Audibility and Useful Hearing Aid FeaturesBy Ross, Mark; Hearing Loss Magazine, Vol. 24, No. 1, pp. 32-35
Publication Date: January/February 2003
Article discusses the concept of audibility as it applies to hearing aid amplification, and the current state of hearing aid technology. Useful hearing aid features, directional microphone hearing aids, feedback cancellation, personal FM systems, and telecoils are described. Hearing aid features discussed include wide dynamic range compression and multi-band hearing aids. A wide dynamic range compression circuit varies the degree of amplification, depending on the intensity level of the input. In a multi-band hearing aid, input speech sounds are divided into a number of separate bands, each of which is separately programmed and controlled. Directional microphones suppress sounds that arrive from the side and from the rear, thus increasing the audibility of the desired speech signal relative to other interfering sounds. Feedback cancellation can involve electronic solutions, including the reduction of the high frequency gain of the hearing aid when feedback is sensed. FM systems utilize a small FM microphone-transmitter placed close to a sound source. The sound signals are picked up by the FM microphone and transmitted to the FM receiver in the hearing aid. A low-cost personal FM system called the Converser is described. The Converser comes in two parts: (1) an FM microphone-transmitter, and (2) a body-worn FM receiver that is suspended around the neck. The suspension cord doubles as a neck loop, and transmits an electromagnetic signal to the telecoil in the hearing aid. Telecoils were designed to pick up the magnetic around telephones. For many people with hearing loss, a telecoil is the most effective way to communicate on a telephone.
Published by: Hearing Loss Association of America (formerly Self Help for Hard of Hearing People) (Website:http://www.hearingloss.org)
This publication is included in the library of the National Rehabilitation Information Center (NARIC), accession number J45085