Hyperacusis- when sounds become intense
You know the feeling you get when you are exposed expectantly to a loud sound, such as a fire alarm, firework or a popping balloon. Especially when taken by surprised, these sounds can startle anyone. What if that intensity of sound was around you during ordinary living conditions- such as when you are mowing your lawn, caught in a thunderstorm or vacuuming your house? Individuals who suffer from hyperacusis live exactly that way. Hyperacusis is a condition where the intensity of sound is amplified by the person’s brain when it’s being interpreted. Ninety five percent of individuals with Williams syndrome experience this phenomenon which usually begins in early infancy.
Although some people in the general population develop hyperacusis due to ear injury, the majority of those with Williams syndrome do not. It is something that researchers think has to do with the way the brain and its neural pathways in WS are “wired” to interpret the sound.
Hyperacusis is NOT hearing loss
Hyperacusis is a condition that is only recently becoming more understood. There are still many Ear, nose and throat specialists (ENT) who are completely unfamiliar with the condition. Many have confused hyperacusis with hearing loss, phobias and behavioral issues. Many doctors who are not aware of this condition, diagnose patients with hyperacusis as having a different condition called recruitment.
Sometimes when people have hearing sensitivities it has to do with damage to the ear itself. When there is a sensitivity to sound due to hearing loss, audiologists call the condition “recruitment”. There are some individuals with WS that may experience recruitment. This issue is associated with damage to the cochlea in the inner ear and can be a result of frequent middle ear infections, called Otis media. (Look for a future blog post on this issue).
In a normal functioning ear, sound enters through the pinna, the part of the ear that is external. The pinna collects sound from the environment. The sound then travels through the external auditory canal, commonly known as the ear canal where it meets the eardrum (tympanic membrane). At this point the sound waves physically move the ear drum and transfer the sound energy into mechanical energy. The movement of the eardrum moves a series of bones in the middle ear (the ossicles) and in turn vibrates the oval window.
The oval window is a second membrane that acts much like a drum. The oval window is attached to a snail shaped tube, called the cochlea, which transfers that mechanical movement into an electrical signal that communicates with the brain. The cochlea is filled with a liquid called endolymph. The vibrations of the oval window create a wave of sorts that travels through the endolymph. The waves activate tiny hairs that line the surface of the cochlea. The hairs that are on the inner section of the cochlea are all sensory nerve endings that when aggravated by the waves, starts a nervous response and activates the auditory nerve. This nerve travels through the brain stem and into the cerebrum where the sound is interpreted by the brain.
Nerves in the brain are activated by stimuli such as sound. You can ignore many sounds in the environment because the threshold or intensity of the stimulus by the hairs in the cochlea is low and easy for your brain to tune out. As the stimuli increases and more hairs in the cochlea are activated, the more intense the message is that is sent and the more attention your brain will place on that sound.
If you’ve ever tried to get the attention of someone with hearing loss, you understand the frustration of the following situation. You ask them a question… no response. You ask a little louder… no response. You increase your volume a touch more and they respond with a startle and accuse you of yelling at them. Hard to understand why that is, but there is a perfect scientific explanation. They are experiencing something called recruitment. When hearing loss is due to damage to the ear, the hairs in the cochlea do not pick up on sound coming in the ear at a low level. More hairs are activated as the sound becomes louder and louder. At a particular decibel the hairs that are activated “recruit” information from other hairs around them. When the movement of hairs reaches a particular threshold, the sound is amplified and perceived as very loud.
Hyperacusis is NOT recruitment. In hyperacusis, the person is always picking up on the sound. They are not deaf to the sound at any level. The brain just interprets sounds coming from lower thresholds as being uncomfortably loud. So it has nothing to do with how the ear works and has everything to do with how the brain works. Sometimes it begins abruptly often prompted by a crisis situation such as an unexpected fire alarm. Other times it gradually becomes more and more of an issue. The root of hyperacusis is a sensory issue. Where a sound that all others would find tolerable is perceived as very loud to the person and makes them feel uncomfortable. Many children with WS find the same types of sounds terrifying- lawn mowers, leaf blowers, fireworks, vacuums and fire alarms or sirens.
What causes hyperacusis?
The cause of hyperacusis is not understood by the medical society in general but there is quite a bit of research out there trying to find the reason it exists. Most researchers believe it is due to the cerebrum’s interpretation of the sound but the details of this hypothesis are still a mystery. Some believe it could be a vestibular issue where the vestibular system of the ear which interprets balance and movement of the body perceives sound as a motion, confusing the input. Some also believe it can be contributed due to low muscle tone and a high startle response.
In a normal functioning ear, you have a couple of different built in mechanisms that protect you from loud noises. When a loud noise travels through the ear canal and crashes into the ear drum, it moves the membrane far back into the middle ear. Around the eardrum, however, there is a muscle called the tensor tympanii muscle that contracts and firms up the eardrum so it doesn’t move quite as much. This decreases the intensity of the noise traveling through your ear. This process occurs again with a membrane called the round window that separates the cochlea from the middle ear which absorbs some of the energy in the ear and dampens the noise that would be transmitted to your brain.
You have a third way of protecting your ear, which has to do with chemical interference within the cochlea. Normally, the hairs in your cochlea communicate with nerves using a chemical called a neurotransmitter. Current research suggests that your body will inhibit the release of these chemicals from the hairs on the outer edge of the cochlea under extreme noise to dampen the intensity of the sound traveling to your brain. All of these protective measures are controlled by the brain. Nerves that travel from the brainstem to the outer hairs of the cochlea control these responses in an effort to protect you from loud intense noises which could cause hearing loss. For those individuals with hyperacusis, some believe these mechanisms to decrease the sound intensity are faulty and may lead to high levels or very intense sound.
Because the system of nerves that interpret sound are so complicated, it’s difficult to study and difficult to find the actual root of the problem. The research for hyperacusis is still relatively new because medical professional are only realizing that this condition is a true physiological issue rather than a behavioral one. Overtime, we would expect a better understanding of what causes hyperacusis as research advances.
Spotting hyperacusis
Hyperacusis is often hard to diagnose with children who are non-verbal. Common signs of hyperacusis would be putting their hands over their ears, crying, hitting biting and fleeing from sounds. When the child is verbal they may express pain when hearing ordinary sounds and fear with sounds that are uncomfortable for the ordinary person. Exposure to very loud noises will often aggravate the issue and it can worsen over time.
Loud noises become unbearable to the person and can accompany ringing in the ears (tinnitus) or a stuffy, burning feeling in the ears. Ringing in the ears is a more common issue than hyperacusis in the general public and there is a lot of research in the medical world to develop a medicine or treatment for tinnitus. Many believe that when treatment is available for tinnitus, it will also help those with hyperacusis.
Treatment
When hyperacusis is suspected it is important to visit an audiologist specialized in special needs. Some people start with an ear nose and throat specialist and often don’t find much support. Audiologists are trained to identify hyperacusis and how to treat it using sound therapy and behavioral counseling if any phobias exist due to the condition. There isn’t a designated method to diagnose hyperacusis but most audiologists will test for the loudness discomfort levels (LDL). People with normal hearing will find discomfort in sounds exceeding 90 decimals. Research has shown that a typical person with WS finds sounds 70 decibels or louder uncomfortable, indicating a hypersensitivity to sounds 20 decibels below the average person. Audiologists have also noted that those with hyperacusis can hear sounds well below the threshold of an average listener making their hearing more acute. Therefore the decibel range they hear comfortably is shifted compared to those of the general population.
Many parents have resorted to using headphones to dull the noise entering a child’s ears or use ear plugs at night to help them fall asleep. While this is an easy and quick “fix” it is actually warned against. By using headphones too much you are training the brain to actually listen more closely or amplify the sound as it comes in. It is an adaptation to the muffled noise. So, if overused, when the child removes the headphones, their hearing sensitivity will actually be greater and it compounds the problem. Headphones and ear plugs are fine to use every now and again. If you anticipate visiting a very loud event, during a fire drill at school for example, headphones are perfectly acceptable. As a rule, just don’t use them in normal levels of noise and around the home or school.
Audiologists will often treat hyperacusis using something called pink noise. Most people are familiar with white noise- the noise that comes from a radio when it is not tuned. White noise contains sound frequencies that are outside the comfortable threshold for someone with hyperacusis. Pink noise is similar but the sound frequencies are lower and more comfortable. The therapy, called Tinnitus (Hyperacusis) Retraining Therapy or TRT uses pink noise to desensitize the brain by listening to long periods of pink noise. The pink noise is not uncomfortable to the ear but the prolonged exposure to the brain trains it to decrease its sensitivity to noise. Audiologists would use special hearing aids that emit the sound at very low levels and the person with hyperacusis would wear it on for 2-8 hours per day. Research has shown to improve hyperacusis in 90% of patients but it usually isn’t covered by insurance and it costs $3,000-4,000.
You can buy a pink noise CD that costs much less. Although not considered as an effective therapy, it has shown to calm those with hyperacusis when played in moments of extreme silence, like at bed time. Pink noise CD’s are widely available on the internet.
When desensitizing it’s important to start with low non-threatening sounds and expose them to these noises for prolonged periods and work your way up the decimal scale. It’s also important to associate the desensitizing session to very positive reward systems so they associate the behavior to positive experiences. Building these experiences up will associate the sounds with the reward center of the brain and help decrease phobias. It will take time and patience to overcome these issues.
When hyperacusis becomes a larger issue
Overtime and especially if hyperacusis becomes worse it can lead to extreme anxiety and behavioral issues. Many with hyperacusis develop the fear of loud noises called phonophobia. Children with phonophobia will not only act out during loud noises but will develop anxiety and worrisome behaviors in anticipation of a loud noise. They may show signs of separation anxiety or school anxiety if they are worried about noises in the school- like fire alarms or loud toilets. If the issue isn’t addressed or occurs during adulthood it can lead to the person choosing to stay home and quarantining his or herself from the noise, highly disrupting their daily life. It is acceptable for parents or teachers to offer ear protection to reduce anxiety but remember, ear protection can make the condition worse if used too often. It is important to see an audiologist, counselor or psychologist to deal with the anxiety since it is now both a hearing condition and a behavioral one.
A second form of behavioral issues that can begin in someone with hyperacusis is called misophonia. In this condition, a person becomes extremely agitated or overstimulated by a particular noise. Many people have sounds that make their skin crawl- like nails on the chalkboard. Research has identified that 91% of individuals with WS will develop misophonia for some sort of noise most commonly those of motors, thunder, fans and fireworks. For many with hyperacusis, an ordinary sound that may be a part of daily life will have this effect. It can cause the child to withdraw from activities in the home or school that are associated with that noise. Again, it’s important to see an audiologist and psychologist in these situations because there are effective treatments. Most with misophonia will be treated with cognitive behavioral therapy (CBT). This treatment has been identified as being extremely affective for individuals with WS in overcoming sensitivity and anxiety in areas including noise, touch and other sensory issues.
It’s not uncommon that when a child becomes desensitized to a sound that once was overwhelming, they will become preoccupied with the sound to a point that they are obsessed with it. The ability for people with WS to identify sound and the obsessive behavior they can develop from previous audiology fears can turn a person with WS into an expert, classifying noises based on their noise in ways that the ordinary person could not. It’s not uncommon for a child with WS to know the sound difference between two different brands of vacuums and could identify them based on the sound they make alone. They often become obsessed with them and want to learn and use the vacuum over traditional toys.
Everyday ways you can help your loved one with hyperacusis
Daily encounters that may be tough for someone with hyperacusis. You may have to experiment with new daily procedures to improve their lifestyle. How to modify your lifestyle to accommodate their sensitivity may help reduce the issues of phobias and anxiety.
Hugging and grooming: The pinna or outer ear is where the sound is collected so touching it during hair brushing or hugging/kissing may be unbearable to those with hyperacusis. Try to avoid touching the outer ear during these activities.
Sleeping: Many people with hyperacusis also have issues with sleep. Hyperacusis can interrupt sleep patterns or a person’s ability to fall asleep because in quiet environments they typically will hear a ringing in the ears. Experiment with different materials on the pillowcase. Some materials like cotton are much louder when the head turns against the fabric. It may help them to have a radio on, noise machine (ideally pink noise) or soft music to eliminate the ringing. Sensitivity will be at its worse when the person is tired. They will need a quiet space to rest their ears. Sensitivity can also be heightened in the morning. When your child’s ears aren’t on guard using those adaptations to dampen sound during the quiet night, there can be a period where the brain has to acclimate to the noise. This explains why people, even some of those with normal hearing, prefer to start their day in a quiet atmosphere.
Attending noisy events: Sit in the back where the sound of clapping or singing will be directed away from you. When exposed to speakers, find a place away from the speaker to reduce noise and avoid surround sound.
Going to public restrooms: Public toilets are often significantly louder than ones in your home. Teach your child to flush with their foot while protecting their ears with their hands.
Visiting the doctor: Many individuals with WS have to encounter medical procedures, like the MRI, that emit uncomfortable noises. Before the MRI, discuss concerns you have with the doctor and request full form ear protection during MRI.
Most importantly, read your child. Identify household noises that bother them and make modifications to help ease the pain of the sound. Visit http://www.hyperacusis.net/hyperacusis/supplement/default.asp for more suggestions on lifestyle changes that will help reduce the intensity of sound in your home if your loved one is suffering from hyperacusis.
Interesting tidbit about hyperacusis
Although hyperacusis can be very frustrating and at times stressful for your child, it has some redeeming qualities, as well. There is extensive research that suggests that the musicality feature that we all love about our loved ones with WS is directly correlated with their hypersensitivity to sound. By having a heightened awareness to sound, the pitch and tones of music take on a whole new meaning to them. In fact some of the world’s most beloved musicians, like Beethoven, had hyperacusis.
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