Understanding Diplacusis

by Debbie Clason for Healthy Hearing

October 3, 2017 - Our auditory system is an amazing, complex mechanism that gathers and processes noise, then translates it into recognizable sound. At any given time, our ears are collecting a multitude of noises – dogs barking, the rumble of a neighbor’s lawn mower, birds tweeting, giggling children, the swoosh of a passing car on a nearby highway – and based on all that incoming information, our brain is making a lot of decisions.

For the most part, our ears hear sounds at slightly different pitches all the time, and if they are very close in pitch, the brain distinguishes them as one sound. Yet one form of hearing loss causes some people to hear sounds so differently it creates a two-sound experience known as diplacusis, sometimes called “double hearing.”

What is diplacusis?

According to a recent study published online in the U.S. National Library of Medicine National Institutes of Health, diplacusis is the “perceptual anomaly whereby the same sound is perceived as having a different pitch depending on whether it is presented in the left or the right ear.” As you can imagine, this sensation can be disturbing and troubling to those who experience it.

Hearing healthcare professionals believe diplacusis occurs when one ear develops more hearing loss than the other. There are several types:

• Diplacusis dysharmonica is the most common type of diplacusis. It occurs when sound is perceived normally in one ear, but is heard at a different pitch in the other.
• Diplacusis binauralis occurs when you hear the same sound differently in each ear. For example, one ear may hear a sound at a different pitch or different timing than the other.
• Diplacusis echoica occurs when the timing of tones is slight different in each ear. As a result, you hear the same sound repeated as an echo.
• Diplacusis monauralis occurs when one ear hears the same sound as two different sounds.

What causes diplacusis?

Those who develop diplacusis usually notice it suddenly after exposure to a loud noise, a bout with an ear infection or trauma to the head. As you can imagine, musicians notice this condition more readily than the average individual as their ears are more sensitive to pitch and tone. In addition to double hearing, individuals with diplacusis may also develop tinnitus, a ringing or buzzing noise, in the affected ear.

Diplacusis can be caused by damage to the inner ear as the result of:

• Noise-induced hearing loss (NIHL)
• Trauma to the head
• Certain medications

Diplacusis can also be caused by an obstruction in the ear because of:

• Ear infection
• Clogged sinuses
• Excess earwax
• Tumor

Treatment

If your diplacusis is caused by an obstruction, your hearing may return to normal once the obstruction is removed or the infection subsides. Diplacusis caused by sensorineural hearing loss is permanent, but it may be treated with hearing aids or cochlear implants.

If you notice symptoms of diplacusis or suspect you are losing your hearing, make an appointment to see a hearing healthcare professional. They can provide easy, painless testing and determine the right course of action. To find a trusted hearing healthcare professional in your community, visit our directory.

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