Introduction to Benign Paroxysmal Positional Vertigo

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Original Editor - Bernard Tonks Top Contributors - Jess Bell, Kim Jackson, Tarina van der Stockt, Rucha Gadgil, Lucinda hampton and Robin Tacchetti

Introduction

Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo that arises from a peripheral vestibular disorder. It accounts for 20 to 30 percent of all patients seen for vertigo in clinics that specialise in dizziness.

While the overall incidence of BPPV in the general population is around 2.5 percent, it is more common in older adults. Some studies show that 50 percent of older adults have BPPV.

Symptoms tend to be provoked by head movements, such as:

• Looking up
• Lying down flat quickly
• Bending forwards
• Rolling in bed

BPPV is a biomechanical problem in which one or more of the semicircular canals is inappropriately excited, resulting in vertigo, nystagmus and occasionally nausea. It occurs when there is displacement of calcium-carbonate crystals or otoconia from the utricle into one of the three fluid-filled semicircular canals of the inner ear. For more information on the anatomy of the vestibular system, please click here.

Aetiology

It is not yet known what causes BPPV. The majority of cases are idiopathic, but it is more likely to recur in older adults.

The two primary theories about its aetiology are that it is:

1. Related to ischaemia and cardiovascular disease
2. Related to vitamin D deficiency and calcium metabolism (seasonal variations may be present)

Predisposing factors include:

• Head trauma in all age groups
  • In a younger population head trauma is a leading predisposing factor
• The recurrence rate may be higher and treatment may not be as effective in a head trauma population
• Surgical trauma to the inner ear
• Vestibular labyrinthitis / neuritis
• Migraines
• Ischaemia of the anterior vestibular artery and cardiovascular disease

The majority of BPPV occurs in the posterior canals  (85 to 95 percent). 5 to 15 percent occurs in the horizontal canals and 1 to 5 percent occurs in the anterior canals.

Variants of BPPV

Two variants of BPPV can be present:

1. Cupulolithiasis
2. Canalithiasis

Cupulolithiasis (i.e. ‘stuck crystals’)

• The debris adheres to the cupula of the affected canal, causing the cupula to be gravity sensitive
• Changes in head position cause an inappropriate deflection of the cupula resulting in nystagmus, vertigo, and nausea
• This is a relatively uncommon form of BPPV

Canalithiasis (‘free floating crystals’)

• This theory better explains the typical characteristics of BPPV
• Otoconia are floating freely within the endolymph of the SCC
• When the head is moved into the plane of the affected canal, the debris moves into the most dependent portion causing movement of the endolymph which deflects the cupula producing vertigo, nystagmus and nausea

The key characteristics of these two variants of BPPV are summarised in Table 1.

Table 1. Characteristics of BPPV variants. Assessing the Vertical Canals The Dix-Hallpike (DH) test is used to assess BPPV (primarily the vertical canals). This test enables the therapist to identify the side of the lesion and frequently the specific canal involved.

• Patient is seated with their head turned 45º toward the test side
• Patient is moved as rapidly (safely) as possible into a supine position with the head extended 20 degrees (CHECK as Bernard says 30 degrees) BPPV CPG
• Have the patient look at your nose and observe his / her eyes for nystagmus - note the direction of the movement, latency, and duration of nystagmus
• Wait until the nystagmus stops and then typically proceed into treatment (see below) if indicated (some therapists will slowly sit the patient up in order to assess the other side, but nausea can be a problem)
• Depending on results, repeat to the other side

	Canalithiasis	Cupulolithiasis
Latency of onset	>1 second before the onset of vertigo and nystagmus	No latency
Duration	Vertigo and nystagmus lasts < 60 seconds	Vertigo and nystagmus persist > 1minute
Direction of nystagmus	Characteristic nystagmus depending on which canal is involved	Characteristic nystagmus depending on which canal is involved
Fatigability	Decreased intensity of vertigo and nystagmus with repeated movement of the patient in provoking positions	Decreased intensity of vertigo and nystagmus with repeated movement of the patient in provoking positions