Editor’s Note: From time to time The Hearing Blog presents guest articles for our Readers to consider. Today’s article written by Peter Phua, a graduate of McMaster University’s medical program, is on AudioNotch, an on-line provider of custom “Notched Sound Therapy” for patients suffering from tinnitus.
Tinnitus is a common hearing-related problem that leads patients to seek help from hearing health professionals. It’s an extremely prevalent problem, affecting millions of people worldwide.4 In layman’s terms, it’s usually referred to as “ringing in the ears.” The majority of individuals with tinnitus have acquired it from hearing loss, although there are a long list of possible causes, and the initial evaluation of tinnitus should always be performed by a physician, since it can be a symptom of serious disease requiring medical intervention. However, the most common variant of tinnitus is “sensorineural” tinnitus — The consequence of a loss of input from the cochlea to the auditory cortex in the brain. [See Bootnotes for more on the subject of addressing the underlying hearing loss — No matter how minimal it may seem… Ed.]
There is no cure for tinnitus, and there are a variety of scientifically unsupported treatments available for patients, the most common of which are homeopathic “treatments,” many of which consist of diluted water. In this context, hearing health professionals are often-times frustrated by the lack of treatment options available for patients dealing with tinnitus. The subject of TRT has been a controversial one, with some research showing efficacy in reducing tinnitus distress, with other study results contradicting this, and others complaining that it does not address the root cause of the problem — The tinnitus percept itself. Generally, patients express a desire for a direct reduction of their tinnitus volume. A great deal of research in the tinnitus treatment space is ongoing, and various forms of sound therapy are available to patients, including under brand names such as Neuromonics, Soundcure, or Acoustic Modulated Reset Therapy. The issue with existing sound therapy treatments is two-fold: Many of the studies have been funded by the firms who also sell the therapeutic devices (thus representing a conflict of interest); and the cost for many patients is prohibitive, usually running into the thousands of dollars.
Editor’s Note: We have received reports of patients having been required to purchase the above devices before the (lack of) effectiveness has been determined, resulting in thousands of dollars in wasted money for a device that sits in the dresser drawer. While not commenting on the efficacy of tinnitus therapy devices, The Hearing Blog recommends tinnitus patients carefully try these devices before purchasing: Most reputable clinics provide demo devices available on a rental basis, or on a loan basis coupled with fees for professional audiology services.
Notched Sound Therapy represents a promising new approach to sound therapy for tinnitus. It has two virtues: It has been independently researched, with positive therapeutic results, by two different European research groups (only one of which has attempted to commercialize their therapy afterwards); and it is available at low cost to patients via third party providers.
Editor’s Note: We like the idea of using wireless streaming of tinnitus therapy sounds directly into the patient’s hearing aids.
Notched Sound Therapy is audio that has been processed with a “notch”centered at the frequency of a patient’s tinnitus.2 In this context, a “notch” is made in the audio by a computer algorithm removes the sound energy at and around the patient’s tinnitus frequency. Different researchers have used different notch widths, ranging from one octave to one equivalent rectangular bandwidth. A group of small psuedo-randomized clinical trials for Notched Music, and one randomized clinical trial for Notched White Noise have demonstrated that listening to Notched Sound Therapy can directly lower the volume of tinnitus, and in doing so, reduce the psychological harm caused by the tinnitus tone.1,2,3 The experiments ran with treatment cycles of twelve month duration, however, significant reductions in tinnitus volume can be seen as early as one week into therapy; provided that it is intense in duration.3
- Step one: The patient determines the frequency of their tinnitus tone. This can be performed in one of two ways: With the use of a web-based tinnitus tuner (or their advanced web-based tuner), or inside an audiology clinic with specialized tools;
- Step two: The patient chooses the audio they wish to have “notched,” which includes options ranging from music to white noise.1,2 The sound is then “notched” by a special software algorithm;
- Step three: Patients listen to their tailor-made Notched Sound Therapy.2 This can be done with any device capable of playing MP3 music files, as the lack of a proprietary device is what allows the cost of Notched Sound Therapy to be dramatically lower than its competitors. After months of listening for several hours per day, the patient’s tinnitus volume should decrease.1,2
Challenges for Partnering Audiologists: Determining a patient’s tinnitus frequency has classically proven to be very difficult. Varying algorithms have been used, with the predominant paradigm being presenting two alternating fixed choices, with a final test for octave confusion. There is some controversy over this, with some providers using more advanced two step algorithms. Patients have a hard time determining the frequency of their tinnitus, and often provide varying readings with little validity.
Further research has shown that there are two sub-groups of patients: About 50% can reliably determine their tinnitus frequency, and about 50% cannot. Tuning accuracy is critical for the success of notched sound therapy, as the notch must align with the actual tinnitus frequency; however, there is some margin for error. Research has shown that the tinnitus pitch detection in an audiology clinic is comparable to the usage of a web-based frequency slider.
The State of the Research: A critical appraisal of the research on Notched Sound Therapy shows that, although encouraging, the studies suffered from multiple limitations, and more work needs to be done in this area to draw firm conclusions.
More studies with larger sample sizes need to be conducted, and long term follow up studies must be performed to determine if the effect of the therapy persists. However, for patients approaching audiologists and other hearing health professionals, it represents a reasonable treatment option that can be recommended in light of provisional scientific support.
Bootnotes from The Hearing Blog Editor:
• Tinnitus goes hand-in-hand with hearing loss, with perhaps 95% of tinnitus sufferers having peripheral hearing loss, many times either unacknowledged or not bothersome enough to be otherwise noticeable, i.e. on a 1-to-10 “pain scale” the underlying hearing loss may be a 1 or 2. In Frustration with so-called “minimal” hearing loss, The Hearing Blog recommends addressing the underlying loss when tinnitus is present; however since then we have been made aware of the Better Hearing Institute’s Across America Hearing Check Challenge, which is a surprisingly accurate survey-based self-assessment. For tinnitus sufferers who score no more than about 3-5 points on the test, a trial of AudioNotch therapy appears to be a viable first step in treatment when little or no communication difficulties are present.
• Along these lines, in correspondence after his submission Phua pointed out there are some individuals who have “normal” audiograms which have no detectable hearing loss shown on them, yet these patients still have tinnitus. These individuals also typically do not have any identifiable cause for their tinnitus. However, this begs the question, what if people who present with normal audiograms have undetectable hearing loss? Phua points out the following theory:
Audiograms measure the “bottom” or “low” threshold of hearing by playing very quiet tones and then increasing the volume until they are detected. However, audiograms assume that hearing loss occurs in an upwards, step wise fashion. It turns out that there are different neurons that detect sound at a high volume threshold – and these are not tested in an audiogram.
From Adding Insult to Injury: Cochlear Nerve Degeneration after “Temporary” Noise-Induced Hearing Loss5, 6 in the Journal of Neuroscience, Phua highlighted from three paragraphs the following:
Overexposure to intense sound can cause temporary or permanent hearing loss. Postexposure recovery of threshold sensitivity has been assumed to indicate reversal of damage to delicate mechano-sensory and neural structures of the inner ear and no persistent or delayed consequences for auditory function.
Here, we show, using cochlear functional assays and confocal imaging of the inner ear in mouse, that acoustic overexposures causing moderate, but completely reversible, threshold elevation leave cochlear sensory cells intact, but cause acute loss of afferent nerve terminals and delayed degeneration of the cochlear nerve. Results suggest that noise-induced damage to the ear has progressive consequences that are considerably more widespread than are revealed by conventional threshold testing.
This primary neurodegeneration should add to difficulties hearing in noisy environments, and could contribute to tinnitus, hyperacusis, and other perceptual anomalies commonly associated with inner ear damage.
“These guys (yes, they are usually guys) wouldn’t be caught dead being treated for their very normal age-related hearing loss, but they run right to the audiologist at the first sign of tinnitus-related ringing, hissing, humming, whooshing or other unwanted sounds in their ears.” Even more interesting, he remarks, “is that when they come home from the audiologist, they often are wearing tinnitus-treatment devices in their ears that look suspiciously like, yes, hearing aids…” Could tinnitus be a way of overcoming the stigma? Are boomers really more likely to seek help for unwanted noise in their ears than for age-related hearing loss? If so, as Copithorne notes, tinnitus might well be an indirect path into the audiologist to catch untreated hearing loss as well.
• Speaking of GN ReSound, binaurally coordinated tinnitus therapy & masking sounds are now finally available in the Verso series of hearing aids at no extra cost; however the Aventa programming software must be upgraded to v3.5 to support the new functionality.
- Lugli M, Romani R, Ponzi S, Bacciu S, Parmigiani S (2009) The windowed sound therapy: A new empirical approach for an effective personalized treatment of tinnitus. Int Tinnitus J 15:51-61.
- Okamoto H, Stracke H, Stoll W, Pantev C (2010) Listening to tailor-made notched music reduces tinnitus loudness and tinnitus-related auditory cortex activity. Proc Natl Acad Sci U S A 107: 1207-1210. Full article as PDF
- Teismann, H., Okamoto, H., Pantev, C. (2011). Short and intense tailor-made notched music training against tinnitus: The tinnitus frequency matters. Plos ONE, 6, 1-8
- Eggermont, J.J., Roberts, L.E. (2004). The neuroscience of tinnitus. Trends in neurosciences, 27, 676-82
- Sharon G. Kujawa and M. Charles Liberman: Adding Insult to Injury: Cochlear Nerve Degeneration after “Temporary” Noise-Induced Hearing Loss. The Journal of Neuroscience, 11 November 2009, 29(45): 14077-14085; doi: 10.1523/JNEUROSCI.2845-09.2009
- Adam C. Furman, Sharon G. Kujawa and M. Charles Liberman: Noise-induced cochlear neuropathy is selective for fibers with low spontaneous rates. Journal of Neurophysiology, AJP – JN Physiol August 1, 2013 vol. 110 no. 3 577-586
- Bloggers Talk About Tinnitus, The Official GN ReSound Blog, 16 November 2012.
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