The organs of the inner ear maintain balance by tracking the movements of the head and its position relative to gravity. Problems with the inner ear or the nerve that carries its information to the brain can cause dizziness and vertigo, which the Merck Manual defines as “the false sensation of movement of the self or the environment.” Distinct from dizziness, vertigo usually involves a spinning or tilting sensation, often accompanied by nausea and lack of balance.
Definition
One type of vertigo, called benign paroxysmal positional vertigo, or BPPV, occurs when components of the inner ear malfunction, disrupting balance and spatial awareness. In BPPV, specific changes in head position cause brief episodes of vertigo, usually lasting less than a minute.
Symptoms
With BPPV, sitting up, lying down, rolling over or tipping the head can cause a patient to feel that the room is spinning or tilting. Lightheadedness, nausea and vomiting can occur with the vertigo. The sensation of spinning, combined with blurry vision, can cause the patient to stagger or stumble, or even tilt over while sitting. Rapid back-and-forth eye movements called nystagmus usually accompany the episode of vertigo.
Causes
About half of all cases of positional vertigo have no identifiable cause, the Mayo Clinic says. Sometimes hitting the head can result in positional vertigo. In other cases, damage to the inner ear from infection or ear surgery can bring on the condition. Whatever the ultimate cause, the malfunction arises when the orientation-sensing crystals in the inner ear become dislodged from their normal position and enter the semicircular canals of the ears, which sense rotation of the head. With head movement, the crystals rattle around to tickle the hairlike sensors of the semicircular canals, setting off a nerve signal similar to that triggered by actual spinning.
Diagnosis
In cases of suspected vertigo, the doctor will perform hearing and simple neurological assessments. If the tests are normal and the patient's symptoms are consistent with BPPV, the doctor will ask the patient to do the Dix-Hallpike maneuver: From a seated position, the patient lies down on his back, turning his head to the side with a slight tilt backward. If the patient has BPPV, this simple change of position brings on nystagmus.
Treatment
A technique known as canalith repositioning treats BPPV. This procedure consists of a series of slow, choreographed head movements designed to move the ear crystals out of the semicircular canals and back to their correct position in the utricle. This treatment usually corrects BPPV after one or two sessions.
