Hearing aids – different types

City Lit Objectives Understand why different aids suit different types of hearing loss Understand how the different types of hearing aids work Relevant for: Assignment 1 c Hearing aids

City Lit Different types of hearing aid Behind-the-ear (BTE) In-the-ear (ITE) In-the-canal (ITC) and completely in the canal (CIC) Open-fit Body worn Bone conduction Bone anchored (BAHA) CROS/ BiCROS Receiver-in-the-ear (RITE) Receiver-in-the-canal (RIC) Wireless FM

City Lit Behind-the-ear (BTE) aids Suitable for most hearing losses. The type of aid generally provided by the NHS. Most have a telecoil (‘T’ setting to use with a loop system and/or radio aid) and direct audio input connection (to use with a radio aid)

City Lit Analogue and Digital – the key difference Analogue The electric signal from the microphone is amplified “as is” and it is then transformed back to acoustic sounds using the speaker. Digital The electric signal from the microphone is transformed to bits and bytes of digital information and manipulated by the most advanced digital technology. The signal is transformed back acoustic sounds. Key difference A digital aid can be programmed to adapt more precisely to the specific hearing loss but may not give such a ‘true’ sound.

City Lit Pros and cons of digital aids Pros Different programmes for different listening environments Adjust automatically May reduce feedback Programmed to suit individual’s hearing loss Can aid more difficult losses

City Lit Real ear measurement (REM) with digital aids Part of the new hearing aid fitting procedure Shape/size of ear canal varies from person to person Measures the effects of the ear canal on sound Audiologist can adjust the hearing aid accordingly

City Lit Pros and cons of digital aids Cons Volume changes automatically – lack of control Batteries fall out when aid off Fitting times longer Staff need more training More costly Expectations may be too high

City Lit In-the-ear aid (ITE) In-the-canal aid (ITC) Completely in the canal aid (CIC) Not suitable for severe hearing losses. No telecoil or direct audio input connection

City Lit Open fit (behind-the-ear-aids) with tips/domes Suitable for mild to moderate hearing loss No earmould needed Can be issued on the day of the hearing test

City Lit Receiver-in-the-ear (in the canal) aid RITE (RIC) Speaker is in ear canal Less feedback No distortion through tubing Part of aid behind the ear is smaller

City Lit Body-worn hearing aids For very severe hearing loss Manual dexterity problems Learning disability

City Lit CROS aid (Contralateral routing of signals) Wired Sound routed from ‘deaf side’ to good side Wireless Sound transmitted wirelessly to good side

City Lit Wireless FM Can alter programme with remote Communication with both hearing aids Blue tooth enabled hearing aids

City Lit Traditional bone conduction hearing aids

City Lit Bone anchored hearing aid (BAHA) Clips onto a screw implanted into the skull behind the ear. Sound is transmitted by vibration into the cochlea (inner ear). Most have a direct audio input connection and an optional plug-in telecoil

City Lit Hearing aids - developments Improved directional microphone systems Automatic feedback cancellation Better background noise reduction Water resistance (Phonak, Siemens) Increased higher frequency range