You turn on a faucet in your studio apartment. Instead of an inaudible trickle, you hear the clamor of an open fire hydrant. You turn on a washing machine, and it sounds like you stuck a stethoscope to a jackhammer. You try to listen to a speech for motivation, but Maya Angelou's soothing voice sounds like Gilbert Gottfried. While you may think you've experienced this with a debilitating hangover or that time you got too high, this is the reality that people suffering from hyperacusis deal with on permanent basis.
Hyperacusis refers to the phenomena, or perhaps more accurately, symptom, where one physically perceives certain sounds and frequencies higher than others. The British Tinnitinus Association estimates that less than 2 percent of the adult population suffer from this oversensitivity to usually negligible sounds. This may sound like a superpower, like Ben Affleck's character in the movie Daredevil, but the reality is even worse than that.
The causes of hyperacusis are varied, and some of them make much more sense than others. Like the common cold, there's more than one way to develop hyperacusis. Smoking a toxic amount of PCP (according to the DSM V), a tick bite (Lyme disease), depression, and having your mom do heroin while pregnant, are all possible ways to develop hyperacusis. The more usual suspects: short-term exposure to extremely loud noises, long-term exposure to constant noises. If it's bad for you in a physical or psychological way, it could give you hyperacusis.
This video explaining Hyperacusis, for example, is unlistenable to someone who suffers from it, because of the wind feedback in the microphone (see first comment).
How is this different than misophonia? Both hyperacusis and misophonia are types of Decreased Sound Tolerance (DST) that make it incredibly painful to hear certain things. Those who suffer from hyperacusis are less sensitive to the origin of sound—if it is above a certain decibel level, it will be painful. Meanwhile, misophonia has a much stronger emotional connotation.
Misophonia, a "phobia" of certain sounds, is not depending on the decibel level of the sound. If someone has an extremely strong negative emotional response to the sound of the word "sumptuous," their misophonia will be triggered whether the word is whispered to them or shouter over an airport intercom.
If you're curious as to which one you suffer from, here's a quick test. If you hear someone smacking their gum, and you end up blacking out and killing that person with a hammer? Misophonia. A plane passes overhead and you double over in pain from the sound? Hyperacusis.
As anything above a whisper may be unbearable, hyperacusis can also precipitate a case of sonophobia (fear of sound), which makes an incredible amount of sense, unfortunately. Those who suffer from hyperacusis often have to wear protective earmuffs, like the ones used when operating a leaf blower or working on an airport runway. A hair dryer sounds like a jet engine. An open faucet sounds like river rapids. Imagine something that doesn't sound that loud. Now, imagine if it was really fucking loud. That's the medical definition of hyperacusis, and it could happen to you.
The social implications of hyperacusis are just as damaging as the symptoms
The social implications of hyperacusis are just as damaging as the symptoms. You can't hang out in loud places (which are often the best ones,) and you are often stuck wearing industrial-grade sound-blocking headphones. Those who suffer from hyperacusis often suffer from the pains of social isolation, which can in turn lead to depression. A survey of patients with Decreased Sound Tolerance shows that many indicated an "inability to enjoy things," as well as an "urge to escape" and "uneasiness." These may seem very vague (because they are) until you consider what happens when one of your main sensory inputs becomes overwhelmingly useless.
The cherry on top of the shit sundae that is hyperacusis, is its difficulty to diagnosis. In order to be tested for hyperacusis, a doctor will play you a series of sounds until they get unbearably loud. The test is not a binary yes or no, and there is much room for error for misdiagnosis and missed diagnosis.
There is no treatment to physically "correct" hyperacusis. Current methods of treatment focus on retraining the brain, basically setting a new baseline for what is loud versus "normal" sound. Retraining therapy often incorporates "pink noise," an ambient sound similar to white noise but with lower frequencies. Introducing pink noise is meant to raise the sufferer's threshold for noise sensitivity, as the constant din may help train the brain to increase the threshold for sound.
The steps to avoid developing hyperacusis are also a great set of guiding principles to live your life: Don't smoke too much angel dust, stay away from ticks, and don't get depression. Be grateful that you can go outside and hear traffic for the beautiful garbage music that it is.
If you do suffer from hyperacusis, take solace in the fact that you're not alone. You can still find love, like this couple: they met in a forum for hyperacusis sufferers, and still live in one of the most god damn noisy cities in the world. It may sound like the great premise for a movie—but I'd suggest writing a book instead.