Benign Positional Vertigo

Benign positional vertigo (BPV) is the most common cause of vertigo which is experienced as the illusion of movement.
Symptoms are due to inner ear dysfunction. Otoliths are displaced from the maculae (the receptor for sensing acceleration in the utricle and saccule) into the semicircular canals (usually the posterior and most inferior one). Symptoms are thought to arise due to the stimulation of the hair cells embedded in otoliths as they are pulled/pushed by the flow of endolymph through the semicircular canals following head movement and terminate as movement ceases.

Most BPV is idiopathic. Causes can be attributed in about 40% and include:

• Head injury
• Spontaneous degeneration of the labyrinth
• Post viral illness (viral neuronitis)¹
• Complication of stapes surgery
• Chronic middle-ear disease

Incidence

Incidence is estimated at 64/100,000 general population per year.²

Prevalence

A German study suggests a lifetime prevalence of 2.4%, and previous year prevalence of 1.6%.³

Risk factors⁴

• Older age, onset most common between 40 and 60
• More common in women (M:F 1:2)
• Meniere's disease (co-diagnosis in up to 30%)
• Migraine

History

• Sufferers endure episodes of vertigo provoked by head movements (such as entailed in rolling over in bed, lying down, sitting up, leaning forward or turning the head in a horizontal plane).
• Patients often volunteer that symptoms are worse when the head is tilted to one particular side.
• Attacks are of sudden onset and usually last 20-30 seconds.
• There is normally a brief latent period (usually about 5 seconds but up to 20 seconds) between the provocative movement and the experience of vertigo.
• Vertigo is usually too brief to cause vomiting, although patients sometimes complain of feeling nauseous whilst symptomatic.
• Symptoms are typically worse in the mornings.

Examination

Diagnosis of posterior canal BPV can be confirmed clinically by the use of a provocation test, known at the Dix-Hallpike test:⁵

• Warn the patient that transient vertigo may occur in any position.
• Ask the patient to keep their eyes open and stare at the examiner's nose.
• Prepare the couch so the headrest is down and the patient's head will overhang the end.
• Begin with patient sitting with head turned 45° to left to test left posterior canal. With head in this position quickly lie the patient down until the head is dependent ~30° below the level of the couch.
• Observe for nystagmus in each position (30 sec) and then return patient to upright position.
• Repeat with the head turned to the right to test the right posterior canal.

If positive:

• The patient experiences vertigo and rotary nystagmus (best seen by looking at scleral vessels and radial markings on iris).
• A short latency period of a few seconds should be expected.
• Nystagmus (fast component) will be upbeat and in the direction of the undermost (affected) ear. This has a limited duration, lasting <30 seconds (adaption).
• On sitting, there is more vertigo, experienced as the room spinning in the opposite direction (with reversal of the nystagmus).

Generally with BPV, only one side should test positive during the Hallpike test. Bilateral posterior semicircular canal BPV is possible but unlikely and points towards horizontal canal involvement, vestibular neuritis or a central cause. Central positional nystagmus tends to persist whilst the provoking position is maintained (no adaption) and it is not as direction specific as BPV, beat in any direction.

• Viral labyrinthitis
• Multiple sclerosis
• Meniere's disease
• Cerebrovascular disease
• Posterior cranial fossa tumours
• Brainstem lesions
• Otosclerosis
• Vertebrobasilar insufficiency

There are no current investigations that will demonstrate otoliths. Further investigation is not required where features are typical of BPV, however neuroimaging (CT or MRI) is indicated where there is diagnostic uncertainty. One study suggested a higher risk of unexpected intracranial pathology where there was no response to the initial Epley manoeuvre and in those with asymmetric hearing.⁶

• Repositioning techniques - the Epley manoeuvre is widely used to treat BPV. Its aim is to reposition otoliths back into the utricles from the semicircular canals. Evidence supports its usefulness aiding short term resolution of symptoms but is lacking for longer term benefit.⁷
  
  To perform the Epley manoeuvre:²
  • Sit the patient upright on the couch with the head turned 45° to the affected side (side that tested positive using the Hallpike test).
  • Place your hands on either side of the patient's head and guide the patient down to lying with the head dependent (same as in the Hallpike test).
  • Rotate the head 90° to the opposite side with the patient's face upward with the head remaining dependent.
  • Roll the patient onto their side whilst holding the head in this position and then rotate the head so that it is facing downward (tell the patient to look to the ground).
  • Sit the patient up while maintaining head rotation.
  • Simultaneously rotate the head to a central position. (There should be no nystagmus by this stage, if the procedure has been successful, as the otoliths should by now be repositioned)
  For success:
  • Whilst dependent, the head should be hanging over the edge of the couch at full neck extension. If a patient is unable to tolerate this, a couch can be used in the Trendelenburg position to simulate it.
  • Each position should be maintained until full resolution of symptoms and nystagmus has been achieved for at least 30 seconds.
  • Some contend that a period of postural restriction (e.g. upright head posture for 48 hours, avoiding lying on affected side for 7 days) also increases success rate.⁸
  • Patients can be taught modified Epley exercises to patients to perform at home following a formal Epley manoeuvre. These appear to improve outcome.⁹
• Self guided positional exercises - thought to aid central accommodation - may also be tried. Tell the patient to:
  • Sit on the side of bed with head rotated 45° to one side.
  • Close eyes to minimise vertigo.
  • Quickly lie down to the opposite side until the head touches the bed (if head turned to the left, lie on the right side).
  • Stay in this position for 30 seconds then sit up.
  • Turn head to the other side and repeat on the opposite side.
  • One session should include 6 repetitions to each side, repeat x3 daily.
• Consider physiotherapy referral. Physical repositioning techniques appear to be more successful than exercise based rehab, at least in the short term.¹⁰ Physiotherapists may be able to assist in teaching Epley derived head exercises and/or offering exercise training based upon vestibular stimulation.¹¹
• Surgery is very much regarded as a last resort¹² - denervating the posterior semicircular canal or obliterating it by laser (transmastoid) but deafness is a risk.

BPV's natural history is for spontaneous remission within a few months but with high chance of recurrence (approximately 50% at 5 years).³ It is considered 'benign' but may increase the risk of falls and injuries, make some occupations impossible (e.g. airline pilot¹³) and frequent episodes of vertigo may diminish quality of life, so it should be treated actively.