Resources
Glossary
The working vocabulary of vestibular neuritis and labyrinthitis. Inline dotted terms throughout the chapter link here.
- Acute vestibular syndrome (AVS)
- Rapid-onset, continuous vertigo or dizziness lasting days to weeks with nausea, nystagmus and gait instability. Its central job is to separate a benign peripheral cause (neuritis) from a dangerous central one (stroke).
- Alexander's law
- Peripheral spontaneous nystagmus increases in intensity when the eyes look in the direction of the fast phase — a feature of a fixed unidirectional, peripheral nystagmus.
- Caloric weakness (canal paresis)
- A reduced caloric response on the affected side — evidence of a horizontal-canal/superior-division deficit. The classic confirmatory test in superior neuritis.
- Central (vestibular) compensation
- The brain's recalibration to a static unilateral vestibular deficit, restoring balance over weeks. Vestibular rehabilitation promotes it; chronic vestibular suppressants and inactivity retard it.
- Head-impulse test (HIT) · Halmagyi–Curthoys test
- A rapid, small-amplitude head turn while the patient fixes on a target. A corrective (catch-up) saccade reveals a deficient vestibulo-ocular reflex on that side — the peripheral sign. Paradoxically normal in central lesions.
- HINTS
- Head Impulse, Nystagmus, Test of Skew — a three-step bedside battery for the acute vestibular syndrome. The dangerous 'central' pattern (INFARCT) is a normal head impulse, direction-changing nystagmus, or a skew deviation.
- INFARCT
- Mnemonic for the central HINTS pattern: Impulse Normal, Fast-phase Alternating (direction-changing nystagmus), Refixation on Cover Test (skew). Any one suggests stroke.
- Inferior vestibular nerve
- The division supplying the posterior semicircular canal and the saccule. Less often affected; its involvement is detected by cervical VEMP and posterior-canal vHIT.
- Labyrinthitis
- Inflammation involving both the vestibular and cochlear portions of the labyrinth, so that acute vertigo is accompanied by sensorineural hearing loss and tinnitus. May be serous (viral), suppurative (bacterial), or autoimmune.
- Persistent postural-perceptual dizziness (PPPD)
- Chronic non-spinning dizziness and unsteadiness, worse on standing and with visual motion, that may follow an acute vestibular event such as neuritis — a functional sequela rather than ongoing damage.
- Scarpa's ganglion
- The vestibular ganglion housing the cell bodies of the primary vestibular afferents — the site where latent herpes simplex virus is hypothesised to reactivate in vestibular neuritis.
- Secondary BPPV
- Benign paroxysmal positional vertigo arising after neuritis, attributed to otoconia dislodged into the spared posterior canal — brief positional spells appearing as the acute syndrome settles.
- Skew deviation
- A vertical misalignment of the eyes from a brainstem (otolithic-pathway) lesion, revealed by a vertical re-fixation movement on alternate cover testing. Part of the central HINTS pattern.
- Superior vestibular nerve
- The division supplying the horizontal and anterior semicircular canals and the utricle. The part most often affected in vestibular neuritis.
- VEMP
- Vestibular evoked myogenic potentials. Cervical VEMP tests the saccule and inferior nerve; ocular VEMP tests the utricle and superior nerve — together they localise neuritis to a division.
- Vestibular neuritis · vestibular neuronitis
- Acute, sustained unilateral peripheral vestibulopathy presumed to follow inflammation of the vestibular nerve, with continuous vertigo lasting days and hearing spared. The prototypical acute vestibular syndrome of peripheral origin.
- Vestibular rehabilitation therapy (VRT)
- A graded, customised exercise programme (gaze stabilisation, habituation, balance and substitution) that accelerates central compensation — the mainstay of recovery after neuritis.
- Video head-impulse test (vHIT)
- An instrumented head-impulse test measuring vestibulo-ocular reflex gain and detecting covert and overt corrective saccades, canal by canal — used to localise the deficit to a division.