Medically Speaking

Vertigo grounds a seasoned pilot, but he eventually settles back into the captain's seat

Frank Kennedy, a 10,000-plus-hour flight instructor, Atlas Air cargo pilot, and former Marine A4 and AV-8 Harrier jock, had always been the consummate practitioner of unusual attitudes. Comfortable in any airborne orientation, he'd never had a problem figuring out how to put the blue side back in its place.

That confidence began to fade last June when he felt a spinning sensation while driving in Ireland on a family vacation. Soon afterward, he lost his balance when emerging from a not-so-stellar performance in a Boeing 747-200 simulator during a regularly scheduled test in Miami. Afterward, Atlas 747-200 Fleet Manager Ron Peck advised him to get home and see his doctor. Back in Maryland, the situation worsened, with the arrival of "spells" of tumbling motion, some lasting as long as several minutes. "I had to hold on to something just to walk," he said.

Kennedy phoned his Air Line Pilots Association representative, who told him to call the organization's medical consulting firm, Aviation Medicine Advisory Service. AMAS is a group of board-certified aerospace doctors who work with the FAA regarding medical issues on behalf of clients like the airline pilots union.

"You've got vertigo," said AMAS' Phillip Parker, a medical doctor, military flight surgeon, and former FAA aviation medical examiner (AME). Next came the advice that Kennedy already knew was appropriate: "Ground yourself."

For Kennedy, the phone call was the official kickoff of an eight-plus-month odyssey to regain his health, his privilege to fly, even his ability to drive a car. In the process he took a crash course in the medical and regulatory aspects of a malady that, despite its prevalence, can be difficult to diagnose and is often misunderstood. What wasn't misunderstood by Kennedy was what he'd have to give up: a front-row seat in the 747 and his role teaching U.S. Naval Academy midshipmen how to fly like fighter pilots. Kennedy is the chief flight instructor at the Navy Annapolis Flight Center, a 14-aircraft training fleet based at Lee Airport near Annapolis.

His route to recovery followed two independent paths: AMAS began working on his behalf to inform the FAA about the vertigo in advance of his next first class physical; Kennedy began the not-uncommon ritual of visiting a long list of medical professionals to try to systematically diagnose the problem. That list included his family practitioner; a longtime Navy doctor; an ear, nose, and throat specialist; a neurosurgeon; and ultimately a neurologist researcher. They all diagnosed him with vertigo, but the cause was to be determined.

It turns out that vertigo, a hallucination of spinning motion, is quite common in the general population. A study by physician Ronald Labuguen of the University of Southern California, Los Angeles, found that 54 percent of the patients who go to their doctors complaining of "dizziness" are actually suffering from vertigo, a symptom of a deeper problem within the body's linear and/or angular sensing mechanisms in the inner ear. Of the vertigo cases, 93 percent are generally caused by benign paroxysmal positional vertigo (BPPV), acute vestibular neuronitis, or Ménière's disease, according to Labuguen. The other 7 percent of the cases don't occur as frequently but can be just as difficult to pin down, hence more difficult to explain to an AME or the FAA. Kennedy's ailment would fall in the latter group.

Although doctors aren't exactly sure what causes BPPV, the problem is fairly straightforward to diagnose and the treatment simple. A widely held theory is that the problem occurs when tiny bits of calcium from the body's linear accelerometers in the inner ear shear off, for unknown reasons, and make their way into the adjacent semicircular canals, the body's angular accelerometers. Once in the canals, certain head movements — such as rolling over in bed or looking up at an overhead panel in the cockpit — can make the debris shift and cause the brain to incorrectly sense an angular rate. The spinning sensation will typically last 30 to 60 seconds, and is accompanied by a jerky eye movement called nystagmus, a telltale sign that's common to most forms of vertigo.

The effect is similar to what happens when focusing on a stationary object from a moving train or car — the eyes follow the object until it leaves the field of view, then snap back to center, ready to start the process again. The nystagmus isn't what causes the spinning sensation in vertigo; it's simply a marker of a problem in the inner ear or elsewhere, said David Solomon, a neurologist at the Johns Hopkins Hospital and Kennedy Krieger Research Institute in Baltimore. Solomon said the chances of experiencing BPPV increase with age — about 50 percent of the population older than 70 years of age is likely to have had an episode at least once. Though BPPV is less common in younger people, head injuries and ear infections also have been known to generate the debris that can cause it.

Tests for BPPV on Kennedy didn't trigger vertigo or nystagmus. That, plus the fact that his spells lasted several minutes and were not triggered by any particular head movement, pretty much ruled out BPPV. Checks for vestibular neuronitis — a viral infection in the nerve that transmits head-movement information from each inner ear to the brain — also proved to be inconclusive. Parker said neuronitis often occurs about two weeks after a pilot has a cold or upper-respiratory infection, and can result in an "uneasy" feeling in some pilots and incapacitation in others. Either way, the malady generally is short-lived, even if not treated with medications. Labuguen reported, "Initial symptoms typically are severe but lessen over the next few days." Since Kennedy's symptoms came in episodes and went from mild to severe, neuronitis was not a likely suspect either.

Another distinct possibility was Ménière's disease, an ailment of the fluids in the inner ear that is poorly understood and often difficult to diagnose. Jay Phelan, former head of ear, nose, and throat medicine at the U.S. Navy's Naval Aerospace Medical Institute in Pensacola, Florida, recalled the case of one military pilot who got off a cruise ship and developed a sense of horizontal tilting. After a few weeks, the man began sensing an increasing pressure in one ear, along with a ringing noise. "Two years later, and after a lot of evaluation by neurologists and otolaryngologists, he was diagnosed with a variant of Ménière's disease," he said. Solomon said the increased pressure and ringing — along with the abrupt onset of spinning vertigo that can last for hours — are signs of "classic" Ménière's. Kennedy had none of those symptoms.

Of the potpourri of other causes that were considered, including Lyme disease and stroke, migraine-associated vertigo — a relatively rare variant of vertigo — emerged as a potential suspect. Solomon, the last in a long list of doctors to evaluate Kennedy, noted that he had a history of occasional stress-related migraines and that his severe bouts with vertigo had been followed by headaches. However, since Kennedy's vertigo had abated for weeks before the visit to Solomon, the diagnosis was not definitive, but was rather "one of exclusion." Regardless, Solomon in his final report wrote that he saw "no evidence of any vestibular or ocular motor dysfunction that would preclude [Kennedy's] return to flight status."

With a green light from Solomon, Kennedy in theory could have returned to flying and simply reported the problems to the FAA during his next medical. That may have landed him in hot water with the FAA, though; Parker said in cases like Kennedy's where there's not a clear, concise diagnosis, or if the form of vertigo is one that tends to reappear, like Ménière's, the FAA prefers that the pilot be grounded for perhaps six months after the symptoms disappear before evaluating a new application.

"We need to know what the vertigo was due to and be made to feel comfortable that it will not return," said Warren Silberman, the FAA's manager of Aerospace Medical Certification. In fact, when Parker sent the FAA a heads-up about Kennedy's situation in advance of his upcoming first class physical, the FAA wrote back asking Kennedy to mail in his medical certificate. The agency said Kennedy could reapply through his AME after he'd been symptom free for at least six months — in February (he'd had no symptoms since August).

That the FAA had taken a conservative route in Kennedy's case was no surprise to Parker. "When they hear short-lived BPPV or neuronitis, the FAA knows there's a predictable clinical course. You can generally go back to flying a few weeks after you recover and report the episode at the next medical," said Parker. "Dizziness of an unclear etiology [the study of the factors that cause a disease], however, really bothers the FAA."

Even with a clear etiology, Parker said, AMEs sometimes muddy the waters. "Most AMEs have a general idea of vertigo and what causes it, but not a good understanding of how the FAA deals with it and what [information] they want to see." Part of the problem is that the FAA's broad-brush medical guidelines in FAR Part 67 call for disqualification for someone with a disease or condition "manifested by, or that may reasonably be expected to be manifested by, vertigo or a disturbance of equilibrium."

Although the FAA ultimately will approve an application if the vertigo is treatable and resolved, said Parker, "a conscientious AME who's inexperienced is going to deny the medical." Parker recommended that pilots who've experienced vertigo query various AMEs beforehand on how they would handle such a situation, selecting a more experienced doctor, or going through an aerospace medicine intermediary to "take the mystery of what the AME is going to do out of the equation."

Although his vertigo was long gone, Kennedy's world was not quite right side up six months after the onset of the illness. Although he enjoyed plenty of quality catch-up time with his family over the holidays and Atlas Air had been completely supportive by keeping him on the payroll and promising to put him back into training, a major part of his self-esteem was on hold until mid-February at least, when the FAA said it would reconsider his medical application.

"It created a void," said Kennedy. "Flying is a huge part of my life." Kennedy received a conditional medical in February, indicating that he would have to be re-evaluated for the vertigo on his next medical. He went back into training at Atlas, with the help of Atlas instructor-pilot Safu Nana, and resumed flying the line as captain of the 747-200 the first week of April. His first trip was from New York's John F. Kennedy International Airport to Dover-Prestwick, Scotland.

John Croft, AOPA 947113, of Upper Marlboro, Maryland, is a 1,000-hour flight instructor.

Common Sensory System Snafus

Presyncope — A sensation of lightheadedness resulting from insufficient blood flow to the brain. It can occur when rising quickly, with hyperventilation, or after exercise. It's always worse when standing up. Passengers in aerobatic aircraft are much more susceptible to this during sustained positive G loads.

Vertigo — The experience of the head, body, or world rotating around in the absence of any true angular motion. It often precedes the development of motion-sickness symptoms. One doctor described it as a "true hallucination of motion, which is usually a unidirectional sense of spinning or the room turning around you."

Spatial disorientation — Brief confusion about one's attitude, heading, or location in space, or when there is some unexpected result of a control maneuver. The disorientation is more experienced as a lag or overshoot, and the actual disorientation is brief, although there may be a longer anxiety reaction that follows.

The Unwelcome Wobblies

The swagger of an aerobatic pilot emerging from the cockpit after a routine may not be a sign of boldness at all; it might be vertigo.

G-induced vestibular dysfunction (GIVD), affectionately known in the aerobatic world as the wobblies, is a form of vertigo about which high-performance aerobatic pilots are quite familiar. According to Thomas Upson Muller, who served as the U.S. team physician during the World Aerobatic Championships in 1998, the word wobblies came from a description of the postflight gait of performers afflicted with GIVD.

In an unofficial survey he took during the 1998 championships, Muller said 75 percent of the team members from the United States, Britain, Australia, Russia, Switzerland, Hungary, and Slovakia said they had experienced at least one episode of the wobblies in the past.

To treat the problem, Muller found that teams used sedating medications or antihistamines for some pilots, but often grounded pilots for one to three months. "This would explain why most pilots traditionally avoid medical evaluation whenever possible," he wrote. At the time, Muller said he was "struck by not only the high incidence of this condition, but by the paucity of published data regarding its evaluation and treatment."

A later study on the relationship between strength training and GIVD, conducted by the International Aerobatic Club, found that one-quarter of all pilots who responded had experienced the wobblies at least once. Of the pilots who did strength training at least three times per week, only 16 percent reported having experienced the problem. For those who did strength training daily, the risk of getting the wobblies had decreased to zero. — JC