Cochlear Implantation for Adults with Prelingual Deafness*
Deafness in Adults: Age of Onset Matters
Adult CI candidates who once had normal hearing and experienced hearing loss later, or had some degree of hearing loss in childhood that worsened over time, typically have spoken language skills including intelligible speech. In contrast, adults with congenital deafness (present at birth) who never derived significant speech perception benefit from conventional hearing aids, generally have less well developed spoken language skills. If they did not use amplification consistently, there is an even greater chance that their use of spoken language is more limited.
Despite the fact that the individuals in the described categories may have similar audiograms indicating bilateral profound hearing loss, their spoken language skills may differ significantly. Further, expected outcomes with a cochlear implant are also quite different.
Congentially Deaf Adults
The speech intelligibility of congenitally deaf adults may be poor. Spoken language may be hampered in other ways and listening ability may be quite limited. These CI candidates likely are unable to detect all speech sounds and many environmental sounds are not detectible. Many such individuals do not demonstrate spontaneous listening behaviors and will require speechreading and/or sign language, even in quiet. Repetition and a slower speaking rate may also be needed.
CI Outcomes for this Adult Population
In light of the above, it can be generalized that congenitally deaf adults will continue to need speechreading and/or sign language following cochlear implantation. Nonetheless, we cannot predict with certainty that they would not benefit from the auditory information they would derive from a cochlear implant. Some individuals with this hearing profile may even gain some open set listening with a CI.
Although cochlear implantation has advanced dramatically, device outcomes are impacted by many factors including patient characteristics. In assessing candidacy, it is important to consider:
- What are your expectations? Can a CI help you to fulfill some or most of these expectations?
- Will you undergo rehabilitation to help you realize potential benefits?
With regard to rehabilitation, it is important to both follow through and find a means to customize a program to meet the person’s specific needs—both subjective and objective outcomes. Assessment of outcomes should include a range of possible benefits including access to speech, one’s own spoken language, environmental sounds and music. Changes in life circumstances may also affect communication needs. Such changes may include, for example, living with parents versus living independently; mainstream educational settings as opposed to supportive settings; moving into a workplace that does not fully accommodate hearing loss.; or expanded social interactions with a greater range of people.
A broader appreciation of possible benefits allows one to assess CI outcomes more accurately, particularly for this group of adults. Therefore, a consideration of CI candidacy should be undertaken without preconceived notions regarding potential benefits of the intervention on someone’s quality of life.
Our ability to understand this complexity is key to defining needs, goals and rehabilitation strategies which may augment the opportunity for a prelingually deaf adult to realize the full benefit of a cochlear implant over time.
In the next post we will discuss these potential benefits.
* Prelingual hearing deafness is defined as hearing loss present at birth or prior to the acquisition of language.