The Medical Guide
How to translate "brain fog" into clinical terms, navigate the healthcare system, and get the right diagnosis.
How to Talk to Your Doctor
Brain fog patients are routinely dismissed. This section teaches you to communicate in the language clinicians are trained to process — not to fight your doctor, but to collaborate effectively. Structured communication reduces harmful diagnostic errors by 38%.
Your 10-Minute Appointment Plan
Open with symptoms
"Persistent cognitive difficulty for [X] weeks — concentration, memory, word-finding."
Show your data
Self-assessment score (X/52), symptom diary with patterns, complete medication list.
Make the ask
"Could we run TSH, Free T3/T4, B12, ferritin, Vitamin D, and hs-CRP? Here's my reasoning."
If dismissed: "Could you note in my record that I requested these tests and they were declined?"
Clinical Translation Table
"Brain fog" isn't an ICD-10 medical code. When you say it, doctors hear "lifestyle complaint." Translate your experience using this terminology:
| Don't Say This | Say This Instead |
|---|---|
| "I feel spacey and can't focus" | "Attentional dysregulation" and "reduced processing speed" |
| "I keep losing my train of thought" | "Working memory deficit" — add frequency: "5+ times daily" |
| "I know the word but can't say it" | "Word-finding difficulty" or "anomia" |
| "I can't multitask anymore" | "Impaired divided attention" and "reduced cognitive endurance" |
| "It feels like dementia" | "I'm requesting a MoCA screening to rule out Mild Cognitive Impairment (MCI)" |
| "I'm exhausted after thinking" | "Post-exertional cognitive malaise" or "cognitive fatigability" |
The 15-Minute SBAR Script
SBAR is a clinical communication framework used in hospitals. Adapted for your appointment to ensure nothing gets missed.
"I'm experiencing persistent cognitive decline that is affecting my ability to work. This is not just fatigue — it's measurable functional impairment."
"Symptoms began [X weeks/months] ago following [trigger]. I've tracked [X] cognitive failures per week. Here's my 14-day symptom log."
"I'm concerned about thyroid dysfunction, B12 deficiency, or post-viral cognitive syndrome. I know 'normal' ranges may not reflect optimal brain function for my age."
"I'm requesting: (1) MoCA screening, (2) comprehensive thyroid panel including Free T3/T4, and (3) B12 with methylmalonic acid. I'd also like a referral based on these results."
If Testing Is Refused
"I understand your reasoning. Since this is affecting my daily function, I'd like to make sure we document this entire conversation — my symptoms, your clinical assessment, and the plan going forward. That way we have a clear baseline if things change."
This is not adversarial. It asks for the same documentation any good clinician would do. If concerns persist, request a referral for a second opinion.
Specialist Routing Map
Brain fog has 64 potential clinical causes spanning multiple distinct medical fields. Here is how to navigate from your GP to the right specialist based on your specific presentation.
| Specialist | When to See Them | Relevant Investigations |
|---|---|---|
| Endocrinologist | Abnormal TSH/T3/T4, hormonal symptoms, adrenal dysfunction, peri/menopause fog, diabetes. | Thyroid (#04), Menopause (#05) |
| Sleep Medicine | Snoring, gasping, unrefreshed sleep, suspected UARS, narcolepsy, or circadian rhythm disorders. | Sleep Disruption (#13) |
| Neurologist | Progressive continuous fog, seizures, vision changes, suspected MS, dysautonomia, or severe migraines. | POTS (#25), Post-Concussion (#22) |
| Gastroenterologist | Bloating overlapping with cognitive drops, SIBO breath testing, celiac screening, IBD, suspected leaky gut. | SIBO (#10), Dysbiosis (#09) |
| Psychiatrist / Neuropsych | Lifelong symptoms, ADHD evaluation, medication management, treatment-resistant depression testing battery. | ADHD (#21), Chronic Stress (#07) |
| Rheumatologist | Positive ANA, joint pain combined with fatigue/fog, autoimmune conditions (Lupus, Sjögren's, RA). | Autoimmune (#02) |
| Infectious Disease | Lyme disease, tick-borne infections, severe post-viral syndromes, chronic undetected infections. | Lyme (#23), Bartonella (#24) |
| Allergist / Immunologist | Mast Cell Activation Syndrome (MCAS), histamine intolerance, or severe allergies triggering cognitive impact. | MCAS (#03) |
When Your Results Come Back "Normal"
General practitioners look for disease. Functional clinicians look for optimization. "Normal" reference ranges include 95% of a sick population.
Thyroid
Doctor: "Your TSH is normal."
You: "Can we also check Free T3, Free T4, and TPO antibodies? I understand TSH alone can miss subclinical thyroid dysfunction."
Iron
Doctor: "Your iron is fine."
You: "What was my ferritin specifically? I've read that levels below 50–70 ng/mL can cause cognitive symptoms even when in-range."
Vitamin B12
Doctor: "B12 is within normal limits."
You: "Could we also check MMA (methylmalonic acid)? Borderline B12 with elevated MMA still indicates a functional deficiency."
Sleep Study
Doctor: "Your sleep study was negative for apnea."
You: "Were RERAs (Respiratory Effort-Related Arousals) scored? Upper airway resistance syndrome can cause fog with a normal AHI."
If Your Doctor Dismisses You
This happens often. Brain fog isn't a formal diagnostic code, so many doctors default to "stress" or "depression." Here are your options:
Documentation Request
"Could you document in my medical record that I requested these tests and they were declined?"
This is your right as a patient and encourages thorough consideration.
Request a Second Opinion
"I'd like to request a referral for a second opinion."
You are legally entitled to one in the UK (NHS) and most US insurance plans.
Functional Medicine Practitioner
Trained to investigate root causes that conventional medicine screens out.
Find one at ifm.org/find-a-practitioner
Direct-to-Consumer Testing
If your doctor won't order the panel, you can order tests privately.
Options: Medichecks (UK), Walk-In Lab (US), LetGetChecked (international)
The Brain Fog Blood Panel Request
Copy this script:
Investigate Intelligently
Take our 18-Biomarker Checklist to your GP. It is optimized for uncovering the 64 root causes of cognitive decline.
View Optimal Biomarker Targets