Call us and get support from one of our advisors.
Get In Touch 0800 111 4471
Welcome to the comprehensive glossary of terms used in the hearing world. From terminology related to audiology and hearing conditions to hearing aids, this resource strives to offer in-depth explanations and insights.
An audiogram serves as a crucial component of your comprehensive hearing assessment, providing valuable insights into the health of your ears. Essentially, it functions as a visual depiction of your auditory perception, illustrating how your hearing sensitivity may deviate from the typical range across various frequencies. The audiogram plots your hearing threshold levels, which represent the minimum intensity at which sounds can be detected by the human ear.
Administered by your audiologist or audiometrist, the audiogram integrates results from a series of straightforward hearing evaluations conducted as part of your comprehensive assessment at Amplifon. For example, one assessment involves exposing you to sounds of varying frequencies through headphones, enabling precise measurement of your hearing capabilities across the entire auditory spectrum.
Additionally, you will undergo a speech audiometry test to assess your ability to understand and repeat spoken words at different volumes, thereby determining your sensitivity to soft speech sounds. Another evaluation focuses specifically on the cochlea, employing a bone conduction test where a small device is placed against the mastoid bone to directly transmit sound waves to the cochlea for assessment.
An audiometry is a diagnostic test designed to evaluate an individual's hearing abilities. This assessment encompasses various aspects and may consist of multiple examinations, all of which are non-invasive. To comprehensively assess hearing, three key components are examined:
A complete audiometry typically involves three distinct steps, each representing a different test:
This comprehensive assessment provides valuable insights into an individual's hearing abilities and aids in diagnosing potential issues. Additionally, it offers essential information to determine the most suitable hearing solutions in cases of hearing loss.
The auditory nerve, scientifically known as the vestibulocochlear nerve or statoacoustic nerve, is part of a pair of nerves within the skull, alongside twelve others. Specifically, it comprises the cochlear nerve, responsible for transmitting hearing-related information, and the vestibular nerve, responsible for transmitting balance-related information. The cochlear nerve is connected to the cochlea, while the vestibular nerve interacts with the vestibular system. Situated within the inner ear, the auditory nerve receives information and relays it to the brain.
The auditory nerve plays a crucial role in transmitting information about hearing and balance to the brain. In terms of hearing, it facilitates the transmission of sound waves collected by the pinna from the external environment, which are then transmitted through various biological mechanisms, including the external and middle ear, before reaching the inner ear. Here, mechanical impulses are converted into electrical impulses, enabling transfer through the cochlear nerve to the brain for interpretation. Similarly, for balance, information about body position and movement is generated through fluctuations in labyrinthine fluids within the vestibular system. These fluid movements are converted into impulses and transmitted to the brain via the vestibular nerve.
Two conditions are particularly associated with the auditory nerve:
Cholesteatoma is a cyst composed of skin tissue that forms in the middle ear, leading to various adverse effects, including:
It is a non-cancerous growth that develops as a complication of a persistent infection. Following this infection, cells from the outer ear migrate into the middle ear, often due to perforation of the eardrum, where they become encapsulated. This results in increased pressure in the area and the development of noticeable symptoms, which can worsen without appropriate treatment. Neglecting treatment may cause the cyst to enlarge further and lead to more severe consequences, such as:
The cochlea, a spiral-shaped structure resembling a snail's shell, resides within the inner ear and is connected to the temporal bone. Its distinctive form has earned it the colloquial nickname "snail" in the nomenclature of ear anatomy. Within this intricate structure lies the organ of Corti, the locus of hearing function. The cochlea interfaces with the middle ear through two membranous apertures, namely the oval window and the round window, which facilitate sound transmission and maintain pressure equilibrium across different ear compartments.
As the primary auditory component of the inner ear, the cochlea interacts with other structures responsible for regulating balance. Functionally, it serves to relay sound impulses from the eardrum to the auditory nerve. Within its intricate system of fluid-filled tubes bounded by membranes, sound vibrations undergo conversion into nerve impulses. This transformative process relies heavily on the involvement of hair cells and the organ of Corti. Sound transmission mechanics unfold as follows:
Disorders affecting the inner ear often manifest as balance-related issues, in addition to hearing impairment. However, certain conditions originating in the vestibular system, responsible for balance regulation, may also impact the cochlea and disrupt sound transmission, leading to hearing loss. Some such ailments include:
Hearing loss resulting from these conditions typically falls under perceptual or sensorineural deafness. Conversely, complications arising from middle ear conditions often result in conductive or transmission hearing loss. Treatment for these injuries often involves the use of osseointegrated implants to partially rectify cochlear dysfunction.
A cochlear implant represents an electronic solution for specific cases of hearing loss. While offering various functionalities, it is particularly suited to individuals with inner ear injuries. Conventional hearing aids may prove ineffective in such cases, as the impairment lies in sound processing. However, cochlear implants can substitute for inner ear function, facilitating hearing restoration. Unlike hearing aids, which amplify sound, cochlear implants transmit sound directly to the auditory nerve and subsequently to the brain.
These implants command a degree of reverence due to the necessity for surgical placement and the delicate technology involved. Nonetheless, they provide solutions for cases of hearing loss that remain unresolved by other means. Cochlear implants comprise two components: an external sound processor and an internal receiver inserted into the inner ear via a straightforward surgical procedure. The external processor, positioned behind the ear, captures sound and digitally encodes it before transmitting it to the internal device. Within the device, these signals are converted into electrical impulses that directly stimulate the auditory nerve. Consequently, the nerve relays these impulses to the brain, where they are interpreted as sound.
Adjusting to a cochlear implant entails some attention, particularly in terms of adapting to the restored hearing and caring for the device. While the implant enables a normal lifestyle, caution is advised in activities such as contact sports to avoid potential damage to the device.
Conductive hearing loss denotes the inability of sound signals to be transmitted effectively from the outer ear and middle ear to the inner ear, rendering sound perception challenging or impossible. Various factors can lead to this disruption of transmission, with some being temporary while others are permanent. One prevalent cause of conductive hearing loss is the accumulation of earwax and the formation of plugs, which typically have straightforward remedies. However, more severe underlying conditions include:
The decibel serves as the predominant unit for measuring sound intensity. While the bel, named in honour of Graham Bell, represents the fundamental unit, common usage across various fields has established the decibel (one-tenth of a bel) as the prevailing measure over time. Represented by the symbol dB, it's important to note that the decibel isn't an absolute value but rather expresses the relationship between two sound pressure levels. Therefore, it's considered a relative measure. Nonetheless, it aids in determining appropriate sound thresholds across different contexts. However, sound intensity isn't the sole factor influencing the impact on our auditory system; exposure duration also plays a crucial role in potential ear injuries.
The hearing threshold ranges from 0 to 25 dB for the quietest sounds audible to humans and up to 100 dB for sounds that shouldn't be endured for prolonged periods. Although 0 dB signifies the threshold of audible sounds, this limit can vary up to 25 dB without causing significant concern, depending on individuals and circumstances. A scale of common sounds might look something like this:
In addition to extremely loud noises, prolonged exposure to high-intensity sounds can lead to damage to the auditory system, particularly causing gradual hearing loss.
The tympanic membrane, commonly known as the eardrum, is a delicate, thin membrane positioned at the end of the ear canal. It serves as the boundary between the external ear and the middle ear, although formally situated within the latter. Apart from responding to sound wave vibrations, it seals off the tympanic cavity, safeguarding the transmission mechanisms within the middle ear from external intrusions. Without the eardrum, the remaining components of the ear, including its most sensitive elements, would be fully exposed, such as to the ingress of water.
Playing a pivotal role in sound transmission, the eardrum contributes to the intricate process of converting mechanical impulses from sound waves, collected by the pinna, into nervous impulses dispatched to the brain for interpretation. It serves as the initial point in the ear where this information is processed, as waves conducted through the ear canal induce vibrations in the membrane. From here, these movements progress through various organs until reaching the inner ear.
Eardrum-related ailments primarily involve perforation of the membrane or, in earlier stages, inflammation or any form of injury that does not result in rupture. The causes of these conditions vary and may include:
Symptoms of eardrum perforation include:
Earwax, commonly known as cerumen, is a fatty, serous substance resulting from the amalgamation of secretions from various glands situated in the outer ear. Typically, it exhibits a yellowish hue, although its shade, volume, and texture vary not only from person to person but also within the same individual at different times. These fluctuations in earwax appearance can offer insights into internal ear processes, ranging from blockages or infections to excessive moisture or dirt accumulation.
Earwax plays a crucial role in maintaining auditory health, although it often garners some aversion. Its functions are multifaceted:
The primary concern associated with earwax is the development of blockages. Contrary to popular belief, this isn't necessarily linked to poor hygiene; rather, it can stem from imprudent cleaning practices. For instance, using cotton swabs can inadvertently push earwax deeper into the canal, resulting in compaction and blockage. Consequently, it's advised to only remove visible earwax at the ear canal's entrance, refraining from probing deep into the ear.
Several indicators may signal the presence of a blockage:
In such instances, seeking assistance from a specialist is recommended, as attempting to remove plugs at home may exacerbate the issue. Typically, professionals can aid in dissolving or extracting the blockage as necessary, with minimal complications.
Endolymph and perilymph are referred to as labyrinthine fluids as they envelop the inner ear's labyrinthine region. These fluids occupy various channels within the cochlea and labyrinth, playing crucial roles in both auditory perception and balance regulation. Perilymph is categorized into two types based on its location within the cochlea—the scala vestibularis and the scala tympani—although they possess similar compositions despite originating differently. On the contrary, endolymph, generated from perilymph, is found in the membranous labyrinth, including the semicircular canals, utricle, saccule, and cochlea, with its volume regulated through absorption in the endolymphatic sac.
Both endolymph and perilymph serve indispensable functions in the inner ear, vital for hearing and balance, as they serve as the mediums in which hair cells immerse their filaments to gather crucial information from auditory and vestibular stimuli. These labyrinthine fluids are attributed with a dual role:
Diseases associated with endolymph and perilymph typically involve disorders related to labyrinthine fluids within the inner ear. Primarily, these include:
The Eustachian tube, measuring between 3.5 and 4 centimeters in length, serves as a passageway linking the nasal passages to the middle ear. Also referred to as the auditory tube, it possesses openings connecting to both the tympanic cavity and the nasal passages, with its surface coated by mucosa akin to that found in the nasal passages, creating a transitional zone.
Functionally, the Eustachian tube operates as a ventilation conduit, performing three vital roles:
Commonly, obstruction of the Eustachian tube arises from challenges in properly draining substances from the nasal passages. The leading causes of this dysfunction include:
Obstruction of the Eustachian tube predominantly occurs during childhood, contributing to recurrent ear infections. This susceptibility stems from anatomical factors; in children, the Eustachian tube is shorter, narrower, and less inclined, rendering it more prone to mucus accumulation during episodes of colds, congestion, or respiratory infections. Consequently, blockages may arise, with secretions potentially reaching the ear, leading to middle ear infections.
Exostosis, often referred to as surfer's ear, earns its colloquial name due to its association with prolonged engagement in water sports, particularly in chilly aquatic environments. Essentially, it entails an abnormal bone growth within the ear canal, which has a tendency to narrow it. Consequently, upon exiting the water, fluid may not entirely drain from the ear canal. Residual liquid can linger, becoming a breeding ground for bacteria and leading to recurrent ear infections in affected individuals.
In particularly severe instances, the constriction of the ear canal resulting from bone growth may impede the normal transmission of sound, potentially resulting in hearing impairment.
Excluding the auricle, or the visible part of the ear, the outer auditory canal stands as the most exterior segment of the ear, concealed from plain sight. Formally defined, it constitutes the passage extending from the ear's auricle to the eardrum, facilitating the transmission of sound gathered by the ear to the mechanisms responsible for interpretation and relay to the brain.
The outer auditory canal serves as the conduit for ushering sound into the auditory system. Positioned horizontally, its "S" shape enables a pathway that not only facilitates sound conduction but also safeguards the delicate eardrum membrane. This design ensures optimal reception and transmission of sound:
Common complications associated with the outer auditory canal encompass:
In technical terms, the frequency of a sound refers to the number of cycles of a sound wave occurring within one second, essentially denoting the wavelength of a sound. In everyday language, high frequencies correspond to high-pitched sounds, such as a screech or a whistle, while low-frequency sounds, like the noise of a bass drum or thunder, are classified as bass sounds. This aspect of sound is also termed pitch and is quantified in hertz (Hz). It constitutes one of the factors, alongside intensity or volume, that must be considered in assessing an individual's hearing capacity.
The human hearing threshold for frequency ranges from 20 Hz to 20,000 Hz. Frequencies below 20 Hz fall into the category of infrasound, which is inaudible to humans but perceptible by animals like moles or elephants. Similarly, sounds above 20,000 Hz are classified as ultrasound and are beyond the auditory range of the human ear; however, they are detectable by animals such as dogs and cats. At even higher frequencies, exceeding 40,000 Hz, they become audible to other animals like bats or dolphins.
Tiny, fragile cells located within the ears, hair cells are set into motion by fluid generated from vibrations of the eardrum and inner ear bones. This movement produces electrical signals that are conveyed to the brain for interpretation as sound.
Situated in the organ of Corti, hair cells are pivotal in detecting sound within the inner ear. They are categorised into two types: inner and outer, positioned differently and exhibiting varied reactions based on sound intensity. These cells derive their name from their appearance, featuring filament-like structures called cilia, which serve as mechanisms for capturing vibrations. Their primary function is to convert sound vibrations into electrical impulses for transmission to the brain, facilitating sound interpretation.
The distinct roles of the two types of hair cells in sound detection are as follows:
The degradation of hair cells leads to sensorineural or perceptual hearing loss. Humans possess a limited and relatively sparse quantity of these cells, with approximately 3,500 inner hair cells and 12,500 outer hair cells. Crucially, these cells do not naturally regenerate, rendering hearing loss irreversible when they sustain damage from exposure to intense sounds. The mechanism by which these cells capture sounds renders them susceptible to harm; the movement of cilia during sound conversion can be disrupted by excessively loud noises, leading to damage. Additionally, aging can affect the functionality of these cells' cilia. Efforts are currently underway to develop therapies for hair cell regeneration, although cochlear implants are also employed to address their deterioration.
The malleus, also known as the hammer, constitutes one of the three ossicles situated within the middle ear, playing a pivotal role in transmitting sound to the inner ear. Positioned closest to the eardrum, it receives the initial vibrations that traverse the ossicular chain. As the largest bone among the three, it forms a crucial link in this auditory mechanism.
The primary function of the malleus is to convey sound vibrations from the eardrum to the incus, initiating the transfer of impulses through the ossicular chain. However, its specific role cannot be isolated from the broader function of this chain in the auditory process. Sound wave-induced vibrations of the eardrum pass to the malleus, then to the incus, and subsequently to the stapes, which contacts the oval window membrane, setting in motion the fluid within the cochlea to transmit auditory information to the auditory nerve and onward to the brain. The position of the malleus in this intricate process underscores the complexity of the ossicular chain, bridging between a membrane (the eardrum) and a bone (the incus).
While the connections within the ossicular chain are intricate, diseases related to this structure are specific:
A hearing aid is an electronic device that is either inserted into the ear canal or worn behind the ear, designed to amplify or conduct sounds to enhance their perception for individuals experiencing hearing loss. Hearing aids represent the most common solution for hearing impairment, complemented by other devices like bone-anchored implants or cochlear implants to address varying hearing needs. They offer a relatively straightforward and immediate improvement in quality of life by restoring access to the auditory world, facilitating clearer hearing, improved communication, and fuller participation in daily activities.
Comprising three essential components—a microphone, an amplifier, and a speaker—hearing aids function by capturing environmental sounds, processing and adjusting them, and then delivering them into the ear. However, these devices are highly customizable, employing diverse technologies to cater to the specific requirements of individuals with different types of hearing loss and lifestyles.
The three predominant types of hearing aids are:
Each type addresses distinct needs and allows for varying levels of adaptation.
The anvil, or incus, forms a crucial part of the ossicular chain, which consists of three bones involved in sound transmission. Positioned between the malleus (hammer) and the stapes (stirrup), the incus serves as an intermediary for conducting sound vibrations. Unlike the other two components, it directly connects with both the hammer and the stirrup and does not touch any membrane. Housed within the tympanic cavity of the middle ear, it plays a vital role in sound conduction.
The primary function of the incus is to relay sound vibrations between the malleus and the stapes, contributing to the overall task of transmitting sound information through the middle ear to the inner ear. Sound wave-induced vibrations of the eardrum are transmitted to the malleus, then to the incus, and finally to the stapes, which contacts the oval window membrane. This vibration sets the cochlear fluid in motion, transmitting auditory information to the auditory nerve, which then sends impulses to the brain.
Despite the precise and delicate connections within the ossicular chain, diseases associated with this structure are specific:
The inner ear marks the culmination of the auditory system, overseeing both hearing and balance functions. Comprising two distinct components—the cochlea and the vestibular system—it channels auditory information and maintains equilibrium. Each component gives rise to a nerve: the cochlear nerve from the cochlea and the vestibular nerve from the vestibular system. These nerves converge to form the auditory nerve, facilitating the transmission of information to the brain. Dominated by the labyrinth, the inner ear is characterised by a network of tubes and ducts immersed in labyrinthine fluids and lined with hair cells. Essentially, all elements within the inner ear work in concert to convert mechanical stimuli—whether auditory or related to balance—into electrical impulses for brain interpretation. This process involves a sophisticated transformation of information.
In the case of hearing, for instance, sound waves, as mechanical stimuli, propagate through the ear's various components as vibrations. However, the nervous system operates on electrical impulses, necessitating translation. Consequently, within the cochlea, the fluids and hair cell mechanisms transmute these vibrations into electrical signals, enabling their conveyance via the auditory nerve to the brain. A similar process occurs with balance. In the vestibular system, bodily movements induce fluid undulations, which hair cells convert into electrical impulses. Upon reaching the brain, these impulses are interpreted as changes in body position or motion.
Numerous disorders stem from inner ear dysfunction, affecting hearing, balance, or both concurrently. Major ailments associated with the inner ear include:
The labyrinth constitutes the intricate network of tubes and ducts nestled within the inner ear. This elaborate structure comprises the anterior labyrinth, encompassing the cochlea responsible for auditory function, and the posterior labyrinth, housing the vestibular system, primarily comprising the semicircular canals, saccule, and utricle, which govern balance. Furthermore, a distinction is drawn between the bony labyrinth, the structural foundation supporting this framework, and the membranous labyrinth, which permeates the interior of the bony structure and sustains the labyrinth's biological activity.
Within the labyrinth dwell the two pivotal functions regulated in the inner ear:
In both instances, the interplay between labyrinthine fluids and the hair cells, which extend their filaments into the fluids, serves to regulate these functions. Diseases affecting the labyrinth can yield repercussions in hearing or balance. Often, given the convergence of both functions within the same space, conditions may influence both:
The mastoid bone or mastoid process is situated at the rear and beneath the pinna, or the outer part of the ear, just behind the ear canal, the passage that leads into the ear. It constitutes a bony projection of the temporal bone, one of the components of the skull, hence its designation. "Apophysis" denotes the projection of bones, while the "mastoid" refers to the lower portion of the temporal bone positioned approximately at the level of the earlobe.
Primarily, the mastoid bone serves as an attachment and stabilizing point for several crucial neck muscles, including the splenius and sternocleidomastoid. Although these muscles are vital for head movements, they do not directly influence hearing. Nonetheless, the proximity of the mastoid to the auditory system becomes apparent when certain complications arise.
Indeed, disorders associated with this bone can impact the auditory system, despite its non-participation in auditory functions:
In cases where bone infections necessitate surgical intervention, procedures typically approach the mastoid from behind the ear, potentially impacting the external auditory canal, especially during extraction.
An excess accumulation of endolymphatic fluid within the inner ear disrupts the proper functioning of the labyrinth, leading to both balance issues and hearing impairment. This condition, known as Ménière's Syndrome, lacks a definitive cause.
The labyrinthine system, responsible for maintaining balance, interprets sensations arising from the endolymphatic fluid present within it. However, when there is an uncontrolled increase in fluid volume, these functions are hindered, resulting in vertigo or dizziness. Additionally, since the inner ear processes sound stimuli, its dysfunction contributes to significant hearing loss.
The tympanic membrane, or eardrum, serves as the gateway to the middle ear in the pathway of sound transmission towards the inner ear. The majority of this intermediate section of the auditory system comprises the tympanic cavity, housing the chain of ossicles. This interconnected system of bones—comprising the malleus, incus, and stapes—plays a crucial role in sound conduction. Additionally, the middle ear houses the Eustachian tube, linking the ear to the nasal passages, facilitating ventilation of the auditory system and maintaining pressure balance within the ear.
The primary function of the middle ear is to transmit sound information from the external ear, where it is captured, to the inner ear, where it is processed. Acting as a transitional stage, the middle ear ensures the accurate conduction of this information.
The intricate connections within the ossicular chain facilitate this conduction process. Sound waves captured by the tympanic membrane cause vibrations, which are then relayed to the malleus, the initial bone in the ossicular chain. Subsequently, these vibrations travel to the incus and then to the stapes. The stapes transmits these movements to the oval window, providing access for information to enter the cochlea—an integral part of the inner ear where it undergoes processing.
However, these transfers of information rely on a delicate system of connections between the bones, necessitating specific conditions for adequate transmission. The Eustachian tube plays a vital role in maintaining the appropriate pressure within the tympanic cavity, ensuring the smooth transfer of vibrations through the elements of the ossicular chain by balancing pressure through its connection with the nasal passages.
Various diseases are associated with the middle ear, with otitis or infections being the most common. Other prevalent ailments include:
Misophonia is a neurological condition wherein certain everyday sounds become intolerable for some individuals, significantly impacting their daily functioning. Typically, those with misophonia experience intense aversion to particular noises, often those that are repetitive and follow a specific pattern.
This condition can sometimes be confused with hyperacusis or phonophobia, necessitating a clear understanding of the distinctions among these three disorders.
The Organ of Corti resides within the cochlea, the auditory component of the inner ear. It constitutes a complex structure wherein the transformation of sound stimuli from mechanical impulses, received from the environment, into electrical signals transmitted to the brain occurs.
This intricate process unfolds through the interplay of various components within the Organ of Corti, including its fundamental constituents: the 20,000 hair cells of two distinct types, labyrinthine fluids, the tectorial membrane, support cells, and nerve fibres, arranged to form channels and cavities. Notably, hair cells lack regenerative capacity; thus, their deterioration leads to irreversible loss of function.
The Organ of Corti undertakes the remarkable task of sound information conversion, translating vibrational input into electrical signals comprehensible to the brain. This transformation hinges on an exquisitely precise biological mechanism. Two distinct types of hair cells within the Organ of Corti respond to different frequencies, detecting minute movements through their filaments. Specifically, sound vibrations induce fluctuations in the labyrinthine fluids enveloping the Organ of Corti's ducts. The tectorial membrane, suspended within these fluids, oscillates in tandem with liquid variations. Hair cell filaments register these oscillations, with connected nerve fibres transmitting resulting electrical impulses.
Conditions linked to the Organ of Corti, often termed cortopathy, typically stem from hair cell deterioration, presenting challenges as these cells cannot regenerate. The inability to replenish hair cells introduces vulnerability to organ function, as malfunctions tend to be irreversible. Hair cell degeneration may arise from various factors:
An osseointegrated implant is an electronic device designed to address hearing loss stemming from issues in the external or middle ear. This device ensures the direct transmission of high-quality sound information to the cochlea, located within the inner ear, facilitating the processing of impulses and their transfer to the brain.
This form of hearing solution is particularly beneficial in cases involving perforated eardrums, completely blocked ear canals, or otosclerosis, which hampers the effective transmission of vibrations from the chain of ossicles to the inner ear. In such instances, where the outer ear components are impaired while the cochlea functions optimally, hearing loss results from the inability to transmit sound impulses.
Osseointegrated implants typically comprise three main components:
In this context, sound conduction occurs not via air but through bone conduction. Depending on individual cases and user requirements, this may involve direct contact with the skin or a small screw implanted into the bone itself.
The ossicular chain, comprising the hammer, anvil, and stirrup, is a trio of small bones situated within the middle ear, housed within the tympanic cavity. These are collectively known as the auditory ossicles and serve as the primary mechanism for transmitting sound impulses from the middle ear to the inner ear.
Measuring approximately 18 millimeters in length when connected, these ossicles constitute the shortest bones in the human body. Together, they form an essential conduit for the transmission of auditory information to the inner ear.
Upon the collection of sound impulses by the pinna and their conduction through the ear canal, the eardrum resonates with these waves. Subsequently, the responsibility for transmission shifts to the ossicles: the vibration of the eardrum is relayed to the hammer, which in turn transfers these movements to the anvil. Finally, the anvil conveys these vibrations to the stirrup. The stirrup, the final link in this chain, makes contact with the oval window membrane, generating vibrations that traverse the fluid-filled cochlea. From here, the auditory nerve carries these signals to the brain.
Despite the intricate and precise connections within the ossicular chain, conditions related to this structure are notably specific:
What's commonly termed as a general earache is scientifically referred to as otalgia. However, this term merely denotes the affliction without providing substantial insights into its origin or implications. While the source of the pain can typically be pinpointed, it distinguishes between:
Acute otitis media is a prevalent ailment among infants and children, particularly those aged between 0 and 7 years, although it can affect individuals beyond this age group. It constitutes an infection in the middle ear triggered by either a virus or bacteria. The heightened susceptibility to acute otitis media in early childhood is attributed to the maturation process of the Eustachian tube. During this period, the Eustachian tube is prone to obstruction, resulting in the accumulation of excess fluid in the middle ear and an increased vulnerability to infection.
Chronic otitis media, on the other hand, entails a persistent or recurring infection of the middle ear, distinguishing it from the acute form. While acute otitis media typically develops rapidly and resolves within two or three days, chronic otitis media persists over time or recurs intermittently. This chronicity gives rise to slightly different symptoms and, more significantly, may lead to more severe complications, particularly concerning the degree of hearing impairment.
Suppurative otitis media represents a specific manifestation of middle ear infection. This condition commonly arises as a complication of otitis media or due to Eustachian tube obstruction. A hallmark indication is the discharge of purulent fluid from the ear, often accompanied by a pronounced odour. Suppurative otitis media frequently occurs concurrently with eardrum perforation resulting from exacerbated otitis media.
Otomycosis denotes an infection that occurs in the skin lining the external auditory canal, representing a variant of otitis externa characterised by fungal involvement.
Certain environmental conditions, such as high humidity and elevated temperatures, create conducive environments for fungal growth. Failure to thoroughly dry the ear area after bathing can contribute to infection under these circumstances. Additionally, the insertion of foreign objects into the ear and prolonged antibiotic use, which weakens the body's innate defences, can facilitate fungal proliferation. Furthermore, individuals with certain dermatological conditions, including dermatitis, psoriasis, or eczema, are at an increased risk of developing otomycosis.
Otosclerosis refers to an anomalous bone growth occurring within the middle ear, which disrupts the proper transmission of sound vibrations through the ossicles, consequently leading to hearing impairment. While the exact cause of this condition remains uncertain, it is widely believed to have a hereditary basis in the majority of cases. Other potential factors have been suggested, including complications arising from certain infectious diseases or even physiological responses during pregnancy, though these instances are relatively rare.
Nevertheless, otosclerosis stands as the most prevalent cause of hearing loss among young adults. The abnormal bone growth typically encases the stapes, hindering its ability to respond to vibrations in the customary manner, thereby disrupting the transmission of auditory signals necessary for sound perception.
Ototoxic medications refer to drugs containing active ingredients capable of inducing hearing loss issues. Some of these medications may lead to temporary hearing difficulties, which typically resolve upon discontinuation of use. In such cases, hearing often fully recovers once the medications are ceased. Conversely, certain ototoxic drugs can instigate progressive hearing loss, resulting in irreversible damage to the inner ear. These medications commonly accelerate the degeneration of hair cells, thereby diminishing hearing capabilities. Moreover, the inability of these cells to regenerate complicates the recovery process.
Specific antibiotics and medications prescribed for the treatment of severe conditions such as certain cancers, cardiovascular disorders, or kidney diseases are among the drugs known to potentially cause hearing loss as a side effect. Children and the elderly are particularly vulnerable to experiencing such adverse effects.
The outer ear comprises primarily the auricle (or pinna) and the external auditory canal, culminating in the eardrum. Essentially, it constitutes the most superficial segment of the entire auditory system, housing the sole organ positioned externally—the auricle. This region of the ear benefits from protection via the secretion of cerumen (earwax), which not only moisturizes and lubricates the ear but also serves as a barrier against foreign particles like dust, bacteria, and other microorganisms that could potentially cause infections or more severe injuries.
Functionally, the external ear is tasked with capturing sound vibrations and initiating their initial transmission to the internal ear structures. Specifically, the auricle's role is to intercept environmental sounds. Engineered to enhance the reception of sound stimuli, the auricle operates akin to a parabolic antenna, adeptly gathering a broad spectrum of sounds and funneling them towards the ear canal. Meanwhile, the anatomical configuration of the ear canal facilitates the effective amplification of captured sound waves before they reach the tympanic membrane, ensuring optimal quality of environmental sound information.
Common afflictions directly associated with the outer ear and frequently encountered include:
Additionally, various anomalies or insufficient development of outer ear components, such as microtia (partial or complete absence of the auricle) or atresia auris (abnormal closure of the ear canal), may also manifest
The oval window is one of the cochlea's membranes. Here, it serves as the entry point for transmitting sound information to the organ responsible for converting it into electrical signals. Positioned adjacent to the oval window's outer surface, the stirrup transfers vibrations that have traversed the ossicular chain. On the opposite side of this membrane lies the cochlear fluid, which resonates with the transmitted vibrations.
An interesting feature of the oval window is its role in changing the medium through which sound impulses travel. While vibrations propagate through an air medium until reaching the stapes, they transition to a liquid medium beyond the oval window. Moreover, the oval window's surface area is notably smaller than that of the eardrum, resulting in transmitted vibrations exerting greater force on the oval window
The oval window represents another stage in the transmission of sound impulses through the auditory system, bearing distinctive characteristics:
While specific ailments of the oval window are uncommonly identified, diseases affecting the middle ear and, more specifically, the ossicular chain may potentially impact this membrane. This susceptibility arises from its direct contact with the stapes, where any variations or deviations in this bone could affect its function, as well as its role in forming the boundaries of the tympanic cavity.
Tympanic membrane perforation refers to a tear or hole in the eardrum, often resulting from an infection in the middle ear where accumulated fluids exert pressure until the eardrum ruptures. Alternatively, it can occur due to trauma, such as the insertion of a foreign object, a forceful impact, exposure to extremely loud noises like explosions, or a sudden change in pressure affecting both sides of the membrane.
This injury, typically accompanied by pain, leads to disruptions in the auditory system. The eardrum acts like a drumhead, vibrating in response to sound waves. However, when it sustains any form of damage, these vibrations no longer accurately correspond to sound stimuli due to the lack of necessary tension in the membrane.
Perichondritis is an infection of the tissue enveloping the ear cartilage. It is typically classified as otitis externa since it affects the pinna, a component of the outer ear. Common triggers for these infections include:
Additionally, individuals with compromised immune systems, inflammatory disorders, or diabetes may also be susceptible to such infections.
Peripheral vertigo refers to the sensation of movement experienced by individuals afflicted with it or their surroundings. Often, sufferers perceive themselves spinning, the room in motion, or the ground tilting, despite none of these scenarios being real. Vertigo is intricately linked to the vestibular system, which governs balance and resides within the inner ear. Specifically, peripheral vertigo occurs when the labyrinth or vestibular nerve is affected. Dizziness, on the other hand, may stem from various other causes.
Peripheral vertigo may manifest in the form of intense, relatively brief episodes known as crises, which can be highly debilitating. In reality, peripheral vertigo commonly indicates underlying conditions, often occurring alongside ailments such as:
Phonophobia is not precisely a disorder of the auditory system, but rather has a psychological or behavioural aspect. It entails an irrational dread of loud or abrupt noises, thus not stemming from any malfunction of the auditory system.
Phonophobia should not be conflated with the startle response typically induced by a loud noise or an unexpected sound, like a horn, for instance; nor with heightened sensitivity to sounds (hyperacusis). In this instance, individuals afflicted with phonophobia live in constant fear of encountering sounds that trigger panic, hence classifying it as a phobia. Consequently, patients may develop apprehension towards common sources of loud or sudden noises, ranging from public announcement systems to traffic congestion, alarms, or loudspeakers. These anxieties can significantly influence the behaviour and lifestyle of those affected.
The auricle, commonly known as the pinna or ear, constitutes the outermost component of the auditory system, being the sole part visible to the naked eye and exposed to the external environment. It comprises a cartilaginous structure enveloped in skin, possessing an oval contour adorned with prominences that spiral directionally, facilitating the reception and guidance of a broad range of sound waves into the inner recesses of the auditory system via the external auditory canal. Together with the ear canal, the pinna forms the external ear. Despite the seemingly random grooves, protuberances, and indentations on its surface, distinct regions can be discerned, each serving specific functions in sound capture.
Primarily, the pinna functions as a sound receptor, akin to the antenna of the human body. It serves as the initial point of contact for sound information emanating from the surrounding environment, directing it inward into the auditory system. Sound waves are intercepted by the protrusions of the pinna and channelled towards the ear canal, courtesy of its helical design. Consequently, the pinna enables the capture of a broader spectrum of auditory information compared to direct entry into the ear canal.
Malformations and dermatological conditions constitute the two primary categories of pinna-related disorders:
Presbycusis manifests when an individual undergoes a gradual decline in their auditory acuity, typically attributed to the natural ageing process affecting the auditory system. While advancing age stands as the primary cause of this progressive hearing impairment, degeneration within the auditory system may also stem from various other factors, including:
The semicircular canals, also known as ducts, are three curved tube-shaped structures situated within the inner ear. As integral components of the vestibular system, these canals contribute to balance function. Comprising bony constructions with membranous formations, the canals contain fluids and are lined with hair cells, facilitating the collection and transmission of position and movement-related information.
Essential to balance regulation, the semicircular canals serve a pivotal role within the vestibular system. Specifically, they maintain balance during bodily movement, complementing the functions of other vestibular organs such as the urticulum and the saccule, which operate during rest. Fluid within the canals conveys spatial information, which hair cell filaments detect and convert into nerve impulses for transmission to the brain. Each canal, owing to its unique shape and orientation, transmits distinct information concerning planes of movement. Consequently, through interpretation of this data, the brain establishes the body's total position and movement to regulate balance.
In addition to congenital malformations or trauma-related consequences, several diseases are associated with the semicircular canals. Common examples include:
Sign language consists of a communication system comprising gestures and visual expressions governed by its complete grammar. It is predominantly used by individuals with certain sensory limitations, particularly in hearing or speech, although it is also employed by others who, for various reasons, do not possess proficiency in oral language.
Sign language is not a universal language; instead, it is prevalent within multiple linguistic communities. There is no direct equivalence with national territories, nor does it have a direct relationship with spoken languages, as different sign languages have naturally developed within distinct linguistic communities. In addition to gestures and visual expressions, sign language incorporates specific movements of the face, lips, or tongue, contributing to its comprehensive grammar.
A variant of sign language has been developed specifically for communication with deafblind individuals, where gestures are tactile and performed on the palm of the hand. In this case, symbols and signs are created directly on the palm, known as fingerprinting.
It's one of the three ossicles in the auditory chain responsible for sound transmission. This bone is notably small, being the tiniest bone in the human body, measuring less than 3 millimeters. Located within the middle ear, its name derives from its shape resembling a stirrup, akin to the stapes of a saddle. Also referred to as the stapedium, it serves as the final link in the ossicular chain for sound transmission. It connects to the incus on one end and to the oval window, which grants access to the cochlea, on the other.
The stapes plays a crucial role in transmitting sound information through a series of bone and membrane connections. Sound wave-induced vibrations of the eardrum pass to the malleus, then to the incus, and finally to the stapes, which presses against the membrane of the oval window. This action sets the cochlear fluid in motion, transmitting auditory information through the inner ear to the auditory nerve, which then relays impulses to the brain. This cascade effect ensures the mechanical transmission of sound from one component to another, optimizing information conveyance while safeguarding the integrity of the organs involved. Encased within the tympanic cavity, the stapes is shielded by the eardrum and its design enhances sound amplification.
Despite the precision and delicacy of the connections within the ossicular chain, diseases affecting this structure are specific, including:
Tinnitus, or ringing in the ears, refers to the sensation of noise without any discernible external source. It stems from the continued presence of sound despite cochlear inactivity, the mechanism responsible for detecting external sounds.
This condition can lead to:
One prevalent complication of tinnitus is its interference with falling asleep and subsequently resting, which can heighten irritability and disrupt the individual's ability to focus on daily tasks. Consequently, the severity of this condition can significantly impact the patient's overall well-being.
The vestibule constitutes a segment of the osseous labyrinth situated within the inner ear. It encompasses the cochlea, which facilitates hearing, alongside the semicircular canals and the vestibule itself, responsible for balance regulation. Together, these latter components comprise the vestibular system. Within the vestibule reside two membranous labyrinthine cavities—the saccule and the utricle—containing endolymph. Additionally, the vestibule connects to the semicircular canals via ampullae.
Playing a pivotal role in balance regulation, the vestibule functions as a vital component of the inner ear's vestibular system. This system governs balance control, with the semicircular canals sensing body position and movement during motion, while the vestibule assumes this role during periods of rest. Through stimuli generated within the endolymph-filled saccule and utricle, the brain receives pertinent information regarding body orientation.
Several disorders commonly associated with the vestibule include:
Earwax accumulations, or wax plugs, occur when this substance builds up in the ear, leading to hearing difficulties. In truth, earwax comprises a blend of secretions from various glands in the outer ear and serves a crucial protective role. It moisturises and lubricates the ear, prevents moisture or water-induced irritation, traps dust or other particles, shielding the ear from potential problems, and safeguards against bacterial and microbial invasion.
The ear canal naturally expels excess earwax periodically, which can be easily removed through superficial cleaning. However, certain circumstances may impede this expulsion, resulting in the accumulation of hardened earwax, combined with dust, debris, or skin remnants, forming a plug that obstructs normal sound transmission through the canal.
With over 100 Amplifon clinics in the UK, we offer free tests and expert advice from our audiologists
This comprehensive glossary delves into key topics essential for understanding and navigating the complexities of hearing health. From the latest innovations in hearing aid technology to the importance of regular hearing tests, our glossary offers thorough coverage. Discover terminology related to common ear diseases, learn about maintaning optimal hearing health, and understand why it's important to use hearing protection in various situations. Whether you're looking for explanations on cochlear implants, audiograms, tinnitus, or simply wish to deepen your knowledge of auditory perception, our glossary is the ultimate resource.
