Hyperacusis (HA) is an increased sensitivity to sound and a low tolerance for environmental noise.
It is categorized into four subtypes: loudness, pain, annoyance, and fear.
Hyperacusis can be a highly debilitating hearing disorder.
The most common being exposure to loud noise.
It is often coincident with tinnitus.
Proposed mechanisms for hyperacusis involve dysfunction in the brain, inner ear, or middle ear.
Little is known about the prevalence of hyperacusis.
Several people have died by suicide due to the severe consequences of the disease.
Symptoms of hyperacusis can include an increased perception of the loudness of sounds, pain (noxacusis), annoyance, and/or fear in response to sounds by which most people are not affected.
HA may affect one or both ears.
The majority of HA patients experience bilateral symptoms but often have one ear that is more affected than the other.
Hyperacusis can also be accompanied by tinnitus.
Hyperacusis can result in anxiety and stress, leading to avoidant behavior is to prevent the effects of hyperacusis and this can include avoiding social situations.
Loudness hyperacusis is associated by an increased perception of the loudness of sounds.
Hyperacusis is often associated with certain volumes and/or frequencies.
HA can occur in children and adults.
HA and can be short-term with a duration of weeks to less than a year before recovery, or, less commonly, span over years and in some cases become permanent.
Sensitivity is often different between ears.
Hyperacusis accompanied by pain is known as noxacusis.
Noxacusis is characterized by pain resulting from sounds, often initiated at certain volumes or frequencies.
Pain can be immediate or delayed, and it sometimes persists for an extended period of time following exposure.
Pain is often described as stabbing, burning, throbbing, or aching.
In healthy listeners, pain from sound is not typically experienced until the volume exceeds approximately 120 decibels.
The loudness discomfort level (LDL) is threshold of sound at which discomfort is initially experienced; measured in decibels (dB).
A setback is a temporary exacerbation of symptoms, with a worsening of the perception of loudness or pain from sound, often due to a particular noise exposure.
To avoid setbacks one uses hearing protection and avoids loud noises.
Pain hyperacusis patients experience setbacks more frequently than patients with loudness hyperacusis.
Conditions that are associated with hyperacusis include:
Acoustic shock
Adverse drug reaction
Anxiety
Asperger syndrome
Attention deficit hyperactivity disorder
Autism spectrum
Bell’s palsy
Depression
Endolymphatic hydrops
Fetal alcohol spectrum disorder
Hypothyroidism
Lyme disease
Migraine
Ménière’s disease
Multiple sclerosis
Noise-induced hearing loss
Posttraumatic stress disorder
Severe head trauma
Sjögren syndrome
Superior canal dehiscence syndrome (SCDS)
Systemic lupus erythematosus (SLE)
Tay–Sachs disease
Temporomandibular joint disorder
Tinnitus
Tonic tensor tympani syndrome
Trigeminal neuralgia
Visual snow
Williams syndrome
The most common cause of HA is overexposure to excessively high decibel sound pressure levels, which can cause acoustic trauma.
Such an acoustic shock can lead to symptoms such as hyperacusis and ear pain, but can also occur after exposure to an unexpected moderately loud to loud noise.
Hyperacusis suddenly can result from taking ototoxic drugs, Lyme disease, Ménière’s disease, head injury, or surgery.
Some people are born with sound sensitivity or develop superior canal dehiscence syndrome.
Bell’s palsy can trigger hyperacusis if the associated paralysis affects the tensor tympani, and stapedius, the two small muscles of the middle ear: stapedius muscle paralysis prevents its function in dampening the oscillations of the ossicles, causing sound to be abnormally loud.
Younger patients exhibiting more severe hyperacusis.
People with one copy of the GJB2 genetic mutation exhibit hearing that is more sensitive than average, and appear to be at greater risk for damage from noise.
Psychoactive drugs such as LSD, methaqualone, benzodiazepines, or phencyclidine can cause hyperacusis.
Ciprofloxacin is known to cause related hyperacusis, as is
Benzodiazepine withdrawal.
No gender differences have been established.
There may be maladaptation processes in the auditory brain that influence the dynamic range of neural responses by input from the inner ear.
This is mainly caused by hearing loss related damage in the inner ear and cochlea.
Noxacusis or pain hyperacusis:
Type II afferent fibers of the cochlear nerve are not responsible for hearing like the type I afferent fibers, but are thought to be cochlear pain neurons.
Gain of function of these type II afferent fibers may be caused by a hair cell damage and increased ATP.
Type II sensitization leads to reaction to the small amount of ATP released during the normal process of hearing: resulting in pain
Symptoms of noxacusis may be initiated by tensor tympani muscle damage or overload due to acoustic shock or trauma.
Hypercontraction or hyperactivity of the tensor tympani muscle may cause an ATP energy crisis, forcing the muscle is to create energy without sufficient oxygen, resulting in the release of lactic acid into the middle ear space, which can activate pain-sensing neurons.
Pain from sound sometimes radiates to the face, scalp, and neck, possibly due to the trigeminocervical complex in the brainstem, which integrates input from and output to various regions of the head and neck, including the middle ear.
The tensor tympani muscle is innervated by the trigeminal nerve, explaining how whiplash injuries, temporomandibular joint dysfunction, and other conditions affecting the head and neck regions may influence the function of the tensor tympani muscle and contribute to ear symptoms such as pain hyperacusis.
Diagnostic test is similar to a normal audiogramin: in addition to the hearing threshold at each test frequency, the lowest uncomfortable sound level is also measured.
This level is called loudness discomfort level (LDL) or uncomfortable loudness level (ULL).
With hyperacusis this level is often considerably lower than in normal subjects, and usually across most parts of the auditory spectrum.
There are currently no evidence-based guidelines regarding the treatment of patients with hyperacusis.
Prevention and reduction of pain symptoms are priorities among those with hyperacusis and noxacusis.
It is often managed by controlling the environment so as to avoid loud sounds, soundproofing, and wearing hearing protection, such as earplugs and safety earmuffs.
Diet may play a role in symptom management in some cases: responses to a migraine diet, low-histamine diet, or low sodium diet reported.
Tinnitus retraining therapy uses broadband noise to treat hyperacusis.: listening to broadband noise at soft levels for a disciplined period of time each day, some patients can rebuild tolerances to sound.
Patients with pain hyperacusis, however, are more likely than individuals with loudness hyperacusis to report worsening of their condition after the use of sound therapy.
Cognitive behavioral therapy has not been established as useful.
Surgery in patients with hyperacusis may improve after round and oval window reinforcement.
Suicide is a consideration in hypereracusis patients: a study found that 15.75% had expressed suicidal ideations in the previous two weeks.