62: Managing Hearing Impairment in Older Adults

Hearing loss is highly prevalent in older individuals and is often overlooked as a potential contributor to morbidity in this population. In the United States, an estimated 26.7 million adults 50 years of age or older suffer from bilateral hearing loss of 25 dB (decibels) or greater, and up to 79% of adults age 80 years and older may suffer from hearing loss. It is likely that many of these individuals could be adequately treated with current technology; however, evidence suggests that this population is vastly undertreated. For example, in the United States, only 14.2% of adults 50 years of age or older with hearing loss use hearing aids. The rate is similar in England and Wales (17.3%) despite having a health care system that covers the cost of hearing aids.

Hearing loss affects an individual’s ability to communicate effectively, but it is often perceived as a normal part of aging, both by patients and health care providers. However, current evidence supports the contrary. Recent studies show that hearing loss is independently associated with incident dementia, accelerated cognitive decline, poorer neurocognitive functioning, and increased falls and gait disturbances. Such significant negative outcomes warrant heightened vigilance by providers in addressing and treating hearing loss in their patients.

Age-related hearing loss in older adults represents the sequelae of multiple insults that can progressively damage the cochlea over time. Although many of these factors cannot be modified (eg, intrinsic aging of the cochlea, sex, genetic predisposition), several factors (eg, noise exposure, ototoxic medication use) can be controlled and are discussed below.

Signs & Symptoms

Patient interview—

Patients are often unaware of their hearing impairment, especially when it progresses gradually over many years. It is useful to ask a patient if they have difficulty hearing in large groups or in loud, crowded venues, or if they often ask people to repeat what they have said. The interviewee may note that she can hear people but that other people mumble too much or are just speaking too softly. Answers to these questions can provide clues to the provider about the presence of hearing loss. If the patient is aware of the hearing loss, the time course and nature of the progression can give vital information about the etiology. It is important to ask about tinnitus (ringing), ear pain (otalgia), ear drainage (otorrhea), dizziness (vertigo, disequilibrium), other neurologic deficits, and cranial neuropathies. A history of intense and/or prolonged noise exposure, ear trauma, head trauma, ear surgery, or ear infections (even remotely as a child or young adult) are necessary components of any interview.

Family member/friend interview—

Often, the insightful person or the impetus for the hearing loss-related office visit is a family member or friend. They are often the first to notice that the patient is asking others to repeat themselves or misunderstanding words or entire conversations. They may note that they have to speak louder to interact with the patient, that the patient may not hear them when speaking from a different room, or that the patient turns the radio or television volume to a level that sounds too loud to other listeners. Interviewing people who spend time with the patient is vital to detecting more subtle hearing impairments.

Physical exam findings—

It is vital that a health care provider inspect the ear with an otoscope. The external auditory canal (EAC) and the tympanic membrane (TM) should be fully visualized. Cerumen can accumulate in the EAC and can cause some hearing loss if it fully occludes the EAC. The EAC can also be occluded by other masses, such as tumors, granulation tissue, cysts, polyps, or even a foreign body. The TM should be translucent and grayish in color. Any perforation of the TM, drainage from the TM or middle ear, masses behind the TM (in the middle ear), middle ear effusion, or significant thickening of the TM is abnormal and may cause hearing loss. A tuning fork exam should also be performed, ideally with a 512-Hz tuning fork, using 2 techniques. A Weber test is performed by placing the tuning fork on a bony prominence in the midline, most often on the upper forehead, to identify any lateralization of sound. A normal test is heard equally in both ears. A Rinne test compares bone conduction to air conduction of each ear by, first, placing the tuning fork on the bony prominence at the tip of the mastoid behind the ear (bone conduction) and, then, comparing its sound when held lateral to the patient’s ear (air conduction). A normal (positive) Rinne test demonstrates air conduction greater than bone conduction. Table 62–1 demonstrates how to interpret the findings of tuning fork tests.

Screening tests—

Screening may take the form of direct questioning of the patient as above. Handheld screening instruments, such as the Welch Allyn AudioScope, and survey questionnaires are also available, for example, the Hearing Handicap Inventory for the Elderly (Box 62–1), but offer limited additional utility over careful questioning. The recent U.S. Preventative Task Force report regarding hearing loss screening for adults age 50 years and older serves as a guide. A hearing impairment screen is a required aspect of the initial Medicare annual wellness visit.

Referral to audiology and otolaryngology—

Any patient with hearing loss should be referred to an audiologist with master’s- or doctoral-level training for formal audiometric testing. Referral to a hearing aid dispenser (or hearing aid specialist) can also be considered. The training for these individuals varies from state to state, with some having only a high school degree. Referral to an otolaryngologist is warranted when a medical concern exists (Table 62–2).

The classic presentations of various causes of hearing loss are given here, but not all of the associated symptoms or additional symptoms may be present with any given condition. Sensorineural hearing loss (SNHL) constitutes 92% of hearing loss in older adults, with the remainder being conductive or mixed (both sensorineural and conductive components). In the vast majority of cases, hearing loss in older adults is multifactorial, and many etiologies concurrently lead to hearing loss over time. Of note, subjective tinnitus, which is a centrally mediated process, can accompany any type of hearing loss as a result of the alteration of auditory input to the auditory cortex in the temporal lobe.

Sensorineural Hearing Loss (Inner Ear Disease)

Presbycusis—

An audiogram typical of presbycusis (age-related hearing loss) shows a down-sloping SNHL, in which the higher frequencies (toward 8 kHz) are more severely affected than lower frequencies (toward 250 Hz) (Figure 62–1). Patients often are unaware of their degree of hearing impairment because of its gradual progression over years. The patient’s friends and family members are often the first to notice and may prompt the patient to seek evaluation and treatment. In some patients, hearing loss may be accelerated due to hereditary factors.

Noise damage—

Noise-induced hearing loss can result from prolonged exposure to noise, in which case the hearing loss would be permanent and occur gradually over months to years, or from brief exposure to intense noise, in which case the hearing loss may be sudden and may be temporary or permanent. The audiogram for these patients typically shows a dip on the audiogram at 3–6 kHz and may be unilateral or bilateral depending upon the nature of the injury. Noise-induced hearing loss is preventable with avoidance and use of ear plugs and other hearing protective devices.

Infection—

Various infections can cause hearing loss. Viral, bacterial, or fungal labyrinthitis can cause hearing loss that is typically unilateral with associated tinnitus and vertigo. Meningitis, particularly bacterial, can cause partial to complete hearing loss through direct damage to the cochlea. Syphilis and lyme disease are known to cause sudden SNHL. Herpes zoster oticus, known as Ramsay Hunt syndrome, because of reactivation of the zoster virus in the geniculate ganglion, begins as painful vesicles in and around the external ear followed by any or all of the following: sudden unilateral hearing loss that may be temporary or permanent, tinnitus, nystagmus, disequilibrium or vertigo, and/or facial weakness that may be temporary or permanent. The diagnosis can be made by isolating the virus from vesicular fluid.

Autoimmune inner ear disease—

A number of autoimmune diseases are associated with hearing loss that is typically progressive and bilateral in nature, including, but not limited to, systemic lupus erythematosus, polyarteritis nodosum, inflammatory bowel disease, Crohn disease, ulcerative colitis, and granulomatosis with polyangiitis. There are also some patients who experience hearing loss and/or dizziness outside of a known disease process who respond to immunosuppressive therapy. The hearing loss in these conditions is thought to be caused by direct damage to the cochlear and vestibular organs through antibody-mediated attack by the host immune system.

Systemic and vascular disease—

Multiple systemic diseases can result in hearing loss, primarily through their effects on the vasculature of the cochlea. The blood supply to the cochlea is composed of terminal branches of the intracranial circulation and is subject to vascular insult with subsequent ischemia or even infarction. Diabetes mellitus, small vessel vasculitides, and microthrombotic or embolic events may lead to sudden or gradual hearing loss. Furthermore, hearing loss, vertigo, and/or nystagmus can be some of the presenting symptoms of a central ischemic or hemorrhagic stroke.

Ototoxic medications—

Signs and symptoms that a patient may be experiencing ototoxic effects include the development of new tinnitus, vertigo or disequilibrium, and difficulty hearing. If these symptoms develop, the patient should be evaluated and the drug should be stopped immediately if possible. Table 62–3 lists some of the most common ototoxic medications.

Acoustic neuroma (Vestibular schwannoma)—

These small tumors of cranial nerve VIII typically present with unilateral, slowly progressive, high-frequency SNHL, but may present as sudden SNHL in up to 25% of patients. Commonly associated symptoms included tinnitus in 70% of patients, disequilibrium or vertigo in 50% of patients, cranial nerve (CN) V dysfunction (often subclinical) in 50% of patients, and/or facial weakness or asymmetry in 2% of patients. MRI with gadolinium is the study of choice for diagnosis.

Meniere disease—

Also known as endolymphatic hydrops, this condition is characterized by episodic rotational vertigo that is typically debilitating and lasts from 20 minutes to 24 hours, but typically 1–2 hours. It is associated with fluctuating low frequency hearing loss, aural fullness, and tinnitus. The symptoms almost always begin unilaterally, but the contralateral ear may become involved in up to 50% of patients over time. The natural history is a relapsing and remitting course with the disease often “burning out” over time. Recurrent attacks can lead to a permanent SNHL.

Trauma—

Temporal bone fractures from falls, motor vehicle accidents, assault, or other blunt trauma can cause SNHL if the inner ear is involved. Additionally, patients can suffer facial nerve paresis that can be delayed or immediate and injury to surrounding structures. A temporal bone protocol CT scan without IV contrast will make the diagnosis in these patients.

Sudden sensorineural hearing loss—

Sudden SNHL is a sudden decrease in hearing thresholds of 30 dB or greater at 3 contiguous audiometric frequencies occurring over 72 hours or less and is an otologic emergency that occurs in an estimated 5–20 per 100,000 people per year. The primary goal in managing these patients is the prevention of permanent SNHL through prompt referral to an otolaryngologist for confirmation and treatment with steroids within 24–48 hours. Distinguishing between sudden SNHL (requiring immediate referral) and an acute conductive loss from an ear infection or middle ear effusion (treated with simple antibiotics or a nasal steroid spray and not requiring urgent referral) can be made using the tuning fork tests described above.

Radiation—

A history of radiation to the head or neck, for either a neoplastic process or environmental exposure, can lead to SNHL by direct damage to the inner ear and auditory nerve.

Conductive Hearing Loss (Middle or External Ear Disease)

Conductive hearing losses are far less common than SNHLs in older adults and can often be diagnosed in the clinic by otoscopic examination or through tuning fork testing. Common causes include EAC obstruction (eg, cerumen), TM perforations, middle-ear effusions, and ossicular chain pathology. Middle-ear effusions caused by eustachian tube dysfunction can often be treated with intranasal steroids and oral antibiotics (if there is a concern for acute otitis media) and followed conservatively for 2 months. Failure of resolution or concern for any other etiology for a conductive hearing loss warrants referral to an otolaryngologist.

In addition to impairing verbal communication, hearing loss has been implicated in a number of other negative outcomes. Figure 62–2 models how age-related hearing loss (ARHL) is associated with poorer cognitive and physical functioning through the pathways of cognitive load and social isolation. Poorly encoded auditory signals from an impaired cochlea require greater brain resources for auditory decoding, and this cognitive load results in a smaller pool of resources being available for other cognitive tasks. Concurrently, ARHL has also been associated with poorer social functioning, one of the determinants of morbidity and mortality in older adults.

Consistent with this model, epidemiologic evidence demonstrating that ARHL is independently associated with cognitive and physical functioning in older adults is beginning to surface. ARHL has now been found to be independently associated with poorer neurocognitive functioning on both verbal and nonverbal tests of executive function and memory, accelerated cognitive decline, and incident dementia. Compared to individuals with normal hearing, those with a mild, moderate, and severe hearing loss have a 2-, 3-, and 5-fold increased risk of developing dementia, respectively. Cognitive resources are also critical for gait, balance, and other tasks, such as driving. Recent studies demonstrate that ARHL is associated with poorer balance, falls, and impaired driving ability. These relationships may be mediated through the effects of hearing on cognitive load or from reduced awareness of the auditory environment.

Most often, the difficulty in treating or attempting to address hearing loss in older adults is convincing them, first, that they have a hearing loss that has potentially significant implications for healthy aging and, second, that current treatment can help them to hear better and improve many aspects of their lives. For a useful review of many aspects of hearing loss in older adults with a substantial section on treatment by Pacala et al, 2012.

Adaptive Techniques

Individuals with hearing loss should directly face the person with whom they are speaking. Family members and friends can be encouraged to speak at a normal volume, enunciate clearly, keep hands and other items away from in front of their mouths, and rephrase sentences instead of repeating them when asked. Also, training in speech reading, word recognition, and active listening has shown some benefit in these patients.

Environmental Modifications

A person with hearing loss should place herself at the center of the conversation, away from background noise. A setting with minimal background noise should be chosen for gatherings or conversations if possible. Lighting should be adequate to see the faces of those speaking.

Assistive Listening Devices

Multiple devices exist that allow for improved communication through personal amplification without hearing aids. These can be useful in a patient who would like hearing aids but cannot afford or manage them. Assistive listening devices (ALDs) typically use a microphone placed close to the desired sound and transmit this sound to the patient. One device is a “pocket talker,” which amplifies nearby sound and sends it to the user through earphones. Many public venues also have listening systems that send sound from the speaker or area of interest to the user through infrared or frequency modulation (FM) signals. Other devices include amplified telephones, telecommunication devices for the deaf (also known as text telephones), closed captioning for television, vibrating alarm clocks, and visual alarm systems (eg, door bells and smoke alarms).

Audiologic Evaluation

The goal of the audiologist or hearing aid specialist is not to simply fit a hearing aid, but to ensure that a patient can effectively communicate in all settings. The hearing rehabilitative process therefore entails counseling, proper fitting of hearing aids and amplification devices, rehabilitation, and training in the use of other systems such as ALDs, amplified telephones, and hearing loop induction systems. To identify an audiologist or hearing aid specialist who shares these goals, ask the following: Does she offer regular audiologic rehabilitation sessions for her patients? Does he have an induction loop system installed in his office? Is she a member of the Academy of Rehabilitative Audiology, an organization focused on the comprehensive management of hearing loss? Given the fee-for-service model of audiologic services that are rarely covered by insurance, it is vital to distinguish between audiologists committed to comprehensive rehabilitative care from those who are focused only on hearing aids.

Hearing Aids

Fewer than 15% of Americans older than the age of 50 years with hearing loss use hearing aids, despite the evidence for improved speech perception, understanding, and hearing-related quality of life, including social, emotional, and mental wellbeing. This may be a result of hearing aids’ cost, appearance, comfort, and performance in different environments. Furthermore, in the United States, most insurance carriers do not cover the cost of hearing aids, which on average cost approximately $1500 each, with premium models costing $3000–$5000 each.

Types of hearing aids—

Digital hearing aids have become standard over the past decade and offer size and performance advantages over the bulky analog hearing aids commonly used a decade ago. There are 4 main types: behind the ear, in the ear, in the ear canal, and completely in the ear canal.

Selection and fitting of hearing aids—

Following audiometric testing by a qualified audiologist, hearing aids need to be correctly fitted, customized with appropriate ALDs, and managed over time. The audiologist will help the patient maximize her experience with regard to performance while attending to the patient’s preferences for appearance, functionality, and cost. Once the hearing aid is chosen and fitted, the patient should take part in aural rehabilitative training, which a conscientious audiologist should offer to all her patients, during which the patient is educated in proper use of the device, management of the device in different environments, speech perception and communication, and strategies to cope and deal with difficulties that may arise during use. Successful amplification requires an ongoing effort by the audiologist and the patient over multiple visits.

Assistive listening devices for use with hearing aids—

Although hearing aids perform well when the sound source is within a 6-foot radius, at farther distances they perform less well. Some public venues are equipped with technology that can transmit sound directly to hearing aids through FM, infrared, or induction loop systems. This improves sound quality by reducing the signal-to-noise ratio. Of particular interest, induction loops or “hearing loops” directly transmit sound to the two-thirds of hearing aids currently equipped with a telecoil, dramatically improving sound quality. The system involves a thin wire that is placed around the periphery of a room or area allowing sound to be transmitted to the telecoil through induction. Such systems are installed in concert halls, ticket booths at train stations, houses of worship, and anywhere background noise or proximity to the sound of interest may interfere with communication.

Cochlear implants—

Cochlear implants are surgically implanted neuroprosthetic devices that are used to treat profound SNHL in patients who do not gain appreciable benefit from optimized hearing aid use. The surgery is typically a 2-hour outpatient operation performed by an otolaryngologist who implants an electrode array into the cochlea by way of a mastoidectomy. Unlike hearing aids, cochlear implants directly stimulate the auditory nerve, functionally replacing the role of the impaired cochlea. Cochlear implantation can substantially improve the ability of older adults to communicate. Many older adults improve from 0% word comprehension preoperatively (without the aid of visual cues) to 100% comprehension several months after surgery. There are no age contraindications to cochlear implant surgery, with many implant centers routinely performing cochlear implantation in adults in their 80s and 90s. Candidates for cochlear implantation are those who have severe-to-profound SNHL even while using optimized bilateral hearing aids. Typically, even while maximally aided, these patients score less than 40% to 50% on word or sentence recognition testing.

In the case of age-related or idiopathic hearing loss, the natural history is that it progresses over time, possibly contributing to social isolation, cognitive load, and morbidity in older adults. There is currently no definitive evidence on whether treating hearing loss could mitigate these negative outcomes. There has only been 1 moderately sized, randomized, clinical trial of hearing aids that has examined effects beyond speech comprehension and quality of life, and it was performed more than 20 years ago. Interestingly, this study demonstrated positive effects of hearing aids on cognition and other functional domains at 4 months posttreatment. A larger trial utilizing more current technology and longer periods of follow-up in a more generalizable study population is currently being planned.