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

The basilar membrane runs spirally through the cochlea and supports 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, enabling tonotopic organization in the auditory system. Damage to the basilar membrane impairs frequency resolution and speech intelligibility. Research into regenerative therapies aims to restore its function after noise-induced damage.

Bilateral hearing loss occurs when both ears show measurable hearing loss. It can be symmetrical or asymmetrical and have various causes, such as exposure to noise, genetic factors, or aging. Those affected often suffer from reduced speech comprehension and social isolation. Treatment usually involves hearing aids or cochlear implants fitted on both sides. Regular audiological checkups ensure that the hearing systems are optimally adjusted.

Békésy audiometry is a method for measuring the hearing threshold in which the patient presses a continuous tone button as soon as they hear a 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 threshold levels and adaptation behavior. The procedure provides detailed 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-assisted 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 coating appears as a whitish or yellowish layer. Treatment involves microscopic cleaning and, if necessary, topical antibiotics. A follow-up examination using tympanometry ensures that the eardrum function has been restored.

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

Ventilation problems in the tympanic cavity occur when the Eustachian tube does not open and close properly. This prevents pressure equalization between the middle ear and the nasopharyngeal cavity. Symptoms include a feeling of pressure, hearing loss, and recurrent otitis. Tympanometry is used for diagnosis, while tube catheters, nasal steroids, or balloon dilation are used for treatment. Chronic cases may require the insertion of ear tubes.

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 accumulation and recurrent middle ear infections. The tubes usually fall out on their own after a few months, once the eardrum has healed. Follow-up checks using otoscopy and tympanometry ensure the success of the treatment. They are used less frequently in adults than in children.

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

Benzodiazepines can, in rare cases, have ototoxic effects and lead to dizziness, tinnitus, or hearing loss. The active ingredients influence GABAergic neurotransmission in the auditory system. Symptoms are reversible after discontinuation, but persistent in severe cases. Audiometric monitoring is recommended during long-term therapy. Alternatives such as SSRIs are considered to avoid ototoxicity.

Occupational hearing loss is caused by chronic noise exposure 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 adjusted in good time. Rehabilitation includes hearing aid provision and noise desensitization training.

Some analgesics and antibiotics (e.g., aminoglycosides) are ototoxic 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 noisy environments. Disturbances 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 differences in transit time (ITD) and loudness (ILD) are evaluated in the superior olive nucleus. Precise directional hearing is essential for speech comprehension and road safety. Hearing aids with binaural networking achieve this capability through coordinated microphone processing. Tests in a free sound field verify the accuracy of localization.

Binaural redundancy refers to the advantage of both ears receiving the same signal, which increases recognizability. Speech comprehension improves in noisy environments 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 results in a loudness gain of approximately 3 dB compared to monaural hearing. This effect supports hearing in noisy environments. Clinically, it is taken into account when fitting hearing aids on both sides.

Binaural suppression describes how the brain suppresses background noise when the useful signal and masker are fed to both ears with a phase difference. The masking level difference (MLD) quantifies the hearing gain achieved through phase-optimized stimuli. Tests using this method help to diagnose central auditory processing disorders. Modern hearing aids use these findings to improve signal-to-noise ratios.

Binaural fitting means fitting hearing aids to both ears at the same time. It preserves localization, speech comprehension, 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 brainstem is the central processing station. Loss of one ear significantly reduces these abilities. Rehabilitation aims to maximize remaining binaural effects.

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

The bit depth specifies 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 low noise. Typical values are 16–24 bits, while professional systems use up to 32 bits.

The Blaupunkt effect describes a temporary increase in the hearing threshold after exposure to noise. Those affected perceive sounds as quieter until the hair cells have recovered. The 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 phones, televisions, or computers. They improve speech comprehension and comfort by blocking out ambient noise. Low latency and binaural synchronization are important quality features. Battery-powered models eliminate the need for battery replacement. 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 mainly affect the posterior semicircular canals. Functional tests include caloric testing and video nystagmography.

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

Bonebridge is an active transcutaneous bone conduction implant that transmits 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 comprehension.

During ear surgery, irritation of the vagus nerve can lead to bradycardia, as parasympathetic fibers are stimulated. Anesthesiologists closely monitor heart rate and blood pressure. Vagolytic drugs are administered as a preventive measure. Surgeons work gently to minimize pressure on the meatus and round window. Any incidents require immediate cardiological intervention.

Ringing in the ears describes low-frequency, often pulsatile noises that those affected find disturbing. Causes include vascular turbulence, muscle tremors, or hearing aid feedback. Auscultation and Doppler sonography help with diagnosis to rule out vascular causes. Masking, biofeedback, or drug therapy are used for treatment. Chronic buzzing can severely impair quality of life.