Laboratory Studies
Since the Dix-Hallpike test is pathognomonic, laboratory tests are not required to make the diagnosis of benign paroxysmal positional vertigo. However, keep in mind that since benign paroxysmal positional vertigo is strongly associated with inner ear disease, lab workup might be needed to delineate other associated conditions.
Imaging Studies
If objective abnormalities are confirmed in the general physical or neurologic examination, or clinical history warrants it, strong consideration should be given to obtaining neuroimaging (ie, MRI of the brain) with particular attention to the brain stem and posterior fossa structures.
Other Tests
See the list below:
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Electronystagmography (ENG): Torsional eye movement cannot be demonstrated directly. Occasionally ENG is helpful in detecting the presence and timing of nystagmus.
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Caloric test can be normal or hypofunctional (unpublished data, personal communication from Mohammed Hamid, MD).
Vestibular response can be reduced secondary to the sluggishness of the particle-laden endolymph.
Benign paroxysmal positional vertigo can originate in the ear with an absent caloric response because the nervous and vascular supply to the horizontal canal is separate from that of the posterior semicircular canals.
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Infrared nystagmography: Torsional eye movement can be demonstrated directly.
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Audiogram: Findings may be normal.
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Posturography: Findings are often abnormal but follow no predictable or diagnostic pattern.
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The steps involved in performing left-sided canalith repositioning procedure (CRP). The head is positioned 30 degrees toward the affected ear (left ear in this example). Next it is brought gently back to a reclining position. Note how the labyrinthine particles gravitate.
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Continuation of the canalith repositioning procedure (CRP). Once supine, the head is rotated 180 degrees (ie, away from the affected side).
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Another view of the canalith repositioning procedure treating the left ear.
