Pediatric cochlear implants in prelingual deafness: medium and long-term outcomes.

Abstract

Unfortunately, no large-scale, well-designed, comprehensive studies on medium and long-term effect of cochlear implants in prelingual children exist. Furthermore, the few studies listed have addressed different aspects of this issue, in a non-standardized manner. With the question of outcomes becoming so important in modern medicine, standardized reporting methods are essential. This would enable a fair comparison between the different commercial devices and between rehabilitation-education methods. The studies presented above were published between 1999 and 2008. Due to the long follow-up period required for reporting medium and long-term outcomes, they actually represent patients implanted one and two decades ago. At present and in the near future, we may expect better results from patients who were implanted in the last few years for several reasons: a) superior cochlear implants with better coding strategies; b) developments in rehabilitation and higher awareness among parents and staff; c) better health care and universal screening programs, leading to implants being performed in an earlier age; and d) a high rate of performing bilateral cochlear implants (either simultaneously or sequentially) in the last decade, which accomplishes even better results compared to unilateral implants. From the studies reviewed above, mainstreaming the child who has auditory-verbal and oral communication is the preferred educational setting for maximizing the medium and long-term benefit from a cochlear implant. Hearing and speech skills continue to improve many years after the implant. Non-use and failure rates (as reported by the authors from the medical centers and not solely by the cochlear implant manufacturers) are low, ranging from 1% to 2.7% per year. Overall, patients have a high rate of employment, close to that of the general population. However, they may be less satisfied, as the individual and the parents may feel compromised by their communication skills.

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editorials
107
IMAJ • VOL 12 • FEBRUARY 2010
Pediatric cochlear implants in Prelingual deafness:
medium and long-term outcomes
Daniel M. Kaplan MD and Moshe Puterman MD
Department of Otolaryngology-Head and Neck Surgery, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
is intrauterine infections such as cyto-
megalovirus. Acquired deafness before
speech and language development is less
common and includes bacterial menin-
gitis and taking ototoxic medication.
The future of a prelingual deaf child,
in terms of hearing, developing speech
and integrating into the hearing society,
depends not only on optimal amplifi-
cation with a hearing aid or cochlear
implant, but also to a large extent on the
type of education he or she receives. In
education based on auditory-verbal com-
munication, the deaf person learns to use
auditory cues optimally, by practicing
and perfecting speech understanding
and precisely articulating spoken lan-
guage. This type of education aims at
completely integrating the deaf person in
the hearing society. In oral communica-
tion the deaf learn to hear and speak sign
language with the aid of lip reading. This
type of education also aims at integration
in hearing society. Total communication
teaches both oral and sign language in
order to maximize the ability to com-
municate. Manual communication is not
based on hearing but rather on manual
sign language. Patients who sign com-
monly do not use amplification, and they
typically belong to "deaf society."
When looking at the advances in
outcomes of cochlear implant recipients
during the last generation, it is impor-
tant to appreciate the developments
in the technical design of the implant.
Since the coding strategies of implants
have dramatically improved, there has
been a significant increase in quantity
and quality of auditory information.
Upgrading the external part of the im-
plant has enabled the patients who were
c
adults and in children. These implants
include an electrical array that is im-
planted into the cochlea and directly
stimulates the different fibers of the
cochlear nerve, thereby bypassing the
damaged hair cells. They are indicated
in young patients with profound and
severe hearing loss who do not benefit
from conventional hearing aids, have
no medical contraindications and do
not harbor unrealistic expectations
(neither the patient nor the parents).
Cochlear implants in children were
first performed in the late 1980s follow-
ing the earlier positive experience in
adults and have exceeded expectations.
However, due to a wide range in short-
term results, it was essential to define
variables contributing to outcomes.
During the early 1990s the factors found
to be associated with good perform-
ance were: a) age at implantation and
length of deafness, b) amount of daily
use, c) mode of communication, and d)
absence of other handicaps.
Deafness in children is commonly
prelingual, which means that deafness
occurred either congenitally or in the
first few years of life, before speech had
been fully acquired. Non-syndromic
genetic deafness is the commonest con-
genital cause Another common cause
ochlear implants have revolution-
ized the rehabilitation of deafness in
implanted in earlier years to enjoy most
of the new developments in coding strate-
gies.
Since the early 1990s a clear benefit
has been shown for cochlear implants
in children. Hundreds of studies have
reported on outcomes, with follow-up
limited to 2–5 years. According to
Summerfield and Marshall [1], the ben-
efits of cochlear implants for profoundly
deaf children may be defined in three
time spans:
Short term: 1–3 years, in the form of •?
enhanced achievements in audition,
speech and language
Medium term: during the subse- •?
quent 5 years, enhanced educational
attainments, greater social versatility
and robustness, and increased qual-
ity of life
Long-term: spanning at least 20 •?
years from implantation and includ-
ing greater social independence and
quality of life in adulthood.
In this issue of IMAJ, Migirov and co-
authors [2] publish the results of ques-
tionnaires completed by prelingual
cochlear implant users on integration
into Israeli hearing society when they
grew up. Their findings, as well as other
research on this issue, are discussed be-
low under the heading Education and
Employment. This editorial will focus
on the outcome of medium and long-
term benefits of prelingually deaf chil-
dren with cochlear implants.
studY designs
Summerfield and Marshall [1] discuss
study designs that would optimally assess
medium and long-term outcomes of
prelingually deaf children with cochlear
cochlear implant, prelingual
deafness, long-term outcome,
employment
IMAJ 2010; 12: 107–109
KeY words:

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IMAJ • VOL 12 • FEBRUARY 2010
editorials
implants. There has been an increasing
demand by health organizations/purchas-
ers to adopt the elective procedures with
the most rigorous evidence of effective-
ness and cost-effectiveness. Randomized
controlled studies are the ideal method-
ology for scientifically studying effec-
tiveness of a medical device, yet no such
study has compared cochlear implants
with alternative devices (for example, a
hearing aid). According to the authors,
this may be explained by the very fast
technological evolution of implants,
which might produce outdated results,
and the fact that such studies would span
over many years.
Performing retrospective popula-
tion-based, cross-sectional comparisons
may prove a more practical method of
assessing outcomes in this group of
patients. This methodology is based
on comparison of implanted children
and non-implanted matched children.
Among the many important variables
that would have to be included are
age, age at onset of deafness, implant
duration, degree of hearing, the qual-
ity of health and rehabilitation, degree
of parent commitment, etc. In such a
way material benefits, effectiveness and
cost-effectiveness could be examined.
Naturally, the strength of the study
would depend on the success or failure
in performing the matching process.
outcomes
In the next part we will review the me-
dium and long-term results of cochlear
implants performed in pediatric prelin-
gual patients, based on available studies,
according to the following subjects: audi-
tory and speech development, education
and employment, non-usage and device
failure, and reimplatation.
auditorY and sPeecH develoPment
Open-set word and sentence recogni-
tion are the most common tests per-
formed for assessing outcomes of hear-
ing, following cochlear implantation.
Presurgery, prelingual children who
are implanted in the first few years of
life commonly score 0%, a result that
reflects their profound hearing loss and
lack of ability to recognize speech, even
when well fitted with hearing aids.
Spencer et al. [3] reported on a cadre
of their first pediatric prelingual implants
(1987 to 1995), with a mean 10 years
follow-up. Patients scored 70% on word
recognition and 68% on sentence test
accuracy. Seventy-nine percent of patients
correctly recognized phonemes (two
syllable-balanced words) with a high cor-
relation between hearing and speech.
Waltzman and collaborators [4] stud-
ied 81 prelingually deaf children with
a follow-up of 5–13 years. The age of
implantation ranged from 13 months to
15 years (mean 4.2 years). Postoperative
open-set word and sentence recogni-
tion after 5 years were 81% and 94%,
respectively, with a statistically signifi-
cant improvement between post- and
preoperative scores.
Beadle et al. (5) studied 30 children
at 5 and 10 years after implantation.
They used the CAP index (Category of
Auditory Performance) with a scale of 0
to 7. The score -0 implies no awareness
of environmental sounds, and 7, the
ability to talk on the telephone with a
familiar speaker. Scores improved from
0 at pre-implantation to a mean cat-
egory of 6 at 5 years, and 7 at 10 years.
The study also examined SIR (Speech
Intelligibility Rating), with 1 implying
unintelligible speech, usually using
manual communication, up to a score
of 5 = intelligible speech. Close to half
the patients scored 4 and 5 (intelligible
speech for an average listener). Median
speech intelligibility rating was 3 at 5
years, and 4 at 10 years, also demon-
strating that patients' speech continues
to improve between 5 and 10 years.
Uziel et al. (6) thoroughly studied the
10 year outcome of 82 children. Seventy-
nine percent reported that they could use
the phone. The mean open-set word score
was 72% and a 44% word recognition in
noise. Two-thirds of patients scored a
speech intelligibility rating of 4 and 5,
while 76% of the group scored signifi-
cantly lower than their hearing peers.
education and emPloYment
Ideally, an implanted child would be
mainstreamed in regular classrooms and
would use auditory-verbal and oral com-
munication. Reports show that the major-
ity of cochlear-implanted children are in
fact educated in mainstream schools.
However, this may not necessarily mean
that the child or adolescent is attending a
normal-hearing class and he or she may
require significant additional assistance.
Certification from a mainstream
high school is a condition for attending
college or university in most countries.
Accordingly, attending a school for the
deaf, whether the individual underwent
a cochlear implant or not, will usually
exclude him or her from higher learning
and, consequently, from better employ-
ment possibilities. Cochlear-implanted
children may shift from mainstream ed-
ucation to special education. Such individ-
uals were observed to enroll in appren-
ticeships and became employed in blue
collar jobs [7].
Spencer and team [3] reported the
series of their first pediatric prelingual
implanted children (1987 to 1995), with
a mean 10 year follow-up. All patients
attended a regular public school and
assisted with a sign language inter-
preter. Seventy-five percent of patients
attended a post-high school institution,
and the scholastic achievements in 10th
grade were at least as good as their hear-
ing peers.
In the series of Waltzman [4] and
Beadle [5], approximately 75% of the im-
planted children used oral communi-
cation. According to Huber and co-
researchers [7], 60% of 15 patients who
completed a mainstream high school
education used oral communication.
After 10 years follow-up, of 19 children
in compulsory and secondary school, a
third attended school for the deaf, a third
were mainstreamed in regular classes,
and a third were in units for the hear-
ing impaired attached to a mainstream

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IMAJ • VOL 12 • FEBRUARY 2010
school [5]. In this study two-thirds of
these adolescents managed well with oral
communication, with occasional help,
and the rest used total communication.
Some of the patients were engaged in
college education, even when using total
communication, with variable success.
Huber et al. [7] found that 40% of
patients who completed high school
received advanced education, which
was similar to their normal-hearing
peers. Although almost all graduates
of secondary school and college were
employed, when compared to normal-
hearing controls, cochlear implant
users had significantly less correspon-
dence between career aspiration and
their actual occupation. This study also
looked at the career prospective from
the parents' view. Parent's expectations
of their children were significantly less
optimistic (26%) than those of normal-
hearing children (73%).
In this issue of IMAJ Migirov et al.
report their results of questionnaires
for cochlear implant users. Eighteen pa-
tients were studied at a mean of 7 years
after receiving their cochlear implants.
Fourteen used oral communication and 4
used total communication. Remarkably,
all but one were either employed or en-
rolled in military service, seminary
(yeshiva), high school or university. Since
the response rates to the questionnaires
were 60%, the authors comment that the
responders may represent the more suc-
cessful cochlear implant users.
non-usage
Successful cochlear-implanted patients
would be expected to use their implants
during all hours of activity. Naturally,
non-use is regarded as a waste of an ex-
pensive resource and every effort should
be made to avoid this situation. Use/
non-use is not an all or nothing phe-
nomenon, since when thoroughly ques-
tioned, patients may volunteer that they
only wear the implant to school or when
they want to listen in social situations
[5]. Complete non-use was reported by
3–5% of patients [4,5,7]. Interestingly,
most of the non-users were older than
10 when implanted [4].
device Failure and reimPlatation
Reimplatation is required in cases of
device failure following local infection
or device extrusion. Waltzman et al. [4]
report a failure rate of 11% after 5–13
years, mostly due to device failure and
to device extrusion. Uziel and colleagues
[7] reported that 13.4% of their patients
required reimplantation after 10 years:
one case was due to local infection
and the others to device failure. Beadle
[6] reported a relatively high rate of
27% device failures after 10 years.
Reimplatation is considered highly suc-
cessful by these authors.
summarY
Unfortunately, no large-scale, well-
designed, comprehensive studies
on medium and long-term effect of
cochlear implants in prelingual children
exist. Furthermore, the few studies listed
have addressed different aspects of this
issue, in a non-standardized manner.
With the question of outcomes becom-
ing so important in modern medicine,
standardized reporting methods are
essential. This would enable a fair com-
parison between the different commer-
cial devices and between rehabilitation-
education methods.
The studies presented above were pub-
lished between 1999 and 2008. Due to the
long follow-up period required for report-
ing medium and long-term outcomes,
they actually represent patients implanted
one and two decades ago. At present and
in the near future, we may expect better
results from patients who were implanted
in the last few years for several reasons:
a) superior cochlear implants with bet-
ter coding strategies; b) developments
in rehabilitation and higher awareness
among parents and staff; c) better health
care and universal screening programs,
leading to implants being performed in an
earlier age; and d) a high rate of perform-
ing bilateral cochlear implants (either
simultaneously or sequentially) in the last
decade, which accomplishes even better
results compared to unilateral implants.
From the studies reviewed above,
mainstreaming the child who has
auditory-verbal and oral communica-
tion is the preferred educational setting
for maximizing the medium and long-
term benefit from a cochlear implant.
Hearing and speech skills continue to
improve many years after the implant.
Non-use and failure rates (as reported
by the authors from the medical centers
and not solely by the cochlear implant
manufacturers) are low, ranging from 1%
to 2.7% per year. Overall, patients have
a high rate of employment, close to that
of the general population. However, they
may be less satisfied, as the individual
and the parents may feel compromised
by their communication skills.
correspondence:
dr. d.m. Kaplan
Deputy and acting chief of Dept. of Otolaryngology-
Head and Neck Surgery, Soroka University Medical
Center, P.O. Box 151, Beer Sheva, 84101, Israel
Phone: (972-8) 640-0521
Fax: (972-8) 640-3037
email: dankap@bgu.ac.il
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