BACKGROUND: Superhero hearing may not be such a good thing. The condition is called Superior Canal Dehiscence Syndrome (SCD). SCD (discovered in 1998) is where the vestibular and auditory symptoms and signs can result from a dehiscence (opening) in the bone overlaying the superior semicircular canal of the inner ear. Patients with SCD will experience vertigo and oscillopsia (the motion of stationary objects) with heightened loud noises and maneuvers that change middle-ear pressure (like coughing, sneezing, and straining). Auditory consequences of this syndrome include the increased resonance of one’s own voice, hypersensitivity to bone-conducted sounds, and hearing loss. (Source: vestibular.org)
RISK FACTORS: With an opening in the bone that is usually supposed to cover the semicircular canal, the fluid in the membranous superior canal can be displaced by pressure and sound. Usually there are only two points of increased pressure in the inner ear: the oval window (through which sound energy is transmitted into the inner ear) and the round window (through which sound energy is dissipated from the inner ear). SCD creates a third mobile window. Symptoms of this syndrome result from the physiological consequences. Those who are diagnosed with SCD are around 45 years old. Patients can experience it unilaterally or bilaterally. About one-third have the condition bilaterally. A common notion of this SCD is that it is due to a developmental abnormality. Studies show that approximately 1-2% of the population has abnormally thin bone overlying the superior canal. A thin layer of the canal suggests that trauma or perhaps over time the pressure of the overlying temporal lobe of the brain that leads to the onset of symptoms. (Source: vestibular.org)
SYMPTOMS: Most of the time patients seek medical attention as soon as they notice the debilitating effects. Specifically, patients note that loud noises cause them to see things move and when they cough, sneeze, or strain. Sometimes patients perceive objects to be moving in the same time with their pulse. Also patients can experience a feeling of constant imbalance. (Source: vestibular.org)
NEW TECHNOLOGY: Treatment options include surgical correction for those who are severely affected by SCD. The middle cranial fossa approach has been used mostly. Plugging of the canal with fibrous tissue has been shown to be more effective than canal resurfacing. Most surgeries involve going through the cranial fossa craniotomy on the affected side (surgery through the brain). The temporal lobe is retracted. The opening in the superior canal can be covered with bone wax, bone cement, or fascia; a small procedure that can fix a life altering condition. (Source: emedicine.medscape.com)
Quinton Gopen, M.D., Neurotologist at UCLA Medical Center, Department of Head and Neck Surgery talks about a procedure to repair a hole inside the ear.
When you first met Kerrie what was she like?
Dr. Gopen: Kerrie is a very nice woman. She had been seen by many doctors that I don’t think indentified the condition that she had and she was frustrated. I would say she was at her wits end for lack of a better term. She was really quite bothered by her symptoms. She was hearing her heartbeat in her ear and when she would talk she would hear an echoing in her ear. She had hearing loss and dizziness problems so she was pretty beaten down. She had lost a lot of weight and she had been to the emergency room on a number of occasions. When the condition was not identified, it was suggested that maybe it was all in her mind, that she had psychiatric problems.
How many patients like Kerrie have you seen before?
Dr. Gopen: Roughly one or two a month. So a reasonable estimate would be between ten and twenty patients in a year.
She said she walked in and within thirty seconds after almost a year of non diagnosis you said I know what your problem is.
Dr. Gopen: This isone of those conditions that is pretty unique so there’s not a lot of people that have those symptoms. When someone says that I hear my heartbeat in my ear that is an uncommon symptom. When Kerrie went on to describe other sounds that were amplified along with having dizziness problems, you’re building a case pretty convincingly at that point that she has this condition. At that point the scans are more a confirmation of what you suspect than anything else. There’s just not a lot of conditions that present in that manner. And I think one of the reasons why it’s not well known is it was discovered fairly recently.
What’s it called?
Dr. Gopen: It’s called superior semicircular canal dehiscence.
Is it something that can heal itself?
Dr. Gopen: It does not. It is usually an acquired lesion. At some point, for unknown reasons, a small pore or hole opens up into the balance chamber. That is when patients become symptomatic. Some people theorize it’s from the pulsations of the brain wearing a small hole in the bone over time. The bone in that area is like a little peak and it wears down a little thin spot in the bone. But once you have that it doesn’t heal spontaneously and the only treatment for that is surgery. There are no medications that you can give a patient that are going to make them feel better or lessen their symptoms. You have to go in there and block that anatomical defect and once you do that the symptoms do improve.
Where is the hole exactly and what is it called, where does it go to and from?
Dr. Gopen: The medical term for hole is dehiscence so that’s the first part. The anatomical location is the superior semi-circular canal. That’s where the balance chamber is. You have three perpendicular chambers that are in charge of sensing different types of spinning rotation. So you can imagine doing summersaults is one, doing cartwheels would be another one and a pirouette would be the third one. Each canal roughly senses a different type of angular rotation. And the superior canal is the one that sticks straight up and so that is the one that is actually going up underneath where your brain rests. And that is the one which is the most likely to open over time. Now you can have abnormal openings in to the other semi circular canals as well, but that is much less common.
It can happen to anybody?
Dr. Gopen: It can happen to anyone at anytime although the factors that provoke it are still unclear. And we do even have a pediatric series and then there are some kids that are born with it. So they have a congenital opening in the inner ear and that is less common than the adult version.
Wouldn’t that be really hard if you’re born with it because babies can’t tell you?