deafness
See deafly.

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Partial or total inability to hear.

In conduction deafness, the passage of sound vibrations through the ear is interrupted. The obstacle may be earwax, a ruptured eardrum, or stapes fixation, which prevents the stapes bone from transmitting sound vibrations to the inner ear. In sensorineural deafness, a defect in the sensory cells of the inner ear (e.g., injury by excessive noise) or in the vestibulocochlear or eighth cranial nerves prevents the transmission of sound impulses to the auditory centre in the brain. Some deaf people are helped by hearing aids or cochlear implants; others can learn to communicate with sign language and/or lip reading.

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      partial or total inability to hear. The two principal types of deafness are conduction deafness and nerve deafness. In conduction deafness, there is interruption of the sound vibrations in their passage from the outer world to the nerve cells in the inner ear. The obstacle may be earwax that blocks the external auditory channel, or stapes fixation, which prevents the stapes (one of the minute bones in the middle ear) from transmitting sound vibrations to the inner ear. In nerve deafness, some defect in the sensory cells of the inner ear (e.g., their injury by excessive noise) or in the vestibulocochlear nerve prevents transmission of sound impulses from the inner ear to the auditory centre in the brain. Deafness at birth is nearly always of the nerve type and cannot be improved by medical means.

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Universalium. 2010.

Look at other dictionaries:

  • Deafness — Deaf ness, n. 1. Incapacity of perceiving sounds; the state of the organs which prevents the impression which constitute hearing; want of the sense of hearing. [1913 Webster] 2. Unwillingness to hear; voluntary rejection of what is addressed to… …   The Collaborative International Dictionary of English

  • deafness — late 14c., from DEAF (Cf. deaf) + NESS (Cf. ness) …   Etymology dictionary

  • Deafness — (Roget s Thesaurus) < N PARAG:Deafness >N GRP: N 1 Sgm: N 1 deafness deafness hardness of hearing surdity| Sgm: N 1 inaudibility inaudibility inaudibleness PARAG:Deafness >V GRP: V 1 Sgm: V 1 be deaf be deaf &c. >Adj …   English dictionary for students

  • deafness — General term for inability to hear. central d. d. due to disorder of the auditory system of the brainstem or cerebral cortex. cortical d. d. resulting from bilateral lesions of the primary receptive …   Medical dictionary

  • deafness — n. partial or total loss of hearing in one or both ears. Conductive deafness is due to a defect in the conduction of sound from the external ear to the inner ear. This may be due to perforations of the eardrum, fluid or infection in the middle… …   The new mediacal dictionary

  • deafness — n. acquired; congenital deafness * * * [ defnɪs] congenital deafness acquired …   Combinatory dictionary

  • deafness — (New American Roget s College Thesaurus) Lack of ability to hear Nouns 1. deafness, hardness of hearing, hearing impairment, hearing loss, loss of hearing, surdity; deaf mutism. 2. (communication with deaf) lip reading, deaf and dumb alphabet,… …   English dictionary for students

  • deafness — deaf ► ADJECTIVE 1) without the faculty of hearing or having impaired hearing. 2) (deaf to) unwilling to listen or respond to. ● fall on deaf ears Cf. ↑fall on deaf ears ● turn a deaf ear Cf. ↑tu …   English terms dictionary

  • deafness — noun partial or complete loss of hearing • Syn: ↑hearing loss • Derivationally related forms: ↑deaf • Hypernyms: ↑hearing impairment, ↑hearing disorder • Hyponyms: ↑ …   Useful english dictionary

  • deafness — noun see deaf …   New Collegiate Dictionary

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