5.6.3 Hearing Loss - Terminology | Military Compensation SRCA Manuals and Resources Library, Permanent Impairment Handbook, Ch 5 Calculation using the Approved Guide

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5.6.3 Hearing Loss - Terminology

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Acoustic trauma – Result of brief high intensity noise exposure.

Air conduction – Passage of sound waves through the outer and middle ear air spaces into the inner ear and the cochlea.

Binaural hearing loss – Hearing is a binaural auditory function, involving the simultaneous functioning and interaction of both ears. Hearing loss is therefore expressed as a percentage loss of hearing for both ears together.

Bone conduction – Transmission of sound waves direct to the inner ear via bone of the head, bypassing the air spaces of the outer and middle ear.

Conductive deafness – Any impediment to the transmission of sound waves through the outer and middle ear.

Cycles per second (CPS) – The number of sound waves arriving at a particular point in one second.

Decibel (dB) – Sound pressure is measured in decibels. The threshold of physical pain is around 135 dB.

Diplacusis – Condition of the ear leading to distortion of tonal quality of a pure tone. The hearing of the same sound differs in each ear.

Frequency – Dependent on CPS (see above). The higher the CPS, the higher the frequency or pitch of the sound.

Intensity – Refers to the loudness of sound.

Hertz (Hz) – One hertz equals one CPS (see above).

AGHS – The Australian Government Hearing Services. AGHS should be used to examine all hearing loss cases.

Otitis External – Inflammation of the external auditory canal. May be due to scratching or eczema, with resulting swelling and infection.

Otitis Media – Obstruction of the eustachian tube followed by the filling of the inner ear with fluid. Also known as 'glue ear'.

Ototoxic drugs – Drugs which have a harmful effect on the ear.

Paracusis – A condition of deafness where hearing is better in a noisy environment.

Permanent threshold shift (PTS) – Any residual impairment remaining after recovery of a temporary threshold shift (see below).

Presbycusis – Sensory-neural deafness caused by the natural ageing process.

Pure tone – When a sound has only one frequency.

Sensori-neural deafness – Occurring in the inner ear, relating to problems with sound conversion and subsequent recognition by the brain. Also known as 'perceptive' or 'nerve' deafness.

Socioacusis – Deafness caused by loud every day or social noise.

Temporary threshold shift (TTS) – Fatiguing of the hair cells in the cochlea. Recovery occurs after cessation of sound.

Threshold of hearing – The minimum intensity of sound which is audible at a particular frequency.

Tinnitus – Ringing in the ear. Tinnitus is a symptom rather than a diagnosis of a specific disease or condition. Exposure to environmental noise pollution and trauma can produce tinnitus. Tinnitus is derived from the Latin word 'tinnire' which literally means 'to jingle'. It can arise without an underlying hearing impairment.

Tone decay – Inability to maintain perception of a continuous tone presented above the auditory threshold.