8 Hearing Aids: Considerations in the Geriatric Population
Introduction
Hearing loss is the most common sensory deficit in the elderly.1 Hearing loss can impair communication, thus creating loneliness, isolation, dependence, frustration, and even communication disorders.1 When left untreated, hearing loss can substantially impair quality of life. Audiological rehabilitation, auditory rehabilitation, and aural rehabilitation are often used interchangeably to describe a patient’s management process designed for individuals who experience deficits in communication, as reported by Weinstein.2 Functional capabilities must be assessed on an individual basis due to wide variations in characterizing elderly adults. Chronological age is not a reliable predictor of physical, social, or mental status; therefore, it is important to understand how individuals view themselves. The impact of hearing loss varies by the degree of loss and the individual’s personality and activity level. The effects of hearing loss cannot be restricted to pathology alone because the mechanics of the ear cannot be isolated from the social aspects of hearing. The personality effects of hearing loss are largely dependent on an individual’s character, including mental, spiritual, societal, and economic resources. These components determine one’s reaction to hearing loss and the level of handicap it generates. Rehabilitation in the elderly must include a comprehensive approach to assessment and a multidimensional intervention. The purpose of rehabilitation with older adults, regardless of the severity or type of impairment, is to assist in recovering lost physical, psychological, and social skills.
The entire auditory system undergoes considerable change as the aging process progresses. Specific conditions may affect the type of aural rehabilitation to provide. For example, older adults develop changes of the outer ear and external auditory canal due to thinning of the epithelium, atrophy of subcutaneous tissue, and decline in secretory abilities of the glands. Hence certain types of hearing aids or audiological testing may not be appropriate due to changes in the ear structure. Although outer and middle ear pathologies are monitored under the care of a physician, the audiologist should be aware of any such issues. It is important to consider age-related changes in the brain when determining auditory rehabilitation in the elderly population. Aging is associated with progressive losses in function across multiple systems, including sensation, cognition, memory control, and affect. Age-related modifications in the central nervous system are associated with declines in the ability to perform selected cognitive and sensorimotor tasks; decreased functional capacity; and alterations in gait control, learning, and memory.3 These deficits may affect the patient’s ability to respond to aural rehabilitation strategies.
Hearing loss may be severe in older persons, whether from causes associated with aging or owing to other etiologies. More severe-to-profound losses may be associated with a change in personality and lifestyle due to the challenges that listening presents. Elderly individuals with hearing loss also find listening in the presence of multiple speakers or background noise especially difficult because their ability to detect signals in noise diminishes with age. All too often, the elderly person begins to believe that the inability to hear and understand a conversation is due to deterioration of the brain (intellectual impairment). Family, friends, and stereotypes of the elderly population may reinforce this belief. People may ignore the hearing-impaired person in group conversations and assume that the person does not know what is going on. Stereotypes of aging, such as physical and mental slowing, further undermine the elderly person’s weakened self-confidence and hasten his or her withdrawal from society. The isolation caused by hearing loss can contribute to delay in elderly individuals’ seeking medical attention to address their hearing handicap.
There is a significant relationship between hearing and speech. The ear is sensitive to a certain frequency range, and speech falls within that range. Speech can be divided into two types of sounds: vowels and consonants. Roughly, vowels fall into the frequencies below 1,500 Hz, and consonants above 1,500 Hz. Vowels are relatively powerful sounds, whereas consonants are weaker sounds and are dropped often in everyday speech or not pronounced clearly. In essence, low-frequency speech sounds provide the listener with a sense of volume, whereas higher-frequency speech sounds provide meaning and clarity. Most commonly, older adults experience a hearing loss configuration that reflects comparatively good low-frequency hearing and poorer high-frequency hearing. High-frequency sensorineural hearing loss often causes deterioration of a person’s ability to understand speech. Speech recognition ability can be correlated with the aging process.4 In some cases, diminished speech understanding is due to peripheral hearing loss. This type of loss typically presents with the ability to hear speech but not understand it. A second cause of trouble understanding speech is central auditory processing issues, such that age-related changes or other changes in the auditory pathways of the brainstem or portions of the auditory cortex degrade the speech signal.5 Individuals with hearing loss may ask people to speak louder in an attempt to achieve better speech clarity. Unfortunately, “louder” is not always the answer. Loudness may actually reduce discrimination ability due to distortion of the speech signal. Distortion occurs more frequently in people with high-frequency hearing losses because overall loudness also amplifies the low-frequency sounds, such as vowels, which they usually hear at a normal or close to normal volume. Speaking in a louder voice creates overpowering vowels with relatively weaker consonants and does not improve the clarity of speech. These factors must be assessed and are critical to proper hearing aid selection.
Before a hearing aid is recommended, it is necessary to determine whether the patient will be helped by it enough to justify purchasing one. Hearing aids are generally not covered by Medicare; however, Medicaid or private insurance plans may cover the cost of hearing aids in whole or in part. Regardless of insurance type, patients must be offered the same services, the cost of the services must be equitable, and national procedure codes must be used for requesting reimbursement. It is important to assist the elderly patient in figuring out what his or her specific insurance will cover, if anything, before proceeding with purchasing hearing aids. For those patients that have served in the military, it is advisable to obtain amplification through the Veteran’s Administration because hearing aids and other assistive devices are fully covered through veteran’s benefits. Both economic factors and individual hearing loss should be taken into account. This is particularly important in a sensorineural impairment in which the problem is more one of discrimination than of amplification. Typically, high-frequency sensorineural hearing loss is attributed to presbycusis—age-related hearing loss that is associated with the cochlear degenerative process of aging. Humes et al reported that the hearing loss of older adults is greatest in the frequency region (≥ 2,000 Hz) for which the amplitude of speech is the lowest.6
Beyond presbycusis, there are also medical causes of hearing loss, including infection, autoimmune disease, medication effects, and many other conditions. These causes should always be evaluated by a physician, and medical causes of hearing impairment generally should be treated in conjunction with auditory rehabilitation and amplification for every patient. A patient being considered for a hearing aid should undergo otologic evaluation first.
Hearing Aid Considerations
Hearing aids, assistive listening devices, and implantable devices may be helpful for older adults with hearing loss and communication issues. A hearing aid is a portable personal amplifying system used to compensate for a loss of hearing. Almost all hearing-impaired patients are candidates for a hearing aid, although some will receive greater benefits from their aids than others. Any patient who is motivated to use a hearing aid deserves a thorough evaluation and a trial with an appropriate instrument. Assistive listening devices include amplified telephones, television amplifiers, and other such tools that can increase signal intensity for the listener. Implantable devices can include bone-anchored hearing aids, cochlear implants, and the auditory brainstem implant. Hearing aids are appropriate for the vast majority of patients, and this chapter does not address cochlear implants or auditory brainstem implants.
According to Kochkin, the average age of new hearing aid users is 71.1 years.7 Of the 34 million people with hearing loss in the United States, only 25% use hearing instruments, which suggests that over 25 million people are living with untreated/unaided hearing loss.8 Despite recent advances in hearing aid technology and miniaturization of hearing aids, negative attitudes persist. Before fitting a hearing aid in an older adult, various factors must be considered, such as communication, physical, psychological, and sociological factors. Some of the issues older adults face when considering use of hearing aids include the following:
1. Experience with hearing aids
2. Financial considerations
3. Attitudes toward hearing aids
4. Degree of hearing loss
5. Lack of need
6. Visual/manual dexterity issues
7. Recommendations from professionals
8. Recommendations from family and friends
9. Stigma
10. Trust
11. Lack of knowledge.
The audiologist is responsible for informing patients fully about the entire process and providing realistic expectations, counseling, and support before fitting a hearing aid.
Prefitting Assessment
The audiologist must administer tests to determine whether a hearing loss is present and, if so, the nature of the hearing loss. Threshold measures used in conjunction with otoscopy and immittance testing can help determine the need for medical or surgical remediation. If a condition requires immediate medical attention, the patient should be referred to the appropriate medical professional. Regardless of any degree or nature of impairment, medical clearance for hearing aids from a physician should always be obtained. If no medically treatable condition is present, the severity of hearing impairment, symmetry, configuration, type of hearing loss, and speech perception should be documented. Once medical contraindications are ruled out and the patient is determined to be a candidate for amplification, the audiologist must discuss thoroughly the nature of the hearing loss, its consequences, and realistic expectations, and must evaluate personal factors and the patient’s motivational level to use amplification.2
The patient should be given a clear explanation of the hearing problem and why he or she has trouble hearing or understanding speech. Patients should understand the difference between hearing difficulty and understanding difficulty, and how amplification affects both. The problems that might easily lead the patient to develop frustration and behavioral changes should be explained clearly so that these problems can be met forthrightly and intelligently. The goal of aural rehabilitation is to prevent or mitigate psychosocial changes and quality-of-life impairments that may result from hearing loss.
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