Hearing

Age-related sensorineural hearing loss cannot be ameliorated with medication or surgery. Rather, the principal form of treatment is amplification using a hearing aid. Analog and digital hearing aids are designed to amplify either all or selective frequencies based on an individual's hearing loss, with the goal of bringing all speech sounds into the range of audibility for the hearing-impaired listener. People with sensorineural hearing loss also experience a reduced tolerance for loud sounds. As a result, most hearing aids incorporate amplitude compression circuits to limit the output level of amplified sound without producing distortion. Hearing aids are quite effective for amplifying sound without producing discomfort. Thus, it is not surprising that older hearing-impaired people demonstrate significant benefit from hearing aids for understanding speech in quiet and noisy listening environments and for reducing their perceived hearing handicap (Humes, Halling, and Coughlin). However, there is wide individual variability in the magnitude of hearing aid benefit. The same amplification that hearing aids provide for a target speech signal is applied as well to noise, including the voices of people talking in a background. As a result, older hearing aid users often report less benefit from their hearing aids in noisy environments than in quiet environments. Only about 20 percent of older individuals with hearing loss purchase hearing aids. The prevailing reasons for lack of hearing aid use among older people are stigma, cost, and limited perceived benefit, particularly in noise. Another possible reason for hearing aid rejection by older people is that personal hearing aids do not overcome the older person's difficulties in understanding reverberant speech or rapid speech.

Frequency-modulated (FM) systems are amplification devices that can be beneficial for older listeners when they are located at a distance from a speaker. These can be independent systems or they can be components attached to a hearing aid and used as a selectable circuit. An FM system includes a microphone/transmitter placed near the speaker that broadcasts the sound, via FM transmission, to a receiver/amplifier located on the user. The amplified sound is unaffected by room acoustics, including noise and reverberation. This type of device is particularly helpful for older listeners in theaters, houses of worship, or classrooms, where a long distance between the speaker and the listener can aggravate the detrimental effects of poor room acoustics for older listeners with hearing loss.

Older individuals with bilateral, severe-to-profound hearing loss generally have widespread damage to the cochlea and derive minimal benefit from hearing aids and FM systems for recognizing speech. These individuals are potential candidates for a cochlear implant, a surgically implanted device that delivers speech signals directly to the auditory nerve via an electrode array inserted in the cochlea. Considerable success in receiving and understanding speech, with and without visual cues, has been reported for older cochlear implant recipients (Waltzman, Cohen, and Shapiro).

Regardless of the type of device used by the older hearing-impaired person, a successful remediation program includes auditory training, speechreading (lipreading) training, and counseling. The emphasis in these programs is training the older person to take full advantage of all available contextual cues, based on the consistent finding that older people are able to surmount most communication problems if contextual cues are available. Another principle of these programs is training effective use of nonverbal strategies (e.g., stage managing tactics for optimal viewing and listening) and verbal strategies (e.g., requesting the speaker to talk more slowly).