Hearing Aids. Bernycia Askew

Transcription

1 Hearing Aids Bernycia Askew

2 Who they re for Hearing Aids are usually best for people who have a mildmoderate hearing loss. They are often benefit those who have contracted noise induced hearing loss with age and have a high frequency loss While those who can be considered legally deaf can acquire hearing aids, the will usually suffer from a extreme sensorineural hearing loss and would benefit more from a cochlear implant. Often recommended to people when there is noticeable difficulty understanding speech.

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4 Pure Tone Testing Air Conduction- used to measure the ability of hearing from the outer and middle ear. Done with headphones place over Outer Ear or inserted into the ear canal. Bone conduction- Measure of inner ear through bone conduction. Tone sent directly through temporal bone to the inner ear.

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7 Hearing Testing Some of the basic measurements when fitting a person for a hearing aid Puretone Average (PTA)-After pure tone air conduction responses have been recorded for each ear, the responses at 500 Hz, 1000Hz and 2000 Hz are averaged and recorded in the summary chart of the audiogram. Measured in decibels (db). Most Comfortable Listening Level Uncomfortable Listening Level Speech Recognition Threshold (SRT)- The Speech Recognition Threshold (SRT) is measured in decibels (db), Two-syllable words, called Spondee Words, are presented to the client. The SRT is defined as the lowest hearing threshold level at which 50% of a list of Spondee Words is correctly identified for each ear. Word Discrimination score (WD)- is based on the percentage of words correctly understood when presented at MCL or at a normal conversational speech level (40dB-60dB).

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10 Types of Hearing loss Conductive- mechanical issues in outer or middle ear Sensorineural hearing loss- Damage to the cochlea or auditory nerve, permanent. Mixed Hearing loss- a combination of conductive and Sensorineural hearing loss.

11 Hearing Aid Parts Microphone- picks up sound from the environment and converts it into an electrical signal, which it sends to the amplifier An Amplifier- increases the volume of the sound and sends it to the receiver. A receiver/speaker- changes the electrical signal back into sound and sends it into the ear. Then those impulses are sent to the brain. A battery-provides power to the hearing aid.

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13 Digital vs. Analog Analog hearing aids amplify sounds -- the trouble is they amplify all sounds equally. Conversational speech is obstructed by other back ground noise (like the television, or a vaccumm cleaner) Some analog hearing aids are programmable, meaning that they can hold separate settings for different listening situations. You can "change the channel" to adjust certain sounds louder or softer, depending on your preferences and hearing loss. They aren't as sensitive as digital hearing aids.

14 Styles Behind the Ear In the Ear In the canal Completely in the canal Hearing aid size can correlate to the amount of loss a person has. Smaller hearing aids have smaller batteries, and are better for those with a mild/moderate loss whereas bigger aids are for more severe cases because they have more power to amplify sound.

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17 Bone conduction HA External bone-conduction hearing aids function by transmitting sound waves through the bone to the ossicles of the middle ear. New technology have also allowed for the BAHA Implants that Allow vibrations to go directly to the Inner ear. Air-conduction hearing aids require the use of ear molds, which may be problematic in patients with chronic middle ear and ear canal infections or an ear canal that cannot accommodate an ear mold. bone-conduction hearing aids may be an alternative. A titanium post is surgically attached to a bone behind the ear. The sound processor attaches to the post and transmits sound vibrations through external abutment to the titanium implant. The implant vibrates in the skull and inner ear, stimulating the nerve fibers of the inner ear and allowing the individual to hear.

18 Some issues. Feedback- a squealing/whistling caused by sound (particularly high frequency sound) leaking and being amplified again, may be a problem for severe hearing losses. To High of a Gain- The ideal Gain for a person is ½ to 1/3. If the fitting of the hearing aid doesn t suit the hearing loss, or if there is too much amplification, the hearing aid can actually cause noise induced hearing loss.