficulties such as forgetfulness, poor concentration, slowed processing speed, and mental fatigue. While not a formal diagnosis, it is a common and often disabling symptom in individuals with hypermobile Ehlers-Danlos syndrome (hEDS). Many describe it as feeling mentally "cloudy," detached, or overwhelmed—like trying to think through a haze.

Causes of Brain Fog in hEDS

Brain fog in hEDS is multifactorial, involving overlapping neurologic, immunologic, cardiovascular, psychiatric, and biomechanical contributors. These include both empirically supported mechanisms and theoretical contributors that are still under investigation.

Empirically Supported Causes

• Dysautonomia (especially POTS): One of the most consistently linked factors, impaired autonomic regulation leads to reduced cerebral blood flow when upright, which may cause acute or persistent cognitive impairment.

• Chronic fatigue and poor sleep: Sleep disturbances, including unrefreshing sleep, insomnia, or disrupted sleep from pain, significantly impair memory, focus, and executive function.

• Chronic pain: Pain consumes attentional and cognitive resources, reduces sleep quality, and is independently associated with slower processing and poor concentration.

• Mast Cell Activation Syndrome (MCAS): Frequently comorbid with hEDS, histamine and other inflammatory mediators released during flares may cross the blood–brain barrier, affecting cognition.

• Neuropsychiatric comorbidities: Depression and anxiety, both highly prevalent in hEDS, are associated with slowed thinking, memory problems, and difficulty concentrating.

• Immune dysregulation: Cited in University of Washington’s GeneReviews guidelines, immune dysfunction may contribute to inflammation-mediated cognitive symptoms, though mechanisms remain unclear.

• Medication side effects: Drugs often used for symptom relief—such as muscle relaxants, opioids, antihistamines, and anticholinergics—can dull cognitive function.

Theoretical Contributors

• Cerebrovascular dysregulation: Impaired regulation of blood flow in the brain, even beyond dysautonomia, may limit oxygen and nutrient delivery during cognitive demand.

• Craniocervical instability (CCI) and Chiari I malformation: In some individuals with hEDS, structural instability at the base of the skull may compress brainstem structures or impair cerebrospinal fluid dynamics, potentially affecting alertness and mental clarity.

• Small fiber neuropathy: Damage to small autonomic and sensory nerve fibers may affect blood vessel regulation in the brain, contributing to symptoms of both POTS and brain fog.

• Fascial and CNS biomechanical abnormalities: Abnormal tension or structure in the fascia and connective tissues of the central nervous system may theoretically affect neural signaling, contributing to mental sluggishness.

• Chronic inflammation: Sustained immune activation may promote neuroinflammation, disrupting cognitive processing via cytokine-mediated mechanisms.

Symptoms of Brain Fog in hEDS

Symptoms may vary day to day and often fluctuate with overall symptom severity or physiologic stressors.

• Trouble concentrating or sustaining attention

• Word-finding difficulty or speech hesitation

• Short-term memory lapses (e.g., forgetting appointments, misplacing items)

• Slowed thinking or reduced mental processing speed

• Mental fatigue, especially after mental exertion

• Disorientation or a sense of mental “disconnect”

• Difficulty multitasking or following complex conversations

These symptoms commonly worsen with

• Orthostatic stress (standing or sitting upright for long periods)

• Sleep deprivation or poor-quality sleep

• Pain flares or widespread inflammation

• Emotional stress or sensory overload

• MCAS flares

Treatment and Management

There is no specific pharmacologic treatment for brain fog itself in hEDS. Management is individualized and focuses on treating contributing conditions, optimizing function, and improving quality of life.

Recommended Multidisciplinary Approaches

• Dysautonomia management (especially POTS)

  • Increase fluid and salt intake

  • Wear compression garments

  • Use of medications such as fludrocortisone, midodrine, or beta-blockers

  • Tailored physical reconditioning

• Sleep optimization

  • Sleep hygiene strategies

  • Identification and treatment of sleep disorders

  • Behavioral therapies if insomnia is present

• Pain control

  • Multimodal pain management

  • Physical and occupational therapy

  • Gentle strengthening or stabilizing exercises

• Psychiatric support

  • Cognitive behavioral therapy (CBT)

  • Medications when needed (e.g., antidepressants)

  • Mindfulness or stress management techniques

• Mast cell activation treatment

  • H1 and H2 antihistamines

  • Mast cell stabilizers (e.g., cromolyn sodium)

  • Low-histamine diet or trigger identification

• Cognitive support strategies

  • Memory aids (e.g., planners, phone reminders)

  • Structuring tasks and breaking them into smaller steps

  • Reducing sensory overload in work or home environments

• Self-management and functional adaptations

  • Energy pacing to avoid physical or mental crashes

  • Support for executive function challenges

  • Adjusted expectations and workload at school or work

Summary

Brain fog in hEDS is a widespread, multifactorial symptom arising from dysautonomia, fatigue, pain, mast cell disorders, psychiatric comorbidities, immune dysfunction, and potentially from biomechanical and neurologic abnormalities. Symptoms are real, disabling, and often fluctuate with overall disease activity. Treatment is highly individualized and aimed at improving contributing factors rather than targeting brain fog directly. With proper support—medical, therapeutic, and practical—many individuals can reduce the impact of cognitive symptoms and improve daily function.