Making the diagnosis
Diagnosis & HINTS
There is no blood test and no first-line scan. The diagnosis is made by examining the eyes — and the single most important question the examination answers is “is this a stroke?”
The diagnostic criteria
Doctors diagnose neuritis from the story and the examination: continuous vertigo for days, a steady flick of the eyes, an off-balance walk, and no signs that point to the brain. A hearing test and sometimes a scan help confirm it and rule out other causes.
The 2022 Bárány Society criteria define acute unilateral vestibulopathy / vestibular neuritis as: acute or subacute sustained spinning vertigo; a peripheral spontaneous nystagmus (horizontal-torsional, fixation-suppressed); a reduced VOR on the head-impulse test toward the affected ear; no acute central or audiological signs; and not better explained by another disorder.3
In practice the criteria are a formalisation of a clean bedside picture. The danger is the AVS that looks peripheral but is not — so the operative skill is the bedside oculomotor exam, applied only in a patient with continuous vertigo and spontaneous nystagmus. Without nystagmus, HINTS does not apply.1
- A. Acute/subacute onset of sustained spinning or non-spinning vertigo (the acute vestibular syndrome).
- B. Peripheral spontaneous nystagmus — horizontal-torsional, unidirectional, suppressed by fixation.
- C. A reduced vestibulo-ocular reflex (head-impulse deficit) toward the affected ear.
- D. No acute central neurological or audiological signs.
- E. Not better accounted for by another disease.
HINTS — peripheral or central?
HINTS — Head Impulse, Nystagmus, Test of Skew — is a three-step bedside battery for the AVS. The reassuring peripheral triad is an abnormal head impulse (a corrective saccade), unidirectional nystagmus and no skew. The dangerous central pattern (INFARCT) is any of: a normal head impulse, direction-changing nystagmus, or a skew — and was more sensitive than early MRI-DWI for stroke.1 Toggle any central finding you observe:
HINTS interpreter
Switch on any central (dangerous) finding you observe. All off = the reassuring peripheral pattern of vestibular neuritis.
For the protocol in depth, the underlying ocular-motor anatomy and worked cases, see the dedicated HINTS chapter and the bedside-exam battery. In the emergency setting, the acute-vertigo chapter sets HINTS within the wider triage.
The head-impulse test
The head-impulse test is the cornerstone: a small, rapid head turn toward the affected ear produces a visible corrective (catch-up) saccade when the vestibulo-ocular reflex on that side is deficient — the sign of a peripheral canal paresis.2 A normal impulse in a patient with acute spontaneous vertigo is the opposite of reassuring — it points to a central lesion.
Confirming and localising
Laboratory tests confirm the deficit and localise it to a division. The horizontal vHIT and bithermal caloric track the superior division; cervical and ocular VEMP separate inferior from superior involvement; and pure-tone audiometry is what distinguishes labyrinthitis from pure neuritis:
| Test | Superior neuritis | Inferior neuritis | Labyrinthitis |
|---|---|---|---|
| Horizontal head impulse / vHIT | Abnormal | Normal | Abnormal |
| Bithermal caloric | Canal paresis | Normal | Canal paresis |
| Ocular VEMP (utricle) | Reduced/absent | Normal | Reduced/absent |
| Cervical VEMP (saccule) | Normal | Reduced/absent | Reduced/absent |
| Pure-tone audiometry | Normal | Normal | Sensorineural loss |
Pure-tone audiometry is the key separator: normal in neuritis, abnormal in labyrinthitis. Cervical VEMP distinguishes inferior-division involvement; ocular VEMP and caloric track the superior division.
Modality detail lives in the vHIT, VEMP and VNG / caloric chapters. Imaging is reserved for when the picture is central or atypical — see Role of imaging.
Key points
- Diagnosis is clinical: sustained vertigo, peripheral spontaneous nystagmus, an ipsilesional head-impulse deficit, and no central signs.
- HINTS applies only with spontaneous nystagmus; the central pattern (INFARCT) outperforms early MRI for stroke.
- A corrective saccade on head impulse marks the peripheral deficit; a normal impulse is a red flag.
- Caloric/vHIT and VEMP localise the division; audiometry separates labyrinthitis from neuritis.