What is the Carhart notch in Pure Tone Audiometry?

Stimulation of the ear via bone conducted vibrations is a well-established way to differentiate conductive from sensorineural hearing loss – but paradoxically, the accurate testing of bone conduction thresholds depends on normal middle ear function. Impairment of bone conducted vibrations, for example by stapes footplate fixation, results in raised thresholds by bone conduction. This effect arises across the frequency range and is related to the resonance properties of the ossicular chain. The result is a “notch” in the bone conduction audiogram which is more pronounced at 2 kHz as described by Carhart in 1950.

Carhart, R. (1950) Clinical application of bone conduction audiometry. Arch Otolaryngol 51, pages 798-808

May 2017
Want to know more about our products or arrange a demonstration? Contact an Interacoustics sales office, call +45-6371-3555, or find a distributor.
Features and/or functions may not be available for all countries or all areas and product specifications are subject to change without prior notification.
Copyright © 2020 Interacoustics A/S. All rights reserved. Privacy policy