a special program of the National Emergency Medicine Association (NEMA) 

Week 620.7

Guest Dr. Alan Lockwood, Neurologist, VA Medical Ctr. Buffalo

Topic Tinnitus

Host/Producer Steve Girard

NEMA Do you know about tinnitus?It's like carrying around a set of sounds that only you can hear...because your mind is making them up. Today we have Dr. Alan Lockwood with us, he's a neurologist at the Veterans Affairs Medical Center in Buffalo, New York...and the lead author of a recent study on tinnitus...

LOCKWOOD Tinnitus, or tinnitus, as it's pronounced by some, is a condition in which people have the false perception of sound in the the absence of a real sound coming from the environment. Usually, this sound is experienced as a hissing or a whistling sound, but scratching or roaring or other, unformed type sounds are also described by some of these people. This is a condition that's been around probably since the dawn of mankind. There are references to tinnitus that are probably found in some of the Egyptian papyruses, and certainly during the middle ages there are clear references to what we probably would diagnose now as tinnitus in patients. So, it's been around for a long time, it's probably getting much more common nowadays...because tinnitus is commonly associated with hearing loss, and hearing loss is becoming a more and more significant problem. And there are a couple of reasons for that. First, people are living longer than they used to, and the older you become, the more likely you are to develop hearing loss...and if you have hearing loss, the more likely you are to develop tinnitus. So, tinnitus is usually a complication of hearing loss, so that if you have some condition that affects your hearing...such as just growing older, or in our society, noise exposure is an important problem that leads to hearing loss. Those are the kinds of conditions that are going to predispose you to the development of tinnitus.

NEMA So there are proportionately more older folks with tinnitus?

LOCKWOOD Yes, hearing loss and tinnitus both become more common as age advances, so that by the time you reach the age of 60 or so, close to a third of the population will have some significant degree of impairment of hearing. And of that group, maybe a third or so will also have tinnitus. it's quite an important public health problem, and one that I've referred to as sort of an orphan disease. People don't die from tinnitus, so that we don't have people marching on Washington demanding a cure, the way they have done with breast cancer and AIDS, and other diseases. But it has a tremendous impact on the lives of some people. It keeps them from working, impairs their ability to concentrate, keeps them from sleeping, interferes with many activities of daily life in some of the people that have significant negative impacts on their emotional state and their ability to function normally in a modern environment.

NEMA Are there a lot of people going undiagnosed with tinnitus?

LOCKWOOD Well, it's sort of a condition that when you mention it, people will say, "Oh yeah, I have that"...and about a third of the people with tinnitus will say that it really is distressing at some point in their lives...getting the kinds of symptoms I described a moment ago. I guess the good news is that for about 2 thirds of the people who have the condition, they're able to carry on with their daily lives in a relatively unimpeded fashion. So that it seems to have little impact on their lives, and is not a terribly serious problem. they've learned to live with it quite successfully.

NEMA I guess for some, they are able to hear selectively enough to block out or ignore the sounds...what does the research show as the origin of the sounds?

LOCKWOOD Well, one of the things that we found in our study of tinnitus patients that was just published recently in a neurological journal, was that in the people that we studied...who all had quite severe tinnitus, that had a big negative impact on their lives, that there was an abnormal connection between the auditory centers of the brain and other centers that control emotions. And we suspect that this link may be the means by which sounds convey some negative emotional content to the psyche that causes the disruption of their lives. I mean this would be an interesting next phase to our study...what it is it about the patients with tinnitus who have a terrible time dealing with their problem that separates from the people that seem to have tinnitus that's just as loud, same frequency but other people have adapted quite successfully to the presence of these "Phantom sounds".

NEMA Tell me more about the study....

LOCKWOOD Well, we set out to test the theory that we would be able to detect differences in brain activity in patients with tinnitus that separated them from people who did not have tinnitus. And one of the key aspects of our study was the identification of a relatively small group of people who were able to exert voluntary control over the loudness of their tinnitus. This is a somewhat unusual phenomenon. These people all reported to us that when they clenched the muscles of their jaw, their tinnitus either got a lot louder or a lot softer. So that this to us appeared to be an ideal study population, because we could compare the neural activity states in condition where there tinnitus was soft, with the neural activity map that we recorded when their tinnitus was very loud. And so by subtracting soft from loud, if there was anything left over, that would be the site in which this excess neural activity was present, that we could link directly with tinnitus. So, the major objective of our study was to try to determine where in the brain the sounds of tinnitus were being recorded. And what we found was that in theses people, who all coincidentally...or by plan, had tinnitus in their right ear. And what we found was that this spontaneous neural activity was confined exclusively to the auditory cortical areas on the other side of the brain. When we compared that situation to the neural activity that was produced by real sounds that we played into the same ear that these people recorded their tinnitus. So when we put a real sound into the right ear of these people, we found the real sound caused a bi-lateral cortical activation, as opposed to the unilateral activation we saw due to tinnitus alone. So that led us away from the notion that these spontaneous sounds were coming from the ear itself...or the cochlea of the ear, to be more specific...and were probably originating in the brain itself.

NEMA Now for the million dollar question what type of physiologic, or brain chemical activity might be responsible for the phantom sounds?

LOCKWOOD That of course is going to be the real interesting question to answer....what is the more immediate cause? Our studies suggest that one of the factors that leads to the development of tinnitus is a formation of abnormal neural circuits in the auditory system in patients who have hearing loss. And we suspect that if some of these abnormal circuits that are actually producing the tinnitus itself...sort of like a short circuit, if you can think of it that way. Where the electrical diagram of the brain has gotten redone in some way, and this reworking of the circuitry of the brain has produced some short circuits that are expressed as tinnitus. There are other neural conditions, such as phantom limb pain, where this clearly seems to be the case. Where the loss or the change in the sensory input coming into the brain causes rewiring of the sensory system of the brain, and some of these people experience phantom limb sensations in pain, that appear to be due to the abnormal circuitrythat's formed. So, we think that there's something very similar going on in the auditory system. Most people who have tinnitus have hearing loss, and hearing loss leads to this reorganization of the auditory system...both in patients and experimental animals. And we think it's this reorganization process that goes on that causes the tinnitus to arise. And if we can get a handle on what causes the reorganization, then I think we'll be in a position to really make a very significant therapeutic contribution.

NEMA How are tinnitus patients treated now?

LOCKWOOD Well, the drug treatments for tinnitus are virtually all a miserable failure. There are no drugs...if you go to the physician's Desk Reference, for example, there are no drugs...that are approved and recommended for the treatment of tinnitus. And part of the reason for this is that we just haven't known enough about the basic abnormalities that occur in the auditory system that cause tinnitus.And we think the major contribution of our study and the data from the study are the identification of the areas in the brain that are responsible for the formation of these phantom sensations. So, by identifying these areas, now we at least know something about where it's occurring, and we can then turn to our knowledge of the anatomy of that area, of the neuropharmacology of that area, genetic factors and other things that might be idiologically responsible for the production of tinnitus. So the more we know about the condition...and we knew very little about tinnitus before this, the better prepared we are to make intelligent decisions about the development of appropriate treatment strategies, or rational approaches to treating patients with this condition.

NEMA Dr. Alan Lockwood of the Veterans Administration Medical Center in Buffalo, New York. The tinnitus study was a joint effort with the University of Buffalo, and is published in the January issue of Neurology magazine. Dr. Lockwood says it's not unusual to hear of tinnitus sufferers threatening to commit suicide because of the maddening sounds in their heads. And there are some people who have tinnitus without hearing loss...but they are very rare.

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NEMA Thanks for joining us for today's program. If you have any comments or suggestions, contact this station. Or visit our home page at ...for a look at transcripts of this or past programs, or to find out more about the National Emergency Medicine Association. I'm Steve Girard at The Heart of the Matter.