Some patients have tinnitus but may also have a hearing test within the normal range. Oftentimes, patients who have a hard time overcoming their tinnitus might have their hearing affected by just one little detail. Nonetheless, if they get a hearing test, the audiologist may still categorize their hearing as normal.
In this instance, something is clearly off and abnormal in the auditory system. Still, your doctor may say that your hearing is normal. While your doctor may not be wrong, he or she may still be using the wrong language. Many patients have normal test results, despite the fact that they have had significant loud noise exposure that has damaged parts of their ears.
Most audiologists use the Pure-Tone test, also known as an audiogram or classical hearing test. With this test, it’s very common for someone with tinnitus to show signs of normal hearing. Millions of people have tinnitus, and a lot of them would be able to score in the normal range.
There’s also a more sophisticated test called the OAE, or Otoacoustic Emission test. This test specifically measures the outer hair cell function of the hearing organ, known as the cochlea. The cochlea has many different cells, and the most important hearing cells are called outer and inner hair cells. For someone who has been exposed to loud noise, it’s very common to have changes or reductions in the outer hair cell function of the ear. For someone who is 50 years old or older, it’s also common to exhibit age-related decline in these hair cells.
Jay Hall, a researcher in the audiology field, and his group have extensively studied the otoacoustic emissions for hearing loss and tinnitus. They found that over 90% of patients who have tinnitus and score in the normal range on the Pure-Tone test nevertheless show reduced function in the OAE test. In these patients, the cochlear outer hair cells are not technically normal, meaning they’re certainly not as clear or as functional as they once were earlier in life.
It’s worth understanding that if you’re someone who has hearing tests in the normal range, there’s a high likelihood that there is damage, decline, or changes to the hair cells in the cochlea. For many, this is an “aha” moment that the tinnitus is actually coming from the ears and not from something else. When the cochlea is damaged, a cascade of events follows where an impartial, distorted signal—not of your choice or control—is sent to the auditory region of the brain, which incorrectly categorizes that signal as tinnitus. It brings the signal into the realm of perception, where a patient might suddenly fall into a vicious circle of hearing it and forming negative thoughts in trying to fix it, which can then create other problems. The essential point is that some patients can have tinnitus with no hearing loss, but can still have their tinnitus diagnosed by the OAE test.
One of the earliest studies relationed to tinnitus, conducted by Heller and Bergman, asked subjects to go into a sound-treated room and report any sounds they might hear. Even though these subjects had normal hearing, after spending 10 minutes in the room they came out and told the researchers that they heard some ringing, hissing, or high-pitched sounds. This was a telltale moment for the audiology research field, as it demonstrated that normal hearing patients are still expected to hear some noise when it’s quiet enough. This revelation can also be helpful in the process of recovering from tinnitus.
To learn what may help you manage your tinnitus, please download our free 10-page e-book, The Ultimate Guide to Tinnitus Relief. Dr. Thompson offers Tinnitus Retraining Therapy via telehealth. Please contact our team at Pure Tinnitus to learn more.