Auditory exclusion is a form of temporary loss of hearing occurring under high

stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...

. As such it is related to

tunnel vision Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision. Causes Tunnel vision can be caused by: Eyeglass users Eyeglass users experience tunnel vision t ...

and "the slowing of time in the mind". Auditory exclusion happens as a result of the physiological effects of the acute stress response, specifically an increased heart rate.

Link to "Fight or Flight" response

In times of high stress, caused by both visual and auditory triggers, a person's “fight or flight” response can be triggered as they descend into a state of hyper-arousal. This is an evolutionary response involving the

sympathetic nervous system The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of th ...

that is triggered as a reaction to a perceived threat to the individual's life to help increase the chances of survival. The

adrenal gland The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...

is alerted and as a result,

adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...

is released into the individual's bloodstream. This causes a number of physiological changes like increased heart rate, increased breathing and hyperfocus on the threat at hand. Additionally,

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in the adrenal gland ...

is released from the adrenal glands which can provide the body with more energy in the short term. Contrastingly, over longer periods of time cortisol can obstruct thought processes, especially in high-emotion environments.

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

scans have been used to investigate how the brain functions during decision making and which areas are responsible for processing different stimuli. From this we can identify areas of the brain linked to processing different senses. The

primary auditory cortex The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to ...

(the area of the brain predominantly responsible for processing auditory information) is in the superior temporal gyrus in the

temporal lobe The temporal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe ...

, whereas the

visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...

(responsible for the process of visual information) is an area of the cerebral cortex in the

occipital lobe The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head". The occipital lobe is the vi ...

. During this “Fight or flight” /acute stress response, both areas of the conscious brain can struggle to process this information at the same time. Consequently, perceptual distortions can occur (e.g. slow motion/ tunnel vision, disruption of hearing) As a part of this, the processing of auditory information can be stopped completely, causing temporary hearing loss. However, it is more common that the auditory cortex's functionality still remains but its efficiency is impaired. It has been reported that individuals can hear an unclear version of the noise around them, almost as if it is muffled. Others reported hearing a “hiss” or “ringing” noise, especially in combat situations.

Auditory exclusion in combat

Auditory exclusion can have a protective purpose too. In situations like combat, where the noise created by gunfire or explosions is loud enough to cause significant damage, an individuals hearing can be suppressed or muted to the point where they are unaware of the severity of the noise until afterwards. Consequently, minimising any damage to the individual's hearing In 2019, author Scott W. Wagner wrote about a personal experience with auditory exclusion, detailing how he was involved in a SWAT raid that required him to “take down” a dangerous subject. Upon firing a taser gun, Wagner was unable to hear the “pop” that is usually heard when it is fired in addition to not hearing the subject's wife screaming less than 20 feet away from him. During the fight or flight response, heart rate and breathing rate significantly increase as a result of the body requiring more energy to fuel a physical response to a stressful stimulus. An elevated heart rate can be used to partially explain the reason for auditory exclusion. With 30+ years in the fire service, Dr. Richard B. Gasaway (contributor to the Situational Awareness Matters campaign) referenced a study in which a participant's base-level hearing was measured using an audiometer. This hearing test continued as the participants exercised on a treadmill to emulate the elevated heart rate that would occur during the stress response. It was revealed that hearing ability began to decline once the heart rate increased over 175 bpm. This is due to the increased blood flow in the eardrums that creates noise, causing the individual to lose hearing of the surrounding environment. This can manifest as a hissing or ringing in the individual's ears which consequently blocks out the noise around them. However, intentionally/voluntarily raising your heart rate to this level through exercise may not cause auditory exclusion. This is because the increase is not due to rapid hormonal changes that trigger the stress response, instead it is a gradual increase in heart rate as a result of exercise, i.e., it does not "shock" the body in the same way we do when encountering stressful situations.

References

Deafness {{Law-enforcement-stub