Tinnitus Masking
by
Barry Keate

In the past I have discussed many of the newer treatment therapies for tinnitus. Now we’re going to return to some of the time honored therapies that have helped many people manage tinnitus sounds. This article will address Tinnitus Masking and next month will discuss Tinnitus Retraining Therapy (TRT).

Historical Perspective
During the early 20th century several attempts were made at masking tinnitus sounds by the application of external sound. In 1903 a doctor named Spaulding used a piano to match the frequency of tinnitus in his patients. He would then produce the same note on a wind instrument so it could be prolonged over a period of time. He would increase the volume of the note until the tinnitus became inaudible for his patient.

In 1928, two researchers, Jones and Knudsen bombarded the auditory system with an outside sound similar to tinnitus but louder. They developed a large instrument that could be placed on a bedside table for patients experiencing difficulty sleeping. This became the very first bedside masker.

In 1973, Jack Vernon, Ph.D. led a research group at the Oregon Health Sciences University. At that time his was the only group in the US formally studying tinnitus. Dr. Vernon was studying an animal model and did not have any treatment options for people suffering from the malady. One day he received a visitor, Dr. Charles Unice, who traveled from California to visit him regarding his severe tinnitus. After several hours of testing they determined his tinnitus sound was in the 10,000 Hz range. With that task completed, they broke for lunch.

As they passed an outdoor fountain, Dr. Unice came to an abrupt stop. Reluctant to leave the soothing sounds of the fountain he told Dr. Vernon, “Standing right here I cannot hear my tinnitus. It’s the first time I’ve been unable to hear that unconscionably wretched sound since it began over two years ago. This is wonderful!” After several more discussions, Dr. Vernon formed the idea of using a wearable masking device as a method of providing relief from tinnitus. The rest, as they say, is history.

Dr. Vernon became the father of modern Tinnitus Masking. He started a tinnitus clinic at OHSU, began seeing patients and offered the first wearable tinnitus maskers in 1976. The clinic is still in operation today and has treated over 6,000 tinnitus patients.

The Sound of Water
Not everyone will be helped by tinnitus masking. A simple test to determine who is a likely candidate is very similar to the experience of masking by Dr. Unice next to the fountain. Stated simply, if you stand by a kitchen faucet running full force or in the shower and your tinnitus is reduced or eliminated, you are a good candidate for tinnitus masking. Water is generally acknowledged to be the best tinnitus masker available.

There are many ways to mask tinnitus. CDs with broad band white noise or natural masking sounds are available. Bedside units are used by many people. These units can produce different sound tracks that emulate rain forest, seaside, rainy day environments, and many others. Sound pillows with small speakers embedded in the pillows are offered by several manufacturers.

Masking Options
Wearable maskers are available through Audiologists. They will conduct a tinnitus and hearing evaluation which will determine frequency and loudness of tinnitus and degree of hearing loss, if any. Wearable maskers fall into three general categories:

1 – Hearing aids. Hearing aids can help people with hearing loss and in many cases they also reduce tinnitus symptoms. There seem to be two or more reasons for this. First, tinnitus is exacerbated by silence because the brain turns up its sensitivity by seeking the neural stimulation it’s being deprived of due to hearing loss. Amplification increases neural activity and assists the brain in turning down its sensitivity. Second, hearing aids amplify enough background noise to partially mask tinnitus sounds for many people.

2 – Tinnitus maskers. Tinnitus maskers are prescribed to patients who do not have significant hearing loss. The devices are similar to hearing aids except that they do not amplify sound; they produce a sound which masks tinnitus. The sound is designed to be more acceptable to the patient than the sound of the tinnitus. The brain can very easily learn to ignore external sound, especially if it’s at a constant level and frequency, though it has much more difficulty ignoring internal sound such as tinnitus. Therefore, if you mask the tinnitus externally, your brain will learn to ignore it and therefore ignore the tinnitus itself.

Recently, maskers have been developed that can be individually tuned to match the tinnitus frequency. These new maskers give more flexibility to the patient because the frequency can be tuned to be both more effective at masking and more acceptable to the patient.

One important side effect that occurs in a small number of people who have tinnitus maskers is after the maskers are turned off, the tinnitus continues at the reduced level for a period of time. This is referred to as Residual Inhibition. For most people this lasts a very short time but for others it can last a considerable amount of time.

3 – Tinnitus Instruments. These devices are a combination of a hearing aid and a tinnitus masker in the same instrument. They are prescribed for those people with hearing loss who do not have significant relief with a hearing aid alone. There are many advantages to tinnitus instruments and they seem to have a higher level of success than either hearing aids or maskers, with the exception of the UltraQuiet masker.

Even if patients experience tinnitus reduction with the use of a hearing aid, they may have trouble sleeping at night, when they don’t want the hearing aid left on. The amplification on a tinnitus instrument can be turned off while the masking is left on to provide relief throughout the night. Also, it’s important to note that residual inhibition never occurs from wearing a hearing aid. It appears that the constant stimulation of the masker is necessary to produce the inhibition.

All of the above instruments are sold or leased on a trial basis. The patients do not purchase the device unless they have been helped by them. OHSU has a Tinnitus Data Registry where they compile results from all instruments. They found that 61% of patients who were prescribed hearing aids for tinnitus eventually purchased them, indicating a 61% success rate. Only 35% of people prescribed maskers made the purchase while 71% of those prescribed tinnitus instruments eventually purchased the units.