Benign Paroxysmal Positional Vertigo

BPPV is what happens when tiny calcium-carbonate crystals (otoconia) escape from the part of the inner ear that shouldcontain them — the utricle — and drift into a place where they don't belong — one of the semicircular canals, usually the one at the back (the posterior canal).

These misplaced crystals make the canal sensitive to gravity. When the head moves into a position where gravity pulls the crystals through the canal, the patient experiences a brief, intense spinning sensation that fades within a minute. Typical triggers are lying down, rolling over in bed, looking up, or bending forward.

The good news: a single bedside manoeuvre, the Epley repositioning procedure, restores the crystals to where they belong in around 80% of patients on the first attempt. No surgery, no medications.

BPPV is by far the most common peripheral vestibulopathy, with a lifetime prevalence of 3–10% in the general population and rising steeply with age.1 First described by Dix and Hallpike in 1952 as a positional vertigo with a stereotyped torsional nystagmus on provocative manoeuvre,2 its mechanism was explained two decades later by Hall, Ruby, and McClure: free otoconia, displaced from the utricular macula, migrate into a semicircular canal where they sit at the most dependent point.3

The posterior canal is involved in roughly 85–95% of BPPV. The lateral (horizontal) canal accounts for most of the remainder; anterior canal involvement is rare. The dominance of the posterior canal reflects geometry — it is the most dependent canal in the head when the patient is supine, so dislodged otoconia tend to fall into it.

BPPV is sometimes idiopathic, sometimes secondary. Common associations include head trauma (often minor), prolonged bed-rest, viral labyrinthitis or vestibular neuritis, ear surgery, and ageing of the otoconial membrane.11 Low bone mineral density and vitamin D deficiency are increasingly recognised as risk factors for both incident and recurrent BPPV.12

Canalithiasis — free otoconia in the canal — is the mechanism in the great majority of BPPV cases. The minority variant, cupulolithiasis (otoconia adherent to the cupula itself, first proposed by Schuknecht in 1969),4 produces a persistent positional nystagmus rather than the brief paroxysm characteristic of canalithiasis. Distinguishing the two matters because cupulolithiasis is more resistant to conventional repositioning and may require liberatory manoeuvres (Semont, Yacovino) rather than the standard Epley.6

The Bárány Society's 2015 consensus diagnostic criteria define three classical BPPV variants and three emerging ones.7 The classical: posterior canal canalithiasis, horizontal canal canalithiasis (geotropic nystagmus on supine roll), and horizontal canal cupulolithiasis (apogeotropic, direction-changing nystagmus). The emerging: anterior canal BPPV, multiple-canal BPPV, and probable/possible BPPV — the last categories carved out to capture patients with a compatible history and either spontaneous resolution or non-diagnostic test results.

Two diagnostic pitfalls deserve named attention. Persistent downbeat positional nystagmus during a Dix-Hallpike, especially if it does not fatigue and is not associated with vertigo, is a central sign and warrants imaging — it is not BPPV. And bilateral posterior-canal BPPV, more common after head trauma, produces an upbeat-torsional nystagmus that changes torsional direction depending on which ear is dependent — a pattern easily missed if only one Dix-Hallpike is performed.

Here is what is happening inside the ear in the figure above. When the patient sits upright (position 1), the otoconia rest at the bottom of the canal — they don't move, so the patient feels nothing. As soon as the head is tipped backward in the Dix-Hallpike position (position 2), gravity drags the otoconia down the canal. This pulls the canal's fluid with them, which in turn deflects the cupula — the gel-like flap that the nerve uses to detect head movement. The cupula wrongly tells the brain the head is spinning, so the patient feels intense vertigo and the eyes show a characteristic jerky movement called nystagmus.

The Epley manoeuvre exploits the same physics in reverse: by rotating the head through a sequence of positions, gravity is used to carry the otoconia all the way around the canal and back out into the utricle, where the body can dispose of them naturally.

Posterior-canal canalithiasis produces a stereotyped clinical signature.7,2 A latency of approximately 2–20 seconds between attaining the provocative position and the onset of nystagmus reflects the time taken for the otoconial mass to begin sliding. The nystagmus is upbeating (vertical fast phase upward, from the activation of the ipsilateral inferior oblique and contralateral superior rectus) and torsional, with the upper pole of the eye beating toward the dependent ear — the dependent ear being the affected one. Intensity rises in a crescendo and then fades over 30–60 seconds as the otoconia reach their new resting position. Reversal of the nystagmus on returning to sitting is characteristic, as is fatigability on repeat testing.

The Epley manoeuvre is the canonical treatment.5 Each of its four positions is held until the otoconia have settled (usually about 30 seconds, or until the nystagmus subsides): begin in the Dix-Hallpike position with the affected ear dependent (1), rotate the head 90° to the opposite side (2), roll the patient onto the unaffected side with the head facing the floor (3), and sit up with the head still angled forward (4). At each step the otoconia move further along the canal, with the goal of expelling them through the common crus into the utricle. Single-treatment success rates are around 80%; a second manoeuvre rescues most of the remainder.9

The biomechanics are worth understanding in detail because they explain almost every variant of BPPV and almost every treatment failure. The posterior canal lies approximately in the sagittal plane, angled posteriorly and inferiorly. In the upright head, the canal's most dependent point is near the ampulla; dislodged otoconia therefore rest there at baseline, where their weight produces no flow because they are pressed against the cupula at its base rather than dragging fluid past it. The Dix-Hallpike manoeuvre — head turned 45° toward the affected side, then dropped into 20° extension below couch level — aligns the posterior canal with gravity such that the otoconia begin a long slide along the canal, away from the cupula. The dragged endolymph deflects the cupula ampullofugally, which is excitatory for the posterior canal afferent, producing the upbeat-torsional nystagmus.2,7

Recognising why this matters at the bedside: an absent latency (nystagmus the instant the patient is positioned), a failure to fatigue, or persistent rather than paroxysmal nystagmus argues against canalithiasis. Apogeotropic horizontal-canal BPPV is the most common diagnostic pitfall in the lateral canal because the geotropic and apogeotropic forms have opposite implications for the affected ear: in the geotropic form, the affected ear is the one toward which the patient is rolled when nystagmus is more intense; in the apogeotropic form, the affected ear is the one toward which nystagmus is less intense.10

When the Epley fails, three causes deserve consideration in order of frequency: canal conversion (otoconia transitioned to the horizontal canal during repositioning — confirmable with a supine roll test before the patient stands up), wrong canal (the supine roll test was never performed), or cupulolithiasis rather than canalithiasis (consider Semont or Yacovino). Persistent failure after correctly performed repositioning manoeuvres on at least two visits should prompt reconsideration of the diagnosis — central positional vertigo from a posterior fossa lesion can mimic BPPV closely enough to fool a careful examiner on a single visit.

One of the most useful things about BPPV is what it does not do. It does not cause hearing loss, tinnitus, or a feeling of pressure in the ear. If a patient describes positional vertigo along with any of those symptoms, the diagnosis is something else.

The audiogram in BPPV is normal — and that normality is itself diagnostic. Cochlear involvement in a patient with positional vertigo redirects the differential toward conditions that affect both labyrinths together (Ménière's disease, perilymph fistula, vestibular schwannoma, advanced otosclerosis with secondary BPPV) or toward central positional vertigo. The audiogram is therefore a routine part of the BPPV workup not because BPPV affects it but because finding an abnormality rules BPPV out as the sole diagnosis.

BPPV may co-exist with hearing-affecting pathology, and the combination matters. BPPV is described after stapedectomy and cochlear implantation (mechanical disruption of the utricle liberating otoconia), in established Ménière's disease (theorised mechanism: the same endolymphatic distortion that produces hydrops also disturbs the otolithic membrane), and following sudden sensorineural hearing loss with vestibular involvement.8 In these settings, the audiogram and the positional findings are independent pieces of information, both of which need acknowledging in the management plan. A clean audiogram in an isolated positional vertigo, by contrast, is the green light to proceed with repositioning without further workup in most patients.

Diagnosis is purely clinical — by history and the Dix-Hallpike manoeuvre at the bedside. No imaging, no blood tests, no hearing tests are required to make the diagnosis (although a hearing test is often done to be sure nothing else is going on in the ear).

Treatment is the Epley manoeuvre. It works the first time in about 80% of patients; if it doesn't, it can be repeated at the same visit or a few days later. Medications like betahistine, prochlorperazine, or benzodiazepines do not treat BPPV — they only mask the symptom, and they should not be used routinely.

The Bárány Society's diagnostic criteria for definite posterior-canal canalithiasis require:7

1. Recurrent attacks of positional vertigo provoked by lying down or turning over in the supine position.
2. Duration of attacks < 1 minute.
3. Positional nystagmus elicited after a latency of one or a few seconds by the Dix-Hallpike manoeuvre or side-lying manoeuvre — upbeating and torsional with the upper pole of the eyes beating toward the lower ear; duration < 1 minute.
4. Not attributable to another disorder.

The AAO-HNS 2017 clinical practice guideline is the authoritative reference for management.8 Its strong recommendations include: treat posterior-canal BPPV with a canalith repositioning procedure; do not recommend post-procedural postural restrictions (an older practice disproven by trials); and do not routinely treat with vestibular suppressants such as antihistamines or benzodiazepines. Vestibular rehabilitation may be offered as an adjunct. Imaging is not indicated unless atypical features raise concern for central pathology.

Patients should be told that recurrence is common (rates of 20–50% over five years), that recurrence does not imply treatment failure, and that the same Epley manoeuvre will generally work again.

A complete BPPV examination has three parts: a Dix-Hallpike to each side, a supine roll test (head turned 90° to each side from the supine starting position) for the lateral canals, and a straight head-hanging manoeuvre when the Dix-Hallpike provokes an atypical pattern. Video-oculography, where available, increases sensitivity for low-intensity nystagmus and is particularly helpful for identifying the torsional component, which can be missed under direct observation.

Treatment selection follows the canal and the mechanism. Posterior-canal canalithiasis: Epley manoeuvre, repeated if necessary. Posterior-canal cupulolithiasis: Semont liberatory manoeuvre. Horizontal-canal canalithiasis (geotropic): Lempert/Gufoni manoeuvre toward the unaffected ear, or the "barbeque roll" (360° rotation in 90° increments). Horizontal-canal cupulolithiasis (apogeotropic): Gufoni for cupulolithiasis (toward the affected ear), then re-test; conversion to a geotropic pattern is favourable. Anterior canal BPPV (rare): straight head-hanging or Yacovino manoeuvre.10,6

Failed repositioning after two or three attempts at the same visit should prompt an exit strategy rather than persistence. Re-examine 3–7 days later; if still failing, reconsider the canal, reconsider canalithiasis vs cupulolithiasis, and — if examination supports it — consider Brandt-Daroff habituation exercises as a self-administered alternative. Surgical management (posterior-canal occlusion) is reserved for the vanishingly rare patient with intractable, debilitating BPPV refractory to repeated correctly-performed manoeuvres.8