Glossary

The difference between the air-conduction and bone-conduction thresholds at a frequency. A gap of roughly 10 dB or more indicates a conductive component.

Also: ABG

See also: Conductive hearing loss, Bone conduction, Air conductionRead in context →

The route by which sound reaches the cochlea through the outer and middle ear. Tested with earphones; it assesses the whole auditory system.

Also: AC

See also: Bone conduction, Air–bone gapRead in context →

A graph of hearing threshold (dB HL) against frequency. The primary record of a pure-tone test.

See also: Decibel hearing level (dB HL), Pure-tone average (PTA)Read in context →

The route by which a vibrator on the skull drives the cochlea directly, largely bypassing the outer and middle ear. Reflects cochlear function.

Also: BC

See also: Air conduction, Air–bone gapRead in context →

An artefactual dip in the bone-conduction threshold around 2 kHz, seen in otosclerosis. Caused by stapes fixation disturbing ossicular resonance; it typically resolves after successful stapes surgery.

Also: Carhart effect

See also: Conductive hearing loss, Bone conductionRead in context →

A hearing loss caused by a fault in the outer or middle ear, with a healthy cochlea. Defined audiometrically by an air–bone gap.

See also: Air–bone gap, Sensorineural hearing loss, Mixed hearing lossRead in context →

Detection of a test tone by the non-test ear after the sound has crossed the skull. The reason masking is sometimes needed.

See also: Interaural attenuation, Masking, Shadow curveRead in context →

The clinical decibel scale plotted on the audiogram, built so that 0 dB HL at every frequency represents the average threshold of normal-hearing young adults.

Also: dB HL, hearing level

See also: Sensation level (dB SL), AudiogramRead in context →

A decibel scale referenced to an individual's own threshold. A tone at 20 dB SL is 20 dB above that person's threshold.

Also: dB SL

See also: Decibel hearing level (dB HL), SISIRead in context →

The loss of energy a sound undergoes crossing the skull from one ear to the other. About 40 dB for supra-aural earphones, higher for insert earphones, and near 0 dB for bone conduction.

Also: IA

See also: Cross-hearing, MaskingRead in context →

Presenting noise to the non-test ear so it cannot respond to a cross-heard tone, ensuring the test ear's threshold is genuinely its own.

See also: Cross-hearing, Plateau method, Masking dilemmaRead in context →

A situation — classically large bilateral conductive losses — in which no masker level can isolate one ear without crossing back to the other, so no usable plateau exists.

See also: Masking, Plateau methodRead in context →

A hearing loss with both a conductive and a sensorineural component: an air–bone gap together with abnormal bone conduction.

See also: Conductive hearing loss, Sensorineural hearing loss, Air–bone gapRead in context →

The technique for finding the correct masking level: the masker is raised in steps and the true masked threshold is the plateau over which it does not change.

See also: Masking, Masking dilemmaRead in context →

Age-related hearing loss: a symmetrical, gently sloping, high-frequency sensorineural loss.

Also: age-related hearing loss

See also: Sensorineural hearing lossRead in context →

A single-figure summary of a loss: the mean threshold at 500, 1000 and 2000 Hz. A four-frequency variant adds 4000 Hz.

Also: PTA

See also: Audiogram, Decibel hearing level (dB HL)Read in context →

An abnormally rapid growth of loudness above threshold, caused by loss of outer-hair-cell compression. A hallmark of cochlear pathology and the basis of the SISI.

See also: SISI, Sensorineural hearing lossRead in context →

Relating to a lesion of the auditory nerve or its central connections — beyond the cochlea. The prototype is the vestibular schwannoma.

See also: Tone decay, SISI, Sensorineural hearing lossRead in context →

A hearing loss caused by a fault in the cochlea or auditory nerve, with air and bone conduction equally impaired and no air–bone gap.

Also: SNHL

See also: Conductive hearing loss, Mixed hearing loss, RetrocochlearRead in context →

A false audiogram of a poor ear, produced when unmasked cross-hearing lets the good ear respond. It mirrors the good ear, offset by the interaural attenuation.

See also: Cross-hearing, Masking, Interaural attenuationRead in context →

Short Increment Sensitivity Index — a test of the ability to detect small (1 dB) loudness increments. A positive result favours a cochlear site of lesion.

Also: Short Increment Sensitivity Index

See also: Recruitment, Tone decay, Sensation level (dB SL)Read in context →

Abnormally rapid fading of a sustained tone, measured by the Carhart test. Marked decay raises suspicion of a retrocochlear lesion.

Also: abnormal auditory adaptation

See also: SISI, RetrocochlearRead in context →

The orderly mapping of frequency to place along the cochlea — high frequencies at the base, low at the apex — that lets audiometry give place-specific results.

Also: tonotopic organisation

See also: AudiogramRead in context →