Functional Neurology

Brain Self-Tests

6 tests that reveal what MRI and CT scans miss. Your brain scan was "normal" — but your brain isn't functioning normally. These tests show why.

If you only do one thing from this page:

Do the Romberg balance test

Stand on one leg, eyes open, for 10 seconds. If you can't: your cerebellum is underperforming — and a 2022 study of 1,702 adults found this predicts 84% higher mortality risk. One test. Ten seconds. Free.

Too foggy to read this page? Start here:

  • Normal MRI ≠ normal brain function. Concussions are functional injuries — invisible to structural scans.
  • These 6 tests map which brain areas are disconnected — cortex (left/right), cerebellum, brain stem.
  • Your pattern (left imbalance, right imbalance, or higher/lower) determines which exercises you need.

"A photo of your phone's hardware won't tell you why the screen froze. A brain scan shows structure — not function. Your MRI is normal. But 40,000 eye movements a day are draining your battery because your cerebellum isn't coordinating them. No scan will ever show you that."

Before You Start

These tests are not diagnostic. They identify functional patterns for self-guided exercise selection. One positive test means nothing — patterns across multiple tests are what matter.

Stand near a wall. Have someone present. Video yourself for objectivity. Remove shoes and socks for balance tests.

The 6 Tests

TEST 01 Motor cortex

Finger Tapping Test

Setup

Seated. Hands on thighs.

Protocol

  1. 1 Left hand: hold up, touch index finger to thumb as WIDE and FAST as possible. 10 seconds.
  2. 2 Rest. Repeat with right hand.
  3. 3 Compare: speed, amplitude (how wide it opens), rhythm, any facial movements.

Watch For

  • One hand clearly slower or stiffer
  • Amplitude decreasing mid-test (decrement)
  • Face scrunching to compensate
  • Dominant hand slower than non-dominant = significant

Scoring

Slower LEFT hand = 1 tick on RIGHT cortex. Slower RIGHT hand = 1 tick on LEFT cortex. Motor pathways cross at the brain stem.

The finger tapping test is a validated Parkinson's screening tool used in clinical neurology. But it also reveals hemisphere imbalances in non-Parkinson's brain fog — the kind that standard imaging misses completely.

Lee CY et al., PLoS ONE, 2016 — smartphone finger tapping validated for bradykinesia (n=144)

TEST 02 Cerebellum

Rapid Alternating Movement

Setup

Standing or seated. Arms in front.

Protocol

  1. 1 Level 1: Arms straight forward. Flip palms up/down as fast as possible.
  2. 2 Level 2: Elbows tucked at 90°. Flip palms up/down.
  3. 3 Level 3: One hand flips while the OTHER hand massages your own wrist in small circles.

Watch For

  • Hand drifting from position
  • Wobbling or irregular rhythm
  • Elbow lifting or dropping (compensation)
  • One side clearly worse than the other

Scoring

Affected side = ticks on SAME side cerebellum. The cerebellum does NOT cross. Level 1 fail = 1 tick. Level 2 = 2 ticks. Level 3 = 3 ticks.

Your cerebellum contains 80% of all brain neurons. It coordinates not just movement but thinking, memory, emotions, and autonomic function. When it fails, everything downstream fails — but MRI shows nothing.

Schmahmann JD & Sherman JC, Brain, 1998 — cerebellar cognitive affective syndrome

TEST 03 Cerebellum + proprioception

Romberg Balance Test

Setup

Standing near a wall (safety). Someone nearby to catch you.

Protocol

  1. 1 Variation A: Feet together, arms at sides, eyes CLOSED. Hold 30 seconds.
  2. 2 Variation B: One foot directly in front of the other (tandem stance), eyes closed. 10 seconds. Switch feet.
  3. 3 Bonus: Stand on one leg, eyes open. Can you hold 10 seconds?

Watch For

  • Which direction you sway or fall
  • Inability to maintain position
  • Massive difference between eyes open vs. closed

Scoring

Fall/sway RIGHT = 1 tick on RIGHT cerebellum. Fall LEFT = 1 tick on LEFT cerebellum. Same side — cerebellum doesn't cross.

A 2022 study of 1,702 adults (ages 51-75) found that inability to stand on one leg for 10 seconds predicted 84% higher all-cause mortality risk over the next decade. Balance isn't just about not falling. It's a window into your entire brain.

Araujo CG et al., Br J Sports Med, 2022 — 10-second OLS and mortality (n=1,702, HR 1.84)

TEST 04 Vestibular + cerebellum

Fukuda Stepping Test

Setup

Remove shoes and socks. Silent room. No music. No visual cues. Clear space.

Protocol

  1. 1 Stand with feet together, eyes closed.
  2. 2 March in place: 50 steps. Knees to 90°. Arms swinging naturally.
  3. 3 Open your eyes. Where did you end up? How much did you rotate?

Watch For

  • Body rotation >45° to one side
  • Forward or backward drift
  • Dizziness after finishing (mild = vestibular stress; severe = significant)

Scoring

Rotation direction = ticks on SAME side cerebellum. Dizziness without rotation = 1 tick on both sides.

Your inner ear, cerebellum, and proprioceptive system work together to keep you oriented in space. When one fails, the others compensate — but that compensation costs energy. The energy bill shows up as brain fog by 4-5pm.

Fukuda T, Acta Otolaryngol, 1959 — Stepping test for vestibular function assessment

TEST 05 Frontal lobe + brain stem

Smooth Pursuit Eye Tracking

Setup

Seated. Hold thumb at arm's length, centered between eyes.

Protocol

  1. 1 Lock eyes on your thumb.
  2. 2 Slowly move thumb LEFT → RIGHT. Your HEAD stays perfectly still. Eyes only.
  3. 3 Do 3-4 complete passes.
  4. 4 Have someone observe or video yourself.

Watch For

  • Head turning to follow (brain can't track with eyes alone)
  • Eyes "catching up" in jumps instead of smooth tracking
  • Excessive blinking
  • After 3-4 passes: eyes start jerking or losing focus
  • Eye strain pulling toward one side

Scoring

Head turns or eyes strain LEFT = 1 tick on LEFT cortex. Head turns or eyes strain RIGHT = 1 tick on RIGHT cortex.

You make 40,000-50,000 eye movements per day. If each one requires your head to compensate because your brain can't coordinate the eyes alone, the cumulative energy cost is enormous. This is why many people feel fine in the morning but crash by late afternoon.

Munoz DP et al., Brain, 2003 — eye tracking deficits in ADHD

TEST 06 Brain stem coordination

Near-Far Convergence

Setup

Seated. Hold a pen or phone at arm's length.

Protocol

  1. 1 Focus on the object.
  2. 2 Slowly bring it toward your nose.
  3. 3 Slowly move it away.
  4. 4 Repeat 3-5 times.

Watch For

  • Double vision at any point
  • One eye "giving up" and drifting
  • Eye strain or pain
  • Unable to maintain single image as object approaches

Scoring

Not formally scored in the brain map — but failure indicates brain stem coordination issues that compound other findings.

Convergence insufficiency is one of the most common undiagnosed causes of reading difficulty, headaches, and screen fatigue. It's treatable — but only if you know to look for it.

Clinical observation — convergence insufficiency prevalence ~5-13% in school-age children (Rouse et al., Optom Vis Sci, 1999)

Score Your Brain Map

Your Brain Map Add ticks from each test. The pattern reveals the disconnection. LEFT RIGHT LEFT CORTEX Ticks: _____ RIGHT CORTEX Ticks: _____ LEFT CEREBELLUM Ticks: _____ RIGHT CEREBELLUM Ticks: _____ BRAIN STEM SCORING RULES Finger tapping → OPPOSITE cortex (motor pathways cross) All other tests → SAME SIDE (cerebellum doesn't cross) High R cerebellum + L cortex = Left brain imbalance High L cerebellum + R cortex = Right brain imbalance WhatIsBrainFog.com

What Your Pattern Means

Left Brain Imbalance

High RIGHT cerebellum + LOW left cortex

ADHD-like pattern: poor sustained attention, impulsivity, difficulty with sequential tasks

Right Brain Imbalance

High LEFT cerebellum + LOW right cortex

Autistic-spectrum pattern: social processing difficulty, sensory sensitivity, rigid thinking

Higher/Lower Dysfunction

BOTH cerebellums high, cortex relatively spared

Foundation problem: dizziness, autonomic symptoms, temperature dysregulation, exercise intolerance. Takes longer to heal — must fix foundation before upper floors.

Clinical Case

"A 12-year-old boy — call him Keith — got hit by a baseball. CT scan: completely normal. But his personality changed overnight. He became aggressive. He developed severe ADHD. His mother was desperate."

Eye movement testing revealed what the CT couldn't: severe frontal lobe dysregulation. His eyes lagged, jumped, and his head compensated on every pass. The structural test showed nothing. The functional test revealed everything.

Treatment: therapeutic eye exercises. Not medication. Result: personality normalized. ADHD reversed. Because the exercises regulated his frontal lobe — the same area the eyes connect to.

This information is for educational purposes only. Always consult with a qualified healthcare professional.