Pediatric audiology is the discipline that deals with acoustic care and hearing aid fitting for children. It takes into account age-specific characteristics such as ear canal anatomy, growing ear molds, and childhood hearing loss profiles. Diagnostic procedures are designed to be playful, such as child-friendly audiometry or otoacoustic emissions as screening tools. Hearing aid programs are preset to suit children before fine adjustments are made in everyday life. Close cooperation with educators, parents, and early intervention specialists ensures optimal language development and participation in social life.

Pediatric audiology encompasses the diagnosis, treatment, and care of hearing disorders in infants, children, and adolescents. It relies on objective testing methods such as OAE screening and AEP measurements, as young children often do not respond reliably to standard audiometry. From preschool age onwards, playful hearing tests are used to determine hearing thresholds and speech comprehension in an age-appropriate manner. Pediatric audiologists fit hearing aids, accompany speech and language therapy, and monitor developmental milestones. An interdisciplinary team including ENT doctors, speech therapists, and teachers ensures holistic support.

The spiral papilla, also known as the organ of Corti, is located on the basilar membrane in the cochlea and is the actual sound perception organ. It consists of inner and outer hair cells, supporting cells, and a gelatinous membrane above the stereocilia. Sound-induced traveling waves in the basilar membrane bend the stereocilia, triggering mechano-electrical transduction. The inner hair cells encode sound information, while the outer hair cells act as active amplifiers. Damage to the spiral papilla leads to sensorineural hearing loss and impairs frequency resolution.

In partial tone audiometry, the hearing threshold is determined using continuous tones, which the patient signals by pressing a button. Unlike impulse audiometry, the tester gradually scans through different frequencies and levels to draw a precise threshold curve. The procedure is suitable for detailed diagnostics, for example, in cases of suspected cochlear nonlinearities or hidden hearing loss. It detects adaptation and fatigue effects of the auditory system. Modern audiometers support automated partial tone protocols for consistent results.

A pathological hearing threshold is present when the determined hearing threshold per frequency deviates from the standard values by more than 20 dB HL over the long term. It indicates the presence of hearing loss and determines its degree (mild, moderate, severe). Pathological thresholds can develop gradually (age, noise) or acutely (acoustic trauma, sudden hearing loss). Conductive and sensorineural loss are differentiated by comparing air and bone conduction thresholds. Follow-up checks show progression or therapy effects and guide treatment decisions.

The tympanic cavity (cavitas tympani) is the air-filled space in the middle ear that encloses the eardrum, ossicular chain, and oval and round windows. It connects to the nasopharynx via the Eustachian tube and serves to equalize pressure. Pathologies such as effusion (otitis media with effusion) lead to increased pressure and sound conduction disorders. Tympanometry measures the compliance of the tympanic cavity and provides information on the ventilation status and middle ear pressure. Surgical access is often gained via the posterior auditory canal for direct intervention in the tympanic cavity.

Eardrum tubes are small plastic or metal cannulas that are anchored in the eardrum to ensure permanent ventilation of the tympanic cavity. They are indicated for recurrent otitis media effusions, tube dysfunction, or risk of cholesteatoma. They enable pressure equalization, secretion drainage, and reduce middle ear infections. The tubes are inserted on an outpatient basis under local anesthesia and usually fall out spontaneously after 6–12 months. Follow-up examinations ensure that the eardrum is closed and hearing function is restored.

Auditory perception encompasses all processes from sound reception to conscious interpretation in the brain. It includes detection, discrimination, recognition, and localization of sound sources. Psychophysical methods measure perception using threshold and discrimination tests, while neurophysiological methods record evoked potentials. Disorders of auditory perception can occur despite normal peripheral function (e.g., central auditory processing disorder). Hearing training and cognitive interventions aim to rehabilitate perception abilities.

Perilymph is the sodium-rich fluid in the scala vestibuli and scala tympani of the cochlea, which conducts mechanical vibrations in the cochlea and enables pressure equalization. It surrounds the membranous canals with the endolymph and forms an electrochemical insulation. Injuries to the basilar membrane can cause perilymph fistula, leading to vertigo and hearing loss. Perilymph pressure fluctuations are indirectly detected during electrocochleography testing. Research is investigating perilymph biomarkers as indicators of hearing damage.

Peritubalitis is an inflammation of the tissue surrounding the Eustachian tube, often as a result of chronic rhinopharyngitis or tubal catarrh. It leads to edema formation, tubal stenosis, and middle ear pressure effusions. Patients complain of pressure, hearing loss, and recurrent otitis media. Diagnosis is made through tube function tests, endoscopic inspection, and tympanometry. Treatment includes anti-inflammatory nasal drops, tube dilation, and, if necessary, ear tubes.

Perceptive hearing loss (sensorineural hearing loss) is caused by damage to the hair cells in the cochlea or the auditory nerve fibers. It shows up on the audiogram as equally high air and bone conduction thresholds and cannot be corrected surgically. Causes include noise trauma, aging, genetic defects, or ototoxins. Those affected complain of reduced speech comprehension, especially in noisy environments, and benefit from hearing aids or cochlear implants. Rehabilitation measures also include auditory training to strengthen central processing mechanisms.

Ringing in the ears is a form of tinnitus in which sufferers perceive a high-frequency, tonal noise. It can occur in one or both ears and varies in volume and frequency. Causes range from noise damage and otosclerosis to changes in the central auditory pathway. Diagnostics include distortion factor audiometry, OAE, and tinnitus screening to determine frequency and level. Treatment approaches include sound enrichment with noise generators, cognitive behavioral therapy, and, if indicated, medication.

The pharyngotympanic tube connects the middle ear to the nasopharynx and enables pressure equalization and ventilation. It opens when swallowing or yawning and otherwise prevents the backflow of secretions into the middle ear. Dysfunctions lead to tube catarrh, middle ear effusion, and hearing loss. Functional tests such as tube function testing and tympanometry assess its ability to open. Balloon dilation and ear tubes are used therapeutically to prevent long-term complications.

The phonatory reflex refers to the involuntary adjustment of voice volume and pitch to the perceived volume of one's own voice. When speaking in a noisy environment, people automatically increase their volume (Lombard effect) to ensure speech intelligibility. This reflex is controlled by auditory feedback loops in the brain. Hearing loss disrupts the phonatory reflex, resulting in changes in voice level and articulation. Speech therapy can retrain the reflex function and improve speech intelligibility.

A phoneme is the smallest meaningful unit of sound in a language, e.g., /p/ vs. /b/ in English. Phonemes are encoded in the auditory system as specific frequency and time patterns and retrieved from the linguistic lexicon. In audiometry and speech therapy, phoneme tests are used to assess articulation and perception abilities. Hearing aid programs often emphasize phoneme-relevant frequency bands to optimize speech comprehension. Misperceptions of individual phonemes are typical in cases of high-frequency hearing loss or central processing disorders.

Phonosurgery encompasses microsurgical procedures on the ear that are intended to improve hearing or alleviate tinnitus, such as stapedotomy, myringoplasty, or implant placement. The aim is to reconstruct the ossicular chain, eardrum, or direct auditory nerve stimulation. Precision and preservation of residual hearing are paramount, often supported by intraoperative monitoring. Postoperative audiometry and tympanometry document the success of the procedure. Innovations such as endoscopic techniques reduce tissue trauma and rehabilitation time.

Phonotypy refers to individual physiological conditions and motor patterns of sound formation, i.e., how speakers articulate phonemes. It includes lip, tongue, and jaw movements as well as glottis shape. Hearing loss often causes unconscious changes in phonotypy, leading to unclear pronunciation. Speech therapy analyzes phonotypy and provides targeted training in articulation patterns. Video and biofeedback improve awareness of sound formation processes.

The pinna is the visible outer ear made of elastic cartilage that captures sound waves and directs them into the ear via the ear canal. Its complex folds create frequency-dependent filter effects that help locate sound sources in the vertical plane. Variations in the shape of the pinna result in individual HRTFs and influence spatial hearing. When fitting hearing aids, the pinna adaptation of the otoplasty must be taken into account to ensure comfort and sound fidelity. Reconstructive surgery (otoplasty) corrects malformations or injuries to the pinna.

In tinnitus, the plateau phenomenon refers to a phase in which the pitch and volume of the ear noise remain stable over a period of time before fluctuating again. This stability provides diagnostic certainty in tinnitus screening and facilitates sound therapy settings. Plateau phases vary in duration from minutes to hours and can be interrupted by stress or noise. Therapeutically, plateaus are used to precisely adjust noise profiles and promote habituation. Documenting plateau duration helps to monitor the progression of tinnitus.

The brachial plexus is a network of nerves originating from the cervical spinal nerves C5–Th1 and innervates the shoulder and arm. Although anatomically located outside the ear area, the accessory nerve (XI cranial nerve) can be manipulated near the brachial plexus during surgery on the mastoid or cerebellopontine angle. Injuries lead to weakness in the shoulder and pain, which can indirectly promote postural changes and tension in the neck, jaw, and ear area. Interdisciplinary planning in otoneurosurgery minimizes plexus damage. Postoperative physical therapy ensures functional preservation and pain reduction.

The padding of an earpiece is usually made of soft silicone or foam and ensures an optimal fit in the ear canal. It dampens mechanical pressure peaks, prevents pressure points, and increases wearing comfort during prolonged listening. At the same time, the padding influences the acoustic tightness and thus the feedback-free performance and frequency response of the hearing system. Different degrees of hardness and material thicknesses allow individual adaptation to the anatomy of the ear and hearing loss profile. Regular replacement prevents material fatigue and hygiene-related sound changes.

The postauricular muscles (m. auricularis anterior, superior, and posterior) are tiny, often rudimentary muscles around the auricle. In some people, they can move the ear slightly, thereby slightly affecting the position of the otoplasty. Their contraction does not usually play a significant role in hearing, but can be observed in certain reflexes and mimic movements. In rare cases, spasms of these muscles lead to objective tinnitus ("pulsating clicking sound"). EMG measurements of these muscles can reveal muscular causes of tinnitus.

The potential distribution in electrocochleography (ECochG) describes the amplitudes and latencies of cochlear and nerve potentials along the scala tympani. A needle electrode on the eardrum or ear canal electrode is used to measure the summation potential (SP) and action potential (AP). The SP/AP ratio serves as an indicator of endolymphatic hydrops in Meniere's disease. In addition, the distribution of potentials across different stimulation levels shows the functional reserve of the hair cells. ECochG potential patterns help to differentiate between cochlear and retrocochlear pathologies.

The pre-canalicular shape refers to a variant of the outer ear in which the ear canal entrance is particularly narrow or barely covered by the concha. This anatomy can make it difficult to insert ITE hearing aids and increases the risk of cerumen impaction in the cartilaginous canal. When taking impressions, the impression material must be carefully inserted into this area and removed again to ensure complete earmolds. Audiologists often choose open earmold designs for the pre-canal form to optimize ventilation and reduce feedback. Surgical corrections are only indicated in exceptional cases where there are functional problems.

The prevalence of hearing disorders indicates the proportion of people affected in a defined population and varies depending on age, noise exposure, and region. According to the WHO, around 5% of the global population suffers from hearing loss requiring treatment, with this figure rising to over 30% among people aged 65 and over. In industrialized countries, age-related hearing loss (presbycusis) is the most common cause, while infectious causes are more prevalent in developing regions. Prevalence studies form the basis for health planning, care provision, and prevention programs. Long-term data show an increase in age- and noise-induced hearing disorders due to demographic change and environmental factors.

Presbycusis is age-related sensorineural hearing loss, which typically begins with a decline in high-frequency hearing. It is caused by degeneration of hair cells, synaptic wear and tear, and reduced microvascular perfusion of the cochlea. Symptoms include poorer speech comprehension in noise, reduced loudness perception, and tinnitus. Treatment involves hearing aids with high-frequency amplification and central auditory training to promote neural plasticity. Prevention through noise protection and avoidance of ototoxicity can delay the onset.

Pseudohyperacusis refers to an apparent hypersensitivity to sound in which measurements show normal comfort thresholds, but patients perceive loud sounds as painful. It is psychogenic or caused by attention and anxiety disorders and is not attributable to peripheral damage. Objective tests (OAE, AEP) are crucial for differential diagnosis in order to rule out true hyperacusis. Treatment includes education, cognitive behavioral therapy, and gradual desensitization with controlled noise exposure. Interdisciplinary care by audiologists and psychologists improves the prognosis.

Psychophysical methods identify correlations between physical stimulus parameters (level, frequency) and subjective perception (loudness, pitch, masking). Standard procedures include threshold determination (hearing threshold), loudness scaling, and difference threshold measurement (JND tests). Adaptive methods dynamically adjust stimuli to test subjects' responses and optimize measurement duration and accuracy. They form the basis for standard curves, hearing aid calibration, and psychoacoustic modeling. Validity depends on test subjects' attention, the test environment, and the stimulus protocol.

Psychoacoustics is the science of sound perception by the human ear and brain. It investigates phenomena such as loudness perception, masking, pitch resolution, and spatial hearing. Psychoacoustic findings are incorporated into the development of hearing aids, audio compression (MP3), and room acoustics design. Methodologically, it combines physical measurements, behavioral studies, and neural modeling. Fields of application range from hearing diagnostics and sound design to tinnitus and hyperacusis therapy procedures.