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.

	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

Assessment

Assessing the Vertical Canals

Dix-Hallpike Test

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 45 degrees toward the test side
• Patient is moved as rapidly (safely) as possible into a supine position with the head extended 20 degrees
• 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 (see Table 2)
• 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 on the other side

Kaplan and colleagues have found that shaking the head during the DH increases the diagnostic yield. Patients who have a negative DH, but positive result with head shaking may have a milder form of BPPV.

If BPPV is likely present, but the DH is negative, this test can be repeated a couple of times to ensure that it is negative (“sticky canalithiasis”).

It is important to try to assess the unaffected side first if possible. You can reason which side this might be based on the patient’s subjective report - i.e. the side she / he does not like to lie on. However, often the patient will not be able to tell you which side is worse.

Side Lying Test

• Patient is seated with head turned 45 degrees away from the side to be tested
• Patient is moved quickly into side lying on the side opposite to the side that the head is turned
• Observe eyes for nystagmus
• Repeat the test with the head turned to the other side

This test is a valid alternative test that can be used when the DH is not considered a viable option (e.g. if there are range of motion limitations).

Assessing the Horizontal Canals

Head Roll Test

The head roll test can be used to assess the horizontal canals as it places these canals in the plane of gravity. It is considered a positive test when:

• Horizontal nystagmus is provoked (see Table 2)
• The patient reports vertigo when rolling to both the right and left sides

The patient is initially positioned in supine with his / her head in a neutral position. The therapist quickly rotates the patient’s head 90 degrees to one side, checking for nystagmus.

To perform the test:

1. Patient lies supine with the head elevated 20 degrees on a pillow

1. Roll the head quickly to the one side (can do whole body rolls)

1. Observe the patient’s eyes for nystagmus and note the direction, latency, and duration. Watch for direction changing nystagmus

1. Bring the patient’s head back to the neutral position in supine and wait until his / her signs and symptoms settle. Then roll the head quickly to the other side and observe

1. Both side lying positions will be positive for vertigo and nystagmus (same pattern) in horizontal semi-circular canal BPPV

There are two types of nystagmus associated with the horizontal canals and they can be used to differentiate between cupulolithiasis and canalithiasis: 

• Geotropic (quick phase towards the earth)
  • Associated with canalithiasis
    • Will have latency before onset and be shorter in duration
  • If geotropic nystagmus is provoked, assume that the most symptomatic side is the affected side and treat this side
• Ageotropic (quick phase towards the ceiling)
  • Associated with cupulolithiasis
    • Will have immediate onset and prolonged duration
  • If ageotropic nystagmus is provoked, assume the less symptomatic side is the affected side and treat this side

Table 2. Identification of canal involvement - nystagmus

Involved Canal	Dix-Hallpike (DH) and Head Roll Test
Right posterior Right DH	Up beating, right torsion
Right anterior Left DH	Down beating, right torsion
Left anterior Right DH	Down beating, left torsion
Left posterior Left DH	Up beating, left torsion
Right / left horizontal canals Head roll test	Horizontal nystagmus, no torsion

Distinguishing Between a Central Nervous System Lesion or BPPV

Lesions of central origin often present with: 

• Atypical nystagmus (sustained downbeating, no torsion)
• No fatiguability of the response with repeated testing
• No decrease in the nystagmus +/- vertigo with prolonged DH position
• No reversal phenomenon (reversal of nystagmus)

See Table 3 for a summary of the key features that distinguish central and peripheral lesions.

	Central	Peripheral