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Benign paroxysmal positional vertigo is the most common form of vertigo and was originally identified in 1921 by Dr. Robert Barany who described the syndrome as paroxysmal vertigo together with nystagmus as a result of changing head positions. Benign paroxysmal positional vertigo is characterized by short-lived, sudden episodes of vertigo brought on by rapid changes in head position. The condition may occur at unpredictable moments for weeks or even years.

Although the exact cause of benign paroxysmal positional vertigo is not known, it appears to correlate very strongly with the aging process since the greatest incidence occurs in the population over 50 years of age. The possibility arises that this type of vertigo may involve a slow degeneration of the vestibular system in the inner ear. The most common cause of benign paroxysmal positional vertigo in people under the age of 50 is thought to be head trauma. However, most cases are idiopathic and cannot be associated with a causative event.

Typically, this vertigo is characterized by the following symptoms:

• Dizziness
• Sense of rotational vertigo
• Rotational nystagmus which resolves with time
• Nausea and/or vomiting

There are three forms of benign paroxysmal positional vertigo and, although some symptoms are specific to the location of origin, the majority of symptoms are common to all types. The three types of benign paroxysmal positional vertigo include posterior, horizontal, and anterior.

Posterior Benign Paroxysmal Positional Vertigo

Posterior vertigo involves the posterior semicircular canal and is the most common form of benign paroxysmal positional vertigo. It accounts for up to 70% of cases where the specific semicircular canal involved can be identified.

Posterior vertigo is characterized by:

• Rapid change in head position causes episodic vertigo
• Episodes last up to one minute
• Nystagmus is horizontal or rotatory (non linear)

Movements that may provoke posterior this type of vertigo include:

• Laying down on a bed
• Rolling over in bed
• Neck extension
• Bending over
• Reaching for something high
• Sudden movement of the head
• Extending the head backward in order to look up

Horizontal Benign Paroxysmal Positional Vertigo

The horizontal semicircular canal is the source of this vertigo. Horizontal vertigo is usually precipitated by turning over in bed from side to side. It is thought to account for approximately 20% of cases of benign paroxysmal positional vertigo. Horizontal paroxysmal positional vertigo is most likely to be seen in patients over 50 years of age. The etiology is thought to be similar to that of vertigo in the posterior semicircular canal but the pattern of symptoms is different. In this form of vertigo, the patient is not affected by changes in body position (e.g., getting up, lying down). Rather, intense vertigo is precipitated by turning the head from side to side while lying down. The direction of nystagmus is horizontal.

Horizontal vertigo is characterized by:

• Short latency of nystagmus (time lapse between the beginning of the event until nystagmus appears)
• Very sudden onset of episode
• Duration of episode is longer than 30 seconds
• Episode is usually very intense and symptoms may remain intense for a longer duration than for posterior vertigo