HEARING LOSS CONDUCTIVE HEARING LOSS. A conductive hearing loss is due to any dysfunction of the outer and/or middle

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1 HEARING LOSS CONDUCTIVE HEARING LOSS A conductive hearing loss is due to any dysfunction of the outer and/or middle ear. It may be congenital or acquired, and it if left untreated it may result in a reduction of hearing at all frequencies on the audiometer. 1

2 SYMPTOMS OF A CONDUCTIVE HEARING LOSS Student may speak in a relatively soft voice Ability to understand speech is relatively unimpaired if made loud enough Tends to have the same degree of hearing loss for all frequencies May complain of tinnitus, a roaring, buzzing or ringing sound ETIOLOGY OF A CONDUCTIVE HEARING LOSS Excessive accumulation of cerumen in the external auditory canal Foreign objects in the external auditory canal Inflammation, infection of the middle ear (otitis media being the most common cause) ETIOLOGY OF A CONDUCTIVE HEARING LOSS Cont. Retraction, distention, puncture or rupture of the tympanic membrane Congenital malformation of the outer and/or middle ear Otosclerosis, a disease affecting the stapes ossicle of the middle ear Normally hard bone turns into a spongy mass usually over the stapedial footplate (usually has onset from mid-childhood to late middle adult life) 2

3 TREATMENT OF A CONDUCTIVE HEARING LOSS Medical treatment can usually cure or relieve these symptoms Surgical intervention may be necessary SENSORINEURAL HEARING LOSS A sensorineural hearing loss is due to an impairment of the inner ear, with an intact outer and middle ear. Occurs when sound cannot be perceived or analyzed properly resulting from an abnormality of the hair cells in the cochlea or the nerve pathways from the inner ear to the brain. SENSORINEURAL HEARING LOSS Cont. This type of hearing loss usually results in severe inability to hear at all frequencies, but not always. Any loss greater than 60 db HL will have some degree of sensorineural loss. High pitched sounds are often affected which makes it difficult for speech to be understood. This is true of high frequency consonant. Loudness has nothing to do with this inability to hear. 3

4 SYMPTOMS OF A SENSORINEURAL HEARING LOSS May speak excessively loud Generally has some trouble understanding speech Typically, has better hearing in the low frequencies Speech sounds are distorted Often a greater intolerance or discomfort for loud sounds than a normally hearing student May experience tinnitus, a roaring, buzzing or ringing sound ETIOLOGY OF A SENSORINEURAL HEARING LOSS Congenital: damage to the developing embryo caused by disease or drugs Acquired: anoxia at birth disease, injury, toxic effects of drugs, fever head injury exposure to intense noise vascular disturbances Meniere s Disease (fluids in the inner ear are affected causing hearing loss and dizziness) TREATMENT OF SENSORINEURAL HEARING LOSS Usually cannot be remedied by medical intervention Neural implants, acupuncture, miracle cures have no documented, scientific evidence of effect on sensorineural hearing loss Losses from vascular dysfunction are sometimes treatable May profit from: Hearing aids and/or auditory trainers Speechreading and auditory training Sign language Cued speech 4

5 MIXED HEARING LOSS A mixed hearing impairment is a hearing loss involving both conductive and sensorineural impairment The outer, middle and inner ear may be affected resulting from any one, or a combination, of the causes listed for conductive and sensorineural losses Likewise, a combination of the symptoms are exhibited. TREATMENT OF A MIXED HEARING LOSS The conductive component may be correctable by surgery or medication If such intervention is successful, hearing will be improved by no more than the amount of loss attributed to the conductive component GLOSSARY External ear: The portion of the ear consisting of the auricle or pinna, external auditory canal, ending at the tympanic membrane. Middle ear: An air filled cavity between the outer and inner ear that includes the tympanic membrane, the ossicles and the opening to the Eustachian tube. Inner ear: That portion of the ear that includes the cochlea an the semi-circular canals. These structures are responsible for the sense of hearing, balance, motion, etc. 5

6 GLOSSARY Cont. Auricle: the external portion of the ear; also called the pinna. External Auditory Canal: The passageway for sound from the auricle to the tympanic membrane. In adults, it is approximately 1-1 ½ incles long. Tympanic Membrane: Called the eardrum, it is a membrane that separates the outer and middle ears. It moves as a results of sound waves striking it and sets the ossicles in motion. GLOSSARY Cont. Ossicles: The three small bones of the middle ear: the malleus, incus, and stapes. They transmit sound vibration from the tympanic membrane to the cochlea. Stapedius muscle: One of the small muscles in the middle ear. Contraction of this muscle in response to a loud sound is an important part of impedence testing. GLOSSARY Cont. Eustachian tube: A bony cartilaginous tube connecting the middle ear with the back of the throat. It functions to supply air to the middle ear and to equalize pressure on both sides of the tympanic membrane. Cochlea: The inner ear structure that contains the end-organ of hearing. 6

7 GLOSSARY Cont. Conductive hearing loss: Impairment of hearing due to the interference of sound transmission to the inner ear, usually occurring in the outer or middle ear. Sensorineural hearing loss: Impairment of hearing caused by damage to the sensory mechanism of the inner ear. Mixed hearing loss: hearing loss resulting from impairment of a combination of conductive and sensorineural mechanism GLOSSARY Cont. Cerumen: Earwax secreted by wax-producing glands in the external auditory canal Otitis Media: Inflammation of the middle ear. If a thin, watery fluid accumulates it is sometimes known as serous otitus media. Pure Tone testing: A method of hearing screening utilizing puretones of various frequencies and intensities. GLOSSARY Cont. Impedance Testing: An objective method of testing the integrity and function of the middle ear system (Tympanometry). Compliance: Relates to the mobility of a system; in this instance, the middle ear. It is the inverse of stiffness. 7

8 DEGREES OF HEARING LOSS Normal hearing; 0-15 db HL Slight; db HL Mild; db HL Moderate; db HL Moderately Severe; db HL Severe; db HL Profound; <91 What is an Audiogram? An audiogram is a graphic representation of one s hearing thresholds Thresholds are the softest sounds one can hear at a specific frequency (pitch) Frequencies of an Audiogram Frequencies or pitches are graphed from left to right low pitches are on the left high pitches are on the right 8

9 Hearing Levels on an Audiogram loudness is graphed from top to bottom in Hearing Level (db) soft sounds are at the top medium sounds are in the middle loud sounds are at the bottom Symbols on an Audiogram X s represent the softest sound one s left ear hears through the air at a certain frequency O s represent the softest sound one s right ear hears through the air at a certain frequency Symbols Cont. We also see other symbols on the audiogram <and> s >s representthe the softest sound heard through one s mastoid bone (bone behind your ear) [ and ] s represent one s bone conduction thresholds with masking noise in the opposite ear 9

10 SLIGHT and MILD HEARING LOSS Difficulty hearing faint or distant speech Needs favorable seating May benefit from speechreading instruction May benefit from hearing aid MODERATE and MODERATELY- SEVERE HEARING LOSS Conversational speech is just audible at a distance of 3-5 feet Use of hearing aid, auditory trainer, speechreading, favorable seating Speech-language therapy to aid the student in the communication skills A student with this degree of hearing loss usually requires special education services 10

11 SEVERE HEARING LOSS May hear a loud voice about one foot from the ear With use of hearing aid and other listening devices may recognize some speech and detect environmental sounds Speech-language therapy to aid the student in the communication skills A student with this degree of loss also requires special education services PROFOUND HEARING LOSS May not be able to detect the presence of even very loud sounds (jet plane, subway, etc) without amplification May perceive sound as vibrations Does not rely on hearing as the primary channel for communication Use of amplification, plus all of the previously mentioned services are needed, but may be less successful in producing adequate oral speech and language Special education services are required 11

So, how do we hear? outer middle ear inner ear

So, how do we hear? outer middle ear inner ear The ability to hear is critical to understanding the world around us. The human ear is a fully developed part of our bodies at birth and responds to sounds that are very faint as well as sounds that are