Benign paroxysmal positional vertigo is a condition of the inner ear, and causes a form of dizziness known as vertigo. To break it up into its constituent parts:

• Benign means it isn't a progressive disease.
• Paroxysmal means it comes and goes.
• Positional means it is triggered by certain positions.
• Vertigo means it causes the room to spin – the sufferer feels as if they are moving when they are not.

So, BPPV is an unpleasant but relatively harmless condition that comes on suddenly upon movement of the head. There tends to be a short delay (latency) before the start of the spinning sensation, which itself lasts only a few seconds. These attacks happen regularly, especially when the individual turns over in bed, and can cause a good deal of nausea.

Other causes of vertigo include Ménière's disease, vestibular neuronitis and trauma. Ménière's causes bouts of vertigo, hearing loss and tinnitus (ringing in the ears) lasting for hours on end. Vestibular neuronitis causes vertigo lasting for a couple of weeks, and trauma to the head may produce vertigo and unsteadiness that improves slowly over time.

What Causes It?

Each inner ear contains a labyrinth, a fluid-filled sac that contains both the organ of hearing and organs of balance. This is no coincidence:

• The cochlea allows you to hear because sound waves disturb the hair cells within it.
• The semicircular canals detect movement of the head based on the movement of fluid past hair cells.
• The saccule and utricle detect the position of the head using the effect that gravity has on tiny stones (otoliths) attached to hair cells.

So each labyrinth is essentially several collections of tiny hairs, each with a different purpose. These collections all sit within the same fluid, known as endolymph.

BPPV is thought to occur when otoliths drift off from the utricle and end up in the semicircular canals. Certain head positions, such as lying with the affected ear down, cause abnormal stimulation of the canal hair cells, sending a false signal to the brain that the head is spinning. The brain sends an instruction to the eyes to compensate, causing them to rapidly flick from side to side. This is known as nystagmus and produces the illusion that the room is spinning towards the side of the affected inner ear.

What Can Be Done About It?

BPPV is remarkable in that it is easily diagnosed and treated, provided the sufferer has access to an experienced ear doctor.

The vertigo and nystagmus that BPPV causes can be recreated using the Hallpike manoeuvre¹; with the patient on a couch, the head is quickly turned toward the affected side and lowered beneath body level. The doctor then looks for eye movements, with the side towards which the eyes move rapidly indicating the side on which the ear is affected. Interestingly, repeated Hallpike testing causes the symptoms to temporarily disappear – this is another characteristic feature of BPPV. A positive Hallpike test with such characteristic signs is considered pathognomonic of BPPV².

Once diagnosed, the condition can be treated using the Epley manoeuvre³. This consists of a series of slow movements of the patient's head aimed at dislodging the otoliths from the semicircular canal. Vertigo may well occur as a result of the manoeuvre, but once this has subsided there can be much improvement of the condition. Repeated treatment and the use of alternative manoeuvres and exercises is sometimes necessary, but BPPV tends to resolve over a course of weeks or months. Rarely, the condition affects both inner ears, thus requiring treatment of one side followed by the other at a later date.

Can BPPV Sufferers Drive?

Individuals diagnosed with BPPV should stop driving immediately and, in the UK, notify the Driver and Vehicle Licensing Agency (DVLA). Driving can be recommenced once the individual has been certified symptom free, though drivers of large goods vehicles and passenger vehicles must remain symptom free for a year before driving such vehicles.

Please Note: h2g2 is not a definitive medical resource. If you have any health concerns you must always seek advice from your local GP. You can also visit NHS Direct or BBC Health Conditions.