The balance organ in the inner ear, consisting of the three semicircular canals and sacculus or utriculus, controls balance and spatial orientation. Movements of the head cause the endolymph in the semicircular canals to flow, mechanically stimulating hair cells. These stimuli are transmitted to the brain via the vestibular nerve, where they are combined with visual and proprioceptive information. Disturbances can cause dizziness, nausea and fluctuations in balance. Caloric testing and VEMP tests are used for diagnostic purposes.

The basilar membrane runs spirally through the cochlea and carries the organ of Corti with its hair cells. Sound waves in the inner ear induce traveling waves on the membrane, whose point of maximum deflection determines the perceived pitch. Depending on the frequency, different sections of the membrane vibrate, which enables the tonotopic organization in the auditory system. Damage to the basilar membrane impairs frequency resolution and speech intelligibility. Research into regenerative therapies is aimed at restoring its function after noise damage.

Bilateral hearing loss occurs when both ears have a measurable hearing loss. It can occur symmetrically or asymmetrically and can have various causes, such as exposure to noise, genetic factors or ageing processes. Those affected often suffer from reduced speech comprehension and social isolation. They are usually fitted with hearing aids or cochlear implants on both sides. Regular audiological checks ensure that the hearing systems are optimally adjusted.

Békésy audiometry is a method of measuring the hearing threshold in which the patient presses a continuous tone button as soon as they hear sound and releases it when they no longer hear it. At the same time, the sound pressure is continuously varied so that conclusions can be drawn about thresholds and adaptation behavior. The method provides differentiated information about hearing thresholds in unilateral and bilateral examinations. It is particularly suitable for diagnosing sensorineural hearing loss. Today it is supplemented by automated computer-aided tests.

A coating on the eardrum is often caused by inflammatory processes such as otitis media or chronic moisture in the ear canal. It can inhibit the eardrum's ability to vibrate and lead to conductive hearing loss. Otoscopically, the plaque appears as a whitish or yellowish layer. Treatment involves microscopic cleaning and, if necessary, topical antibiotics. A follow-up check by tympanometry ensures that the eardrum function is restored.

The annoyance volume is a psychoacoustic measure of how annoying a noise is perceived, regardless of its sound pressure level. It is determined in studies by interviewing test subjects and is incorporated into noise protection guidelines. Factors such as pitch, duration and context influence the subjective annoyance. Measures to reduce noise include noise barriers, room acoustics optimization and hearing protection. Annoyance levels are important parameters for the planning of living and working areas.

A ventilation disorder of the tympanic cavity occurs when the Eustachian tube does not open and close properly. This prevents pressure equalization between the middle ear and the nasopharynx. Symptoms include a feeling of pressure, hearing loss and recurrent otitis. Tympanometry is used for diagnosis, tube catheters, nasal steroids or balloon dilatation help therapeutically. Chronic cases may require tympanostomy tube implantation.

A tympanostomy tube is a small tube that is surgically inserted into the eardrum to ensure permanent ventilation of the middle ear. It prevents fluid build-up and recurring middle ear infections. The tubes usually fall out by themselves after a few months as soon as the eardrum has healed. Follow-up checks by otoscopy and tympanometry ensure the success of the treatment. They are used less frequently in adults than in children.

In benign paroxysmal positional vertigo (BPLS), otoliths in the posterior semicircular canal become detached and irritate the cupula. Even small head movements lead to severe, short-lasting attacks of vertigo. The diagnosis is made clinically using the Dix-Hallpike test. The Epley maneuver repositions the otoliths and usually relieves the symptoms immediately. Recurrences are common, so patients can learn simple positioning exercises.

In rare cases, benzodiazepines can have an ototoxic effect and lead to dizziness, tinnitus or hearing loss. The active substances influence GABAergic neurotransmission in the auditory system. Symptoms reversible after discontinuation, persistent in severe cases. Audiometric monitoring recommended for long-term therapy. Alternatives such as SSRIs are being considered to avoid ototoxicity.

Occupational hearing loss is caused by chronic exposure to noise in the workplace, for example in industry or construction. It usually manifests itself as sensorineural hearing loss in the high-frequency range. Prevention through hearing protection, noise reduction and regular audiometry is required by law. Early detection allows protective measures to be adapted in good time. Rehabilitation includes hearing aid fitting and noise insensitivity training.

Some analgesics and antibiotics (e.g. aminoglycosides) have an ototoxic effect and can damage hair cells in the inner ear. Symptoms range from tinnitus to permanent hearing loss. Reducing the dose or changing the substance can often reverse early damage. Regular otoacoustic emission tests monitor cochlear function during therapy. Interdisciplinary coordination between ENT and oncology prevents hearing damage.

Binaural interaction refers to the processing of different signals from both ears in the brain to localize and distinguish sound sources. It enables spatial perception and speech comprehension in noise. Disruptions lead to reduced directional hearing and communication problems. Audiological tests such as Binaural Masking Level Difference quantify the interaction. Hearing systems promote it through synchronized signal processing.

Binaural localization uses time and level differences between the ears to determine the direction of sound. Small time differences (ITD) and volume differences (ILD) are evaluated in the superior olive nucleus. Precise directional hearing is essential for speech comprehension and safety in road traffic. Hearing aids with binaural networking maintain this ability through coordinated microphone processing. Tests in the free sound field check localization accuracy.

Binaural redundancy refers to the advantage of both ears receiving the same signal, which increases recognizability. In noise, speech intelligibility is improved because the brain uses multiple copies of the signal. Redundancy effects can be measured in speech audiometry. Hearing aids should not reduce redundant information in order to maximize intelligibility.

Binaural summation describes the improved perception of loudness and recognition threshold when both ears are involved. The combined information leads to a gain in loudness of around 3 dB compared to monaural hearing. This effect supports hearing in noisy environments. Clinically, it is taken into account when hearing aids are fitted on both ears.

Binaural suppression describes how the brain suppresses background noise when the useful signal and masker are fed to both ears in a phase-differentiated manner. The Masking Level Difference (MLD) quantifies the hearing gain through phase-optimized stimuli. Tests on this help to diagnose central auditory processing disorders. Modern hearing aids use these findings to improve signal-to-noise ratios.

Binaural fitting means the simultaneous fitting of hearing systems in both ears. It preserves localization, speech understanding and sound quality. Clinical studies show better hearing performance and less listening effort compared to monaural fitting. Synchronized programs and microphones optimize binaural effects.

Binaural hearing is the interaction of both ears for spatial sound perception. It enables directional hearing, noise suppression and speech comprehension in complex acoustic situations. The superior olivary complex in the brain stem is the central processing station. Loss of one ear significantly reduces these abilities. Rehabilitation aims to maximize remaining binaural effects.

A biphasic tinnitus masker alternately generates two different frequencies to modulate the tone and perception of the tinnitus. Phase shifts break neural adaptation, resulting in greater relief. Maskers can be integrated into hearing aids or stand-alone devices. Clinical studies have shown a short-term reduction in tinnitus volume.

The bit depth indicates how many bits are used to represent an audio sample and determines the dynamic resolution. Higher bit depth enables finer gradations and lower quantization noise. In hearing aids, it influences sound fidelity and noise reduction. Usual values are 16-24 bits, professional systems use up to 32 bits.

The blue dot effect describes a temporary increase in the hearing threshold after exposure to noise. Those affected perceive sounds more quietly until the hair cells have recovered. This phenomenon demonstrates the protective function of acoustic adaptation. Long-term or repeated exposure can lead to permanent hearing loss. Audiometric checks document recovery times.

Bluetooth hearing aids use wireless radio technology to receive audio signals directly from telephones, televisions or computers. They improve speech intelligibility and comfort by blocking out ambient noise. Low latency and binaural synchronization are important quality features. Battery-powered models avoid battery changes. Compatibility with standard profiles (APT-X, LE) ensures a wide range of applications.

The three semicircular canals in the vestibular apparatus (horizontal, superior, posterior) register rotational movements of the head. They are filled with endolymph and contain hair cell sensors in the cupula. Each movement generates a specific flow that is transmitted to the brain. Diseases such as BPLS primarily affect the posterior semicircular canals. Functional tests are caloric testing and video nystagmography.

Bone conduction transmits sound by vibration of the skull directly to the inner ear, bypassing the outer ear and middle ear. It is used in audiometry to differentiate between conductive and sensorineural hearing loss. Bone conduction hearing systems are used for patients with middle ear problems. Modern implants such as BAHS offer permanent bone conduction solutions.

Bonebridge is an active transcutaneous bone conduction implant that conducts sound vibrations directly into the temporal bone. It is suitable for patients with conductive hearing loss and unilateral deafness. The external sound processor unit transmits signals magnetically to the implanted vibration module. Clinical studies show high patient satisfaction and speech understanding.

During ear surgery, stimulation of the vagus nerve can lead to bradycardia as parasympathetic fibers are stimulated. Anesthetists closely monitor heart rate and blood pressure. Vagolytic medication is given as a preventative measure. Surgeons work gently to minimize pressure on the meatus and round windows. Events require immediate cardiologic intervention.

Humming in the ear describes low-frequency, often pulsatile noises that those affected find disturbing. Causes include vascular turbulence, muscle tremors or hearing aid feedback. Diagnostically, auscultation and Doppler sonography help to rule out vascular causes. Maskers, biofeedback or vascular therapy with medication are used therapeutically. Chronic humming can severely impair quality of life.