In hyperacusis, the threshold of sensitivity to sound is below normal. In misophonia, the presence of certain sounds such as those arising from typing a keyboard is extremely annoying.
Hyperacusis, that causes intolerance to low intensity sound, is a rarity as only 1 in 50,000 is affected by this type of ear problem.
It is a known fact that the human ear cannot tolerate high decibel sounds. This is understandable as our ears are not equipped to handle loud sounds. Sensitivity to noise is something we are born with. However, what would you say if a person experiences discomfort after exposure to low-decibel sound? It points towards auditory processing disorder. This decreased sound tolerance has been associated with hyperacusis and misophonia. Although the terms are used interchangeably, these disorders related to the auditory system are not the same.
A person affected with hyperacusis is unable to tolerate sounds that are normal for an average listener. Sound that crosses the 80 dB mark is considered a noise. However, for hyperacusis patients, hearing a 40 dB sound can be a cause of great discomfort. Usually, people have no issue listening to low decibel sounds but in case of hyperacusis, the person is extremely sensitive to low intensity sounds. So, listening to a conversation at home or in a restaurant can be quite painful.
To put it simply, hyperacusis makes normal environmental sound unbearable. Everyday sounds become ear-splitting music and mundane sounds appear amplified. Affected patients describe a low decibel sound as painfully loud. So, even if you speak softly, the person will feel as if you are uttering something loudly.
Ear fatigue is common in patients after coming home from a day’s work. Majority of them report a feeling of ear fullness, as if something is pressing the eardrum. Patients tend to wear ear plugs or earmuffs during the day to protect their ears from the perceived offending sound. Due to their collapsed tolerance to sound, they often desire for complete silence, which they usually get at night.
Although causes of hyperacusis are not identified, it is believed to be occurring from head injury that damages the central auditory system. Other possible risk factors include brief exposure to noise, Lyme disease, brain infections such as meningitis, prolonged use of earplugs or earmuffs, and Bell’s palsy.
Misophonia refers to aversion to certain sounds, no matter at what decibel they are being played. The person hates to hear a particular sound, not because he perceives it as loud; it is because he simply dislikes it, especially if it is repetitive. Misophonia has nothing to do with the volume of the sound. The person is comfortable hearing everyday sounds. It is just that particular patterns of sound, though soft, appear offending. For instance, sounds related to coughing, laughing, snoring, and yawning are extremely annoying for patients and make them angry.
Some patients have an intense dislike for repetitive sounds that occur from brushing teeth, clipping nails, rubbing of hands, eating, clicking the mouse, and even typing on the keyboard. The decibel level of these sounds is very low, yet they are unpleasant to people suffering from misophonia. It is thought to be associated with incorrect processing of sound waves in the brain.
In both hyperacusis and misophonia, patients exhibit negative emotions such as anxiety, fear, and rage, after getting exposed to the offending sound. These patients tend to avoid social events and reduce their interactions, which makes them susceptible to depression.
People affected with hyperacusis need to undergo tinnitus retraining therapy (TRT) to increase their sound tolerance. The purpose of TRT is to increase the threshold of sensitivity to sound, which is achieved by exposing the patient to wide range of sounds, followed by counseling from an audiologist. This combination of sound therapy and counseling often works to improve sound tolerance.
As far as treatment for misophonia is concerned, the patient may require consultation with an audiologist as well as a psychologist. The audiologist recommends a specific type of sound therapy to offset the impact of offending sounds. The psychologist conducts cognitive behavioral therapy (CBT) sessions that may help him tackle his negative response to the perceived annoying sound.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.