Neuro-Otology
Neuro-Otology
What Do You Need to Know?
- Peripheral vertigo = more symptomatic (severe spinning, nausea); central vertigo = more dangerous (stroke, subtle findings)
- HINTS exam >98% sensitive for posterior fossa stroke — more sensitive than initial MRI within 48 h
- BPPV = most common cause of vertigo; posterior canal 80–90%; Dix-Hallpike → Epley maneuver
- Normal head impulse test in acute vertigo is alarming — suggests central cause (brainstem stroke)
- Vestibular migraine = most common episodic vertigo in young adults (after BPPV); can occur WITHOUT headache
- Meniere triad: episodic vertigo (20 min–12 h) + low-frequency SNHL + tinnitus ± aural fullness
- COWS: Cold Opposite, Warm Same (fast-phase direction of caloric nystagmus)
Peripheral vs Central Vertigo
Master Comparison Table
| Feature | Peripheral | Central |
|---|---|---|
| Onset | Sudden | Sudden or gradual |
| Vertigo severity | Severe spinning | Mild-moderate (may be imbalance only) |
| Duration | Seconds to days (self-limited) | Variable; may be persistent |
| Nystagmus direction | Unidirectional (fast phase away from lesion); horizontal-torsional | Direction-changing, vertical, or purely torsional |
| Fixation suppression | Yes (nystagmus decreases) | No (nystagmus persists or worsens) |
| Hearing loss | May be present (labyrinthitis, Meniere) | Usually absent (except AICA stroke) |
| Nausea/vomiting | Prominent | Variable, often less severe |
| Neurologic signs | Absent | Present (diplopia, dysarthria, ataxia, weakness) |
| Gait | Unsteady but able to walk | Severe ataxia; may be unable to sit unsupported |
| Head impulse test | Abnormal (catch-up saccade) | Normal (no catch-up saccade) |
| Skew deviation | Absent | Present |
Red Flags for Central Vertigo
- Vertical nystagmus (downbeat or upbeat)
- Direction-changing nystagmus (changes with gaze direction)
- No fixation suppression
- Skew deviation (vertical misalignment on alternate cover test)
- New neurologic signs: diplopia, dysarthria, dysphagia, limb ataxia, weakness, numbness
- Normal head impulse test in acute sustained vertigo
- Inability to walk (cerebellar stroke/hemorrhage)
💎 Board Pearl
- Peripheral vertigo = more symptomatic; central vertigo = more dangerous — classic board teaching point
- Vertical nystagmus is always central until proven otherwise
HINTS Exam (Head Impulse, Nystagmus, Test of Skew)
HINTS Components
| Component | Peripheral (Vestibular Neuritis) | Central (Stroke) |
|---|---|---|
| Head Impulse Test (HIT) | Abnormal — catch-up saccade (positive) | Normal — no catch-up saccade |
| Nystagmus | Unidirectional (fast phase away from lesion) | Direction-changing or vertical |
| Test of Skew | Negative (no skew deviation) | Positive (vertical eye misalignment) |
Key Facts
- Sensitivity for posterior fossa stroke: >98% — superior to initial MRI (DWI can miss 12–20% within first 48 h)
- Only valid in acute vestibular syndrome (acute sustained vertigo + nystagmus + nausea/gait instability)
- Any ONE central finding = central until proven otherwise
InFARCT Mnemonic — Central Pattern
| Letter | Meaning |
|---|---|
| Impulse | Normal (no catch-up saccade) |
| Fast-phase | Alternating (direction-changing nystagmus) |
| Refixation on | Cover Test (skew deviation present) |
⚠ Warning
A normal head impulse test in a patient with acute vertigo means the VOR is intact — the brainstem is likely the problem, NOT the inner ear. Do NOT be reassured by a normal HIT.
💎 Board Pearl
- HINTS beats early MRI for posterior fossa stroke detection — a classic board question
- InFARCT = Impulse Normal, Fast-phase Alternating, Refixation on Cover Test → think INFARCT
Benign Paroxysmal Positional Vertigo (BPPV)
Overview
- Most common cause of vertigo overall
- Pathophysiology: free-floating otoconia (calcium carbonate crystals) displaced from utricle into semicircular canal
- Posterior canal = 80–90% of cases; horizontal canal = 5–15%; anterior canal = rare
- Recurrence rate: ~15–20% per year
Dix-Hallpike Test (Posterior Canal)
| Feature | Peripheral (BPPV) | Central Mimic |
|---|---|---|
| Latency | 2–5 seconds | None (immediate onset) |
| Duration | <60 seconds (transient) | Persistent (>60 s) |
| Nystagmus type | Upbeating + torsional (toward affected ear) | Downbeating or pure vertical |
| Fatigability | Yes (diminishes with repetition) | No (does not fatigue) |
| Vertigo | Intense, brief | Variable |
Horizontal Canal BPPV
| Variant | Mechanism | Nystagmus on Supine Roll Test | Stronger Side |
|---|---|---|---|
| Geotropic | Canalithiasis (free debris) | Horizontal, toward ground (both sides) | Affected ear (more intense) |
| Apogeotropic | Cupulolithiasis (debris on cupula) | Horizontal, away from ground (both sides) | Unaffected ear (more intense) |
Treatment by Canal
| Canal | Diagnostic Test | Treatment Maneuver |
|---|---|---|
| Posterior | Dix-Hallpike | Epley (canalith repositioning) |
| Horizontal (geotropic) | Supine roll test | Lempert (BBQ roll / 360° roll) |
| Horizontal (apogeotropic) | Supine roll test | Gufoni maneuver or forced prolonged position |
| Anterior | Dix-Hallpike (downbeat nystagmus) | Reverse Epley or deep head-hanging |
💎 Board Pearl
- Dix-Hallpike nystagmus with no latency or non-fatigable = think central lesion, NOT BPPV
- Posterior canal BPPV = upbeating + torsional; downbeating nystagmus on Dix-Hallpike suggests anterior canal or central pathology
- Meclizine does NOT treat BPPV — repositioning maneuvers are the treatment
Vestibular Neuritis & Labyrinthitis
Comparison
| Feature | Vestibular Neuritis | Labyrinthitis |
|---|---|---|
| Vertigo | Acute, severe, sustained (days) | Acute, severe, sustained (days) |
| Hearing loss | No | Yes (SNHL) |
| Tinnitus | No | Yes |
| Etiology | HSV-1 reactivation in vestibular ganglion (Scarpa’s) | Viral/bacterial infection of labyrinth |
| Anatomy | Vestibular nerve (superior division most common) | Vestibular nerve + cochlea |
| Head impulse test | Abnormal (catch-up saccade toward affected ear) | Abnormal |
| Nystagmus | Fast phase away from affected ear; suppressed by fixation | Same |
| Caloric testing | Reduced/absent on affected side | Reduced/absent on affected side |
Treatment
| Phase | Treatment | Duration |
|---|---|---|
| Acute (1–3 days) | Vestibular suppressants: meclizine, diazepam, promethazine | Limit to ≤3 days |
| Steroids | Methylprednisolone taper or prednisone (within 72 h) | Short course (1–3 weeks) |
| Rehabilitation | Vestibular rehabilitation therapy (VRT) — most important long-term treatment | Weeks to months |
⚠ Warning
Do NOT use vestibular suppressants (meclizine, benzodiazepines) beyond 3 days — they delay central compensation and prolong recovery. Early vestibular rehab is key.
💎 Board Pearl
- Vestibular neuritis = vertigo without hearing loss; labyrinthitis = vertigo with hearing loss
- Long-term vestibular suppressants impair compensation — classic board question on what NOT to do
- Superior vestibular nerve is most commonly affected (supplies superior + horizontal canals and utricle)
Meniere Disease
Diagnostic Criteria
- Definite Meniere: ≥2 spontaneous vertigo episodes (20 min–12 h) + audiometrically documented low-to-mid frequency SNHL + fluctuating aural symptoms (hearing, tinnitus, fullness) in affected ear
- Pathophysiology: endolymphatic hydrops (distention of endolymphatic compartment)
Key Features
| Feature | Detail |
|---|---|
| Classic triad | Episodic vertigo + fluctuating low-frequency SNHL + tinnitus (± aural fullness) |
| Attack duration | 20 min to 12 hours (never seconds, never days) |
| Hearing loss pattern | Low-frequency SNHL initially → all frequencies with progression |
| Bilateral disease | 25–40% over time |
| Tumarkin crisis | Sudden drop attack without LOC (otolith-mediated) |
| Lermoyez variant | Hearing improves during vertigo attack (reverse Meniere) |
| MRI role | Exclude vestibular schwannoma (acoustic neuroma); endolymphatic hydrops visible on 3T delayed gadolinium |
Treatment Ladder
| Step | Intervention | Notes |
|---|---|---|
| 1 | Low-sodium diet (<2 g/day) + diuretics (HCTZ/triamterene) | First-line; reduces endolymph volume |
| 2 | Betahistine | Used widely outside US; modest evidence |
| 3 | Intratympanic dexamethasone | Non-ablative; reduces vertigo frequency |
| 4 | Intratympanic gentamicin | Ablative (vestibulotoxic); effective but risk of hearing loss |
| 5 | Surgery: endolymphatic sac decompression | Controversial efficacy |
| 6 | Labyrinthectomy / vestibular nerve section | Definitive; destroys residual vestibular function |
💎 Board Pearl
- Meniere duration = 20 min to 12 h; seconds = BPPV; days = vestibular neuritis — duration is the key differentiator
- Tumarkin crisis = sudden falls without LOC in Meniere — favorite board distractor from epileptic drop attacks
- Always get MRI with gadolinium to rule out vestibular schwannoma before diagnosing Meniere
Superior Canal Dehiscence Syndrome (SCDS)
Key Concepts
- Bony dehiscence over the superior (anterior) semicircular canal → creates a third mobile window (oval window, round window, + dehiscence)
- Sound/pressure energy diverted through dehiscence rather than through cochlea normally
Clinical Features
| Feature | Description |
|---|---|
| Tullio phenomenon | Vertigo/nystagmus triggered by loud sounds |
| Hennebert sign | Vertigo/nystagmus with tragal pressure or pneumatic otoscopy |
| Autophony | Hearing own voice, breathing, or heartbeat amplified |
| Conductive hyperacusis | Hearing internal body sounds (eye movements, footsteps) |
| Pulsatile tinnitus | From transmitted vascular pulsations |
| Apparent conductive hearing loss | Audiometry may show air-bone gap (bone conduction supranormal) — mimics otosclerosis |
Diagnosis
| Test | Finding |
|---|---|
| High-resolution CT temporal bone | Bony dehiscence over superior canal (coronal + Pöschl reformats) |
| cVEMP | Reduced threshold (≤70 dB) + increased amplitude |
| oVEMP | Increased amplitude (most sensitive VEMP measure) |
| Audiometry | Low-frequency air-bone gap with supranormal bone conduction |
| ECoG | Elevated SP/AP ratio |
Treatment
- Conservative: avoidance of triggers, symptom management
- Surgical: canal plugging or resurfacing via middle fossa approach (definitive)
💎 Board Pearl
- Tullio phenomenon (sound-induced vertigo) + autophony = think SCDS until proven otherwise
- Air-bone gap on audiometry with normal tympanogram — do NOT confuse with otosclerosis; check VEMP and CT temporal bone
- SCDS = third mobile window; VEMPs show reduced threshold + increased amplitude (opposite of vestibular neuritis)
Vestibular Migraine
Diagnostic Criteria (International Classification)
- A. ≥5 episodes of vestibular symptoms (moderate/severe, 5 min–72 h)
- B. Current or previous history of migraine (with or without aura)
- C. ≥50% of vestibular episodes associated with ≥1 migraine feature: headache (migraine-type), photophobia, phonophobia, visual aura
- D. Not better accounted for by another diagnosis
Vestibular Migraine vs Meniere Disease
| Feature | Vestibular Migraine | Meniere Disease |
|---|---|---|
| Duration | 5 min to 72 h (variable) | 20 min to 12 h |
| Hearing loss | Usually absent | Low-frequency SNHL (fluctuating) |
| Migraine features | Present in ≥50% of episodes | May coexist but not required |
| Headache | Common (but NOT required) | Not typical |
| Aural fullness | Can occur (overlap) | Classic feature |
| Audiometry | Usually normal | Low-frequency SNHL |
| Caloric testing | Usually normal | Reduced unilateral response |
| Triggers | Migraine triggers (sleep, stress, diet) | Salt intake, stress |
Treatment
| Approach | Options |
|---|---|
| Acute | Triptans (if headache present), vestibular suppressants (short-term), anti-emetics |
| Prophylaxis | Same as migraine: topiramate, venlafaxine, propranolol, amitriptyline, nortriptyline |
| Non-pharmacologic | Lifestyle modification (sleep hygiene, trigger avoidance), vestibular rehabilitation |
Clinical Pearl
Vestibular migraine can present without headache in up to 30% of episodes. A history of migraine (even remote) plus episodic vestibular symptoms with photophobia or visual aura should raise suspicion.
💎 Board Pearl
- Most common cause of episodic vertigo in young adults (after BPPV) — frequently tested
- No headache required for diagnosis — only migraine history + migraine features during ≥50% of vestibular episodes
- Overlap with Meniere exists — if audiometry shows progressive SNHL, favor Meniere
Central Causes of Vertigo
Vascular Syndromes
| Syndrome | Artery | Key Features |
|---|---|---|
| AICA stroke | Anterior inferior cerebellar artery | Vertigo + hearing loss + facial weakness + cerebellar signs; AICA supplies labyrinth via internal auditory artery |
| PICA / Lateral medullary (Wallenberg) | Posterior inferior cerebellar artery / vertebral artery | Vertigo, nystagmus, Horner syndrome, dysphagia, hoarseness, ipsilateral facial numbness + contralateral body pain/temperature loss |
| Cerebellar hemorrhage/infarction | SCA, AICA, or PICA | Severe vertigo, inability to walk/sit, headache; may need emergent decompression (hydrocephalus, brainstem compression) |
| Basilar artery occlusion | Basilar artery | Vertigo, bilateral motor/sensory signs, decreased consciousness, locked-in syndrome |
Non-Vascular Central Causes
| Condition | Key Features | Nystagmus Pattern |
|---|---|---|
| Multiple sclerosis | Vertigo can be presenting symptom; INO common; brainstem/cerebellar plaques | Variable; INO = impaired adduction + contralateral abducting nystagmus |
| Episodic ataxia type 2 (EA-2) | CACNA1A mutation; episodic vertigo + ataxia lasting hours; responds to acetazolamide | Interictal downbeat nystagmus |
| Chiari I malformation | Tonsillar herniation >5 mm; headache + vertigo worse with Valsalva/cough | Downbeat nystagmus (especially on downgaze) |
| Vestibular schwannoma | Progressive unilateral SNHL + tinnitus ± imbalance; CN V/VII involvement late | Gradual compensation; may have subtle nystagmus |
| Cerebellar degeneration | Paraneoplastic (anti-Yo, anti-Hu), alcoholic, or hereditary | Gaze-evoked, downbeat, or positional |
Clinical Pearl
AICA stroke is the only central vertigo syndrome that commonly causes hearing loss (internal auditory artery supplies the labyrinth). This mimics peripheral vertigo and is a classic board trap.
💎 Board Pearl
- Downbeat nystagmus = Chiari malformation, EA-2, cerebellar degeneration — always think craniocervical junction
- CACNA1A = EA-2, FHM1, SCA6 — same gene, three phenotypes; EA-2 responds to acetazolamide
- Cerebellar hemorrhage with hydrocephalus = neurosurgical emergency — do not just place EVD (risk of upward herniation); needs suboccipital decompression
Vestibular Testing
Caloric Testing
| Stimulus | Fast Phase Direction | Mnemonic |
|---|---|---|
| Cold water (30°C) | Away from stimulated ear (contralateral) | COWS: Cold Opposite, Warm Same |
| Warm water (44°C) | Toward stimulated ear (ipsilateral) |
- Tests horizontal canal VOR (lateral semicircular canal → CN VIII → vestibular nuclei)
- Canal paresis: >25% reduced response on one side = unilateral vestibular hypofunction
- Absent bilateral calorics = bilateral vestibular loss (think ototoxicity, bilateral Meniere)
- In comatose patients: only slow phase remains (fast phase requires cortex) → cold water = eyes deviate toward stimulated ear
Vestibular Test Summary
| Test | What It Measures | Key Finding |
|---|---|---|
| Video HIT (vHIT) | Individual canal VOR (high-frequency) | Catch-up saccades (overt/covert) = peripheral deficit |
| Caloric testing | Horizontal canal VOR (low-frequency) | Canal paresis = unilateral loss; COWS for direction |
| Rotary chair | Bilateral VOR across frequencies | Gold standard for bilateral vestibular loss |
| cVEMP (cervical) | Saccule + inferior vestibular nerve | Absent = inferior nerve dysfunction; low threshold = SCDS |
| oVEMP (ocular) | Utricle + superior vestibular nerve | Absent = superior nerve dysfunction; increased amplitude = SCDS |
| ENG/VNG | Nystagmus recording, positional testing, calorics | Documents nystagmus patterns, positional vertigo |
| Audiometry | Hearing function (air + bone conduction) | Low-frequency SNHL (Meniere), high-frequency SNHL (schwannoma), air-bone gap (SCDS, otosclerosis) |
VEMP Quick Reference
| VEMP Type | Receptor | Nerve | Muscle Recorded | SCDS Finding |
|---|---|---|---|---|
| cVEMP | Saccule | Inferior vestibular nerve | SCM (ipsilateral) | ↓ Threshold, ↑ amplitude |
| oVEMP | Utricle | Superior vestibular nerve | Inferior oblique (contralateral) | ↑ Amplitude (most sensitive) |
💎 Board Pearl
- COWS (Cold Opposite, Warm Same) = fast-phase direction; in comatose patients only slow phase persists (eyes deviate toward cold)
- Rotary chair = gold standard for bilateral vestibular loss (bilateral gentamicin ototoxicity, bilateral Meniere)
- Audiometry is mandatory in all vertigo workups — differentiates BPPV (normal), Meniere (low-freq SNHL), schwannoma (high-freq SNHL), and SCDS (air-bone gap)
References
- Kattah JC, Talkad AV, Wang DZ, et al. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504-3510.
- Bhattacharyya N, Gubbels SP, Schwartz SR, et al. Clinical practice guideline: benign paroxysmal positional vertigo (update). Otolaryngol Head Neck Surg. 2017;156(3_suppl):S1-S47.
- Lempert T, Olesen J, Furman J, et al. Vestibular migraine: diagnostic criteria. J Vestib Res. 2012;22(4):167-172.
- Lopez-Escamez JA, Carey J, Chung WH, et al. Diagnostic criteria for Meniere disease. J Vestib Res. 2015;25(1):1-7.
- Minor LB. Superior canal dehiscence syndrome. Am J Otol. 2000;21(1):9-19.
- Strupp M, Mandalà M, López-Escámez JA. Peripheral vestibular disorders: an update. Curr Opin Neurol. 2019;32(1):165-173.
- Bisdorff A, Von Brevern M, Lempert T, Newman-Toker DE. Classification of vestibular symptoms. J Vestib Res. 2009;19(1-2):1-13.