Literally this means vertigo that happens suddenly due to position change, and is benign (nothing serious). We have an organ called the “labyrinth” in the inner ear that controls our balance (see Diagram — Anatomy of the Ear). If tiny loose flakes of calcium form inside, and a movement jars them, they interfere with normal balance sensation. This develops mainly due to age, after 40, especially after 60. It’s very common.
The key to diagnosis is a history of very brief moments of vertigo, lasting seconds, that occur with changes of position of head or body. Vertigo means a sensation of movement in a single direction, either the person or the environment; it may be spinning, or feeling thrust, but isn’t simply wobbly or woozy. Episodes may be constant throughout the day, or infrequent. They may last days, weeks, or months; may go away completely, or keep recurring.
There may be nausea, even vomiting, at the time of vertigo, but often not. Sometimes we can provoke vertigo & notice nystagmus (rapid, jerky back-&-forth eye movements) with a maneuver called Dix-Hallpike (the first step in the Epley Maneuver, see below). But even if that test is negative, we make the diagnosis based on history. Other causes of vertigo last longer than seconds each time.
Symptoms that make us worry about a stroke include double vision, slurred speech, & swallowing problems that go along with the vertigo. But mainly we worry about other conditions when each episode of vertigo lasts longer than seconds. Each attack of BPPV is extremely short, however many times they may recur.
Treatment consists of the Epley positioning maneuver, to get rid of the calcium flakes (also called “debris”). See the link for an explanation.
Try the Epley beginning on the side where the Dix-Hallpike was positive (see link); if that doesn’t work, try the other side. If the Epley seems to help, keep performing it as long as episodes continue. Many clinicians prescribe an antihistamine called meclizine; I think it’s no better than placebo, but won’t do harm as long as you don’t drive while taking it. It can also cause urinary problems in older men, who should be careful with it.