Benign paroxysmal positional vertigo (BPPV) is a mechanical disorder of the semicircular canals of the inner ear.  There are three of these ring-shaped canals in each ear, along with two other sensors that are able to sense gravity because they are capped by a bed of relatively heavy crystals.  It is the shifting of these crystals on the gravity sensor that give you the sensation of going up and down in an elevator, or let you know when your head is tilted.  The problem is that all of the canals and the gravity sensors are interconnected by fluid pathways, so if these gravity-sensor crystals become dislodged, they can migrate into other parts of the ear.  

BPPV arises when some of these crystals enter a semicircular canal. The openings to the semicircular canals lie just above the gravity sensors when a person is upright, so particles can’t easily enter. However, when you lie down flat on your back, the openings are located just below the sensors, allowing gravity and side-to-side rolling movements of your body to accidentally shift the particles into a canal.  The semicircular canals are only capable of sensing rotation or turning and do not detect gravity, so the presence of particles moved by gravity causes normal tilting motions of the head to be incorrectly sensed as violent spinning.

Symptoms usually first come on while in bed.  Rolling over in bed to one side can cause a very sudden, strong sensation of head-over-heels whirling that lasts for several seconds and then dies away. If your eyes are open, the room can appear to spin violently. Attempting to sit up from lying down, to lie back down, or to roll over in bed can set off a spell.  After you get out of bed, another spell can be brought on by tipping the head upward (while shampooing or reaching up toward a high shelf, for example), looking up and back over one shoulder, or by bending over forward and then lifting your head quickly.  In people who are sensitive to motion sickness, there can be vomiting and prolonged, less severe dizziness even when upright.   Older people may notice their balance is affected in between spells.

The dizzy spells end when the displaced crystals leave the semicircular canal, which can happen spontaneously within a couple of hours, or can be delayed for many years.  Certain movements can help to roll the particles back out of the semicircular canals.  These therapeutic maneuvers can be performed by a trained health care worker like a physician, nurse practitioner, audiologist or physical therapist, but they can often be done easily as a home exercise.  All maneuvers cause the dizziness to recur, so some people are not able to do them without assistance.  The video and book on our home page show how to treat this at home. If symptoms don’t improve, a health care provider should evaluate you.

How long do spells last?

Earlier blog pages have discussed the different feelings of dizziness that the inner ear can generate:  spinning, tilting or rocking, and elevator sensations.  The most common sensation indicating an inner ear problem is a feeling of whirling.  The inner ear has three sensors for spinning, the semicircular canals.  Because your head is firmly connected to your neck, every time you move your head on your neck, the head rotates to some degree.  It rotates in three-dimensional space, so three sensors can fully detect any rotation.  There are three major directions of rotations:  yaw, which is horizontal turning back and forth (detected by the horizontal semicircular canals);  pitch, tipping or nodding the head up and down (detected by the vertical semicircular canals);  and roll, tilting the head so the ear tips down toward the shoulder on either side (detected by the otolith organs).  Natural head turns tend to mix the various directions (like looking up and to the side for example), so all of the sensors in both ears are being used to feel and respond to these motions. 

Continue reading “How long do spells last?”

What triggers your dizzy spells?

Some spells come on out of the blue with no warning at all.  Others can be set off by something you do, or something you encounter—a trigger.  Spells with triggers are more likely to be benign, meaning that they often do not harm the ear.  Spells that come on without any warning are more likely to be damaging. 

Continue reading “What triggers your dizzy spells?”