Module · Compare

Compare disease signatures

Pick two entities — diseases, the normal reference, or the inferior-vestibular-neuritis teaching variant — and surface the discriminators that distinguish them. Side-by-side mode tables every dimension; overlay mode places each entity's audiogram alongside the normal reference.

First entity

Second entity

SCDS — superior canal dehiscence

Third-window symptoms with characteristic pseudo-conductive audiogram.

→ Read the module

Ménière's disease

Episodic vertigo with fluctuating low-frequency SNHL.

→ Read the module

Clinical pattern

Chronic, progressive over years. Episodes are brief sound- or pressure-triggered.

Discrete attacks of vertigo lasting 20 min to 12 hours, with symptom-free intervals.

Triggers

Loud sounds (Tullio), Valsalva, blowing nose, lifting, pneumatic pressure (Hennebert).

Spontaneous onset. Some patients identify salt, stress, or sleep deprivation.

Associated symptoms

Autophony — hearing one's own voice, eyeballs, footsteps amplified. Pulsatile tinnitus.

Tinnitus, aural fullness, and fluctuating hearing loss in the affected ear.

Head impulse

Normal (canal function is preserved despite dehiscence).

Often normal between attacks; may be abnormal during/after.

Nystagmus

Vertical-torsional eye movement evoked by sound or pressure (in plane of affected canal).

Spontaneous nystagmus during attacks (irritative or paretic depending on phase).

Skew

No skew.

HINTS pattern

Not applicable

Peripheral pattern

Audiogram

Low-frequency conductive pattern with SUPRANORMAL bone conduction (−5 to −10 dB at 250–500 Hz) on the affected side. Pseudo-conductive — preserved acoustic reflexes distinguish from otosclerosis.

Low-frequency rising sensorineural hearing loss (reverse slope), no air-bone gap — the audiometric fingerprint.

Audiogram traces

cVEMP

ENHANCED on affected side — supranormal amplitude and lowered threshold (often < 75 dBnHL). One of the most specific findings.

Often reduced/absent on the affected side; may evolve to bilateral involvement in advanced disease.

oVEMP

Also enhanced on affected side, often more sensitive than cVEMP. Amplitude > 17 μV is highly suggestive.

Variable — may be reduced bilaterally; helpful for monitoring progression.

Diagnostic criteria

Bárány 2021 (Ward et al.): clinical symptoms + dehiscence on high-resolution temporal-bone CT in Pöschl reformat + ≥1 physiologic confirmation (enhanced VEMP, low-frequency air-bone gap, or third-window nystagmus to stimulation).

Bárány/AAO-HNS 2015 (Lopez-Escamez et al.) — definite: ≥2 spontaneous vertigo episodes 20 min–12 h, audiometrically documented low/medium-frequency SNHL in affected ear, fluctuating aural symptoms, no better alternative.

Management

Conservative management for mild symptoms (avoid triggers). Surgical management for disabling symptoms: middle-cranial-fossa or transmastoid approach with plugging or capping of the dehiscent canal. Stapes surgery is contraindicated.

Ladder: low-salt diet + diuretics → betahistine → intratympanic steroids → intratympanic gentamicin (ablative) → endolymphatic sac decompression or labyrinthectomy in selected cases. (Basura 2020 CPG; AAO-HNS 2020 update.)

How clinicians use comparison

Differential diagnosis is the central skill of vestibular medicine. Most of the conditions in this atlas share overlapping features — two of them are episodic, several produce acute vertigo, several have hearing involvement, and several show abnormal HINTS findings. The discriminators are subtle and pattern-based: SCDS and otosclerosis both show a low-frequency air-bone gap, but only SCDS has supranormal bone conduction. Vestibular migraine and Ménière's both produce episodic vertigo, but only Ménière's shows persistent low-frequency SNHL between attacks.

Use this tool when reviewing a difficult case: pick the favoured diagnosis and pick its closest mimic, then read across the rows to find the discriminating feature. The audiogram row is rendered with the same component used on each disease module, so the patterns you learn here are the patterns you'll see on real tracings.