COCHLEAR IMPLANTS
Ayça Ciprut, Ph.D. / Sezer Kulekci, Ph.D. Şengül Terlem ez, M .Sc. / Ferda Akdaş, Ph.D.
S u b - d e p a r t m e n t o f A u d i o l o g y , D e p a r t m e n t o f O t o r h i n o l a r y n g o l o g y , S c h o o l o f M e d i c i n e , M a r m a r a U n i v e r s i t y , I s t a n b u l , T u r k e y .
ABSTRACT
Objective:
The aim of this study was to evaluateauditory performance and speech perception of congenitally deaf children after implantation.
Methods:
The study consisted of 24 prelinguallydeafened children with cochlear implants (Cl). Auditory performance and speech intelligibility after cochlear implantation were assessed using two scales: Speech Intelligibility Rating (SIR) and the Categories of Auditory Performance (CAP).
Results:
The auditory performance and speechintelligibility of all children increased after implantation. CAP and SIR results of the children who were implanted before the age of four, who used hearing aids before implantation and who had strong family support were superior to the group of children implanted after the age of 4, who did not used hearing aids and who did not have family support.
Conclusion:
All children participated to the studybenefited from cochlear implant in terms of increase of auditory performance. As the time of Cl usage increases, speech intelligibility also increases. Intelligibility becomes significant by the end of third year of Cl use. Strong family support, use of Cl and early implant age are found to be important for succes with Cl.
K ey W o rd s : Cochlear implant, Speech
intelligibility, Auditory Performance, Children
INTRODUCTION
Profound sensorineural hearing loss in children has a major impact on language acquisition. For some children with profound sensorineural hearing loss, conventional hearing aids provide little or no benefit. It is difficult for them to hear sounds and spoken language and to communicate easily with others. Cochlear implant provides access to spoken language when the hearing aids fail. Cochlear implants provide the audition necessary to develop intelligible language for these children (1-9). Cochlear implants have become a widely accepted form of (re) habilitation for profoundly deaf children. Children with congenital deafness who receive cochlear implants have shown significant gains in hearing and language development (10-12). Several researches have shown that children demonstrate a wide range of benefits from the implants. Factors such as the time of implantation, age at onset of deafness, residual hearing, educational setting, family support and communication mode can affect the outcome (13-16).
M a r m a r a M e d i c a l J o u r n a l 2 0 0 3 ; 1 6 ( 1 ) : 2 0 - 2 6
C o rre sp o n d e n ce to: A yça Ciprut, Ph.D, - S u b -d e p a rtm e n t o l A udiolo gy, D e p a rtm e n t o f O to rh in o la ryn g o lo g y. M a rm a ra U niversity H ospital, A itunizad e, 8 1 1 9 0 Istanbul, Turkey,
The aim of this study was to evaluate auditory performance and speech perception of prelingually deaf children after implantation.
M ETHOD
The study was undertaken in the Marmara University Medical School, Audiology Sub department. Twenty-four children who had received cochlear implants participated in the study. Patients ranged in age from 5 to 14 years with a mean of 8.4 years. Table I shows the demographic information of each subject.
Of 24 patients, 14 were congenitally deafened with unknown etiology, 2 patients had hereditary hearing loss, 4 were deafened after menengitis, 3 had Mondini malformation and one patient had sudden hearing loss of unknown cause.
Sixteen out of 24 patients used hearing aids prior to cochlear implantation. The patients were
accepted as appropriate candidates for cochlear implantation on the basis of medical, radiological and audiological evaluations. They had good general health and their temporal bone computerized tomography scans did not contraindicate placement of the electrode array. Audiologically, they were found to have profound hearing loss. Their speech detection thresholds with the hearing aids were 65dB or greater. Audiological assessment at the preoperative evaluation consisted of standard pure tone and speech testing under earphones, acoustic immitancemetry and otoacoustic emissions. Auditory Brainstem Response (ABR) was performed when it was found to be necessary. The mean preoperative auditory thresholds for right and left ear,the preoperative aided thresholds in the sound field and the postoperative thresholds with the cochlear implant are shown in (Fig.1).
Table I: Demographic information of the subjects
Patients Age H.Aid.use Cl use Cl Strategy Etiology
HH 7 — 4 years 24 M SPEAK' Genetic
UA 7 — 3 years 24M ACE Meningitis-hyperbilirubinemia
ED 11 — 4 years 24M SPEAK Genetic
ZG 9 4 years 4 years 24 M SPEAK Idiopathic-congenital
KM 7 2 years 4 years 24M ACE2 Idiopathic-congenital
SD 5 — 4 years 24M ACE Meningitis
PO 5 2 years 1.5 years 24M ACE Idiopathic-congenital
IA 9 2 years 5 years 24 M ACE Idiopathic-congenital
SNA 3 6 months 1 year 24M ACE Idiopathic-congenital
KO 10 — 4 years 24 M SPEAK Meningitis
SY 9 2.5 years 6 years 22 SPEAK Congenital malformation
DK 13 7 years 4 years 24 M SPEAK Idiopathic-congenital
DB 14 10 years 1 year 24M ACE Idiopathic-congenital
ECG 9 6 years 2 years 24M ACE Idiopathic-congenital
RNE 7 1.5 years 3 years 24M SPEAK Congenital malformation
CG 10 4 years 4 years 24 M SPEAK Idiopathic-congenital
ME 10 3 years 4 years 24M SPEAK Idiopathic-congenital
ZT 8 6 years 1 year 24M CIS3 Congenital malformation
MZE 7 5 years 1 year 24M SPEAK Idiopathic-congenital
BB 9 — 5.5 years 20+2 SPEAK Meningitis
MY 10 3 years 4 years 24M SPEAK Idiopathic-congenital
HK 10 — 4 years 24 M SPEAK Idiopathic-congenital
BP 7 — 4 years 24M ACE Unknown sudden
EO 6 3 years 2 years 24M SPEAK Idiopathic-congenital
1: SPEAK = Spectral peak
2: ACE = Advanced combination encoding 3: CIS = Continious interleaved sampling
F ig .1 : Mean preoperative auditory thresholds for the right (O)
and the left (X) ears and preoperative aided thresholds in the soundfield (A) and postoperative thresholds with the cochlear implant (Cl).
The mean thresholds in the right ears were 90 dB at 250 Hz, 102 dB at 500 Hz, 110 dB at 1000 Hz, 115 dB at 2000 Hz, 120 dB at 4000 Hz. The mean thresholds for the left ears were 100 dB at 250 Hz, 105 dB at 500 Hz, 115 dB at 1000 Hz, 116 dB at 2000 Hz and 120 dB at 4000 Hz. The mean hearing thresholds in the free field with cochlear implant ranged from 30 to 45 dB HL, 250 to 8000 Hz.
All patients underwent implantation with the Nucleus cochlear implant device. 22 patients received Nucleus 24 M device, 1 patient Nucleus 22 and one Nucleus 20+2. 4 patients used ESPrit behind the ear speech processor, 18 used Sprint body worn speech processor and 2 used Spectra speech processor. 14 of them were programmed with the spectral peak (SPEAK) coding strategy, 9 with the advanced combination encoding (ACE) and one patient with continious interleaved sampling (CIS).
Length of cochlear implant use ranged from 1 to 6 years.
Auditory and speech performance were assessed through Speech Intelligibility Rating (SIR) and the Categories of Auditory Performance (CAP) (17,18). The CAP provides an ordinal scale of auditory receptive capabilities and is designed to reflect the real life progress of children in developing the use of audition. It is composed of eight categories ranging from “No awareness of environmental sounds” through to “Use of telephone with known listener".
The Speech Intelligibility Rating (SIR) was designed as an outcome measure of the hearing impaired children's speech development (19). It is a real life descriptive rating scale for speech intelligibility consisting of five categories ranging from sign language to intelligible connected speech.
The data on cochlear implant patients were collected preoperatively and 6,12, 24, 48 months postoperatively. Results before implantation (n=24), 6 months (n=24), 1 year (n=21), 2 years (n=15), 3 years (n=12), 4 years (n=5), 5 years (n=2) were reported.
RESULTS
Data obtained from the scales showed that more than half of the children were not aware of environmental sounds before implantation. All children obtained substantial benefit from the implant. All children had their auditory performance increased after use of cochlear implantation. (Table II).
Table II: Categories of auditory performance results for all patients
CATEGORIES OF AUDITORY PERFORMANCE
Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years
7. Use of telephone with known speaker 0 0 0 0 1 0 0
6. Understand conversation without lipreading 1 2 3 2 2 1 0 5. Understand common phrases without lipreading 1 0 2 4 3 2 1 4. Discriminate some speech sounds without lipreading 1 4 6 5 4 1 0
3. Identify environmental sounds 1 6 3 3 1 0 0
2. Respond to some speech sounds 5 3 6 0 0 0 0
1. Aware of environmental sounds 2 9 1 1 1 1 1
0. Not aware of environmental sounds 13 0 0 0 0 0 0
By the end of one year all children were able at least to respond to speech sounds.
Performance data presented in Table III shows that before implantation, 13/24 children were using signs as means of communication, 8/24 had unintelligible speech with single words. At the end of the third year, post implant data demonstrated that 9 of 12 children who fulfilled 3 years of implant use had acquired intelligible speech.
The data obtained through these rating scales were also evaluated in terms of factors affecting cochlear implant benefit such as cochlear implant age, family support and use of hearing aids before Implantation.
Implanted children were evaluated separately according to their cochlear implant age. Table IV Indicates the auditory performance of children implanted before and after 4 years of age, table V shows the SIR results. The progress of these two groups of children was not found to be different since many of the children implanted after 4 years old were using their hearing aids effectively and had some speech before Cl. Table VI shows SIR results for children with and without family support. Before implantation most
of the children without family support were preverbal they used sign language, with time, their progress in speech production was not as good as children with strong family support. Table VII demonstrates the auditory performance of these children. The ones with good support were all able to at least discriminate speech sounds without lipreading by the end of the second year.
The group of children without family support were not as good as the others in auditory perception Table VIII Is the auditory performance of children who used hearing aids before cochlear Implantation and children who did not. Table IX shows the results of speech Intelligibility of the children with or without use of hearing aids. At the precochlear implant period, 9 children who had not used hearing aids previously were not aware of environmental sounds, only 4/15 children who were hearing aid users prior to implantation were not aware of sounds. 3 of these 4 children were congenital malformation cases. With the use of cochlear implant the children who had used hearing aids had higher scores on the CAP scale and SIR scale than the ones who did not.
Table III: Speech Intelligibility Rating results for all patients
SPEECH IN TELLIG IBILITY RATING
Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years
5. Intelligible to all 1 1 1 0 2 0 0
4. Intelligible to listener with little experience 1 1 2 2 1 1 1
3. Intelligible to experienced listener 1 2 4 5 6 3 0
2. Unintelligible 8 11 12 7 2 0 0
1. Sign language 13 9 2 1 1 1 1
Total number of children 24 24 21 15 12 5 2
Table IV: Categories of auditory performance for children implanted before and after age 4
CAP FOR CHILDREN IMPLANTED BEFORE AGE OF 4 CAP FOR CHILDREN IMPLANTED AFTER AGE OF 4
Pre-CI 6 months 1 year2 years3 years 4 years 5 years Pre-C 6 months 1 year 2 years 3 years 4 years 5 years
7. Use of telephone with known speaker 0 0 0 0 1 0 0 0 0 0 0 0 0 0
6. Understand conversation without lipreading 0 0 1 2 1 0 1 1 2 2 0 0 0 0
5. Understand common phrases without lipreading 0 0 2 2 1 0 0 1 0 0 2 2 2 0
4. Discriminate some speech sounds without lipreading 0 2 2 2 2 2 0 0 1 4 2 2 0 0
3. Identify environmental sounds 0 2 1 2 0 0 0 2 4 2 2 1 0 0
2. Respond to some speech sounds 3 1 2 0 0 0 0 2 3 4 0 1 0 0
1. Aware of environmental sounds 1 5 1 1 1 1 1 2 4 0 0 0 0 0
0. Not aware of environmental sounds 7 0 0 0 0 0 0 5 0 0 0 0 0 0
Table V: Speech Intelligibility Rating for children implanted before and after age 4
SIR FOR CHILDREN IMPLANTED BEFORE AGE OF 4 SIR FOR CHILDREN IMPLANTED AFTER AGE OF 4
Pre-CI 6 months 1 year2 years3 years 4 years 5 years Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years
5. Intelligible to all 0 0 0 0 0 0 0 1 1 1 0 0 0 0
4. Intelligible to listener with little experience 0 0 1 2 2 1 1 1 1 1 0 0 0 0
3. Intelligible to experienced listener 0 1 2 2 2 1 0 1 1 2 3 3 2 0
2. Unintelligible 4 5 6 3 2 0 0 4 6 6 4 2 0 0
1. Sign language 7 5 1 1 1 1 1 6 4 1 0 0 0 0
Total number of children 11 11 10 8 7 3 2 13 13 11 7 5 2 0
Table VI: Speech Intelligibility Rating for children with and without family support
SIR FOR CHILDREN WITH FAMILY SUPPORT SIR FOR CHILDREN WITHOUT FAMILY SUPPORT Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years
5. Intelligible to all 1 1 1 2 2 0 0 0 0 0 0 0 0 0
4. Intelligible to listener with little experience 1 1- 2 1 1 1 0 0 0 0 0 0 0 1
3. Intelligible to experienced listener 0 1 3 5 5 1 0 1 1 1 1 1 2 0
2. Unintelligible 7 7 5 0 0 0 0 1 4 6 5 2 0 0
1. Sign language 3 2 0 0 0 0 0 10 7 3 1 1 1 1
Total number of children 12 12 11 8 8 2 0 12 12 10 7 4 3 2
Table VlhCategories of auditory performance for children with and without family support
CAP FOR CHILDREN WITH FAMILY SUPPORT CAP FOR CHILDREN WITHOUT FAMILY SUPPORT Pre-CI6 months 1 year 2 years 3 years4 years 5 years Pre-CI 6 months1 year 2 years 3 years 4 years 5 years
7. Use of telephone with known speaker 0 0 0 0 1 0 0 0 0 0 0 0 0 0
6. Understand conversation without lipreading 1 2 3 2 2 1 0 0 0 0 0 0 0 0
5. Understand common phrases without lipreading 1 0 2 3 3 1 0 0 0 0 1 1 1 1
4. Discriminate some speech sounds without lipreading 0 2 4 3 3 0 0 1 2 2 1 1 1 0
3. Identify environmental sounds 1 4 1 0 0 0 0 0 2 2 3 1 0 0
2. Respond to some speech sounds 4 1 1 0 0 0 0 1 2 5 2 0 0 0
1. Aware of environmental sounds 0 3 0 0 0 0 0 2 6 1 1 0 1 1
0. Not aware of environmental sounds 5 0 0 0 0 0 0 8 0 0 0 0 0 0
Total number of children 12 12 11 8 9 2 0 12 12 10 8 3 3 2
Table VIII: Categories of auditory performance for children with and without use of hearing aids.
CAP FOR CHILDREN WITH USE OF HEARING AIDS CAP FOR CHILDREN WITHOUT USE OF HEARING AIDS Pre-CI 6 months 1 year 2 years 3 years4 years 5 years Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years
7. Use of telephone with known speaker 0 0 0 0 0 0 0 0 0 0 0 1 0 0
6. Understand conversation without lipreading 1 2 3 1 1 1 0 0 0 0 1 1 0 0
5. Understand common phrases without lipreading 1 0 1 3 3 1 1 0 0 1 1 0 0 O
4. Discriminate some speech sounds without lipreading 1 3 4 1 1 1 0 0 1 1 4 3 0 0
3. Identify environmental sounds 1 6 2 2 0 0 0 0 0 2 1 1 0 0
2. Respond to some speech sounds 5 0 3 0 0 0 0 0 3 3 0 0 1 0
1. Aware of environmental sounds 2 4 0 0 0 0 0 0 5 1 1 1 1 1
0. Not aware of environmental sounds 4 0 0 0 0 0 0 9 0 0 0 0 0 0
Total number of children 1 5 1 5 1 3 7 5 3 1 9 9 8 8 7 2 1
Table IX: Speech Intelligibility Rating for children with and without use of hearing aids
SIR FOR CHILDREN WITH USE OF HEARING AIDS SIR FOR CHILDREN WITHOUT USE OF HEARING AIDS Pre-CI 6 months 1 year 2 years 3 years 4 years 5 years Pre-CI 6 months 1 year 2 years 3 years 4 years5 years
5. Intelligible to all 1 1 1 0 1 0 0 0 O 0 0 1 0 0
4. Intelligible to listener with little experience 1 1 2 1 0 1 1 0 0 0 1 1 0 0
3. Intelligible to experienced listener 1 2 3 4 4 2 0 0 O 1 1 2 O 0
2. Unintelligible 7 9 6 2 0 0 0 1 2 6 5 2 1 0
1. Sign language 5 2 0 0 0 0 0 8 7 2 1 1 1 1
Total number of children 1 5 1 5 12 7 5 3 1 9 9 9 8 7 2 1
DISCUSSION
Cochlear implantation has been proven to be a method of choice for the habilitation and/or rehabilitation of the profoundly hearing impaired. The data presented here demonstrated that all children in this study received benefit from their implants when compared with the results obtained preoperatively. The results of this study are consistent with those of previous investigations showing that children achieve higher levels of performance on auditory perception and speech perception tests. (2,9,12,20,21).
The results obtained from the CAP and SIR scales were evaluated in terms of the factors affecting the benefit obtained from the cochlear implant.
Previous researches have shown that children fitted with implants at a younger age derive more benefit than children fitted with implants at an older age. Greater benefit may be obtained from implanting prelingual deaf children at the earliest possible age in order to take advantage of critical periods of language development (15,22). Our data suggested that the performance for prelingually deafened children implanted at a younger age was not different when compared to those implanted after 4 years. The group of children implanted after the age of four were using their hearing aids effectively before the implantation and they had education support. For this reason, no big difference was observed when the two groups were compared.
Close collaboration with the parents is an important requirement to help cover the post operative success to a high degree. The family plays a particular role In developing the child’s communication behavior In a natural way and in helping to develop speech(23). The group of children who had strong family support had better scores in both CAP and SIR scales compared to the group without family support.
Another important factor which contributes to implant performance in prelingually deafened children might be the use of hearing aids before implantation. Children who used hearing aids before they received cochlear implants and
who had better speech perception and production abilities tended to perform better with their implants (2,20,21,24,25). The group of children who used hearing aids and had auditory-oral therapy before implantation tended to perform better with their implants than the children who did not use hearing aids. Preoperative speech perception abilities with the hearing aids contributed to the post implant performance.
Cochlear implant provides significant auditory benefit to profoundly deaf children. All children participated to the study benefited from cochlear implant in terms of increase of auditory performance. As the time of Cl usage increases, speech intelligibility also increases. Intelligibility becomes significant by the end of the third year of Cl use. Strong family support, use of Cl and early implant age are found to be important for success with Cl.
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O t o la r y n g o l H e a d H e c k S u r g 1 9 9 7 , 1 1 7 : 1 8 0 - 1 8 7 . 2 3 . B e i t e r A L , S t a ll e r S J , D o w e l l R C . E v a lu a t io n a n d d e v ic e p r o g r a m m i n g in c h i ld r e n . E a r H e a r 1 9 9 1 ; 1 2 ( S u p p l) : 2 5 S - 3 3 S . 2 4 . Q u i t t n e r A , S t e c k J T . P r e d ic t o r s o f c o c h le a r i m p l a n t u s e in c h i ld r e n . A m J O t o l 1 9 9 1 , 1 2 ( s u p p l) : 8 9 - 9 4 . 2 5 . S o m e r s M , S p e e c h p e r c e p t i o n a b i l i t i e s in c h i ld r e n w it h c o c h le a r im p l a n t s o r h e a r in g a id s . A m J O t o l 1 9 9 1 ; 1 2 ( S u p p l) : 1 7 4 - 1 7 8 .
