ABOHNS Neurotology key terms

Abnormal accumulation of endolymph within the membranous labyrinth, producing episodic vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural fullness. It is the underlying histopathologic finding in Meniere disease.

A clinical syndrome of recurrent spontaneous vertigo lasting minutes to hours, fluctuating low-frequency sensorineural hearing loss, tinnitus, and aural fullness, attributed to endolymphatic hydrops. Diagnosis is made clinically using established criteria after excluding other causes.

Brief vertigo triggered by specific head position changes, caused by displaced otoconia entering a semicircular canal, most often the posterior canal. It is diagnosed by a positional maneuver reproducing characteristic nystagmus and treated with canalith repositioning.

A bedside positional test in which the seated patient's head is turned and the trunk laid supine with the head extended below horizontal. It provokes and identifies posterior canal BPPV by eliciting upbeating, torsional nystagmus after a latent period.

A sequence of guided head and body rotations, such as the Epley maneuver, that uses gravity to move dislodged otoconia out of a semicircular canal back into the utricle, relieving positional vertigo.

Microscopic calcium carbonate crystals resting on the otolithic maculae of the utricle and saccule that sense linear acceleration and gravity. When they dislodge and enter a semicircular canal, they cause benign paroxysmal positional vertigo.

Acute unilateral vestibular weakness, probably viral or postviral, presenting with sudden prolonged vertigo, nausea, and spontaneous horizontal nystagmus without hearing loss. Symptoms peak over hours to days and improve with vestibular rehabilitation and short-term symptomatic medication.

Inflammation of the inner ear affecting both vestibular and auditory structures, producing acute vertigo together with sensorineural hearing loss. It is distinguished from vestibular neuritis by the presence of cochlear symptoms.

An involuntary rhythmic oscillation of the eyes, described by direction, waveform, and whether it is spontaneous or provoked. In vestibular disease the fast phase defines the named direction and can localize peripheral versus central pathology.

A bedside test in which the examiner rapidly turns the patient's head while the patient fixates on a target. A corrective catch-up saccade indicates reduced vestibulo-ocular reflex gain on that side, typical of a unilateral peripheral vestibular deficit.

An instrumented version of the head impulse test using high-speed cameras to quantify the vestibulo-ocular reflex gain and detect covert catch-up saccades at each semicircular canal, improving sensitivity for peripheral vestibular loss.

A short-latency brainstem reflex that moves the eyes opposite to head motion, stabilizing images on the retina during movement. Its gain and symmetry are assessed by head impulse and caloric testing.

A test that irrigates each ear with warm or cool water or air to induce convection-driven endolymph flow and horizontal nystagmus. Comparing responses quantifies unilateral vestibular weakness and is a standard component of electronystagmography.

A battery of eye-movement recordings using surface electrodes or video to assess spontaneous, positional, and caloric-induced nystagmus, providing objective measures of vestibular function and central oculomotor control.

A test in which loud clicks or tone bursts evoke a reflex response recorded from a contracted neck or eye muscle, assessing saccular or utricular function and their brainstem pathways. It complements caloric and head impulse testing.

A structured exercise program using habituation, gaze stabilization, and balance training to promote central compensation for vestibular deficits and reduce chronic dizziness and fall risk.

Reduced function of one peripheral vestibular apparatus, which may be acute or chronic, producing imbalance, oscillopsia during head movement, and abnormal caloric or head impulse results on the affected side.

A bony defect over the superior semicircular canal creating a third mobile window in the inner ear. It causes sound- or pressure-evoked vertigo, autophony, pulsatile tinnitus, and low-frequency conductive hearing loss with intact reflexes.

An abnormal opening in the bony labyrinth, as in superior canal dehiscence or enlarged vestibular aqueduct, that shunts acoustic energy away from the cochlea and alters pressure transmission, producing conductive-appearing hearing loss and sound-induced vestibular symptoms.

A congenital widening of the vestibular aqueduct, often associated with sensorineural hearing loss that may fluctuate or progress, sometimes with vertigo or head-trauma-induced deterioration. It is a common inner-ear malformation on temporal bone imaging.

Hearing loss arising from damage to cochlear hair cells or the auditory nerve, characterized by reduced air and bone conduction thresholds together and often by impaired speech discrimination. It is usually irreversible.

Rapid-onset hearing loss of at least 30 dB across three contiguous frequencies within 72 hours, typically idiopathic. It is treated as an otologic urgency, usually with high-dose corticosteroids, because early therapy improves recovery.

Faint sounds generated by active outer hair cell motility in a healthy cochlea and measurable in the ear canal with a microphone. Their presence suggests intact cochlear function and they are used in newborn hearing screening.

A far-field recording of neural activity evoked by sound, showing waveforms generated along the auditory pathway from nerve to brainstem. It estimates hearing thresholds objectively and is used in newborn screening and retrocochlear evaluation.

The standard behavioral hearing test that establishes air- and bone-conduction thresholds across frequencies, defining the type, degree, and configuration of hearing loss and guiding rehabilitation decisions.

The lowest presentation level at which a patient correctly repeats about half of a list of spondaic words, providing a cross-check on pure tone thresholds and helping quantify functional hearing ability.

The percentage of correctly repeated phonetically balanced words presented at a comfortable suprathreshold level. It reflects auditory clarity and helps predict benefit from hearing aids or cochlear implantation.

A surgically placed device that converts sound into electrical pulses delivered by an electrode array within the cochlea to stimulate auditory nerve fibers, restoring hearing in severe to profound sensorineural loss.

A device that transmits sound through bone conduction via a surgically implanted fixture or magnetic coupling, used for conductive, mixed, or single-sided deafness when conventional air-conduction aids are unsuitable.

Reduced hearing caused by impaired transmission of sound through the external or middle ear, shown by abnormal air-conduction thresholds with normal bone conduction. Many causes are surgically correctable.

Surgical repair of the tympanic membrane and, when needed, the middle ear sound-conducting mechanism, performed to close a perforation, eradicate disease, and improve hearing.

Reconstruction of the ossicular chain using prosthetic material or reshaped bone to restore sound transmission when ossicles are eroded or fixed, often performed together with tympanoplasty.

An expanding keratinizing squamous epithelial cyst within the middle ear or mastoid that erodes adjacent bone and can cause chronic drainage, hearing loss, and complications. Definitive treatment is surgical removal.

Surgical removal of mastoid air cells, performed via canal wall up or canal wall down approaches, to eradicate chronic infection or cholesteatoma and to access the middle ear and surrounding structures.

A benign Schwann cell tumor arising from the vestibular division of the eighth cranial nerve, typically in the internal auditory canal or cerebellopontine angle. It causes asymmetric sensorineural hearing loss, tinnitus, and imbalance.

A lateral skull base surgical route through the mastoid and inner ear to reach the internal auditory canal and cerebellopontine angle. It sacrifices hearing on the operated side but offers early facial nerve identification.

Escape of cerebrospinal fluid through a dural and bony defect into the ear, nose, or wound, presenting as clear rhinorrhea, otorrhea, or postural headache. It risks meningitis and may require surgical repair.

Herniation of brain tissue through a skull base or temporal bone defect, sometimes into the middle ear or mastoid, causing conductive hearing loss, a mass behind the drum, and risk of cerebrospinal fluid leak or meningitis.

Intraoperative electrophysiologic surveillance of facial muscles that alerts the surgeon to mechanical or electrical stimulation of the facial nerve during ear and skull base surgery, helping preserve function.

Surgical opening of the bony canal surrounding the facial nerve to relieve pressure on the nerve, used in selected cases of traumatic paralysis or severe Bell palsy with persistent degeneration.

Acute idiopathic unilateral peripheral facial weakness of sudden onset, often with postauricular pain and altered taste, diagnosed after excluding other causes. Most patients recover, and corticosteroids improve outcomes.

Facial paralysis with a vesicular rash in the ear canal or auricle caused by varicella-zoster virus reactivation in the geniculate ganglion, often accompanied by hearing loss, vertigo, and severe pain. Antiviral therapy plus steroids is used.

A standardized scale, such as the House-Brackmann system, that classifies facial function from normal to total paralysis based on resting tone, symmetry, and movement, allowing comparison over time and between treatments.

Rhythmic tinnitus synchronous with the heartbeat, often vascular in origin such as a dural arteriovenous fistula, glomus tumor, or venous anomaly, and sometimes caused by increased pulse transmission in third mobile window disorders.

A vascular paraganglioma of the temporal bone, such as glomus tympanicum or jugulare, presenting with pulsatile tinnitus, a retrotympanic mass, and conductive hearing loss, and treated by embolization and surgical resection or radiation.