An aviation medicine 'Dear Doctor'. Dr. Dougal Watson.
From the March 1997 issue of the AOPA (Australia) magazine.
This month Flyin' the ointment discusses a question from a US AOPA member that was received via e-mail. He asks about ear popping and pressure buildup in the ears. I'd like also to thank Dr. Al Parmet, an American friend and colleague, for his learned advice and assistance in helping me with this gentleman's problems.
I enjoyed his letter, especially the flattering opening, and have included most of it. This man, despite having only just started along the road of aviation, clearly has a love for the activity. It's not difficult spending the time responding to this sort of query - you know you're helping another lover of aviation.
The views expressed in this article are those of the author and do not, necessarily, agree with those of the AOPA committee, CASA, the RAAF, BASI, or any other organization.
All of the Flyin' the ointment columns, can be found on the World Wide Web (WWW)
on http://aeromedical.org.
Your questions can be forwarded to Dr. Watson, directly via electronic mail, at
dougal.watsonparadise.net.nz.
Next: Noise exposure in civil aviation and the problems it causes.
Making friends with your middle ear.
Dear Dr. Watson,
I read your article on "Spatial orientation and Disorientation During Flight", which I thought was the best, most concise, explanation of the relationship between sight and balance I have yet read. I am not an MD, but a 43 year old guy who can finally afford to learn to fly. (Though I know I have gotten the cart before the horse since I bought a plane just last week, an Aircoupe, the first Alon A2A actually, or the last Forney F1 since it was the factory experimental platform for Alon back in 1964.) This last fact would normally incline a Doctor to refer me to a psychiatrists, but since you are an aviator, you know the enthusiasm which might be mistaken by non flight obsessed folks as insanity, and perhaps you can refer me to someone you trust about the following problem.
It is time for me to get the Medical for my private pilots license and begin lessons. The CFI will work with the Aircoupe but I am a little worried that an odd phenomena which seems to be manifesting some visual oddities will cause a problem. My eustacian tubes are continually building the slightest pressure as I go about the day. I am not talking about flying. Just living. Every so often I have to open my mouth wide and kind of crack my jaw so that I can feel the tubes open and the ear drum crack. (Please don't think I'm nuts.) This has been going on for years now and seems to be aggravated by allergies, which are basically symptomless, except for increased inner ear pressure and dizziness during certain non specific pollen events. Antihistamines help. Ten years ago I went to a non aviation ENT and was prescribed Antivert which helped but didn't cure. (I was not always saddled with this. It started in my twenties.) Also the condition is really inflamed by heavy floral perfumes.
The visual seems to be a kind of crossing of images, especially when tired or staring for a long time at a tv. I have a slight stigmatism. Though a year ago I asked an opthalmologist if I was good for flying and he said no problem. ( I plan to see another shortly.)
A few months ago I went up in a C152 just to see if it would bother me, and it did a little, gum helped, cracking my jaw helped, I was slightly dizzy, but not stricken with vertigo, as when it first struck in my twenties.
The middle ear sits between your ear-drum and the ear's specialized sensor organs and balance organs. It is sealed at the ear-drum and where it links to the sensor organs but has a floppy tube connecting it to the back of the nasal passages. This tube is called the Eustachian tube.
When you move up and down in altitude the pressure changes result in a differential pressure between the middle ear cavity and the outside air. This results in a full feeling in the ear, sort of cotton-woolly, and some reduction in hearing capacity. When this pressure difference reaches a certain level air often vents through the Eustachian tube and the pressures equalize. As the pressures equalize the ear-drum moves quickly back to its normal position - the 'pop' that you hear as your ears pop. Sometimes, especially if there is fluid in the middle ear or the eustachian tube, there is more of a 'crackle' or a 'squelch' than a pop (Sounds a bit like a Rice Bubbles commercial doesn't it?)
When the eustachian tube is blocked the differences in air pressure can't equalize and the ear-drum can be stretched beyond it's limits and bleed or rupture. The eustachian tube can become blocked when you have a cold or when you have hay fever type allergies. These conditions cause the blockage because the skin at the opening of the eustachian tube swells up and squeezes the opening shut.
Most people can deliberately pop their ears during flight or when stationary at a fixed altitude. It's not difficult to do. You can often pop your ears just by wiggling your jaw or moving it with a chewing action. Then there's the Valsalva manoeuvre where you force air up into your eustachian tubes by blocking your nose, closing your mouth and blowing to gently increase the pressure in your mouth, nose and throat. The Frenzel, or jaw thrust, manoeuvre is where you slide your lower jaw forward to open the entrance to the eustachian tubes.
Sometime, especially in some sensitive people, when you pop your ears the sudden change in pressure is transmitted, as a miniature shock wave, into the inner ear's balance sensors. This pressure wave confuses the balance sensors which send tumbling or spinning signals to the brain. The brain receives these signals and immediately sets the eyes moving to allow for the perceived tumble or spin. This phenomenon is called alternobaric vertigo which translates roughly as ' dizziness from pressure change'.
The dizziness and visual disturbance you describe does sound like it could well be mild alternobaric vertigo. It also sounds like you might have some hay fever allergy problems. It is also possible, but seems a little less likely, that some of your problem is jaw joint irritation (Temperomandibular Joint irritation). None of these conditions, if appropriately treated, need necessarily to preclude your flying in your beloved Aerocoupe.
Untreated, if the vertigo and visual disturbances persist, your condition is probably incompatible with your getting a student pilot licence. It is, therefore, very important that you follow this up. You will need to find an aviation savvy medical practitioner to help you sort this all out.
Your first step is to learn to let your middle ear pressures equalize without sending a pressure wave up to those balance organs. The best way to do this is to not use the Valsalva manoeuvre but to try, whenever appropriate, to use either the Frenzel manoeuvre or chewing or waggling your jaw to assist in popping your ears. This may take a little practice but after a while it will come quite naturally.
Your hay fever can be remedied by a number of medications, many of them quite compatible with ongoing fitness to fly. The group of drugs known as antihistamines is probably the most widely used for this sort of problem. Many of these drugs have quite sedative side effects, and are dangerous for pilots, so your doctor will probably try some of the newer less sedating antihistamines.
You do need to find a sympathetic aviation medical practitioner (Dr. Parmet is helping here) to follow this up but I have little doubt that you'll be up there flying your little Scare-Coupe some day soon. Happy flying.
paradise.net.nz.