Hyperacusis & misophonia

Hyperacusis is an abnormal intolerance, a heightened sense of volume and physical discomfort from ordinary, everyday sounds, which other people can tolerate well. Sounds that are typically difficult to tolerate are loud/impact/sustained sounds, particularly if they are unexpected or in close proximity. High frequency (pitch) sounds tend to be tolerated less well. Hyperacusis can be a consequence of a conscious and/or subconscious sense of threat that those sounds will exacerbate pre-existing aural symptoms such as tinnitus, hearing loss or are potentially damaging.

Misophonia is a strongly aversive response to certain specific sounds, irrespective of their volume and often made by other people. Sounds that are difficult to tolerate trigger high levels of annoyance, disgust and anger. These typically include: the sounds of other people eating / breathing / swallowing / sniffing etc, repetitive sounds (eg a pen tapping, keyboard tapping), neighbour’s music, dogs barking, noise from a nearby factory etc. Misophonia can develop when those sounds become perceived, at both a conscious and subconscious level, as an intolerable intrusion into one’s sense of personal space.

Hyperacusis and misophonia can range from mild to severe to extreme.

Avoidance of intolerable sounds can have a major impact on the lives of people with significant hyperacusis and misophonia, severely limiting their horizons and creating high levels of anxiety and distress.

People with hyperacusis and/or misophonia often feel the need to regularly and sometimes constantly monitor their auditory environment to anticipate and avoid intolerable sounds. Hypervigilance of the acoustic environment enhances the sense of threat from these sounds, and results in cognitive distraction and reduced concentration. In people with hyperacusis, frequent monitoring of the ear symptoms described above is common, and they may feel a need to protect their ears or sense of hearing from exposure to these sounds. In both conditions, they are likely to want to limit the high levels of emotional reaction they feel following exposure. Significant hyperacusis and misophonia can therefore be considered as "attention" disorders.

There is little understanding of hyperacusis and/or misophonia in the community. Hyperacusis, misophonia and any physical symptoms in and around the ear following exposure to intolerable sounds are involuntary and subjective. The unusual cluster of these symptoms is readily misunderstood or not believed. Explaining such an abnormal reaction to sound to other people, including at times health professionals, is difficult and clients with hyperacusis and/or misophonia often feel misunderstood, isolated or trivialised.

Westcott M et al. Tonic Tensor Tympani Syndrome in Tinnitus and Hyperacusis Patients: A Multi-Clinic Prevalence Study. Noise and Health Journal, Mar-Apr 2013, Volume 15, Issue 63 pp117-128

Acoustic shock and TTTS Guide for Medical Professionals

In the middle ear, the tensor tympani muscle and the stapedial muscle contract to tighten the middle ear bones (the ossicles) as a reaction to loud, potentially damaging sounds. This provides protection to the inner ear from these loud sounds.

In many people with tinnitus, particularly if they have developed hyperacusis, an increased, involuntary activity can develop in the tensor tympani muscle in the middle ear as part of a protective and startle response to some sounds. This lowered reflex threshold for tensor tympani contraction is activated by the perception/anticipation of sudden, unexpected, loud sound, and is called tonic tensor tympani syndrome (TTTS). This response can then generalise to other types of sound and to lower sound volume levels, resulting in the development as well as the potential escalation of hyperacusis. In some people with hyperacusis, it appears that the tensor tympani muscle can contract just by thinking about a loud sound.

TTTS typically does not develop in people with misophonia.

Following exposure to intolerable sounds, this heightened contraction of the tensor tympani muscle can:

• affect the opening of the Eustachian tube, which ventilates the middle ear cavity, and is normally closed but opens when we yawn or swallow
• tighten the ear drum
• stiffen the middle ear bones (ossicles)
• lead to irritability of the trigeminal nerve

As a result, TTTS can cause a range of symptoms in and around the ear(s). These include: pain, numbness and burning sensations in and around the ear; pain in the jaw joint and down the neck; the development of tinnitus or an increase in pre-existing tinnitus; a clicking / fluttering sensation in the ear; a sensation of blockage, fullness or frequent "popping" in the ear; unsteadiness; muffled hearing.

It is important for people with hyperacusis to accept and understand the neurophysiological basis of TTTS, which is responsible for many of the physical sensations experience in their ears after exposure to an intolerable sound.

It does not harm the ear to experience TTTS, and even though the TTTS symptoms can seem as if the ear is being damaged by some sounds, this is not the case. Moderate, everyday sounds are safe and do not harm the ear or cause a hearing loss.

TTTS-like symptoms may be due to middle or inner ear pathology, and medical investigation should be carried out to exclude this possibility. Conversely, TTTS symptoms in people with hyperacusis can be mistakenly diagnosed as due to middle/inner ear pathology or jaw joint dysfunction or temporomandibular disorder (TMD).

It is therefore important for people with tinnitus and hyperacusis who experience these symptoms to consult an Ear, Nose and Throat Specialist/TMD Specialist to ensure there is no underlying medical condition causing them.

As TTTS develops from the way intolerable sound is perceived in the brain, using strategies aiming for tinnitus habituation and hyperacusis desensitisation will help reduce TTTS symptoms. Individual guidance from a physiotherapist for relaxing the facial muscles in and around the ear, as well as identification and massage of any muscular trigger points in the shoulder and neck, can be of benefit.

We provide a unique, individualised program to assist you in achieving increased tolerance to everyday sound, utilising Ms Myriam Westcott's experience and research in hyperacusis and misophonia therapy.

A detailed description of the peripheral (the outer, middle and inner ear) and central (the brain) auditory pathway is essential to understand how hyperacusis and/or misophonia develops.

Our program involves:

• an evaluation of your hyperacusis and/or misophonia and its impact on you.
• providing a detailed understanding about the development of your hyperacusis and/or misophonia.
• a personalised explanation of the peripheral and central auditory system, including the neurophysiological basis of hyperacusis/misophonia and TTTS (if symptoms are present).
• a hyperacusis/misophonia therapy program.