| resonance theory of hearing | That the basilar membrane of the cochlea acts as a resonating structure, recording low tones from its apical turns and high tones from its basal turns. Synonym: Helmholtz theory of hearing. (05 Mar 2000) |
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| Weber's test for hearing | The application of a vibrating tuning fork to one of several points in the midline of the head or face, to ascertain in which ear the sound is heard best by bone conduction, that ear being the affected one if the sound-conducting apparatus (middle ear) is at fault (positive test), but probably the normal one if the neurosensory apparatus is diseased (negative test). (05 Mar 2000) |
| hearing | The sensation of sound. (12 Dec 1998) |
| hearing aid | An electronic amplifying device designed to bring sound more effectively into the ear; it consists of a microphone, amplifier, and receiver. (05 Mar 2000) |
| hearing aids | Devices which amplify sound to help persons with hearing loss. (12 Dec 1998) |
| hearing impaired persons | Persons with any degree of loss of hearing that has an impact on their activities of daily living or that requires special assistance or intervention. (12 Dec 1998) |
| hearing impairment | Hearing loss A reduction in the ability to perceive sound; may range from slight to complete deafness. See: deafness, threshold shift. (05 Mar 2000) |
| hearing level | The measure of the status of hearing as read directly on the hearing loss scale of an audiometer; described in decibels as a deviation from a standard value for zero on the audiometer. (05 Mar 2000) |
| Helmholtz theory of hearing | That the basilar membrane of the cochlea acts as a resonating structure, recording low tones from its apical turns and high tones from its basal turns. Synonym: Helmholtz theory of hearing. (05 Mar 2000) |
| normal hearing | The ability to perceive sound normally. Synonym: normal hearing. Origin: G. Akousis, hearing (05 Mar 2000) |
| organ of hearing | The content of the cochlea including the portion of the membranous labyrinth containing the spiral organ (cochlear duct) and the perilymphatic channels (scalae) which lie on either side. Synonym: labyrinthus cochlearis, organ of hearing. (05 Mar 2000) |
| alveolar bone loss | The resorption of bone in the supporting structures of the maxilla or mandible as a result of periodontal disease. (12 Dec 1998) |
| axon loss polyneuropathy | A type of polyneuropathy in which axon degeneration is the sole/predominant feature; many aetiologies, particularly toxic and metabolic; on nerve conduction studies, affects amplitudes of the responses, but does not cause conduction slowing or block. Synonym: axonal polyneuropathy. (05 Mar 2000) |
| blood loss, surgical | Loss of blood during surgery. (12 Dec 1998) |
| Parallel Electron Energy Loss Spectroscopy | <technique> Electron energy loss spectroscopy analyses the inelastically scattered electrons present in the beam after it has been transmitted through the sample. An electron energy loss spectrum typically consists of a monatomic decreasing background on which are superimposed a number of peaks. Each peak is characteristic of the scattering process that has occurred in the sample. The peaks can be used to obtain information about the chemical composition and electronic structure of the sample. Electron energy loss spectra are acquired typically in a magnetic sector spectrometer located under the camera chamber of the transmission electron microscope. Spatial resolution is typically limited by the minimum probe diameter of the microscope. Electron energy loss spectroscopy tends to be complimentary to EDS in that it can be used to analyse very thin samples of low Z materials. Acronym: PEELS (05 Aug 1998) |