POSTIONAL VERTIGO (BPPV)
BENIGN PAROXYSMAL POSITIONAL VERTIGO
In Benign Paroxysmal Positional Vertigo (BPPV) dizziness is generally thought to be due to debris, which has collected within the wrong part of the inner ear. This debris can be thought of as “ear rocks” or “crystals”, although the formal name is “otoconia”. Otoconia are small crystals of calcium carbonate derived from a structure in the ear called the “utricle”. The utrical and saccule, or “gravity detectors” use these crystals to pull their sensory cells toward the ground with gravity. (While the saccule also contains otoconia, they are not able to migrate into the canal system.) Crystals migrate into one of the semicircular canals. These three canals are the “motion detectors.” When the crystals enter they cause the sensory cells to react abnormally causing dizziness or imbalance.
The cause of BPPV is often unknown. The utricle may have been damaged by head injury, infection, or other disorder of the inner ear, or may have degenerated because of advanced age. Normally otoconia appear to have a slow turnover. They are probably dissolved naturally as well as actively reabsorbed by the “dark cells” of the labyrinth (Lim, 1973, 1984), which are found adjacent to the utricle and the crista, although this idea is not accepted by all (see Zucca, 1998, and Buckingham, 1999).
BPPV is a common cause of dizziness. About 20% of all dizziness is due to BPPV. While BPPV can occur in children (Uneri and Turkdogan, 2003), the older you are, the more likely it is that your dizziness is due to BPPV. About 50% of all dizziness in older people is due to BPPV. In a recent study, 9% of a group of urban dwelling elders were found to have undiagnosed BPPV (Oghalai et al., 2000).
The symptoms of BPPV include dizziness or vertigo, lightheadedness, imbalance, and nausea. Activities that trigger symptoms will vary among persons, but symptoms are almost always precipitated by a change of position of the head with respect to gravity. Getting out of bed or rolling over in bed are often common “problem” motions. Since people with BPPV often feel dizzy and unsteady when they tip their heads back to look up, sometimes BPPV is called “top shelf vertigo.” Women with BPPV may find that the use of shampoo bowls in beauty parlors brings on symptoms. An intermittent pattern is common. BPPV may be present for a few weeks, then stop, and then come back again.
BPPV can be treated with specific exercises performed with an audiologist that move the crystals into an area that does not cause symptoms. BPPV can also resolve on its own by “dark cells” of the labyrinth actively absorbing the crystals.