Glossar zum Hören & Gehör

Echolocation is the active localization of objects by emitting sound pulses and evaluating the returning echoes. Bats and some marine mammals use this method to navigate in the dark or murky water and find prey. In humans, echolocation can be trained, for example by blind people who use it to derive spatial information acoustically. Neurobiological studies show that auditory areas in the brain are plastically reorganized in the process. Technical applications are adapting the principle for sonar and ultrasound devices in medicine and industry.

Intrinsic sensitivity refers to the minimum signal that a measuring device or hearing system can still reliably detect from its own noise. In hearing aids, it corresponds to the internal microphone and amplification noise, which is the lower limit for amplification. A low value is important so that quiet environmental noises are not masked by inherent noise. Manufacturers optimize electronic components and filter algorithms to reduce the inherent sensitivity. In measurement technology, the noise floor is shown as a key figure.

Intrinsic noise is the continuous background noise of electronic systems in the absence of an input signal. In hearing systems, it can impair the perception of very quiet sounds and reduce wearing comfort. The level of self-noise depends on circuit topology, component quality and filter design. Modern digital hearing aids use noise reduction algorithms to actively minimize self-noise. Regular maintenance and cleaning of the microphones also prevent extraneous noise.

Acoustic sleep aids such as white noise, the sound of the sea or gentle piano music promote falling asleep and staying asleep by masking disturbing ambient noise. People with tinnitus in particular benefit from continuous sound patterns that draw the focus away from the ear noise. Studies show that such sounds shorten the time it takes to fall asleep and improve sleep quality. Apps and hearing aid programs offer customizable sound profiles and timer functions. It is important to keep the volume below 40 dB so as not to put additional strain on the hearing.

The transient response describes the initial reaction of a vibrating system to a sudden sound stimulus before a steady state is reached. In the ear, this applies to the eardrum and ossicular chain, which initially vibrate excessively before reaching stable amplitudes. Audiometric impedance measurements use the transient process to detect middle ear pathologies such as otosclerosis or tube occlusion. Abnormal transient response times indicate altered stiffness or mass of the structures. In hearing aid technology, the transient response of filters is optimized in order to minimize distortion during rapid level changes.

The setting range of a hearing aid defines the level range that the device can process and amplify without distortion. It ranges from the minimum input volume, at which amplification still takes place, to the maximum volume, at which compression sets in. A wide adjustment range allows very quiet and loud signals to be heard without clipping or discomfort. Audiologists select a device with an appropriate range based on the individual hearing loss profile. Technical datasheets provide the range of adjustment along with compression ratio and gain factors.

Single frequency analysis breaks down complex sound signals into their individual frequency components using Fourier transformation. It provides amplitude and phase-specific information on each frequency component and is the basis for spectral analysis in audiology. Applications can be found in the analysis of otoacoustic emissions, room acoustics measurements and hearing aid fine-tuning. Diagrams show level curves across the frequency spectrum and allow conclusions to be drawn about filter behavior and cochlear function. In research, single frequency analysis is used to investigate neuronal response patterns in the auditory system.

In single tone audiometry, sounds of individual frequencies and levels are presented one after the other to determine the hearing threshold per frequency. The results are visualized in the audiogram as air and bone conduction curves. This procedure is standard in the diagnosis of conductive and sensorineural hearing loss. Modern audiometers offer automated test protocols and adaptive procedures for faster, more reliable measurements. The validity depends on the subject's cooperation and reaction time.

Electrocochleography measures electrical potentials in the inner ear and auditory nerve in response to acoustic stimuli. A needle electrode on the eardrum or an ear canal electrode is used to record the summation potential and endolymphatic pressure. ECochG is used to diagnose Meniere's disease, endolymphatic hydrops and acoustic trauma. Peak pressure amplitudes correlate with the severity of the hydrops. The examination is minimally invasive and provides important data on internal ear mechanics.

The sensitivity range describes the level range in which the human ear or a hearing system can process acoustic stimuli without distortion. For the human ear, this range lies between the hearing threshold (0 dB HL) and the pain threshold (~120 dB SPL). Hearing aids use compression to adapt this range to the residual hearing in order to attenuate loud sounds and make soft sounds audible. Measurement systems calibrate the sensitivity range to ensure linear response within this window.

The threshold of sensitivity is the lowest sound pressure level that can just be perceived by the ear. In audiometry, it is determined separately for each test frequency and documented in the audiogram. Deviations from normal values define the degree of hearing loss. Together with the pain threshold, the sensitivity threshold forms the dynamic range of hearing. Clinically, it helps to differentiate between conductive and sensorineural hearing loss.

Endolymph is the potassium-rich fluid in the cochlear duct and the membranous semicircular canals. It transmits mechanical vibrations to hair cells and generates electrochemical signals. A pressure disturbance of the endolymph, as in endolymphatic hydrops, leads to dizziness and hearing loss. Laboratory measurements and clinical tests of endolymphatic function support the diagnosis of Menière's disease. Research focuses on the regulation of endolymph volume for the treatment of vestibular disorders.

Energy measurement integrates sound levels over time and frequency to assess cumulative noise exposure. It forms the basis for occupational noise protection guidelines that define maximum daily doses. Devices continuously record level values and calculate daily exposure values (LEX,8h). Epidemiological studies correlate energy exposure with the risk of hearing loss. Preventive measures are based on energy measurements to reduce noise damage.

Relaxation sounds such as white noise, the sound of the sea or gentle melodies mask disturbing noises in the ears and promote sleep and stress reduction. In tinnitus patients, they reduce the focus on the ringing in the ears and improve quality of life. Clinical studies show that controlled exposure to sound reduces anxiety and sleep onset latency. Apps and hearing aid programs offer personalized sound libraries. It is important to keep levels below 40 dB to avoid additional hearing stress.

The extended high-frequency range covers frequencies above 8 kHz to around 16 kHz and contributes to sound color and music perception. Early detection of high-frequency loss serves as an early indicator of noise damage. High-frequency audiometry tests this range to detect subtle deficits. Hearing aids with high-frequency amplification improve music and speech intelligibility in complex sound environments.

The Eustachian tube connects the middle ear and nasopharynx, regulates pressure equalization and protects against nasal secretions. It opens when swallowing or yawning and closes passively to ensure ventilation of the middle ear. Dysfunctions lead to a feeling of pressure, hearing loss and effusions. Balloon dilatation and nasal corticoids are established therapies. Functional tests measure opening pressure and duration.

Evoked potentials are electrical responses of the auditory system to sound stimuli, measured by scalp electrodes. They are divided into ABR (brainstem), MLR (midlatency) and CAEP (cortical). These objective tests check the integrity of the auditory pathway without active cooperation. Used for newborn screening, neurological diagnostics and CI fitting. Analysis of latency and amplitude provides information about lesion locations.

Glossary

Taxonomies

E