Benign positional vertigo (BPV) is one type of dizziness that is especially disconcerting because it comes on suddenly and with such routine activity. Any sudden tilt of the head – looking up at the top kitchen shelf or washing one’s hair in the shower – can bring on a topsy-turvy sensation. You suddenly feel as if you’re not quite sure where your feet are or where the ground is.
The symptoms of benign positional vertigo are almost infinitely varied. They can be severe or mild, long-lasting or brief, complex or simple, frequent or rare. The good news for patients is that in most cases, dizzy spells can be prevented or controlled with medication, exercise or time.
Inside each inner ear are three semicircular canals that sense rotation of the head and two tiny sacs that sense vertical and horizontal motion. Each sac contains calcium granules – like microscopic grains of sand floating in a gel. When the granules, called otoliths, are pulled by gravity (as in an elevator) or acceleration (as in a subway car) against sensitive nerve fibers, they remind the brain which way it is moving.
If the inner ear is disturbed by injury, infection or a loss of blood supply, the otoliths sometimes float free of their sac and land on the sensor in one of the semi-circular canals that normally senses rotation. The brain then thinks the head is rotating when it isn’t, or when it is merely tilting to one side or moving forward.
The balance system is well protected inside the ear. But the very quality that makes it so effective also makes it vulnerable to being thrown out of kilter by a blow to the head, medication, infection or nerve degeneration.
Diagnosis of benign positional vertigo usually begins with lots of questions for the patient and may proceed through a battery of tests – of vision, hearing, reflexes, nerves, head movement. If there is any reason to suspect a possible tumor, a brain scan is in order. Mostly, the doctor wants to hear exactly when the dizzy spells occur and what they feel like.
Doctors can prescribe a set of exercises deliberately designed to trigger an attack of dizziness so that the brain and inner ear can begin to “unjam” the confusing signals and overcome them.
In some cases, “treatment” of benign positional vertigo involves no treatment at all besides careful monitoring of symptoms until they moderate or go away. In other cases, it’s a matter of adjusting the dose or type of medication a patient is taking for another illness.