It is a condition that affects the way you perceive sounds.
You may experience increased sensitivity to particular sounds that are generally not a problem for others.
This means loud noises, like fireworks, and everyday sounds, like telephones, can be uncomfortable and sometimes painful. It can vary in severity, from being a minor inconvenience to a life-changing condition.
Loudness perception disorders, long a clinical enigma, can pose a severe challenge to the patient.
Hyperacusis has been defined as “unusual tolerance to common ambient sounds” and, more pejoratively, as “consistently exaggerated or inappropriate responses to sounds that are neither threatening nor disturbing to a typical person.”
Common to both is the implication that low-intensity sounds can evoke the experience and that sounds in general, rather than specific sounds, are problematic.
This is less true for phonophobia (fear of sound) and recently proposed misophonia (aversion to sound), suggesting that intolerance may be specific to certain sounds with emotional associations.
In neurology, phonophobia tends to be explicitly used for volume intolerance reported by some migraine patients.
Therefore, the term hyperacusis is preferable for the broader types of auditory hypersensitivity.
Loudness recruitment describes an experience commonly associated with cochlear hearing loss and specifically with dysfunction of the outer hair cells of the organ of Corti: with increasing sound level, the perceived volume increases faster than usual.
This phenomenon can be distinguished from hyperacusis if the individual perceives that the moderate-intensity sound is deafening (recruitment) or the low-intensity sound is uncomfortably loud (hyperacusis). Still, the two experiences are not mutually exclusive.
The recruitment of loudness, however, does not vary with mood.
Symptoms of hyperacusis
If you think you are suffering from hyperacusis, you will feel sudden discomfort when hearing particular sounds. Sometimes it can be excruciating, and in some cases, it seems that all the sounds are too loud.
Sometimes it can be accompanied by phonophobia and fear of noise. This is often triggered by the pain that sounds can cause as you begin to associate the noise with pain.
The condition can also be related to anxiety and depression, and it can turn into a problem of isolation. Hyperacusis can often be experienced if you also suffer from tinnitus.
Causes of hyperacusis
What causes it to occur can vary from person to person.
While it may occur as a result of an existing medical condition, or you may experience it through damage to your hearing, especially from long-term noise exposure, or as a condition resulting from PTSD.
People are generally not born with hyperacusis; it is usually caused by certain diseases or health problems. The most common are:
A head injury (for example, a cause of an airbag, also called an air cushion or air mattress), damage to one or both ears due to medications or toxins, or a viral infection affecting the inner ear or the facial nerve (Bell’s palsy).
Temporomandibular joint disorder (TMJ), Lyme disease, Tay-Sachs disease, migraines, using valium regularly, certain types of epilepsy, and chronic fatigue syndrome.
Meniere’s disease, post-traumatic stress disorder (PTSD), depression, and autism.
Being around loud noise can also cause hyperacusis. Something like a single strong shot can trigger the condition. But it can also come from being around loud noises for an extended period.
On the other hand, some may experience it for no apparent reason. While the specific causes of the condition are somewhat debatable, there are ways to help alleviate the problem.
Treatment for hyperacusis
As it often appears as a result of another medical condition, investigating this may be the first step in treatment and is something your GP can begin with.
Once this has been ruled out, you will often undergo sound therapy to address the problem, similar to how tinnitus can be treated.
Not enough research has been done on some other treatments used for hyperacusis to know if they are helpful. These include acupuncture and relaxation exercises.
There is still very little evidence to guide best practices. Here are some tips on clinical management and the fundamentals of course based on my current understanding of hyperacusis and clinical experience:
Counseling patients on safe sound levels: They appreciate knowing that even if sounds are uncomfortable, the sounds that bother them do not necessarily cause permanent damage to their ears or hearing system.
If those around you are not physically uncomfortable or holding by the ears, the patient will likely not have to worry about the sound causing damage to their ears.
Explain the mechanism of hyperacusis: Patients are often told that their ears are too sensitive because the brain’s volume control is stuck on ‘high,’ making the sound uncomfortably loud.
Encourage patients to slowly remove hearing protection that is not necessary to prevent hearing loss.
A study by Formby et al. found that subjects who wore earplugs throughout the day developed a decreased tolerance to sound, suggesting that improper hearing protection may trigger or exacerbate hyperacusis.
Encourage your patients to gradually increase their exposure to sound in safe and relatively predictable environments.
Hyperacusic patients need to feel that they are not trapped in a situation that they consider intolerable, as this will increase stress activation and enhance their negative response to sound.
This may mean increasing sound exposure at home before venturing outside for some. For others, it may mean returning to challenging situations with an escape plan or earplugs that can be worn “just in case.”
Depending on the severity of hyperacusis, some deaf patients will need to delay or limit the use of amplification until their tolerance to sound has improved.
The amplification will gradually increase over several months before reaching the target gain.
The patient needs to understand that their instruments will not provide all the benefits for hearing loss until sound tolerance has improved.
Severe cases of hyperacusis may require the use of sound generators to reduce the contrast between offensive sounds and background sounds. Patients generally enjoy the “damping” effect of using sound generators.
Additionally, low-level sound generators before or in conjunction with amplification may allow hearing aid users with hyperacusis to better tolerate amplified sounds and possibly facilitate the recalibration of central hearing gain.
Marshall Chasin has developed a clever desensitization exercise using a piano. “A three-finger approach to hyperacusis.”
Good quality electronic ear muffs such as Peltor Tactical Pro (Class A) or Bilsom Impact provide hearing protection (Class B) for sounds more significant than 82 dBA.
At lower sound levels, they provide smooth amplification. These are appropriate for patients with hyperacusis and tinnitus exposed to intermittent noises at work or home and will help them avoid overuse of hearing protection.
Keep in mind that hyperacusis has a psychological component.
Refer patients complaining of sound-induced ear pain and discomfort and transient aural fullness to a physical therapist certified in temporomandibular disorders and cervical treatment, especially with a history of head or neck injury.
A prior medical evaluation for earache and hearing fullness is necessary to rule out any serious medical problems that may contribute to these symptoms.
Psychological intervention may be warranted to address the emotional component of hyperacusis and any comorbid anxiety or depression that may contribute to sound intolerance.
The first reaction to hyperacusis is to protect themselves with earplugs, wristbands, or other devices for many patients.
However, there is reason to believe that such strategies to decrease sound intensity entering the auditory system may further increase central gain, exacerbating rather than improving hyperacusis.
Sound therapy is used to help you feel less and less affected by the noises to which you are sensitive.
Cognitive-behavioral therapy (CBT) has been identified as the treatment of choice for the psychological distress associated with tinnitus.
You may find that cognitive-behavioral therapy can help significantly if you may suffer from anxiety or depression. Hyperacusis can make these problems worse or even cause them.
Cognitive-behavioral therapy helps address the emotions that come with it and change them to reduce feelings of anxiety.
This seems like a reasonable strategy to counteract the distress and stress associated with hyperacusis, along with counseling and information, relaxation therapy, and sound therapy.
People can have hearing loss and sensitivity to sound, and hearing aids can be adjusted to allow amplification without excessive amplification.
In the past, patients had no choice but to turn to hear protection devices as hyperacusis was not widely regarded as a genuine symptom.
For tinnitus, tinnitus retraining therapy (TRT) was introduced in 1993, and with minor modifications, this has also been recommended for hyperacusis.
After an audiological and medical evaluation, the protocol requires classification of the patient according to tinnitus and hyperacusis status and then ‘directive advice’ on the auditory system, tinnitus, hyperacusis, and distress associated with them.
From ear-level broadband generators, Binaural sound therapy is carried out even when symptoms are one-sided.
Treatment is based on the notion of desensitization, and the intensity of the sound gradually increases from a low level over time.
There have been no randomized controlled trials of reeducation therapy for hyperacusis; they would be challenging to design given the twin elements of counseling and sound therapy.
Several observational studies have reported improvements in volume tolerance, but the nature of tinnitus retraining therapy training (attendance at an author-led vetted course) raises concerns about objectivity.
However, the approach taken by tinnitus therapy practitioners, which promotes understanding and comprehension and the use of low-level, non-threatening, and broadband noise, appears to be based on common sense.
Another experimental treatment is called auditory integration therapy (TIA). It is often used in the treatment of autism. It involves listening to music at different volumes over some time every day.
Your doctor may also give you medicine to help you manage the stress that the condition can cause.
If you have hyperacusis, you may be tempted to wear earplugs to muffle sounds or avoid social situations where sounds may bother you.
While these may provide short-term relief, they can worsen your symptoms in the long term. When you finally remove your earplugs or go to a social setting, the sounds can seem even louder.
Evidence on the efficacy of such an approach is not yet available, and at present cognitive behavioral therapy therapists in the UK show little interest in tinnitus or hyperacusis.
There is currently some tension between advocates of reeducation therapy and psychological therapy, but the differences are not significant. Patients would probably benefit if the knowledge of both could be used.
Although the exact cause of hyperacusis is unknown, you may experience this condition due to hearing damage due to excessive exposure to noise.
To avoid this and other hearing concerns, such as hearing loss and tinnitus, there are several steps you can take to ensure that you protect your hearing. These include:
Try listening to music at a reduced volume for shorter periods. Wear hearing protection, for example, at concerts or work if necessary. Be aware that prolonged exposure to sounds above 85 decibels can damage your hearing.
Prevalence, incidence and quantification
The lack of robust epidemiological data is a significant shortcoming of the published work on hyperacusis. Fabijanska et al. conducted a postal tinnitus questionnaire in Poland that included an unspecified question on hyperacusis.
Of the 10,349 respondents, 15.2% reported hyperacusis (12.5% of men, 17.6% of women). Regional differences were also reported. A weakness of this report is the lack of specificity.
More recently, Andersson and colleagues investigated the prevalence of hyperacusis in the Swedish adult population.
Two methods were used: an Internet study. Visits to a large-format Swedish newspaper website were invited to complete an online questionnaire and a postal population study.
Of 1,167 people who clicked on the web banner, 595 responded, with a response rate of 52%. The point prevalence of hyperacusis in this group was 9%.
The postal group consisted of 987 people, of which 589 responded (response rate 60%), and the point prevalence was 8%.
The participants were not asked if they had ever sought a medical opinion regarding their hyperacusis. Incidence data for hyperacusis do not appear to have been reported anywhere.
A coincidence between the tinnitus complaint and hyperacusis experiences has been widely noted.
Among patients attending tinnitus clinics with a primary complaint of tinnitus, hyperacusis is approximately 40%. In patients with a primary complaint of hyperacusis, the prevalence of tinnitus has been reported to be 86%.
The apparent link has led to speculation about common mechanisms.
Until recently, it has not been possible to quantify the disability associated with hyperacusis, but two instruments have now been published.
Khalfa et al. describe data from a self-report hyperacusis questionnaire with 14 “standardized” items in 201 individuals who responded to a recruitment advertisement.
The principal component analysis indicated that three factors explained 48% of the variance — attentional, social, and emotional.
With a 27-item questionnaire examined in 226 patients with hyperacusis, Nelting et al. reached similar conclusions: 51% of the variance was due to cognitive reactions, national/bodily behavior, and emotional factors.
The latter questionnaire is currently available only in German and is not sensitive to treatment effects, but such instruments represent a step forward.
In most cases, no underlying medical condition can be found. Katzenell and Segal have reviewed the requirements for hyperacusis to be reported as a symptom.
However, it should be noted that of the identified peripheral conditions, several involve facial nerve dysfunction.
Since the facial nerve innervates the stapedial reflex, which is a mechanism for reducing the perceived intensity of the impulse sound, these conditions can reduce the effectiveness of that reflex and therefore increase the perceived power of the sound.
As such, this does not meet a strict definition of hyperacusis.
What about the core conditions?
Lyme disease is a systemic infection with the tick-borne spirochete Borrelia burgdorferi that targets specific body organs, including the peripheral and central nervous systems.
Some caution should be exercised when interpreting reports of hyperacusis because facial paralysis may be a feature, hence stapedial reflex dysfunction.
However, there are reports of hyperacusis in Lyme disease without facial nerve dysfunction.
Williams syndrome is a disorder characterized by deficits in conceptual reasoning, problem-solving, motor control, numeracy, and spatial cognition, with an incidence of 1 in 20,000 live births.
Up to 90% of people with this syndrome report hyperacusis, and a proposed mechanism is 5-hydroxytryptamine (5-HT) dysfunction; see next section.
Other conditions in which hyperacusis has been reported include middle brain aneurysm and migraine stroke. Several cases of hyperacusis in multiple sclerosis have been reported, although the association is unusual.
Although most cases of hyperacusis are not syndromic, that is. They do not reflect an underlying medical disorder; a medical evaluation is desirable.
Hyperacusis has several potential mechanisms that are not mutually exclusive; As with tinnitus, the patient population is likely to be heterogeneous.
The high prevalence of hyperacusis in Williams syndrome led Marriage and Barnes to consider the mechanism in that condition and how it could be generalized to other people.
His suggestion that 5-HT might be involved was based partly on the clinical observation that hyperacusis tends to occur in other conditions where the 5-HT function is believed to be impaired: migraine, depression, and stress disorder. Post-traumatic.
5-HT appears to play a role in modulating hearing gain and determining the importance of sound.
However, there is no evidence that 5-HT disruption contributes to hyperacusis of non-syndromic types.
Furthermore, even in Williams syndrome, the excessive hearing gain may be partly explained by the high incidence of otitis media with effusion and the associated conductive hearing loss.
Sahley and Nodar observed that hyperacusis (and tinnitus) appear to increase in intensity at times of fatigue, anxiety, or stress. They hypothesize that, during stress, endogenous dynorphins are released in the synaptic region below the inner hair cells.
This could boost the neurotransmitter glutamate, causing the sound to be heard at excessive volume.
The model applies to both externally and internally generated sound (tinnitus), but supporting empirical evidence has not yet been obtained.
Another potential mechanism is auditory efferent dysfunction. An auditory efferent system is common to all mammals, and in humans, it consists of a lateral system and a medial system.
In the lateral system, whose function remains unclear, the pathways originate around the superior lateral olive and end in the primary afferent dendrite below the inner hair cell.
In the medical system, they begin medially with the superior olivary complex and end at the base of the outer hair cells. The system’s functions appear to include modulation of auditory gain and behavioral response to sound (manifested in anatomical links with the formation of reticular).
Middle auditory dysfunction can contribute to hyperacusis and tinnitus; therefore, altering the ability to modulate the center gain can result in persistent sensitivity despite exposure to moderate to high-intensity noise.
However, evidence is against such a role since patients who have undergone vestibular nerve section (generally due to symptoms of vertigo refractory to other treatments) do not complain of increased tinnitus or volume intolerance.
And the psychoacoustic tests of these patients do not reveal a decrease in hearing performance.
For patients, hearing hypersensitivity can lead to anxiety and even fear. This can be true for specific sounds or sounds in general.
The links between the central auditory system and brain areas in anxiety and fear are now under scrutiny.
Specifically, anatomical and functional links have been identified between the central auditory system and the tonsils (the tonsils are an essential element of fear conditioning).
These processes have been described as an integral part of the development of tinnitus-related distress and the fear and anxiety component of hyperacusis.
Given the evidence that the central auditory system has a role in establishing hearing gain, the possibility of some central hyperexcitability should be considered.
Jastreboff and Hazell discussed this as a potential mechanism for hyperacusis. The experience of hyperacusis in patients without apparent dysfunction or involvement of the peripheral auditory apparatus is circumstantial evidence in favor of this mechanism.