How the balance system works
Introduction:
Have you ever rolled over in bed to kiss your spouse goodnight, turn off the alarm clock, or to toss "Fluffy" the cat, out of bed and then suddenly felt as though the world was spinning out of control? Well, you may have experienced the most common form of vertigo, known as Benign Paroxysmal Positional Vertigo. It is often referred to as BPPV.
This most common form of vertigo is prevalent in all age groups. By age seventy, fifty-percent of all individuals will experience this frightening sense of falling, tumbling, or spinning at least once in their lives. In younger individuals, it may occur following medical conditions such as Meniere’s disease, vestibular neuronitis, labyrinthitis, migraine, or after even a mild head trauma.
The sensation can be quite frightening. It can be strong — feeling like you’re being pushed off a bridge, or being pulled down by a giant magnet. The condition itself is rarely dangerous or life threatening. However, the consequences of being acutely dizzy with such strong sensations of being out of control is what can really get you in trouble.
How the balance system works:
Most of us, when asked about the main function of the inner ear, would respond, "It is our sense of hearing". The correct answer is the primary function of the inner ear is equilibrium. Within the inner ear there are two distinct parts: the hearing portion, referred to as the cochlea; and the balance portion, which we call the vestibular system or labyrinth. The labyrinth is comprised of two portions. The undermost portion, referred to as the otolith system, is actually a gravity sensor, which tells our brain about the pull of gravity. This is made up of both the utricle and the saccule, and within these two structures are calcium carbonate crystals whose weight responds to the pull of gravity by resting on nerve endings that sends a signal to the brain about the force or pull of gravity. When astronauts travel into micro gravity, the lessening of the weight against the nerve endings will cause them to become "space sick". When they return to earth, the weight now pressing on the nerve endings causes them to be "land sick".
Why do we get positional vertigo?
Most of the time, this system works quite well. Any normal degeneration of these calcium carbonate crystals, also called otoconia, fall into the back semicircular canal, aptly named the posterior canal. The semicircular canals (the three balance canals) are designed to be velocity sensors and not gravity sensors. So, when the additional weight of the otoconia enters into these canals, it converts this velocity sensor into a gravity sensor. While our head is erect, seated, or standing, it may not cause difficulty. When we look up, however, or when we lie flat with our head completely back or rolled to one side, the debris, which is now in the back balance canal (the posterior canal), causes the nerve endings to be misdirected. This, in turn, causes the hallucination of rolling, spinning, or turning, which we term "vertigo". During this instance, if our eyes are open, our vision may seem blurred or the world around us may appear to be in a spin. This is because our inner ears are responsible for influencing eye movement.
The calcium carbonate needs to be in sufficient quantities where it becomes heavy enough to be able to push or move the nerve endings. We all have some amount of otoconia loose in our balance canals. The biochemistry of the human body is such that our bodies should normally absorb this calcium within hours, or certainly days, and it never gets to a point where it is heavy enough to cause dizziness symptoms. There are now some theories that the reason some individuals become symptomatic with BPPV is their body’s biochemistry is having difficulty with calcium absorption. This, of course, is only a theory and is not intended to discourage the use of calcium, a critically important element in all organ functions, as well as necessary for our nervous system. It is just one of those odd things that seems to occur in some individuals.
Treatment:
The good news about BPPV is that for many people, the experience will not last more than a few days, and it will seem to disappear as quickly as it came. For others, however, it may last for days, weeks, months, and even years. There is no medication that will treat this problem. Anti-motion medication such as meclizine or Antivert may minimize the dizziness or accompanying nausea, but will not treat the problem itself.
In 1988, at the Paris Ear Institute, a French physiatrist, Alain Semont, along with a group of French ear, nose and throat physicians wrote a paper and presented a simple treatment, a five-minute physical therapy maneuver, which moved the debris to circulate through the long arm of the posterior canal and drop back into the utricle. Once the debris entered the utricle, if the patient did not return to the problem position for a day or two, the symptoms would resolve. The theory was that the biochemistry of the utricle, because it is a larger space, is different from that of the posterior canal, and this allows the calcium carbonate to readily dissolve in the larger space, while it could not do so when in the smaller area of the posterior canal.
Since Semont’s article, dozens of studies and methods of varying techniques from balance specialists around the world have been published. The treatments may be referred to as Semont Liberatory Maneuver, Epley Repositioning Maneuver, Gans Repositioning Maneuver, or simply Canalith Repositioning Maneuver. These treatments, all basically achieve the same thing, but require the patient to be moved into slightly different head or body positions. The treatments are usually performed by an audiologist, physical therapist, or physician.
It is possible that other canals, predominantly the side canals (referred to as the horizontal canals) may also contain some trapped debris. These canals require other forms of treatment, which also have been written about for many years, and may include treatments known as Appiani, Casani, or Bar-b-que Roll. Research has not shown that one treatment is better than the other, but are decided upon by the individual clinician or therapist based on the nature of the problem, as well as any physical limitations or restrictions such as the range of motion of your neck, and any back or shoulder problems. The treatment is very simple, and may range anywhere from three to ten minutes to perform, depending upon the variation.
It has been customary to ask the patient not to lie flat for at least one or two nights following treatment, and to perhaps avoid lying on the side of the affected ear for several nights. Sometimes patients have been provided with a soft cervical collar as a friendly reminder to help them to keep their head from tipping or moving. Recent studies suggest, however, that some of these restrictions may not be necessary, but the jury is still out on this. In the meantime, it is likely that if you find you have BPPV and seek treatment, your clinician will ask you to restrict some of your daily activities or your head positions. There are a number of excellent web sites that provide additional information concerning the diagnosis and treatment of BPPV.
A word of caution: Although some web or information sites may show you the treatment diagrams, I am not in favor of having patients self-perform them. The reason being, it is very important that a proper diagnosis be made before treatment starts! There are a number of other rather serious medical conditions that share some of the same symptoms and may mimic BPPV. Positional vertigo can be caused by such other disorders as Arnold Chiari malformations, vascular loop, subdural hematoma, or posterior fossa cyst. Likewise, if a patient has cervico-spinal problems where there is a compression of blood flow through the vertebral artery, it is possible that if they are not properly screened and were to hyper-extend and rotate their neck improperly, a stroke could result.
The purpose of these comments is not to unnecessarily frighten anyone, but to further confirm that although BPPV is not a serious condition and can be treated quite readily with no discomfort or special equipment, there can be a number of other medical conditions, which are far more serious, which may need to be completely differentiated by a trained professional.
SUMMARY:
In summary, you can learn more about BPPV from various websites, but most importantly, recognize the fact that if you indeed are diagnosed with this condition, you do not have to learn to live with the problem because it can be treated simply and quickly.
PLEASE NOTE:
This article is meant for informational purposes only. It is certainly recommended that patients experiencing dizziness or vertigo consult with their physician.