Vertigo: Dizzy Pilots Make Distraught Passengers

Vertigo is a common experience. It's not just a feeling of light headedness but a sensation that the world is spinning around. When you were a kid and spun around you intentionally set off a form of positional vertigo. Something like that can happen in flight. For example, when you're in the clag and abruptly bend down, let's say to pick up a pencil; suddenly it seems as if either you or the plane is in a spin.

Hold still. Don't do anything funny with the stick and it goes away. Accelerate rapidly and the aircraft seems to be pitching up. Slow down quickly and it seems to pitch down. In all of these instances you are fooling your balance or "vestibular apparatus." It is located in the inner ear. You may remember from your private pilot training that positional sense and movement are in part detected by the vestibular apparatus' semicircular canals. These fluid-filled tubes are lined up in each of the three planes of movement. When your head changes position, movement of fluid in the canals is sensed by nerve filaments that line the canals.

At the bottom of these canals is another pair of sensors, the utricle and saccule. They are also lined with motion detecting filaments as well as small particles called otoliths. They bump around in the utricle and saccule to increase the sensation of acceleration or deceleration. The signals generated by the vestibular apparatus are sent by the auditory nerve to the brain where movement is sensed. The brain correlates this input with that from the eyes. When you don't have much eye input flying in IMC, it is very easy for the vestibular apparatus to mislead you. When eye and vestibular inputs are at odds with each other, trouble follows. The room seems to spin, nausea centers in the midbrain get upset and your stomach can churn. Vertigo can be caused by a number of things. The positional changes we just described are examples of what is called "Physiologic Vertigo." Motion sickness and height vertigo are the most common more severe forms. Another very common type is "Benign Positional Vertigo" (BPV). If you've ever had it you know it is certainly not "benign." Severe sudden attacks of vertigo come on with change of head position. Turning over or getting out of bed, bending over or straightening up can trigger it. BPV is caused by some of the otoliths in the saccule wandering out into the semicircular canals. Happily, it often can be controlled with some simple movements of the head. So called "Vestibular Neuritis" or "Labyrinthitis" is caused by a viral infection of the vestibular nerve. It often follows a cold. It usually goes away in a week or two. Some residual dizziness can hang on for months, however. Head trauma or concussion as well as migraines are often associated with vertigo. Older folks with some hardening of the arteries can get it when blood supply to the brain is not what it should be. Occasionally, some really nasty stuff like brain tumors or Meniere's disease can cause vertigo. Bottom line-if the cause of dizziness is not obvious, it is something that a physician should evaluate. So what does the FAA have to say about vertigo? Obviously, if the world is spinning around for whatever reason you have no business in the cockpit. Therefore the cause of the vertigo and its likelihood to recur while flying determines the action the FAA will take. The Aviation Medical Examiners Guide states that "transient processes, such as those associated with acute labyrinthitis or benign positional vertigo may not disqualify an applicant when fully recovered."

At the other end of the spectrum, stuff like a brain tumor is disqualifying and will require a special issuance (SI) after acceptable recovery from treatment. Vertigo associated with migraines also is disqualifying until the condition is under good control. You need to consult a neurologist and see if the attacks can be reliably prevented with medications that in themselves are not disqualifying. Again you are looking at an SI. This is also the case with just about any other cause of recurrent disturbance of equilibrium. Understandably, the FAA wants to take a very close look at any of these conditions. You will need to work with you AME and your primary physician to get the information that they need to make a decision. Fly wisely. See you next month!

As always, comments, questions and suggestions are welcome: jdlakinmd@gmail.com.Also, we've moved our office to Airlake Airport's FBO (KLVN)! Call 952-469-4414 or email hannah@wpflights.com for a flight physical appointment.