Biomaterial Database

Carhart notch and electric bone-conduction audiometry. 1994

K Laitakari, and H Löppönen

Department of Otolaryngology, University of Oulu, Finland.

The Carhart notch is a depression in the bone-conduction audiogram of patients with clinical otosclerosis. The middle frequencies from 0.5 to 2 kHz, which correspond to the resonance frequency of the middle ear, can be substantially improved following successful stapes surgery. Twenty-nine consecutive patients with clinical otosclerosis were tested 2 weeks before and 7 months after stapes surgery with conventional air-conduction (AC) and bone-conduction (BC) audiometry and electric bone-conduction (EBC) audiometry using an Audimax 500 audiometer. The BC thresholds improved at 0.5-2.0 kHz corresponding to the Carhart notch. On average, the EBC thresholds remained more stable, showing no Carhart phenomenon, which supports the concept that EBC stimulation is not entirely equivalent to conventional BC audiometry, but has a different mode of action on the inner ear.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010040	Otosclerosis	Formation of spongy bone in the labyrinth capsule which can progress toward the STAPES (stapedial fixation) or anteriorly toward the COCHLEA leading to conductive, sensorineural, or mixed HEARING LOSS. Several genes are associated with familial otosclerosis with varied clinical signs.	Otospongiosis,Otoscleroses,Otospongioses
D001844	Bone Conduction	Transmission of sound waves through vibration of bones in the SKULL to the inner ear (COCHLEA). By using bone conduction stimulation and by bypassing any OUTER EAR or MIDDLE EAR abnormalities, hearing thresholds of the cochlea can be determined. Bone conduction hearing differs from normal hearing which is based on air conduction stimulation via the EAR CANAL and the TYMPANIC MEMBRANE.	Bone Conduction Hearing,Conduction Hearing, Bone,Conduction, Bone,Hearing, Bone Conduction
D004432	Ear, Middle	The space and structures directly internal to the TYMPANIC MEMBRANE and external to the inner ear (LABYRINTH). Its major components include the AUDITORY OSSICLES and the EUSTACHIAN TUBE that connects the cavity of middle ear (tympanic cavity) to the upper part of the throat.	Tympanic Cavity,Tympanum,Middle Ear,Cavities, Tympanic,Cavity, Tympanic,Ears, Middle,Middle Ears,Tympanic Cavities,Tympanums
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005260	Female		Females
D006319	Hearing Loss, Sensorineural	Hearing loss resulting from damage to the COCHLEA and the sensorineural elements which lie internally beyond the oval and round windows. These elements include the AUDITORY NERVE and its connections in the BRAINSTEM.	Deafness Neurosensory,Deafness, Neurosensory,Deafness, Sensoryneural,Neurosensory Deafness,Sensorineural Hearing Loss,Sensoryneural Deafness,Cochlear Hearing Loss,Hearing Loss, Cochlear,Deafnesses, Neurosensory,Deafnesses, Sensoryneural,Neurosensory Deafnesses,Sensoryneural Deafness,Sensoryneural Deafnesses
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults