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18 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the referral for conductive loss on PTA? |
A gap of 20db or more between BC and AC at 3 or more frequencies at 1K, 2K, 4K and 500Hz |
BSA |
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What is the referral for Asymmetrical loss on PTA? |
A gap of 20db or more between AC and AC at 2 or more frequencies at 1K, 2K, 4K and 500Hz |
BSA |
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What is the referral for deterioration of hearing loss? |
A change of 15db at 2 or more points in the last 24 months. |
BSA |
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How does noise reduction in hearing aids work? |
Depending on what frequencies the background noise is, the hearing aid reduces the gain at that channel to get rid of the noise and increases it again when speech is detected. |
Hearing aid technology |
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What is noise reduction for? |
To maximise speech intelligibility |
Hearing aid technology |
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What is notch filtering? |
Where the hearing aids reduce the gain in between syllables of speech. Used to reduce noise and enhance speech. |
Hearing aid technology |
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What is a directional microphone used for? |
To improve speech to noise ratio, improve sound localisation and improve speech audibility. |
Hearing Aid technology |
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What is an omnidirectional microphone? |
A microphone in the hearing aid that picks up sound from most angles, this is a default and general setting. |
Hearing aid technology |
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What is acoustic feedback? |
When there is sound leakage from the canal and is reamplified by the hearing aid. |
Hearing aid technology |
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How do you stop acoustic feedback? (5 things) |
Check fit of dome or mould (acoustic seal). Check for wax. Check critical gain. Reduce vent sizing. Reduce high frequencies. |
Hearing aid technology |
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What mould would you use for a severe loss and why? |
Soft silicone mould, comfortable and creates good acoustic seal. |
Mould materials |
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How do you reduce occlusion in hearing aids? |
Vents, open fit domes or open skeletal moulds. |
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What are the contraindications for impressions? (5 things) |
- excessive wax - foreign bodies - signs of discharge, inflammation or infection. - certain abnormalities (lots of exotoses) - recent surgery |
BSA |
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What are the contraindications for PTA? |
-Infection/ discharge -Pain -Wax -Foreign body -Recent noise exposure |
BSA |
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What three types of hearing aid vent is there? |
- parallel - diagonal - external |
Hearing Aid technology |
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What is the best vent and why? |
Parallel is the best as it reduces the low frequencies better than a diagonal vent. |
Hearing Aid technology |
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How would the correct vent size be selected? |
Bigger vent for good low frequency hearing, smaller vent for bad low frequency hearing as you need a good acoustic seal and the sound pressure level from a severe loss may cause feedback. A vent is needed to allow moisture to escape the ear and to equalise air pressure in the canal for better comfort. |
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What is a libby horn? What is it used for? |
A tubing that is wider at one end towards the canal. It is used to restore some lost high frequencies because of the change in diameter reduces high frequency attenuation caused by the turbulence. |
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