- pure-tone threshold audiometry is the measurement of an individual's hearing sensitivity for calibrated pure tones (1)
- assesses hearing loss by air and bone conduction.
- pure tone signals between 125Hz and 12kHz and at variable intensities are fed to the patient either via a vibrator applied to the mastoid process - for bone conduction - or via earphones - for air conduction. The intensity at which 50% of tones for a particular frequency are reported is charted as the threshold for that frequency on an audiogram.
- the symbols
used on most audiograms are:
- x - left, air conduction
- o - right, air conduction
- ] - left, bone conduction
- [ - right, bone conduction
- its results have significant influence on the medical, legal, educational, occupational, social, and psychological outcomes (1)
- degrees of Hearing Loss (2):
Normal Hearing -10-26 dB Mild Hearing Impairment 27-40 dB Moderate Hearing Impairment 41-55 dB Moderately Severe Impairment 56-70 dB Severe Hearing Impairment 71-90 dB Profound Hearing Impairment >= 91 dB
- (1) The American Speech-Hearing-Language Association (ASHA).Guidelines for Manual Pure-Tone Threshold Audiometry. 2005
- (2) Katz, J. Handbook of Clinical Audiology, Williams and Wilkins, 1985.