context: Vertigo is a very specific kind of dizziness: the feeling that you're going around and around or that the inside of your head is spinning. Benign paroxysmal positional vertigo ( BPPV) is the most common cause of this condition. Each part of the name describes a key part of the inner-ear disorder: Benign means it's not very serious. Your life is not in danger. Paroxysmal means that it hits suddenly and lasts a short time. Positional means you trigger the vertigo with certain postures or movements. It's common, and usually can be treated in a doctor's office. In rare cases, the problem can be serious if it increases your chances of falling. If you get these attacks often, it could point to other medical conditions. They're often hard to diagnose, though. Inside your ear are tiny crystals of calcium carbonate. You might think of them as âear rocks.â They're also called âotoconia.â Sometimes the crystals come loose from their normal spot in your ear and move to other areas, including the canals in your ears that sense your head's rotation. Once there, they can clump together. Because the clump is heavy compared with other things in your ear, it will sink to the lowest part of your inner ear. When you turn or change position, the clump will cause the fluid in your inner ear to slosh around after you've stopped moving. That creates the sense that you're moving even though you are still. There are any number of ways you could trigger BPPV: Rolling over in bed Getting in and out of bed Bending over Tipping your head back Quick head movements If you move one of these ways and find yourself dizzy or it seems as though the room is spinning, you may have BPPV. Other symptoms include nausea, vomiting, and losing your balance. Usually, you can expect to have rhythmic eye movements when you get BPPV. Your doctor might call this ânystagmus,â and it's what she'll likely look for if she thinks you have vertigo. You're more likely to get BPPV if you're older. That's because parts of the inner ear start to show wear and tear. In many cases, it simply comes on without warning. In people younger than 50, head injury is the most common cause of BPPV. Other causes include: Having your head in the same position for a long time -- at the dentist's office or the hairdresser, for instance High-intensity aerobics Riding a bike over rough trails An inner-ear disorder such as Meniere's disease Being in the hospital or on bed rest at home for a long time A certain type of migraine If you have dizziness off and on for more than a week, you should make an appointment with your doctor. You may be able to figure out before your visit which ear is affected. Here's how to do that: Sit on your bed so that your head will hang over the edge when you lie down. Turn your head to the right and lie down quickly. Wait 1 minute. If you feel dizzy, the right side is affected. If you don't feel dizzy, sit up, wait a little bit and repeat the test with your left side. If you feel dizzy when you repeat the test, your left side is affected. Call your doctor at once if you're dizzy or: A new or severe headache sets in. You have a fever. You're seeing double or not at all. It's hard to talk. You're falling down or you can't walk. Your doctor will ask questions about your general health and your symptoms. She will also look for the telltale eye movement of nystagmus. She may ask you to lie on your back on a table with your head tilted back off it. This is to show whether you can control your eye movements. Your doctor also will look to see if symptoms of dizziness happen when your eyes or head move in a certain direction, and if doing so makes you dizzy for less than a minute. The doctor might also conduct a test using infrared goggles. Your doctor may be able to stop your BPPV with a treatment in the office that moves the loose crystals in your ear into a spot that will cause less trouble. To do this, she most likely will use the Epley maneuver. A less common action -- at least in the U. S. -- is the Semont maneuver. Each one takes about 15 minutes. You will have to rest in the office for about 10 minutes before you can go home to make sure you don't have any quick episodes of vertigo as the crystals resettle. You will need someone to drive you. Wear comfortable clothes so you can move easily. Once you get home, you'll need to follow specific instructions. These may include: Sleeping with your head at a 45-degree angle -- either in a recliner or propped up on a sofa -- for 2 nights. Keeping your head vertical for 2 days. You may have to avoid certain exercises and modify your movements during shaving and washing your hair. For a week, you will need to avoid head movements that might bring on BPPV. You may need to sleep with two pillows and avoid sleeping on the affected side. In very rare cases, you might need surgery to cure the problem. It involves plugging part of your inner ear to prevent the small calcium crystals from moving in your ear canal. Surgery carries a small chance of complications, including loss of hearing. Even after successful treatment for your BPPV, it can come back. However, you can come up with a plan at home to help keep future bouts at bay. You should: Be aware of your chances of falling. Sit down at once if you feel dizzy. Use good lighting if you get up at night. If your BPPV comes back, you can take steps to deal with your symptoms until you see a doctor. For instance, you can: Avoid sleeping on the affected side. Sleep with two or more pillows under your head. When you wake in the morning, lift your head slowly and sit on the side of the bed for a moment before you stand up. Avoid bending over to pick things up. Your doctor may teach you a maneuver you can try at home to move the loose ear crystals back into a better place.