Benign Paroxysmal Positional Vertigo - Diagnosis

Diagnosis

The condition is diagnosed by the patient's history, and by performing the Dix-Hallpike maneuver and/or the roll test. Patients with BPPV will report a history of vertigo as a result of fast head movements. Many patients are also capable of describing the exact head movements that provokes their vertigo.

The Dix-Hallpike test is a common test performed by examiners to determine whether the posterior semicircular canal is involved. It involves a reorientation of the head to align the posterior semicircular canal (at its entrance to the ampulla) with the direction of gravity. This test will reproduce vertigo and nystagmus characteristic of posterior canal BPPV.

When performing the Dix-Hallpike test, patients are descended quickly to a supine position with the neck extended by the clinician performing the maneuver. For some patients, this maneuver may not be indicated and a modification may be needed that also targets the posterior semicircular canal. Such patients include those who are too anxious about eliciting the uncomfortable symptoms of vertigo and those who may not have the range of motion necessary to comfortably be in a supine position. Obesity can also present a challenge when performing this assessment. The modification involves the patient moving from a seated position to side-lying without their head extending off the examination table, such as with Dix-Hallpike. The head is rotated 45 degrees away from the side being tested and the eyes are examined for nystagmus. A positive test is indicated by patient report of a reproduction of vertigo and nystagmus. Both the Dix-Hallpike and the side-lying testing position have yielded similar results and as such the side-lying position can be used if the Dix-Hallpike cannot be performed easily.

The roll test can determine whether the horizontal semicircular canal is involved. The roll test requires the patient to be in a supine position with his/her head in 20° of cervical flexion. Then the examiner quickly rotates the head 90° to the left side, and checks for vertigo and nystagmus. This is followed by gently bringing the head back to the starting position. The examiner then quickly rotates the head 90° to the right side, and checks for vertigo and nystagmus. In this roll test, the patient may experience vertigo and nystagmus on both sides, but rotating towards the affected side will trigger a more intense vertigo. Similarly, when the head is rotated towards the affected side, the nystagmus will beat towards the ground and be more intense.

As mentioned above, both the Dix-Hallpike and roll test provoke the signs and symptoms in subjects suffering from archetypal BPPV. The signs and symptoms patients with BPPV experience are typically a short-lived vertigo, and observed nystagmus. In some patients, though rarely, the vertigo can persist for years. Assessment of BPPV is best done by a health professional skilled in management of dizziness disorders, commonly a physiotherapist, audiologist or other medical physician.

The nystagmus associated with BPPV has several important characteristics which differentiate it from other types of nystagmus.

• Positional: the nystagmus occurs only in certain positions
• Latency of onset: there is a 5-10 second delay prior to onset of nystagmus
• Nystagmus lasts for 5–120 seconds
• Visual fixation suppresses nystagmus due to BPPV
• Rotatory/Torsional component is present or (in the case of lateral canal involvement) the nystagmus beats in either a geotropic (towards the ground) or ageotropic (away from the ground) fashion
• Repeated stimulation, including via Dix-Hallpike maneuvers, cause the nystagmus to fatigue or disappear temporarily.

Although rare, CNS disorders can sometimes present as BPPV. A practitioner should be aware that if a patient whose symptoms are consistent with BPPV, but does not show improvement or resolution after undergoing different particle repositioning maneuvers, which are detailed in the Treatment section below, need to have a detailed neurological assessment and imaging performed to help identify the pathological condition.