Hyperacusis and acoustic shock

Hyperacusis is defined as an abnormal intolerance, heightened sense of volume and physical discomfort in response to certain sounds, which other people can tolerate comfortably.

Sounds that are typically difficult to tolerate are loud/impact/sustained sounds, particularly if they are unexpected or close to the ears.  Hyperacusis can develop due to a conscious and/or subconscious sense of threat that those sounds are potentially damaging or will aggravate pre-existing tinnitus.

In most people with hyperacusis, an increased, involuntary activity develops in the tensor tympani muscle in the middle ear as part of a protective and startle response towards sounds perceived as threatening.  This is called tonic tensor tympani syndrome (TTTS).  TTTS can trigger symptoms in and around the ear from changes in eardrum tension, alterations in middle ear ventilation and trigeminal nerve irritability without objectively measurable dysfunction or visible pathology.

Symptoms consistent with TTTS can include ear pain, a sensation of fullness/blockage in the ears, a fluttering sensation, distorted/muffled hearing and tinnitus, often with a clicking, rhythmic or buzzing quality.

Acoustic Shock

Acoustic shock is characterised by the involuntary development of symptoms consistent with TTTS after exposure to an unexpected loud sound (acoustic incident) perceived as particularly threatening or traumatic. Acoustic shock symptoms are often temporary.  For some, symptoms can persist, almost always in association with the development and escalation of hyperacusis.

Hyperacusis can therefore develop gradually or, in the case of acoustic shock, can develop suddenly in response to a specific acoustic incident.

Musicians with tinnitus and high levels of anxiety about the possibility of ongoing damage to their hearing are vulnerable to the development of hyperacusis and acoustic shock.  If symptoms consistent with TTTS develop or are aggravated by exposure to loud music or unexpected sounds near their ears, musicians can readily believe that their ears are no longer able to physically tolerate those sounds, or that those sounds are causing damage to their ears/hearing, and should be avoided. This can result in high levels of distress – their passion for music and their livelihood are potentially under threat.

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.

All musicians need to find a balance between using hearing protection appropriately and relaxed, joyful, uninhibited playing and listening to music.

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 can be mistaken for middle, inner ear or jaw pathology.

As TTTS develops from the way intolerable sound is perceived in the brain, using strategies aiming for hyperacusis desensitisation will reduce TTTS symptoms.

Desensitisation of TTTS symptoms can be achieved, but is often best found in the support of a care team. Audiologists can assist with hearing evaluations, hearing counselling and management plans, however, psychologists are often engaged to assist in reframing the underlying maladaptive and manage auditory hypervigilance.

If you think you are experiencing symptoms of the hyperacusis, acoustic shock, or TTTS, see your GP or local audiologist for support.  

By Myriam Westcott

Myriam Westcott is a Melbourne based audiologist specialising in evaluation, diagnosis and therapy for patients with tinnitus, hyperacusis, acoustic shock and misophonia.  She first began working with tinnitus and hyperacusis patients 20+ years ago.  Myriam is committed to the development of innovative approaches to hyperacusis therapy, carries out clinically based research, provides medico-legal opinions and regularly gives presentations/lectures on tinnitus, hyperacusis, acoustic shock and misophonia.

You can contact Myriam directly via email: myriam@dineenwestcottmoore.com.au, or her website: www.dineenwestcottmoore.com.au