Acoustic shock is the set of symptoms a person may experience after hearing an unexpected, loud sound. The loud sound, called an acoustic incident, can be caused by feedback oscillation, fax tones, or signalling tones. Telemarketers and call centre employees are thought to be most at risk. [1]
During the exposure, most people experience discomfort and pain. After the exposure, some people might report shock, nausea and anxiety or depression. [2] Headache, fatigue, hypersensitivity to loud noise and tinnitus may continue for days, weeks or indefinitely. [3] It has not been established how such unrelated symptoms might be caused by an acoustic exposure, or whether such symptoms are even a direct result of exposure. [4] There is literature that suggests acoustic shock is not a pathological entity but predominantly psychogenic. [5]
It has been suggested that the tensor tympani is involved in causing the disorder (see tonic tensor tympani syndrome). [6] [7] In France, researchers report the study of a case of acoustic shock in a scientific publication. They suggest that these symptoms may result from a loop involving the middle ear muscles, peripheral inflammatory processes, activation and sensitization of the trigeminal nerve, the autonomic nervous system, and central feedbacks. [8]
There are many methods of attempting to reduce the risk of AS. Several devices attempt to remove potentially harmful sound signals by digital signal processing. None has yet been shown to be fully effective. Devices which solely limit noise levels to about 85 dB have been shown in field trials to be ineffective (data from these trials has not been released into the public domain). Limiting background noise and office stress may also reduce the chance of an acoustic shock. Proper use of the headset and preventing mobile phones from being used in call centers reduces the chance of feedback. [3]
84 BT employees with depression, headaches and other health problems demanded compensation for injury sustained from acoustic shock at work. BT has already paid £90,000 to one worker who had tinnitus. [9]
In March 2018, a musician won a claim for damages against the British Royal Opera House for acoustic shock caused by excessive noise during orchestral rehearsals. [10]
Tinnitus is a variety of sound that is heard when no corresponding external sound is present. Nearly everyone experiences faint "normal tinnitus" in a completely quiet room; but it is of concern only if it is bothersome, interferes with normal hearing, or is associated with other problems. The word tinnitus comes from the Latin tinnire, "to ring". In some people, it interferes with concentration, and can be associated with anxiety and depression.
Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earphones or, colloquially, cans. Circumaural and supra-aural headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone.
A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers such as personal sound amplification products (PSAPs) or other plain sound reinforcing systems cannot be sold as "hearing aids".
The acoustic reflex is an involuntary muscle contraction that occurs in the middle ear in response to loud sound stimuli or when the person starts to vocalize.
Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ or the vestibulocochlear nerve. SNHL accounts for about 90% of reported hearing loss. SNHL is usually permanent and can be mild, moderate, severe, profound, or total. Various other descriptors can be used depending on the shape of the audiogram, such as high frequency, low frequency, U-shaped, notched, peaked, or flat.
Indometacin, also known as indomethacin, is a nonsteroidal anti-inflammatory drug (NSAID) commonly used as a prescription medication to reduce fever, pain, stiffness, and swelling from inflammation. It works by inhibiting the production of prostaglandins, endogenous signaling molecules known to cause these symptoms. It does this by inhibiting cyclooxygenase, an enzyme that catalyzes the production of prostaglandins.
Hyperacusis is the increased sensitivity to sound and a low tolerance for environmental noise. Definitions of hyperacusis can vary significantly; it can refer to normal noises being perceived as: loud, annoying, painful, fear-inducing, or a combination of those, and is often categorized into four subtypes: loudness, pain, annoyance, and fear.
Acute stress disorder is a psychological response to a terrifying, traumatic or surprising experience. It may bring about delayed stress reactions if not correctly addressed. Acute stress may present in reactions which include but are not limited to: intrusive or dissociative symptoms, and reactivity symptoms such as avoidance or arousal. Reactions may be exhibited for days or weeks post the traumatic event.
Presbycusis, or age-related hearing loss, is the cumulative effect of aging on hearing. It is a progressive and irreversible bilateral symmetrical age-related sensorineural hearing loss resulting from degeneration of the cochlea or associated structures of the inner ear or auditory nerves. The hearing loss is most marked at higher frequencies. Hearing loss that accumulates with age but is caused by factors other than normal aging is not presbycusis, although differentiating the individual effects of distinct causes of hearing loss can be difficult.
Tinnitus retraining therapy (TRT) is a form of habituation therapy designed to help people who experience tinnitus—a ringing, buzzing, hissing, or other sound heard when no external sound source is present. Two key components of TRT directly follow from the neurophysiological model of tinnitus: Directive counseling aims to help the sufferer reclassify tinnitus to a category of neutral signals, and sound therapy weakens tinnitus-related neuronal activity.
The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunder. Because its reaction time is not fast enough, the muscle cannot protect against hearing damage caused by sudden loud sounds, like explosions or gunshots.
Sidetone is audible feedback to someone speaking or otherwise producing sound as an indication of active transmission. Sidetone is introduced by some communications circuits and anti-sidetone circuitry is used to control its level.
Noise health effects are the physical and psychological health consequences of regular exposure to consistent elevated sound levels. Noise from traffic, in particular, is considered by the World Health Organization to be one of the worst environmental stressors for humans, second only to air pollution. Elevated workplace or environmental noise can cause hearing impairment, tinnitus, hypertension, ischemic heart disease, annoyance, and sleep disturbance. Changes in the immune system and birth defects have been also attributed to noise exposure.
Noise-induced hearing loss (NIHL) is a hearing impairment resulting from exposure to loud sound. People may have a loss of perception of a narrow range of frequencies or impaired perception of sound including sensitivity to sound or ringing in the ears. When exposure to hazards such as noise occur at work and is associated with hearing loss, it is referred to as occupational hearing loss.
Geniculate ganglionitis or geniculate neuralgia (GN), also called nervus intermedius neuralgia, Ramsay Hunt syndrome, or Hunt's neuralgia, is a rare disorder characterized by severe paroxysmal neuralgic pain deep in the ear, that may spread to the ear canal, outer ear, mastoid or eye regions. GN may also occur in combination with trigeminal or glossopharyngeal neuralgia.
The semicircular canal dehiscence (SCD) is a category of rare neurotological diseases/disorders affecting the inner ears, which gathers the superior SCD, lateral SCD and posterior SCD. These SCDs induce SCD syndromes (SCDSs), which define specific sets of hearing and balance symptoms. This entry mainly deals with the superior SCDS.
Tinnitus maskers are a range of devices based on simple white noise machines used to add natural or artificial sound into a tinnitus sufferer's environment in order to mask or cover up the ringing. The noise is supplied by a sound generator, which may reside in or above the ear or be placed on a table or elsewhere in the environment. The noise is usually white noise or music, but in some cases, it may be patterned sound or specially tailored sound based on the characteristics of the person's tinnitus.
Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing is a rare headache disorder that belongs to the group of headaches called trigeminal autonomic cephalalgia (TACs). Symptoms include excruciating burning, stabbing, or electrical headaches mainly near the eye and typically these sensations are only on one side of the body. The headache attacks are typically accompanied by cranial autonomic signs that are unique to SUNCT. Each attack can last from five seconds to six minutes and may occur up to 200 times daily.
Acoustic trauma is the sustainment of an injury to the eardrum as a result of a very loud noise. Its scope usually covers loud noises with a short duration, such as an explosion, gunshot or a burst of loud shouting. Quieter sounds that are concentrated in a narrow frequency may also cause damage to specific frequency receptors. The range of severity can vary from pain to hearing loss.
Tonic tensor tympani syndrome is a disease of the tensor tympani muscle, described by Klochoff et al in 1971. It involves a decrease in the contraction threshold of the tensor tympani. This hypercontraction leads to chronic ear pain, in particular in the case of hyperacusis and acoustic shock.