Dr. Rebecca Blaha, lead audiologist at the Pennsylvania Ear Institute (PEI) and assistant professor at the Salus University Osborne College of Audiology (OCA), and Dr. Martin Pienkowski, associate professor at OCA, discuss tinnitus during National Tinnitus Awareness Week.
Pienkowski: Unlike Rebecca, I'm not an audiologist or a clinician of any kind. I'm a hearing researcher. I've done quite a bit of research on tinnitus and hyperacusis, published a number of papers on those topics, so I often get contacted by tinnitus and hyperacusis patients, and am always happy to help them informally, provide them with advice.
Blaha: What generates tinnitus? Tinnitus is often the first reason that anyone would seek the advice or expertise of an audiologist, but what does science believe generates this perception?
Pienkowski: The main cause, the one that affects most patients, is hearing loss. Sometimes tinnitus manifests itself before really noticeable hearing loss. In most patients, there is an underlying hearing loss, but there are other causes or etiologies of tinnitus. Some of these include jaw muscle problems — there is a neural pathway from muscles of the head and neck into the auditory system. So problems of the somatic sensory system, in the head and neck, can lead to these phantom auditory sensations. If you've had a head injury, a concussion, that can also trigger some tinnitus [or] a rare condition of spastic contractions of the middle ear muscles, that can also lead to phantom sounds.
These causes lead to so-called subjective tinnitus. This is tinnitus for which there is no identifiable sound source of any kind, so the tinnitus is entirely a product of your own ear or auditory nervous system. There is no physical sound source. The vast majority of tinnitus patients have this so-called subjective tinnitus.
There's another type of tinnitus called objective tinnitus, and this has identifiable sound sources. These sound sources are within the body, and they're usually abnormally loud, pulsating blood vessels close to the ear. There's some other body sounds that can be heard, but the pulsating blood vessel is the most common.
Hearing loss itself can be due to many things. One of the most common is noise exposure and another is aging, the loss of sensory hair cells and nerve fibers as we age, [which] is why the prevalence of both hearing loss and tinnitus is greater in the elderly.
Blaha: I've often heard the statistic that about 90% of patients with tinnitus will have hearing changes. What officially generates the tinnitus signal? What is that disconnect that we see between the hearing changes and the brain's reaction?
Pienkowski: One of the leading theories for what we think is going on is that after hearing loss, we have this reduction of auditory system activity. If we have a high frequency hearing loss, we've lost the ability to hear high frequencies. Those areas of the brain that are normally responding to high frequencies just sits silent in the brain for some time, and the brain doesn't like that. It doesn't like parts of it to go unused. And so it begins to do a number of things. One of the things that happens is that the neighboring frequency regions, these mid-frequencies, become overrepresented and so the mid-frequencies generate activity in this high-frequency region, and that is heard as tinnitus.
Another compensation is the brain tries to silence as a result of the high-frequency hearing loss, the brain tries to make those high-frequency neurons more efficient. So it sort of strengthens the synaptic connections between neurons in an attempt to amplify external sound. But as it does that, sometimes this spontaneous activity, they generate electrical activity in the absence of stimulation. And this spontaneous activity is also amplified by this to compensate for the hearing loss. This increase in spontaneous activity is another so-called neural correlate or neural signature of tinnitus.
Blaha: As a clinician, the current methods for management is counseling. If there are truly neural changes taking place, why would counseling be effective?
Pienkowski: Counseling just helps people cope. It helps people cope with any condition, not just tinnitus. And tinnitus potentially comes on quickly, sometimes out of the blue, and patients don't know what hit them. They don't know that this is probably a consequence of their hearing loss or some other issue, and they may worry that this is a first sign of dementia or something like this. One role of counseling is just to reassure patients and hopefully tell them that their tinnitus has an identifiable cause and that we can try to treat it.
If the hearing loss and tinnitus is due to loud noise exposure, a very important message that needs to be told to patients on day one is that they have to try really hard to avoid further noise exposure because that could make tinnitus much worse very quickly.
So those are the two roles for counseling: to educate patients and to have them change their habits potentially, if those habits are causing hearing loss in tinnitus. You could get more complicated from there, there is so-called cognitive behavioral therapy, which would be probably delivered by a trained psychologist where the goal is to focus on the tinnitus less. And so as a result, the tinnitus is still there, but it'll seem quieter or more in the background.
Counseling or cognitive behavioral therapy can be successful that way, even without reversing those neural changes. That said, we can try some things to reverse those neural changes. One idea is to address the cause of the tinnitus. If the tinnitus is caused by hearing loss and if we can address the hearing loss with hearing aids, in extreme cases with cochlear implants, then restoring some of the loss stimulation with these devices can reverse these brain changes and can make the tinnitus go away. Similarly, if the tinnitus is due to jaw muscle issues, then dental therapy is highly effective. If it's due to those middle ear muscle spasms I mentioned, surgery of the middle ear is highly successful for those specific cases.
One thing that anybody can try, and is often successful, is called sound therapy. This is the same idea for wearing hearing aids or cochlear implants. You use sound therapy to try to stimulate the brain, especially in those frequencies that have been affected by the hearing loss. There are a number of commercially available devices to play sounds that are appropriate for your tinnitus, so your audiologist will give you some guidance there. There's also a large number of apps that are free to download that will allow you to match the sound of your tinnitus to external sounds. The thinking is that we should listen to sounds that sound like our tinnitus. Not only are these sounds most effective in masking your tinnitus, but they also stimulate the ear in these frequencies that have been affected by the hearing loss.
There are a large number of YouTube videos that have a whole myriad of sounds that are changed to different frequencies. They're amplitude modulated, so they wax and wane at different rates, and you can pick and choose, find some sound files that effectively mask your tinnitus and give you some relief. You can listen to these sounds at some points during the day when you have quiet moments or when your tinnitus is particularly bothersome. If you can stand it, you can listen to sounds as you fall asleep, might be preferable to tinnitus, which is often keeping sufferers awake. There's a large number of sound therapies to potentially try and if you stick with it and if you feel that it's working, they can be effective.
Again, they rarely make the tinnitus go away. And this also goes for hearing assistive devices. When your hearing aids are off, the tinnitus often comes back when the sound therapy stops. But the idea is that maybe it comes back a little quieter, a little weaker each time, and the relief that you gain from wearing your hearing aids or from the sound therapy lasts longer and longer and your tinnitus over time hopefully gets quieter and quieter.
There is no universal magic pill that you can take that will cure your tinnitus. There's currently no FDA-approved drug that that's known to be effective. There is no quick fix, but with determination and with the help of your audiologist, you can improve. In some cases, the tinnitus can vanish entirely, but it's not usually a quick process. For these more common onsets due to noise exposure, where the damage to your auditory system is permanent, and the tinnitus has been there for a while, it usually does take some time to get better, but you should try to remain optimistic because these things can work over time.
Blaha: I'm often asked by patients if there are any research studies that they can participate in for tinnitus, because at some point they may have gone online and they've looked at all of the possible options, they've been to numerous specialists and they need something new. What's on the horizon with tinnitus research?
Pienkowski: Even the things that we've discussed so far, hearing aids, sound therapies, it's not a hard science yet. Different things can work for different people and different things provide different levels of relief. You should just try to experiment and do whatever you can to give yourself some relief.
If you've tried many things and you're still suffering, first of all, that does occur. If you're really suffering from tinnitus, you do almost anything to have it gone. One thing though is that some of these new treatments on the horizon are invasive, they involve some sort of surgical intervention. One's been tried for almost a decade now with mixed success. There's still many clinical trials right now looking to really see if this is effective and to fine tune these techniques. Through the skull, transcranial electrical and magnetic stimulation, and the goal of both of those techniques is the same. It's to shut down or reduce the activity of the brain area that's contributing to the tinnitus.
The problem is that we don't know exactly for all patients where the tinnitus is or what areas of the brain are causing this phantom sensation. There's more work that needs to be done. This therapy, this transcranial magnetic or electrical stimulation, may ultimately be something that needs to be customized to individual patients. You may need fMRI scans to identify hyperactive brain regions before this therapy.
Another one that's more invasive is deep brain stimulation. This is where you have an electrode, instead of the electrical stimulation being delivered through the skull, the electrode is actually implanted in your brain. This deep brain stimulation has had a lot of recent success in treating things like epilepsy, like Parkinson's, where we know exactly where in the brain problem is, and if these areas can be stimulated or suppressed, this is often beneficial for epileptics, for Parkinson's patients. The same approach is being tried to reduce the activity of the brain in tinnitus patients.
There are also so-called multimodal stimulation devices. We talked about sounds therapy. So in addition to the sound being delivered on its own, the sound is paired with electrical stimulation of various nerves. For example, one company makes a tongue stimulator. So you have a little electrode that goes on the tongue and delivers little mild shocks to the tongue that are paired with the sound stimuli. Remember I mentioned that there is a pathway from a somatic sensory pathway via the trigeminal nerve from the head and neck into the auditory system into the cochlear nucleus. The idea is that this electrical stimulation and the sound will produce some synergistic effect.
There's a lot on the horizon and a lot of experiments and work and clinical trials being done. Unfortunately at this moment, there isn't so much in the way of results, at least results that have been repeated, validated, have stood the test of time. Another one is electrical stimulation of the vagus nerve. So this again, involves the implant of an electrode to stimulate the vagus nerve, which is a major source of activity for the brain, which is believed to drive these plastic changes. The goal is, again, to reverse the hyperactivity, the neural activity that's responsible for the tinnitus.
So there are all of these techniques on the horizon, and there are things to try. I mentioned that there's no FDA-approved drug, but those trials are also in progress. There have been drugs that have been found to work in animal studies. Unfortunately, as is often the case, they come with side effects. So they lead to sometimes even worse problems than the tinnitus.
Blaha: Before you choose to participate in anything, you want to have your hearing tested; the first step would be to know what is it that you're trying to treat. You would want to start with a hearing exam and then to discuss the results with an audiologist who is experienced with the management of tinnitus, and then they will come up with an individualized plan and direct you to the appropriate resources.