Hearing differences between your two ears are normal. They are so normal that most people never notice. But, when the differences become too great to ignore your brain may interpret them as two different sounds. This condition, called diplacusis, may occur suddenly or may increase gradually over time. If you or someone you love is struggling with this rather unusual condition, you probably have a lot of questions.

What is Diplacusis?

Diplacusis is sometimes referred to as double hearing, and there is a good reason for that. People suffering from diplacusis hear two different sounds from their ears. While most people hear a slightly different pitch in each ear, the brain typically compensates for the difference and you perceive it as one pitch. Sometimes, however, the difference is too great for your brain to reconcile as one sound. This results in the perception of two different sounds. While differences in pitch are common, there are other forms of diplacusis.

1. Diplacusis Dysharmonica - With this type of diplacusis you hear the correct pitch in one ear, while the other ear hears the pitch incorrectly. The faulty pitch may sound either higher or lower than the true pitch. 
2. Diplacusis Binauralis - This type is similar to dysharmonica, as the ears hear two different sounds, but binauralis refers to differences in timing. As odd as it may seem, someone with this condition doesn't hear the sounds from each ear at the same time.
3. Diplacusis Echoica - In this unusual form, the person hears the sound repeated in the same ear. The initial sound is followed by an echo of the original sound, which gives rise to the term double hearing. 
4. Diplacusis monauralis - Like in echoica, the ear hears two sounds in the same ear. These sounds are not echoes. They may be different pitches or tones or exhibit distortions and variations in sound.

What Causes Diplacusis?

Diplacusis generally results when you experience some hearing loss in one ear, or experience uneven hearing loss in both of your ears. It is typically the result of inner ear hearing loss referred to as sensorineural hearing loss, but that is not always the case. 

• Conductive Hearing Loss - You may experience temporary diplacusis from an ear infection, a blockage in the ear (such as ear wax) or from foreign objects in the ear (like insects or dust and debris). It can also be the result of a sinus infection, blocked sinuses or clogged eustachian tubes. In these instances, the diplacusis is caused when the ear is unable to transmit the message to the brain because the passageway is blocked or partially blocked. Because your ears are not functioning properly, you may experience the perception of more than one sound or sounds may be distorted.
• Sensorineural Hearing Loss - Like other hearing loss, diplacusis can be the result of exposure to loud noises or trauma to the head that have caused permanent damage to the ear. This type of hearing loss may also occur due to health conditions that affect hearing or from medications used to treat other ailments. If this is the case, the diplacusis may be a permanent condition.

How is it Treated?

Treatment for double hearing depends on the underlying cause. Diplacusis caused by conductive hearing loss typically goes away once the underlying condition is treated. However, diplacusis caused by inner ear hearing loss is not always as easy to treat. While some cases may respond favorably to hearing aids or other listening devices, some do not.

If you or someone you love suddenly experiences double hearing, don't assume the worst. Talk to your doctor or audiologist for a thorough evaluation to determine the underlying cause of the distorted hearing. You may be pleasantly surprised to read more learn that the condition is temporary and will clear up on its own once the underlying cause is treated.