Transcript Document
TOPIC 1 TYPES OF HEARING IMPAIRMENT Types of Hearing Impairment A loss of sensitivity Auditory nervous system pathology Important Terms Time of onset Congenital: Acquired: Adventitious: present at birth obtained after birth acquired after birth Important Terms Time Course Acute: duration Chronic: Sudden: Gradual: time sudden onset/short long duration rapid onset changes slowly over Important Terms Time Course Temporary: Permanent: Progressive: Fluctuating: time limited duration irreversible advancing changes in degree over Important Terms Number of Ears Involved Unilateral: Just one Bilateral: Both Hearing Sensitivity Loss “The ear is not as sensitive as normal in detecting sound” Types: Conductive Sensorineural Mixed Conductive Hearing Loss “Caused by an abnormal reduction or attenuation of sound as it travels from the outer ear to the cochlea” Conductive Hearing Loss An audiogram of a bilateral conductive hearing loss Conductive Hearing Loss Differences in the air-bone gap across different types of hearing loss Sensorineural Hearing Loss “Caused by a failure in the cochlea to transduce the sound from the middle ear to neural impulses in the VIII Nerve.” Sensorineural Hearing Loss n Implications include: A reduction in the sensitivity of the receptor cells in the cochlea A reduction in the frequency resolving power of the cochlea A reduction in the dynamic range of the system Sensorineural Hearing Loss An audiogram of a bilateral sensorineural hearing loss Sensorineural Hearing Loss Differences in the air-bone gap across different types of hearing loss Mixed Hearing Loss “A loss with both a conductive and sensorineural component.” Mixed Hearing Loss An audiogram of a bilateral mixed hearing loss Mixed Hearing Loss Differences in the air-bone gap across different types of hearing loss Types of Hearing Impairment A loss of sensitivity Auditory nervous system pathology Auditory Nervous System Impairment Causes: Disease Disordered auditory nervous system development Auditory Nervous System Impairment Kinds: Retrocochlear disorders Central auditory processing disorders Auditory Nervous System Impairment § Auditory Characteristics: Reduced ability to understand speech in a noise background Problems understanding speech with reduced redundancy Problems with localization and lateralization Problems processing normal or altered temporal cues