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“In physics, sound is a vibration through a medium, in our case ‘air’, that causes what is known as an acoustic wave. In humans, sound involves both the reception of the acoustic waves and the perception.Perception is different for everyone. In fact, our perception of sound is like an individual fingerprint. In some cases, there are confusing signals and diplacusis is one example.” - Drew Sutton, MD, Board-Certified Otolaryngologist
There are several different hearing conditions that people are diagnosed with. Sensorineural hearing loss, conductive hearing loss, tinnitus, and auditory processing disorders represent the main groups of hearing disorders.
While these conditions are fairly common, it isn’t to say that there are no unique presentations of each. One unique presentation of hearing loss is diplacusis. Diplacusis is a condition that is more commonly known as double hearing and results in people perceiving multiple sounds from one stimulus.
Below is a closer look at diplacusis, its connection to hearing loss, and what you can do to help.
What Is Diplacusis?
Diplacusis is a hearing disorder that is characterized by having doubled hearing. Essentially a single sound is perceived as two separate sounds rather than one. You can think of diplacusis as the doubled vision of your ability to hear.
The brain is typically quite good at meshing multiple sensory inputs and allowing you to perceive them as one, but in some cases, this doesn’t occur. Many cases of diplacusis have an underlying hearing loss, but they still vary from person to person.
Diplacusis can present itself in either one ear or both ears. Diplacusis, where two sounds are heard in one ear, is referred to as monaural. In contrast, diplacusis binaural refers to diplacusis, where a sound is heard differently from one ear to the other. Diplacusis binaural is the most common form of doubled hearing.
Below is a closer look at the different types of diplacusis and what is thought to cause them.
Diplacusis Dysharmonica
Diplacusis Dysharmonica is a subtype of diplacusis that focuses mainly on double hearing due to a difference in perceived pitch. Diplacusis dysharmonica is one of the most common forms of diplacusis and can be caused by several different things, including an ear infection, loud noise exposure, or even a head injury.
Diplacusis dysharmonica is a common result of a one-sided ear infection. While most people go on about their day acknowledging their one ear is slightly muted or not pitch-perfect, professionals such as musicians and those that require high auditory acuity could face more difficulty performing tasks to the best of their ability.
Diplacusis Echoica
Diplacusis echoica is caused by a delay in the perception of sound. Essentially when sound enters the ears, one ear hears and interprets it quicker than the other ear. This results in the brain being unable to interpret the sounds as one sound, resulting in an echo effect.
Diplacusis echoica can be caused by several ear problems, but most likely are caused by outer and middle ear issues. The process of conduction is where sound energy is transferred and conducted to the sensorineural organ known as the cochlea.
When sounds have an off timing but the same pitch, this points to something slowing down the process of conduction rather than an issue actually slowly sensing the sound. Impacted earwax, an ear infection, or other blockages can cause sound to travel less efficiently and may cause an echo-like effect.
Mixed Diplacusis
Mixed diplacusis occurs when both forms of hearing discrepancy occur simultaneously. This could sound as if there is an echo with a slightly different pitch. Mixed Diplacusis is not common and is not well understood. Many people will diagnose mixed diplacusis as either echoica or diplacusis, but it isn’t a big deal because causes and treatments are so similar.
Can Diplacusis Be Treated?
Diplacusis has many different presentations and potential causes. Diplacusis is best thought of as a symptom, and to get rid of it, the underlying health issue needs to be addressed. In the case of diplacusis, this means that the underlying asymmetrical hearing loss needs to be properly taken care of.
There are two main forms of hearing loss: conductive hearing loss and sensorineural hearing loss. Both can cause impairment in auditory acuity, but they differ in their physiology and how they are treated. Below is a closer look at both forms of hearing loss and what can be done about them.
Sensorineural
Sensorineural hearing loss is a form of hearing loss that has to do with the ability of the ears to convert physical sound into a neurological impulse. Sensorineural hearing loss is typically caused by a dysfunction within the cochlea or auditory nerve.
The most common sensorineural hearing loss involves the damage of the cochlea’s internal hairs, which are responsible for detecting noise and conveying it as a certain pitch and loudness. When these hairs become damaged, it reduces the body’s ability to perceive that specific tone.
Sensorineural hearing loss tends to be long-term, and treatments mainly revolve around trying to regain a quality of life that allows you to hear the world around you a little better.
One of the most common medical interventions utilized for sensorineural hearing loss is a hearing aid. Hearing aids work by increasing the intensity of incoming sound waves and relaying that amplifies the sound to the ear.
Conductive
Conductive hearing loss has to do with the outer and middle ear. Many forms of conductive hearing loss can be treated and effectively reversed, such as ear infection, earwax impaction, and ear obstructions. Obstructions and impacted earwax can simply be removed, and normal hearing typically is regained.
Potentially lasting forms of conductive hearing loss can include a perforated eardrum or malformation of the middle and outer ear when born. A perforated eardrum carries a risk of more lasting hearing loss. At the same time, a malformation can reduce the ear’s ability to conduct sounds to the cochlea properly and result in a reduced ability to perceive sounds.
More severe forms of conductive hearing loss can respond well to surgery, but hearing aids may also be utilized to help increase sound stimuli to a point where they can properly activate the cochlea.
Does Diplacusis Effect Everyone the Same?
One interesting finding is that diplacusis seems to be more noticeable to some people than others. Those frequently dealing with the precision of sound seem to be more sensitive to the slight differences in noise perception and are more likely to notice when something is awry.
In fact, a recent study found that among professional musicians, those who specialized in classical music appeared to have a higher prevalence of diplacusis than other musicians. The attention to pitch and accuracy in classical music could explain why those musicians are more likely to notice and seek care for differing auditory cues.
Treatments and Prevention
While several variables can go into the formation of diplacusis, there are also many treatments and preventative measures that may help find you relief from the distress of hearing double or stop it from occurring in the first place.
Below is a closer look at some specific treatments and preventative methods that may help mitigate diplacusis or help you better deal with it.
Prevention of Diplacusis
Prevention of diplacusis mainly revolves around protecting your hearing. Your sense of hearing is robust, but exposure to certain medications, loud noises, or other outside environmental factors can contribute to hearing loss, leading to diplacusis.
As stated previously, musicians are at a higher risk of developing diplacusis and other hearing problems like tinnitus. Since musicians rely heavily on sound for their careers, diplacusis could severely affect their livelihood. To avoid hearing loss, musicians can utilize musician earplugs which are specialized earplugs that reduce the intensity of all frequencies of sound evenly to allow musicians to ensure they are playing accurately.
Treatment for Diplacusis
Both types of hearing loss can cause Diplacusis. Because of this, it is important to seek the assistance of an audiologist to understand the underlying cause of your specific diplacusis and go about the right treatment option for you. After a hearing test, an audiologist will be able to determine if you may benefit from a hearing aid.
For conductive hearing loss, an audiologist may resolve it if it is due to obstruction or an ear infection. In the case of sensorineural or severe conductive hearing loss, an audiologist can work with you and find the best option that fits you and your needs.
Conclusion
In summary, diplacusis is a condition that is characterized by doubled sound. This can be in the form of an echo or can be that you perceive the same sound like two separate pitches. Regardless of the type of diplacusis, treating the underlying issue leading to a skewed auditory perception is essential. Treating the underlying hearing loss can allow those with diplacusis to have a greater sense of normalcy when it comes to hearing.
Sources:
Types of Hearing Disorders | John Hopkins All Children’s
Ruptured Eardrum (Acutely Perforated Tympanic Membrane) | Cleveland Clinic
