Boz Banner


  • Audiometry
  • Tympanometry
  • Adv Audiology
  • Vestibular
  • Allergy Testing
  • Tinnitus
  • Hyperacusis
  • Misc. Audiology
  • Clinical Photography

  • Decreased sound tolerance, including hyperacusis, misophonia, and phonophobia, is a challenging topic to study, and a challenging symptom to treat.  Many questions are unanswered; the aetiology is not clear, neural mechanisms are speculative and treatments are not yet proven.

    Overload Image There are many differing terms to name certain conditions relating to a subjective decreased sound tolerance in people. The terms hypersensitivity, hyperacusis, recruitment, dysacusis, auditory hyperesthesia, misophonia, phonophobia and many other terms have been used indiscriminately to describe conditions relating to any kind of reduced tolerance to sound or discomfort in the ears with sound exposure.

    Although there is no generally accepted term to describe the various decreased sound tolerance conditions it must be remembered that this topic is only recently starting to gain some momentum after the original work of Jastreboff and other authors. This subject is still not well researched or documented and for many sufferers, due to a lack of understanding regarding a firm diagnosis, the causative pathophysiology and resultant treatment options, patient satisfaction is often poor.

    Clinical research reveals that in many cases, decreased sound tolerance is a complex phenomenon and frequently consists of multiple conditions. In some cases, it is not necessarily loud sounds but quiet sounds that can cause discomfort. It has been recognised that decreased sound tolerance might reflect a physical discomfort, or can be related to a dislike or a
    fear/anxiety of sound.

    A major caveat is that hyperacusis, misophonia or phonophobia does not necessarily have any relation to hearing thresholds. Patients with hyperacusis, misophonia or phonophobia may have normal hearing or they may have some hearing loss. They may also have tinnitus but this is not exclusive.

    From the current literature, the following is the generally accepted description of each term.



    A simple definition of hyperacusis is:

    An Increased Sensitivity to Noise.

    In more detail, hyperacusis can be defined as an abnormally strong reaction to sound occurring within the auditory pathways. At a behavioural level, it manifests by the subject experiencing physical discomfort because of exposure to sound. This same sound would not result in a similar reaction to the average person. There is limited data available regarding the prevalence of decreased sound tolerance.


    Most frequently decreased sound tolerance results from a combination of hyperacusis and misophonia/phonophobia but has been reported as an isolated finding or as a component of multi-symptom diagnosis.

    It is important to assess the presence and the extent of all these phenomena in each patient, as these phenomena need to be treated using different methods. Some research shows that hyperacusis and tinnitus co-exist at the same time. They quote that around 40% of tinnitus patients exhibit some degree of decreased sound tolerance and that 86% of subjects questioned with hyperacusis suffered from tinnitus.

    Decreased sound tolerance can exist as an independent medical diagnosis, or may be associated with problems that are more complex. Medical conditions previously linked to decreased sound tolerance include: tinnitus, Bell's palsy, Lyme Disease, Williams Syndrome, Ramsay Hunt Syndrome, ear surgery, perilymphatic fistula, head injury, migraine, depression, withdrawal from some antidepressants, increased Cerebral Spinal Fluid pressure and Addison's disease.  Hyperacusis has also been linked to sound exposure (particularly short, impulse noise), stress and drugs. In some cases, a negative life event appears to be associated with the onset of hyperacusis as well as children on the autistic spectrum.

    There may be a learned association of fear/anxiety with their problem noise and may actively avoid these environments and this may lead to social isolation. In the majority of decreased sound tolerance cases, the aetiology of hyperacusis is unknown.


    A good clinical evaluation is required to obtain as much information about the different aspects of the decreased sound tolerance. It is recommended that a full medical history be taken in addition to questions that will help define the factors relating to the decreased sound tolerance and provide a differential diagnosis. The types of sounds that cause a negative reaction, the loudness of these sounds, explicit details of the actual negative effect and any coping mechanisms. Sometimes a diary recording symptoms and severity (on a scale of 1-10 for example) is useful, especially for longitudinal study. 

    The clinical history may provide some important clues about the aetiology of the decreased sound tolerance, such as exposure to loud noise or viral illnesses. It should be noted that anxiety, depression, concentration or sleep issues are frequently co-morbidities.

    A full ENT examination should be undertaken with otoscopy, tympanometry, audiology and vestibular assessment for balance/vertigo problems. Temporomandibular dysfunction should also be ruled out. Blood tests will be useful to screen for infections or endocrinological dysfunction. Brain MRI or temporal CT may be indicated. 

    While there is no clearly accepted 'consensus' method for the evaluation of decreased sound tolerance, some people advocate assessing loudness discomfort levels (LDLs) to provide a reasonable estimation of the problem. However, this may also have a detrimental effect on the subject with decreased sound tolerance and may make them anxious.

    If LDL’s are to be advocated, then the subject should be fully aware of testing procedure and if possible have full control over the maximal sound level to which they will be exposed.


    Historically, advice offered to those who insisted upon help was to 'use ear plugs,' or 'learn to live with it.' Even though the aetiology is largely unknown there are some options, however, misophonic/phonophobic components (See below for definition) are unlikely be removed by desensitization and a separate approach needs to be implemented.

    Subjects with hyperacusis often suffer from a lack of understanding from others as their condition is not visible and is subjective. Hyperacusis can have an impact on a subjects overall wellbeing and may affect sleep, concentration, work performance and life in general. Therefore, good communication with a clinician that can offer good explanation of the condition will reassure the patient that they have a recognised problem, this will help to alleviate some anxiety and reassure them that they are believed and understood.

    This will then encourage the subject to be more forthcoming with information regarding specific behaviours and emotions when exposed to their trigger noise. They may be more likely to express repressed anxieties. The physical occurrence of pain with noise exposure should be acknowledged, even though the condition may be maintained by anxiety. Assume that any noise which is seen to be aversive is also uncomfortable and work to break down the fear association.

Treatment Options:

    There are three main ways in which it was proposed to treat hyperacusis, two are diametrically opposed to each other and the other has limited clinical success in only specific subjects with tinnitus.

Sound Desensitisation

    The sound desensitisation approach has a more evidence-based success with the treatment of hyperacusis especially when used in conjunction with Cognitive Behaviour Therapy (CBT) and has similarities to Gradual Immersion Therapy. This approach encourages the sufferer to listen to barely audible noise for a set period of time each day. Over time the loudness of the sound exposure is gradually increased, in this way the tolerance to sound is built up and sensitivity to normal sounds should become no longer painful over time. It is important keep the sound signal carefully graded to be acceptable and under the control of the listener.

    The particular sounds that are chosen vary from clinic to clinic but may be broadband noise or environmental noises. The choice of noise will depend on if the subject is sensitive to specific noise (such as chalk on black board) or general noise (such as aircraft/crowd noise). The sound desensitisation protocol can take up to 12 to 18 months.

    As it seems that auditory over-sensitivity is increased with generalized stress and anxiety, it is important that anxiety issues are addressed in parallel to this process.

Hearing Protection

    Historically the most common approach was to advise patients to avoid sound and use hearing protection. This was based on reasoning that because patients became sensitive to sound this may indicate that they are more susceptible to sound exposure (not true) and consequently need extra protection.

    Sufferers embraced this philosophy and started to protect their ears, even to the extent of using ear plugs in quiet environments. Unfortunately, research has shown that this approach of continually attenuating the perception of sound through the use of earplugs results in making the auditory system even more sensitive to sound, an outcome known as a ‘threshold shift’. The result is that the hyperacusis is exacerbated rather than improving the functionality of the individual.

    With the advent of modern hearing protection there may be some merit in using filtered hearing protection to attenuate very loud noise and allow speech to be less attenuated however, there is no long term research to validate the usefulness of these types of hearing protection.

Pink Noise

    This method has only limited success with hyperacusis and is more useful in the treatment of subjects with reduced sound tolerance and tinnitus in the form of Tinnitus Retraining Therapy (TRT). This method involves assessing the LDL’s of the subject and then applying pink noise over a period of 6 months or so at varying loudness levels for periods of time, multiple times a day.

    The pink noise can be delivered by miniature sound generators that look similar to hearing aids and can be Behind-the-Ear or In-the-Canal. An alternative method would be to obtain the pink noise on a CD or via the internet (YouTube for example) and a set of headphones or earphones.

Other Options

    These days most hearing aid manufacturers have applications for mobile devices (iOS/Android) that facilitate tinnitus treatment that may benefit those with decreased sound tolerance issues.


Oticon Tinnitus Sound
Phonak Tinnitus Balance
Resound Tinnitus Relief
iOS Android
Beltone Tinnitus Calmer
iOS Android
Widex Zen - Tinnitus Management
iOS Android
Starkey Relax
iOS Android
Siemens Signia Counseling Suite
PC (Download)

    Other experimental treatments are available, including biofeedback, relaxation strategies, and acupuncture. It is important to research any hyperacusis management technique before beginning to use it. Treatments should be personalised to the individual. Medication is not generally a treatment for hyperacusis but may be a part of the treatment process, helping sufferers cope with the stress related to the disorder. Through future research, a better understanding of the underlying causes of hyperacusis will lead to new and better treatments.

Misophonia (Sometimes called Annoyance Hyperacusis)

    Means a ‘dislike of sound’, in misophonia subjects generally have a negative attitude to certain sounds that is unrelated to the volume. It is thought that the mechanisms of this reaction may be related to an enhancement of the functional links between the auditory and limbic systems or may be at the cognitive/subconscious level. Usually misophonia is distinguished by an individual who reacts strongly to soft sounds and is sometimes further affected by seeing the source of the offending sound. This reaction could be irritation, dislike or even induce some anxiety.

    Common examples of misophonia would include the sound of people eating, sniffing, repetitive sounds or certain repeated environmental sounds like a door rattling. There are many more examples of misophonia.

Phonophobia (Sometimes called Fear Hyperacusis)

    Meaning a literal fear of sound. This is also an adverse emotional response involving fear or anxiety in response to sound, again the volume of the sound is not necessarily a factor. With phonophobia the potency of the reaction is only partially related to the sound and is also dependent upon the subjects’ recollection of the previous negative experience of it. Phonophobia is thought to have more of a relationship with the cognitive and subconscious aspects of a subject. The fear/anxiety from sound can be experienced in real time or from the expected near future occurrence of the sound.

    Some examples of phonophobia would be gunshot, the sound of a potential threat or a sound that brought a negative experience previously such as bad news delivered over the telephone and a resultant fear/anxiousness of telephones ringing.

Hypersensitivity (of Certain Frequencies)

    The term hypersensitivity is used when an individual, who is usually born sound sensitive, is less tolerant to sounds but the sensitivity is only to specific frequencies at a typically loud level (above 70 dB) as opposed to hyperacusis. These subjects can usually tolerate most sounds at normal or even loud levels but have difficulty with a certain problem frequency or frequencies. These problem frequencies can be identified or narrowed down by audiometric testing or by careful questioning.
    Autistic children are good examples of this as they can tolerate sound at normal levels or even loud volumes but at some frequencies, the sound is difficult for them to tolerate. Some organisations advocate treatment with auditory integration therapy (AIT), however there is insufficient evidence to support its use.  AIT takes regular music and filters out the problem frequencies through a special machine called an audiokinetron (  Somehow, this therapy allegedly seems to 'retune' their ears and normalizes their hearing tolerances.  The music is listened to at decibel levels which can reach up to 90 decibels. 

Recruitment (Loudness)

    Loudness recruitment is usually related to cochlear impairment or damage with a resultant hearing loss. The term refers to the subjective perception of sounds becoming disproportionately louder with increasing sound level. So even though there is only a small increase in the noise levels, sound may seem much louder and it can distort and cause discomfort. This problem can arise over numerous frequencies or at a very few, usually high frequency ones due to the hearing loss caused by the cochlear damage.

    Although the exact mechanism behind recruitment is not fully understood, the theory behind this condition relates to hair cells within the cochlea that are adjacent to damaged hair cells and these are ‘recruited’ to respond (or hear) to the frequency the damaged hair cells were meant to respond to in addition to their own specific frequency. This results in ‘over stimulation’ of the working hair cells and the perceived sound processed in the brain is louder. Put another way the ‘recruited’ hair cells still function in their original critical frequency bands and also in the adjacent ones that they have been recruited into.

    This condition manifests commonly when people with cochlear hearing loss ask you to speak up as they cannot hear you and then complain that there is no need to shout.
Recruitment Image


    This where a person’s own voice is perceived to themselves as disproportionately loud, it is sometimes echoic or booming. This commonly caused by an unusually large or temporarily enlarged Eustachian tube so the sound of one’s voice travels directly into the middle ear.


    The simple definition of this term is dysfunction of hearing. This is more often related to a processing issue with a person’s inability to comprehend sound due to sound distortion in frequency or intensity. This condition is usually a symptom of hearing loss through aging or disease.

Usefull Links:

Copyright © 2018 by Lee Boswell                                Disclaimer