The T-coil (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 aid. It bypasses microphones and significantly improves the signal-to-noise ratio as ambient noise is suppressed. The T-coil is activated manually or automatically, depending on the hearing aid model. Standardized induction loops generate a standardized magnetic field of 100 mA/m, which optimally scans the T-coil. The T-coil is essential for barrier-free communication in public facilities.

Diurnal hearing fluctuations describe natural changes in the hearing threshold or tinnitus level during the course of 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 the timing of hearing aid programs and noiser use.

The tegmen tympani is the thin bony covering of the tympanic cavity and separates the middle ear from the middle cranial fossa. It protects the brain from inflammation from the middle ear and serves as an access point for certain neurotologic operations. Defects in the tegmen can lead to cerebrospinal fluid fistulas and cerebral infections. Imaging procedures (CT, MRI) check the integrity of the tegmen in 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 sound events in close temporal succession 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 central auditory processing disorders or hidden hearing loss. Hearing training can improve the neuronal processing of temporally fine stimuli.

The temporal lobe is the area of the brain in which the primary auditory cortex (Heschl's cortex) 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 speech tasks. The plasticity of the temporal lobe enables successful rehabilitation after hearing loss and implantation.

Therapeutic hearing is the targeted use of acoustic stimuli - such as music, speech exercises or noisers - to treat hearing disorders and tinnitus. It combines hearing 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 stress and promote neuronal 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 neuronal activity in the auditory system, often following hair cell damage or central maladaptation. Tinnitus can be pulsatile, tonal or noise-like and varies in volume and intensity. Diagnosis includes anamnesis, tinnitus screening (frequency and level determination) and exclusion of organic causes. Therapeutic 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 neuronal adaptation. At the same time, cognitive strategies are learned to reduce negative reactions to tinnitus. The process usually takes 12-18 months and many patients experience a significant reduction in tinnitus. Regular evaluations adjust sound profiles and counseling content.

The tinnitus generator is the individual 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 by 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 consciousness and promote habituation. Integrated maskers in hearing aids allow situational activation and adjustment of volume and spectrum. Masking therapy improves sleep and concentration in tinnitus patients.

Tinnitus perception comprises the subjective experience of tinnitus, including sound characteristics, loudness, localization and emotional response. It is recorded using questionnaires (e.g. TFI, THI) and acoustic matching methods. Perceptual dimensions only partially correlate with objective measures, as cognitive and emotional factors play a major role. The success of therapy is mainly assessed via changes in tinnitus perception. Long-term tracking of perception helps to individualize therapy approaches and make adjustments.

Tone audiometry is the standard procedure 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 person via headphones or bone conductors; 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 the 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 density tone or difference tone tests and is specified as the smallest detectable frequency difference (Δf). Good resolution is essential for understanding music and speech perception, as it differentiates formants and melodic progressions. Resolution deteriorates with cochlear damage, resulting in blurred sound. Hearing aid and implant strategies aim to preserve remaining tonotopic precision.

Pitch recognition is the ability to determine the absolute or relative pitch value of what you hear, for example in melodies or telephone conversations. Tests such as melody discrimination or musical intervals test this ability. It depends on coherent processing in the cochlea and auditory cortex. Disorders can be seen in central auditory processing disorders or after a stroke in the temporal lobe. Musical auditory training can improve pitch recognition through plasticity.

The scale test is a psychoacoustic procedure in which test subjects have to recognize or reproduce successive scales (ascending/descending). It tests pitch recognition, sequential 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 show fitting success in musical scenarios. Variations with different intervals analyze frequency resolution in detail.

Scale listening refers to the perception and cognitive processing of scales as a musical structure. It includes recognition of scale type (major, minor), intervals and melodic progressions. Neuroimaging shows specific activation patterns in the temporal lobe and associated areas. Hearing loss reduces scale hearing 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 allocation of frequencies along the cochlea (base = high frequencies, apex = low frequencies) and in the auditory cortex. It forms the basis for frequency coding in the auditory system and allows precise filtering in hearing aids. Tonotopic maps in the cortex show how auditory stimuli of different frequencies are mapped topographically. Damage in certain cochlear regions leads to frequency-specific hearing loss. Cochlear implants use tonotopy by stimulating electrodes along the cochlea in a frequency-sorted manner.

An increase in hearing thresholds refers to an increase in the hearing threshold for sounds in certain frequency ranges, which is visible on 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 affected frequencies and initiates targeted amplification in hearing systems. Progression measurements document progression or recovery after therapy.

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

The tragus is the cartilaginous protrusion in front of the ear canal that partially shields the entrance and serves as a natural sound barrier. It influences interaural level differences and thus the localization of sound sources. Clinically, it serves as an anatomical landmark during otoscopy and tragus reflex testing. Pressure on the tragus can cause pain in the external reflex test and indicate inflammation in the ear canal. In earmold design, the tragus contour is precisely shaped to ensure sealing and comfort.

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

TEOAEs are sound 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 as it works without active cooperation. If TEOAEs are missing, this indicates external hair cell damage and possible sensorineural hearing loss. Measurement takes place within a few milliseconds of the stimulus 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 investigated in the building industry 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 insulating layers minimize transmission sound. Standards specify minimum requirements for living and working areas.

The transmission sound loss is the difference between the incoming and outgoing sound pressure level at a partition wall, stated in dB. It characterizes the sound insulation properties of building components. Higher values mean better insulation. Tests are carried out in laboratories with standardized sound fields; field measurements validate on site. Transmission sound loss is decisive 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.

An eardrum 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, larger ones require myringoplasty. Tympanometry documents the degree of perforation via flat curves and increased compliance signal. Postoperative monitoring ensures successful closure and hearing gain.

A tympanogram is the graphical representation of the middle ear impedance as a function of the external air pressure. It is produced during tympanometry when the eardrum is stimulated with alternating pressure and compliance is measured. Typical curve types (A, B, C) indicate normal middle ear, effusion or tube dysfunction. Tympanograms help to differentiate between sound conduction disorders and assess the need for tympanostomy tubes. Standard 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 evaluates the mobility of the eardrum and the ventilation status of the tympanic cavity. A tympanometer produces 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 detect 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 aims are to seal the middle ear, control infection and improve hearing. The procedure is performed under a microscope, often with autologous transplant material. Long-term success is monitored by audiometry and imaging.