Basic hearing aid tech_Day2_Delta.ppt

March 2002 Module 5 Basic hearing aid technology Hearing aids Types Settings Standard types of hearing aid Behind the ear aids: advantages/disadvantages Advantages Can be adjusted in the open ear Directional microphone Relatively invisible Room for telecoil or FM Greater amplification Room for large battery In the ear aids: advantages/disadvantages Advantages Acoustically superior Directional microphone Relatively invisible Special types of hearing aid Bone-anchored aids Body-worn hearing aids: advantages/disadvantages Advantages BW aids provide the greatest possible amplification Limited feedback problems Large control buttons Large batteries Room for technological features Special types of hearing aid Basic hearing aid design Microphone and telecoil MicroLink Linear nonlinear hearing aids Compression Linear nonlinear hearing aids Speaker, telephone, receiver Analogue hearing aids Analogue Unlimited options for values: Digital hearing aids Analogue to digital conversion Analogue ? digital conversion Digital ? analogue conversion Digital hearing aid principle User settings For the user Volume control M (T, MT and ON/OFF) switch Adaptive options For the audiology assistant Amplification - limiter - frequency characteristics Hearing aid interface Analogue adjustment Hearing aid interface Current adjustment and fitting Hearing aid interface: fitting devices The audiology assistant’s access to the hearing aid Hearing aid maintenance Daily check the condition of the battery make sure you have spare batteries wipe the ear plug after use Hearing aid batteries Hearing aid batteries In-situ battery testing Krishnamurti sp?rger om der opst?r en lyd, n?r et tr? falder i skoven, hvis der ikke er nogen til at h?re den. Der sker i hvert fald ikke meget for den h?reh?mmede som udelukker den ene halvdel af verden. Cochlea Implant: Elektroder - 22 plus to referance elektroder Sp?ndingsniveauer pr. elektrode - 255 (8 bit) Pr?sentere formant