| Hearing aid | |
|---|---|
 In-the-canal hearing aid | |
| Other names | Deaf aid |
A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers such as personal sound amplification products (PSAPs) or other plain sound reinforcing systems cannot be sold as "hearing aids".
Early devices, such as ear trumpets or ear horns,[1][2] were passive amplification cones designed to gather sound energy and direct it into the ear canal.
Modern devices are computerised electroacoustic systems that transform environmental sound to make it audible, according to audiometrical and cognitive rules. Modern devices also utilize sophisticated digital signal processing, aiming to improve speech intelligibility and comfort for the user. Such signal processing includes feedback management, wide dynamic range compression, directionality, frequency lowering, and noise reduction.
Modern hearing aids require configuration to match the hearing loss, physical features, and lifestyle of the wearer. The hearing aid is fitted to the most recent audiogram and is programmed by frequency. This process called "fitting" can be performed by the user in simple cases, by a Doctor of Audiology, also called an audiologist (AuD), or by a Hearing Instrument Specialist (HIS) or audioprosthologist. The amount of benefit a hearing aid delivers depends in large part on the quality of its fitting. Almost all hearing aids in use in the US are digital hearing aids, as analog aids are phased out.[3] Devices similar to hearing aids include the osseointegrated auditory prosthesis (formerly called the bone-anchored hearing aid) and cochlear implant.
- ^ Bentler RA, Duve MR (December 2000). "Comparison of hearing aids over the 20th century". Ear and Hearing. 21 (6): 625–639. doi:10.1097/00003446-200012000-00009. PMID 11132788. S2CID 46218426.
- ^ "Ear Horn Q&A". Archived from the original on 24 July 2008. Retrieved 6 December 2007.
- ^ Kochkin S (January 2010). "MarkeTrak VIII: Consumer satisfaction with hearing aids is slowly increasing". The Hearing Journal. 63 (1): 19–20. doi:10.1097/01.HJ.0000366912.40173.76. S2CID 73880581.