Hearing hell! The woman who heard too much
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?
Dr. Gopen: Yes. They don't complain about it and as they are growing up their brain takes a lot of what it's given. And so they don't understand that it's not normal to hear their heartbeat in their ear or they don't understand that their hearing should be better. So unlike an adult who complains about hearing loss pretty much immediately kids don't tend to complain about hearing loss. And that does make it more tricky and difficult to diagnose the condition in the pediatric population.
Is it sometimes caught as a learning disability?
Dr. Gopen: Certainly. Hearing loss often is perceived as a delay and so they think that the child is slow or there's some developmental difficulty and it's really just hearing loss. It tends to occur with some balance problems so the kid can be a late walker. Instead of walking at twelve months or fourteen months they might not walk until they're two years of age. And no one really at the time thinks much of it but in retrospect in some of these cases it's very clear that they walked very late and they do have hearing loss and it's from this condition.
With Kerrie's ear you said the hole was just two millimeters. Can you put that in perspective for people? How do you find a hole that small?
Dr. Gopen: It's a pretty tiny little hole. When I'm seeing patients in the clinic I give them a demonstration. I say this hole is smaller than the tip of my pen. Two or three millimeters is a very small little pore that's opening. So even on the CAT scans it's hard to appreciate exactly how big that hole is. But it's a very, very small little pore. One of the main challenges with the surgery is to find that little opening. Part of what helps is just knowing the anatomy and with the CT scan you can look at it ahead of time and see what is the topography of that person and the floor of the skull base how does it look and where are the peaks and valleys. And this particular opening is almost always in one of the main little prominences in the bone called the arcuate eminence and so you look for that. And there are things that you can use intraoperatively to find that spot. There is image guidance which helps you to precisely say okay, where am I at on the scans. And that can be helpful although there is some play with that system. But it's just really knowing the anatomy, knowing where the structure is supposed to be and then looking for that little pore. In some cases it's pretty obvious and in Kerrie's it was very obvious. But in other cases especially when it's smaller and not as big a defect as she has it can be challenging to find that little spot.
So what do you do once you find the hole?
Dr. Gopen: In order to block it there's been many ways that have been described but the way that I prefer to do it is to take a little bone wax which is a sort of tacky like material and to gently force it in to that small opening and that's a water tight seal. I then line the area above that with fascia which is some of the lining of muscle. Then I take a small piece of bone which I get from the craniotomy which is the little plate of bone that's removed from the side of the head and I take a small chip of that and place that over the area. And the purpose of that is really to block a new pressure from eroding a new location in to the inner ear. And that seems to be very effective at solving this problem. The patients wake up pretty much immediately with the resolution of their symptoms.
So is it an invasive surgery because you have to go through the skull?
Dr. Gopen: Yes, it's a craniotomy. That's what the neurosurgeons use to do brain surgery. So you're talking about making a window in the side of the bone here, retracting the brain over about a couple of centimeters to get access to the floor where the brain rests and find that little pore. You can use a different technique to come in through the ear but that is more dangerous to the hearing because you actually have to drill through the inner ear to get to that little opening and block it off. And not as physiologic as just covering up the top part of the opening. You have to block off the hole from the outside.
Does it fix the problem forever?
Dr. Gopen: It usually does. There have not been a lot of recurrences of this. The condition was discovered in nineteen ninety eight so we don't have long term follow up data to know twenty, thirty years out how these patients are doing. But in my experience I haven't seen patients that have had the repair done successfully and then relapse later on the same side. I've had some contralateral sides come up with a new condition on the opposite ear but not on the same side that's been repaired.
There's not a lot of surgeries that are that invasive that you can do and the person wakes up and the problem is completely gone.
Dr. Gopen: Usually it's more of a waiting game that's right. I've had times where people wake up in tears not from pain but from joy because the noise is gone immediately after the surgery. It's rare that you know the solution will be such a quick and dramatic improvement.
You changed Kerrie's life. She said she's a different person.
Dr. Gopen: Yes. She's much better off now than she was back then that's for sure.
You get a person like Kerrie who said she was contemplating suicide and now she's out playing Frisbee and eating ice cream with her daughter and back to normal.
Dr. Gopen: Well it's nice, it's nice to be able to see that. Obviously it's not something that's happening every single day but it's worth the time and the effort for sure.
She went to doctors for years. Why was it so tough?
Dr. Gopen: It's certainly not a common condition. The more common the condition you have the more likely you are to get the standard of care. Certainly if you have a heart attack and you go to the emergency room you're going to get a standard set of blood work done and treatment for that. This is a condition that is not super rare but rare enough that most people don't know to look for it. Also, being in a location like UCLA where we're dealing with tertiary referrals from all over the world these rare conditions are bunched up and you see them from time to time and then you're more prepared to deal with them and better off at identifying them. I would encourage patients that until they're fixed keep seeking out treatment. Keep pushing until you get the answers that you need to get. In some cases it can be a little bit of a battle but the end point is making people better. And until you're better it's worth pushing.
FOR MORE INFORMATION, PLEASE CONTACT:
Quinton Gopen, MD
UCLA Medical Center
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