Cochlear Implantation in the Old Old with Cognitive Decline

A 103-year-old female with early cognitive impairment presented with profound sensorineural hearing loss to one of us (M.D.E.) for evaluation and management. She was socially active and had significant trouble communicating because of her hearing loss. Her benefit from hearing aids had waned and audiometrically she was a cochlear implant candidate.

With increased longevity, both sensorineural hearing loss and cognitive decline become more prevalent. In fact, recent research suggests hearing loss is a major risk factor for cognitive decline in the geriatric setting. ¹ A cohort study from 2018 suggested that while hearing loss and cognition are linked, it is untreated hearing loss that drives the association. ² It is noted that social isolation is the mediating factor in the link for those who have untreated hearing loss.

As the severity of hearing loss increases with age, cochlear implantation (CI) becomes an option for hearing rehabilitation. There is ample literature on CI efficacy in the geriatric population with respect to hearing, but little with respect to cognitive decline. A prospective observational study from 2018 showed improvements in cognitive function and low rates of progression to dementia following CI. ³ These results highlighted that CI may be strongly considered in patients with severe hearing loss—even those with mild cognitive impairment—as there may be a possible positive effect of hearing rehabilitation on neurocognitive functioning. ³ Cognitive decline, like age-related sensorineural hearing loss, is progressive. Thus, the ability to understand the risks associated with the surgical management and compliance with postoperative rehabilitation and training could be compromised depending on the severity of cognitive decline. Given that the two comorbidities coexist, the relevant factors affecting decision-making with regard to CI need to be defined in the elderly patients. Centers for Medicare and Medicaid Services, the main payor of geriatric health care services, has no upper age limits on CI. The most common potential complications of CI to consider include vestibular complications (specifically balance problems); changes in taste, device failure, or extrusion; skin/wound infection; mastoiditis; recurrent otitis; facial nerve injury; and electrode issues. ⁴ Of these complications, balance problems are the most prevalent in elderly adults (age >75 years old) ⁴ and represent a significant risk factor for falls and fractures. Surgical risks aside, general anesthesia is a known risk factor for postoperative delirium and exacerbation of cognitive decline in the geriatric setting. ⁵ Thus, although audiological criteria may suggest a patient will benefit from CI, other criteria are needed to evaluate the candidacy of the elderly patients for CI in light of risk/benefits and likelihood of positive outcomes. Relevant factors include severity of cognitive dysfunction at implantation, rate of cognitive decline, and a robust support system which can promote compliance with the postoperative rehabilitation and training regimens. Preoperative assessment of cognitive function is also important for documentation of surgical consent. If a patient is deemed not be competent, then the conservator will be in the challenging position to decide on an elective surgery which may improve the quality of life and possibly help slow the rate of cognitive decline. In this case, the hospital ethics board was consulted and a decision was made to proceed with the surgery. Patient underwent a successful CI. She lived for 2.5 more years and during that time she and her family appreciated her improved communication with the CI.