The telecoil is a coil in the hearing aid that receives electromagnetic signals from induction loop systems (e.g., in theaters or churches) and feeds them directly into the hearing system. It bypasses microphones and significantly improves the signal-to-noise ratio by filtering out ambient noise. The telecoil is activated manually or automatically, depending on the hearing aid model. Standardized induction loops generate a standardized magnetic field of 100 mA/m, which the telecoil scans optimally. The telecoil is essential for barrier-free communication in public facilities.

Daily hearing fluctuations describe natural changes in hearing threshold or tinnitus level throughout the day. They result from circadian rhythms, hormone levels, and fluctuations in middle ear and cochlear fluids. Patients often report better hearing in the morning and increased tinnitus in the evening. In diagnostics, repeated measurements at different times of the day are recommended in order to obtain representative findings. Treatment plans take fluctuations into account by adjusting hearing aid programs and noise generator settings over time.

The tegmen tympani is the thin bony roof of the tympanic cavity and separates the middle ear from the middle cranial fossa. It protects the brain from inflammation originating in the middle ear and serves as an access point for certain neurotological surgeries. Defects in the tegmen can lead to cerebrospinal fluid fistulas and cerebral infections. Imaging techniques (CT, MRI) are used to check the integrity of the tegmen in cases of chronic otitis media. Surgical reconstruction with autologous or alloplastic materials restores the barrier function.

Temporal resolution is the ability of the auditory system to perceive closely spaced sound events as separate. It is measured using tests such as gap detection or double-click audiometry. Good temporal resolution is crucial for speech comprehension in fast speech passages and for music perception. Temporal resolution is often reduced in cases of central auditory processing disorders or hidden hearing loss. Auditory training can improve the neural processing of temporally fine stimuli.

The temporal lobe is the area of the brain where the primary auditory cortex (Heschl's gyrus) is located. It processes basic sound characteristics such as frequency and volume and is involved in speech comprehension (Wernicke's area). Lesions in the temporal lobe lead to auditory agnosia, speech comprehension disorders, and tinnitus processing difficulties. Functional imaging (fMRI, PET) shows activation patterns during acoustic and linguistic tasks. The plasticity of the temporal lobe enables successful rehabilitation after hearing loss and implantations.

Therapeutic listening is the targeted use of acoustic stimuli—such as music, speech exercises, or noise—to treat hearing disorders and tinnitus. It combines auditory training, desensitization, and cognitive therapy approaches. Programs are individualized and can be carried out in clinical sessions or via app-supported home training. The aim is to improve speech comprehension, reduce tinnitus distress, and promote neural plasticity. Studies show long-term effects on hearing comfort and quality of life.

Tinnitus is the perception of sounds (e.g., whistling, hissing) without an external sound source. It is caused by spontaneous neural activity in the auditory system, often following damage to hair cells or central maladjustments. Tinnitus can be pulsatile, tonal, or noise-like and varies in volume and severity. Diagnosis includes medical history, tinnitus screening (frequency and level determination), and exclusion of organic causes. Treatment approaches range from sound therapy and tinnitus retraining to cognitive behavioral therapy.

Tinnitus retraining therapy (TRT) combines sound therapy with psychological counseling to promote habituation to tinnitus. A noiser or broad noise is played continuously or situationally to mask the tinnitus signal and enable neural adaptation. At the same time, cognitive strategies are learned to reduce negative reactions to tinnitus. The process usually takes 12–18 months and shows a significant reduction in tinnitus distress in many patients. Regular evaluations adjust sound profiles and counseling content.

The tinnitus generator is the specific location or mechanism in the auditory system that produces tinnitus, e.g., damaged hair cells, increased central gain control, or somatosensory influences. It can be localized using electrocochleography, OAE mapping, or imaging techniques. Knowledge of the generator enables targeted therapies, such as focal drug administration or neurostimulation. In complex cases, multiple generators exist at the peripheral and central levels. Research uses animal models to decipher generators and their interactions.

A tinnitus masker is a device or function that generates an external noise signal to mask the tinnitus. Maskers can be broadband noise, notch filter noise, or narrowband tinnitus spectral sounds. The aim is to suppress the tinnitus signal in the consciousness and promote habituation. Integrated maskers in hearing aids allow situational activation and adjustment of volume and spectrum. Masker therapy improves sleep and concentration in tinnitus patients.

Tinnitus perception encompasses the subjective experience of tinnitus, including sound characteristics, volume, localization, and emotional response. It is assessed using questionnaires (e.g., TFI, THI) and acoustic matching procedures. Perception dimensions only partially correlate with objective measurements, as cognitive and emotional factors play a major role. Therapy success is mainly evaluated based on changes in tinnitus perception. Long-term tracking of perception helps to individualize therapy approaches and make adjustments.

Tone audiometry is the standard method for determining hearing thresholds for pure tones via air and bone conduction. Test tones at defined frequencies (125 Hz–8 kHz) are presented to the test subject via headphones or bone conduction; the minimum perceived levels are recorded in the audiogram. It differentiates between conductive and sensorineural hearing loss by comparing both transmission paths. Automated and manual protocols ensure precision and reproducibility. The results form the basis for hearing aid fitting and diagnosis of middle and inner ear pathologies.

Pitch resolution describes the ability to perceive two tones of different frequencies as separate. It is determined psychoacoustically using dense tone or difference tone tests and is expressed as the smallest detectable frequency difference (Δf). Good resolution is essential for understanding music and perceiving speech, as it differentiates between formants and melodic patterns. Cochlear damage impairs resolution, resulting in blurred sound. Hearing aid and implant strategies aim to preserve remaining tonotopic precision.

Pitch perception is the ability to determine the absolute or relative pitch of a sound, such as in melodies or telephone conversations. Tests such as melody discrimination or musical intervals assess this ability. It depends on coherent processing in the cochlea and auditory cortex. Disorders occur in cases of central auditory processing disorders or after a stroke in the temporal lobe. Musical auditory training can improve pitch perception through plasticity.

The scale test is a psychoacoustic procedure in which test subjects must recognize or reproduce successive scales (ascending/descending). It tests pitch recognition, sequence memory, and musical abilities. In audiology, it is used to assess sound quality and temporal processing in hearing aid users. Differences in test performance before and after hearing aid fitting demonstrate the success of the fitting in musical scenarios. Variations with different intervals analyze frequency resolution in detail.

Scale hearing refers to the perception and cognitive processing of scales as a musical structure. It includes recognizing scale type (major, minor), intervals, and melodic progressions. Neuroimaging shows specific activation patterns in the temporal lobe and associated areas. Hearing loss reduces scale listening due to impaired frequency and time resolution. Rehabilitative music therapy uses scale exercises to promote auditory processing and quality of life.

Tonotopy is the systematic spatial mapping of frequencies along the cochlea (base = high frequencies, apex = low frequencies) and in the auditory cortex. It forms the basis for frequency coding in hearing and enables precise filtering in hearing aids. Tonotopic maps in the cortex show how auditory stimuli of different frequencies are topographically mapped. Damage to certain regions of the cochlea leads to frequency-specific hearing loss. Cochlear implants utilize tonotopy by stimulating electrodes along the cochlea in a frequency-specific manner.

Tone threshold elevation refers to the raising of the hearing threshold for tones in certain frequency ranges, as shown in the audiogram as hearing loss. It can be mild (20–40 dB), moderate (41–70 dB), or severe (>70 dB). Causes include noise trauma, presbycusis, or ototoxic damage to hair cells. The increase provides information about the frequencies affected and initiates targeted amplification in hearing systems. Progress measurements document progression or recovery after therapy.

Toxic hearing loss is caused by ototoxins such as aminoglycoside antibiotics, cisplatin, or solvents, which destroy hair cells and synaptic connections. It usually begins in the high-frequency range and progresses downward with further exposure. Early detection via OAE monitoring during therapy can reduce irreversible damage. Protective strategies include dose adjustment, otoprotective substances, and regular audiological checks. Long-term consequences range from tinnitus to permanent sensorineural hearing loss.

The tragus is the cartilaginous protrusion in front of the ear canal, which partially shields the entrance and serves as natural sound insulation. It influences interaural level differences and thus the localization of sound sources. Clinically, it serves as an anatomical reference point for otoscopy and tragus reflex testing. Pressure on the tragus can cause pain during foreign reflex testing and indicate inflammation in the ear canal. In otoplasty design, the contour of the tragus is precisely replicated to ensure a seal and comfort.

The tragus reflex (also known as the otalgia reflex) is a pain or chewing reflex triggered by pressure on the tragus or pulling on the earlobe. A positive reflex indicates inflammation or pressure pain in the external auditory canal (otitis externa). It supplements otoscopy with a functional test of the skin and sensitivity in the canal. In terms of differential diagnosis, it helps to distinguish otogenic pain from causes related to the teeth or temporomandibular joint. The reflex is triggered by light finger pressure; intensification in the case of pathology is typical.

TEOAE are acoustic responses of the cochlea to short clicks or pulses measured in the external auditory canal. They are generated by active feedback from the outer hair cells and are an objective indicator of cochlear health. TEOAE screening is used in newborn hearing screening because it works without active cooperation. The absence of TEOAE indicates damage to the outer hair cells and possible sensorineural hearing loss. Measurement takes place within a few milliseconds after stimulation and offers high sensitivity and specificity.

Transmission sound refers to sound that is transmitted from one room to another through walls, ceilings, or other structures. It is examined in construction to ensure noise protection between apartments or offices. Measured variables are transmission loss (TL) and weighted sound reduction index (Rw). Structural measures such as double walls, vibrating substructures, and insulation layers minimize transmission sound. Standards specify minimum requirements for residential and work areas.

Transmission sound loss is the difference between the incoming and outgoing sound pressure levels at a partition wall, expressed in dB. It characterizes the sound insulation properties of building components. Higher values indicate better insulation. Tests are carried out in laboratories with standardized sound fields; field measurements validate the results on site. Transmission sound loss is crucial for sound insulation classes and building acoustics planning.

The eardrum (membrana tympani) is a thin, semi-transparent membrane that separates the outer ear from the middle ear and converts sound into mechanical vibrations. It consists of three layers: skin, connective tissue, and mucous membrane. Intact mobility and tension are essential for effective sound conduction. Perforations or scarring impair impedance matching and lead to conductive hearing loss. Surgical reconstruction (myringoplasty) restores integrity and function.

A tympanic membrane perforation is a defect in the tympanic membrane caused by infection, trauma, or barotrauma. It appears otoscopically as a hole or tear and leads to conductive hearing loss and an increased risk of infection. Small perforations can heal spontaneously, while larger ones require myringoplasty. Tympanometry documents the degree of perforation via flat curves and an increased compliance signal. Postoperative monitoring ensures successful closure and hearing gain.

A tympanogram is a graphical representation of middle ear impedance as a function of external air pressure. It is produced during tympanometry when the eardrum is stimulated with varying pressure and compliance is measured. Typical curve types (A, B, C) indicate a normal middle ear, effusion, or Eustachian tube dysfunction. Tympanograms help to differentiate between sound conduction disorders and assess the need for ear tubes. Normal values vary depending on age and measurement system.

Tympanometry is the measurement of middle ear impedance by varying the air pressure in the ear canal. It assesses eardrum mobility and the ventilation status of the tympanic cavity. A tympanometer generates a tympanogram, which allows conclusions to be drawn about fluids, perforations, or functional disorders of the Eustachian tube. It is rapid, objective, and complements audiometry and otoscopy in ENT diagnostics. Normative curves help to identify pathologies such as otitis media with effusion.

Tympanoplasty is the surgical reconstruction of the eardrum and ossicular chain to restore sound conduction. Procedures range from classic myringoplasty (eardrum closure) to combined tympanomastoidoplasty for cholesteatoma. The goals are to seal the middle ear, control infection, and improve hearing. The procedure is performed under a microscope, often using autologous graft material. Long-term success is monitored by audiometry and imaging.