9 Cochlear Implantation in the Elderly

Daniel H. Coelho and Brian J. McKinnon

Introduction

Cochlear implantation (CI) has become a well-established means of addressing severe to profound sensorineural hearing loss in children and adults who cannot benefit from conventional amplification. It is understood to be both clinically effective and cost-effective,^1–3 and it is estimated that over 324,200 patients have received this medical device.⁴ Nevertheless, although there is evidence supporting the benefits of CI in the general population, concern remains that there is insufficient evidence to support geriatric CI as appropriate, safe, effective, and cost-effective.⁵ This chapter provides a broad description of the clinical challenges associated with CI and the potential benefits to recipients.

Epidemiology

Hearing loss is one of the most common disabilities in the elderly, the fastest-growing segment of our population. The U.S. population aged 65 and older will grow from 40.2 million in 2010 (13.5% of the population) to 88.5 million in 2050 (20.5%). One fifth of this 20% will be 85 and older. Studies based on the National Health and Nutrition Examination Survey (NHANES) show that an increasing proportion of the population has age-related hearing loss, reaching over 80% of those over 85 years of age.⁶ For up to 10% of older patients with hearing loss, the impairment is so severe that conventional amplification devices fail to provide significant benefit.⁷ Beyond speech perception, inability to communicate significantly impacts quality of life and overall well-being and is associated with cognitive impairment, dementia, personality changes, depression, and reduced functional status.^8,9

Fortunately, as with younger patients, CI has proven to be an extremely effective intervention for older patients and is widely gaining in popularity. Several factors have contributed to the rapid increase in the number of elderly CI recipients. Chief among them is the growth in the overall population over the age of 65, increasing the absolute number of eligible recipients. In addition, not only does the incidence of hearing loss increases with age, but those with hearing loss will experience worsening of their hearing over time. The prevalence of hearing loss nearly doubles with every decade of age.⁶ These factors, combined with a small but significant increase in awareness of this technology, have led to more patients opting for CI than ever before. Of all patients receiving CI, the over-65 age cohort is the fastest-growing segment, with the biggest growth in the over-80 subgroup.⁶

Despite the many elderly patients who have benefited from this life-changing technology, the rate of CI use in older adults who meet candidacy criteria is less than 5%.⁶ Numerous myths and barriers exist—beliefs widely held by both the public and the medical communities. Among them are the perception that CI is exclusively for congenital hearing loss or children, CI is an untested/experimental technology, outcomes are poor for older adults, CI is not covered by insurance, the surgery poses an unacceptably high risk, or the device is too complicated to use, among others. Referral patterns likewise contribute to the bottleneck of access to CI. Few primary care providers screen for hearing loss at a new patient visit, with even fewer addressing hearing at follow-up visits.¹⁰ In addition, some audiologists and otolaryngologists may have well intentioned though misplaced faith in conventional hearing aids, irrespective of a potential financial disincentive to refer.

Preoperative Considerations

Once an elderly patient has been identified audiologically as a candidate for CI, the process does not differ greatly from that for younger candidates. A thorough history must be obtained, with particular attention given to duration of hearing loss, especially severe-to-profound hearing loss. As with younger patients, speech performance outcomes are closely related to deafness duration and are critical in counseling patients and their family on reasonable expectations. Cognitive evaluations, although not common practice, can help guide assessment and counseling when appropriate.11 Likewise, insofar as varying etiologies may have a higher risk of labyrinthine ossification (postmeningitic, posttraumatic, ototoxic, etc.), this, too, may influence both preoperative imaging choice and expected performance outcomes. Speech performance and expectations must be managed accordingly if traumatic or incomplete implantation is a possibility.

Careful attention must be paid to medical comorbidities. Although age itself is not a known risk factor for perioperative complications, the likelihood of coexisting cardiopulmonary pathology does increase with age. Medical optimization and clearance by the patient’s primary care provider, cardiologist, pulmonologist, and care providers can be extremely helpful in assuring a successful procedure and recovery. Many older patients may be on aspirin, clopidogrel, warfarin, or other anticoagulative therapy. Collaborating with the prescribing physician can help to bridge the perioperative period, leading to a timely transition back to therapeutic anticoagulation.

Intraoperative Considerations

There is a pervasive, but erroneous, perception among both health care professionals and consumers that age is a significant risk factor for general anesthesia and for anesthetic and surgical complications. Current literature suggests that comorbidities and the American Society of Anesthesia (ASA) rating of physical status are more important than age as prognostic factors for adverse anesthetic outcome. Coexisting conditions of advanced age that potentially have an impact on the risk of anesthesia include cardiopulmonary insufficiency, arthritis, hepatorenal disease, endocrine dysfunction, nutritional status, and pharmacokinetic issues.¹²

Coelho et al reviewed 70 patients over the age of 70 undergoing CI and found that general anesthesia is well tolerated without significant risk in the majority of patients.¹³ In their review of 50 patients 80 years or older, Carlson and colleagues found no higher rates of surgical complications when compared with younger CI recipients, though they did find a small but statistically significant higher risk of cardiovascular complications and hospital admission rate for this population.¹⁴ Nonetheless, of great import to patients and physicians, there was no mortality associated with this elective procedure. This is not surprising: unlike other, nonelective surgeries that elderly patients frequently must undergo, CI usually requires only 1 to 2 hours to perform with ~ 1.5 to 2.5 hours of general anesthesia. Furthermore, the small incision and minimal blood loss do not result in significant hematologic or fluid imbalance.

Other studies have agreed that age alone is not an independent risk factor in geriatric populations, particularly in the nonemergent or outpatient procedures in geriatric populations. Lau and Brooks demonstrated that age itself is not a reliable predictor of unanticipated hospital admission after laparoscopic cholecystectomy.¹⁵ In comparing age and ASA status, Trus and colleagues and Matin and colleagues independently found no increased risk contribution from age in patients older than 65 years who underwent laparoscopic reflux and urological surgery, respectively.^16,17

Although “best anesthetic” technique has yet to be defined in patients with cardiovascular disease, hemodynamic stability and speed of recovery are impacted by choice of anesthesia. Kirkbride et al showed improved intraoperative blood pressure maintenance in older outpatients induced with the high-dose inhalation agent sevoflurane compared with those randomly assigned for intravenous propofol induction.¹⁸ In addition to myocardial depressant effects of anesthetic agents, atelectasis associated with mechanical ventilation, and volume loading due to intravenous fluid administration contribute to cardiac and pulmonary complications, including congestive heart failure, hemodynamic instability, and pulmonary insufficiency. Cardiopulmonary complications can be reduced by minimizing intraoperative fluid administration and the duration and amount of anesthesia used. Elderly patients require up to 30% less minimum alveolar concentration of inhalational anesthetic compared with young adults.¹⁹ The use of bispectral index (BIS) monitors may aid in the titration of anesthetic and improve early recovery.²⁰

Postoperative Considerations

Stay updated, free articles. Join our Telegram channel

Join