NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
Raman G, Lee J, Chung Met al., authors; Sen S, editor. Effectiveness of Cochlear Implants in Adults with Sensorineural Hearing Loss [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2011 Jun 17.
This publication is provided for historical reference only and the information may be out of date.
Effectiveness of Cochlear Implants in Adults with Sensorineural Hearing Loss [Internet].
Show detailsBackground
Hearing loss is the third most common chronic condition among the elderly in the United States, affecting about one-third of adults over 65 years of age and half in their 80s.1 The three types of hearing loss are conductive, sensorineural, and central. Of these, sensorineural is most prevalent among older adults, and is the third leading cause of disability during the adult years, according to the World Health Organization.1 Sensorineural hearing loss most commonly occurs gradually and becomes worse with age, with clinical manifestations typically appearing during the fifth and sixth decades. Sensorineural hearing loss is also usually permanent.
Sensorineural hearing loss is characterized by the gradual attenuation of the intensity of sound. For a pure attenuation loss, acoustic amplification, such as that with a hearing aid, is an excellent option. With increased levels of sensorineural hearing loss, there also comes loss of frequency selectivity and other forms of distortion within the inner ear. These effects cannot be addressed with hearing aids. The result is significant speech perception difficulties, particularly during conversations. This occurs both during one-on-one and group conversations (especially in the presence of ambient noise in a public setting), and while listening to speech conveyed via transmitting equipment (e.g. telephone, fast-food drive-through, etc.). Untreated hearing loss among adults may contribute to the overall decline of health during aging and leads to depression, social withdrawal, underemployment, diminished quality-of-life secondary to communication problems, and may be a factor in dementia.1, 2
Presbycusis is the most common type of sensorineural hearing loss among elderly in the United States. In adults (≥ 18 years of age), causes of sensorineural hearing loss can include ototoxicity, otosclerosis, trauma, autoimmune diseases, and others. Among the elderly, chronic systemic conditions including heart disease, high blood pressure, diabetes, and other circulatory problems are common and may exacerbate hearing loss.2, 3 In addition, some commonly prescribed medications regularly used by adults including some antibiotics, loop diuretics, and anti-inflammatory agents have ototoxic side effects.2
Most cases of hearing loss are treated using a number of electronic-acoustic devices such as hearing aids, personal listening systems, bone-anchored hearing aids, and cochlear implants. Of these devices, hearing aids and cochlear implants are the most commonly used devices in the treatment of sensorineural hearing loss.1 Traditional hearing aids may improve hearing function by amplifying sound, but are often ineffective in people with severe (between 70-94 decibels [dB]) to profound (≥ 95 dB) sensorineural hearing loss. The clarity and comprehension of speech is measured by word recognition (formerly called speech discrimination) with scores in persons with unimpaired hearing typically > 90 percent. In recent years, cochlear implants have been used in older adults.3 Cochlear implantation is not a treatment option for people with conductive or central deafness.
Cochlear Implantation
Cochlear implants replace the function of sensory hair cells in the cochlea that are no longer able to generate electrical impulses in response to sound. Therefore, cochlear implants may provide a viable alternative to hearing aids among adults with profound sensorineural hearing loss as they bypass the damaged hair cells by directly transmitting electrical impulses to the acoustic nerve. These devices consist of external components positioned to rest on the head just behind the ear, and internal components that are placed beneath the skin. The external components consist of a microphone; a speech processor, which analyzes and codes the sounds received by the microphone; and a transmitter coil. An internal receiver/stimulator converts signals received from the speech processor into electrical impulses. The impulses are passed into a series of wires that comprise an electrode array, a group of electrodes that are positioned within the cochlea to collect the impulses from the stimulator into the cochlea where they will pass to the acoustic nerve.
Food and Drug Administration Labeled Use
Cochlear implants can improve the user’s ability to distinguish speech and hear conversations amid noisy conditions,3 hear and speak on the phone, and listen to music and the television at more adequate levels than before.1 Currently, patients are fitted with unilateral cochlear implants, with some receiving contralateral assistance from a hearing aid when residual hearing is present but insufficient. The Food and Drug Administration (FDA) recommended the use of cochlear implants only in adults with profound hearing loss as early as the 1970s,4 and first approved the use of multichannel cochlear implant devices in 1985 for adults aged 18 and older who are postlinguistically deaf with bilateral, profound sensorineural hearing loss and score 0 percent on aided speech recognition tests, indicating little to no open-set sentence discrimination. As advances were made in cochlear implant technology, these criteria for adults were expanded to include those with residual hearing who are either prelinguistically or postlinguistically deaf with moderate-to-profound sensorineural hearing loss in the low frequencies or profound loss in the mid-to-high frequencies (Table 1 in the Results section lists the current FDA-approved devices).5
Social Security Administration Guidelines
Patients fitted with cochlear implants are eligible for disability status. Recent guidelines from the Social Security Administration cite the following hearing loss criteria: adults with implants qualify for disability one year after initial implantation or, if after one year, achieve a speech recognition score of < 60 percent on the Hearing in Noise Test (HINT) as administered in quiet conditions.6
Recent Health Technology Assessment
The UK-based National Institute for Health and Clinical Excellence (NICE) guidance document for hearing loss is based on a technology assessment by the NICE Appraisal Committee, which reviewed English-language literature published through 2007 on multichannel cochlear implants using whole-speech processing coding strategies.7 The findings for adults from the systematic review were as follows: unilateral cochlear implantation benefitted adults who had postlinguistic hearing loss, as compared with those with prelinguistic hearing loss, and reported statistically significant improvement in quality-of-life outcomes following unilateral implantation. For comparisons of bilateral implantation versus unilateral implantation, statistically significant acoustic benefit and speech perception occurred among subjects with bilateral implantation, but mixed results were found for quality-of-life outcomes. The guidelines included an additional cost-effective analysis. Unilateral implantation was recommended as a treatment option for adults with profound deafness as it is highly likely to be cost-effective. In addition, the NICE guidelines included recommendations for bilateral simultaneous cochlear implantation for adults with disabilities, such as blindness, who may rely primarily on their auditory senses. Although NICE does not recommend bilateral implantation for the treatment of severe-to-profound hearing impairment, it does defer to the clinician’s decision regarding individual benefit after informed discussion with potential patients. NICE also recommends that candidacy be determined by a multidisciplinary team that considers each individual’s level of disability (physical and cognitive as well as linguistic), and suggests that care be taken to administer speech assessment tests in language familiar to patients. The guideline suggests bilateral implants in adults are likely to provide added benefits for communication in social situations.
As additional studies on adults with cochlear implantation have been published since the recent systematic review,3 the Centers for Medicare and Medicaid Services (CMS) is interested in a review of current literature on cochlear implantation in adults with prelinguistic or postlinguistic sensorineural hearing loss. The Coverage and Analysis Group at CMS requested this report from The Technology Assessment Program (TAP) at the Agency for Healthcare Research and Quality (AHRQ). AHRQ assigned this report to the following Evidence-based Practice Center: Tufts Evidence Practice Center (Tufts-EPC) (Contract Number: 290 2007 10055 I).
Key Questions
Our objective was to answer the following key questions on the use of cochlear implantation in adults with sensorineural hearing loss and evaluate their applicability in a subset of Medicare populations (65 years of age or older). The key questions were formulated in consultation with CMS and AHRQ.
- What current cochlear implantation devices are approved by the FDA for individuals ≥ 18 years of age? What are the indications for their use?
- What are the communication-related health outcomes as well as the quality-of-life outcomes that are achieved in the population of adults (≥ 18 years old) who undergo unilateral cochlear implantation? How is a “successful” implantation defined?
- 2a.
For those individuals ≥ 18 years of age with sensorineural hearing loss, what are the preoperative patient characteristics associated with the successful attainment of the aforementioned improved communication-related health outcomes as well as quality-of-life outcomes in those who undergo unilateral cochlear implantation? At a minimum, the evidence surrounding the following will be discussed:
- Speech recognition/word understanding
- Auditory sensitivity/audibility
- Duration of impaired hearing
- Associated ear or bone disease
- Pre vs. postlinguistic deafness
- Presence of other disabilities (e.g. visual impairment, impending or current)
- Age at implantation
- Degree of preimplant residual hearing
- Choice of implanted ear
- Site or center (expertise) of cochlear implant team
- Implanted device
- 2b.
For studies included in key question 2 and 2a, report the available evidence separately for those individuals with sensorineural hearing loss as demonstrated by preimplantation test scores of > 40 percent and ≤ 50 percent, as well as those with test scores > 50 percent and ≤ 60 percent (best aided listening on tape or otherwise recorded tests of open-set sentence recognition).
- 3.
For those individuals ≥ 18 years of age, what are the additional communication-related health outcomes as well as quality-of-life outcomes (as compared with those achieved in question 2) that are gained from the use of bilateral cochlear implants over a unilateral cochlear implant? How is a “successful” bilateral cochlear implant defined?
- 3a.
What are the preoperative patient characteristics associated with the successful attainment of the communication-related health outcomes as well as quality-of-life outcomes in questions 2 or 3 in individuals who are ≥ 18 years of age who undergo simultaneous bilateral cochlear implantation?
- 3b.
What are the preoperative patient characteristics associated with the successful attainment of the communication-related health outcomes as well as quality-of-life outcomes in questions 2 or 3 in individuals who are ≥ 18 years of age who undergo sequential bilateral cochlear implantation?
At a minimum, the evidence surrounding the following will be discussed:
- Speech recognition/word understanding
- Auditory sensitivity/audibility
- Duration of impaired hearing
- Associated ear or bone disease
- Pre vs. postlinguistic deafness
- Presence of other disabilities (e.g. visual impairment, impending or current)
- Age at implantation
- Degree of preimplant residual hearing
- Choice of implanted ear
- Site or center (expertise) of cochlear implant team
- Implanted device
- 3c.
For studies included in key question 3, 3a, and 3b, report the available evidence separately for those individuals with sensorineural hearing loss as demonstrated by preimplantation test scores of > 40 percent and ≤ 50 percent, as well as those with test scores between > 50 percent and ≤ 60 percent (best aided listening on tape or otherwise recorded tests of open set sentence recognition).
- Introduction - Effectiveness of Cochlear Implants in Adults with Sensorineural H...Introduction - Effectiveness of Cochlear Implants in Adults with Sensorineural Hearing Loss
Your browsing activity is empty.
Activity recording is turned off.
See more...