1. Cochlear Implant Outcomes in Adults and Children
with Inner Ear Malformations
Szudek
1,
J
1University
Dettman
2,
S
Sadeghi-Barzalighi
2,
A
Zraika
2,
L
and Briggs
1
RJS
of Melbourne, Department of Otolaryngology, 2University of Melbourne Department of Audiology
Introduction
Bony cochlear or vestibular malformations occur in about 20% of patients with congenital
sensorineural hearing loss. Intuitively, one would expect such malformations to influence
surgical and audiologic outcomes in patients undergoing cochlear implantation. However,
the precise impact of these malformations on surgical and audiologic outcomes has not
yet been elucidated.
Results - Adults
Table 3: Outcomes in Adults by Type of Congenital Malformation
Patients and Methods
A retrospective review of the Cochlear Implant Clinic database at the University of
Melbourne identified 57 children and 31 adults with cochlear and/or vestibular
malformations who had undergone cochlear implantation. The patients’ CT and MRI scans
were classified into ordinal categories of cochlear malformation according to the scheme
of Sennaroglu1: common cavity (CC), incomplete partition -I (IP-I); IP-II with or without
enlarged vestibular aqueduct (EVA); IP-III, or EVA alone.
Analysis of variance (ANOVA) was used to compare speech perception (open-set word,
phoneme and sentence scores), language development (Peabody Picture Vocabulary
Test (PPVT) standard scores and delay), and surgical outcomes (occurrence of a CSF
gusher and insertion depth) among the groups of malformations. Pearson’s correlation
coefficients were calculated between the duration of profound hearing loss and speech
perception and language outcomes. T-tests were used to compare speech perception and
language outcomes between groups of patients with and without gushers and incomplete
electrode insertions. SPSS5 was used to perform all statistical analyses.
Duration of profound hearing loss was significantly correlated with OSW Word (r=-0.36,
p=0.04) and BKB Sent (r=-0.41, p=0.02), but not with OSW Phon (r= -0.27, p=0.14), .
Table 4: Outcomes in Adults with Gushers and Incomplete Insertions
Results - Children
Table 1: Outcomes in Children by Type of Congenital Malformation
Discussion
Pre-operative imaging is a routine and essential part of planning cochlear implantation.
However, based on this retrospective study of children and adults , the extent of preoperative cochlear/vestibular malformation alone cannot predict post-operative cochlear
implant performance (Tables 1 and 3).
“Other” malformations in Table 1 included two IP-I cochlea, one hypoplasia and one
unclassified malformation.
Duration of profound hearing loss was significantly correlated with OSW Phon (r= -0.43,
p=0.004), OSW Word (r=-0.32, p=0.03), BKB Sent (r=-0.35, p=0.02), and PPVT delay
(r=0.49, p=0.001) but not with PPVT SS (r=-0.25, p=0.1).
Table 2: Outcomes in Children with Gushers and Incomplete
Insertions
On the other hand, the presence of gusher, incomplete insertion and a longer duration of
pre-implantation hearing loss were associated with worse speech perception and
language outcomes in children and adults (Tables 3 and 4). Of the 11 gushers
encountered in children, 4 were accompanied by an incomplete insertion. Of the 5
gushers encountered in adults, all had a complete insertion. The only incomplete insertion
in an adult did not have a gusher. This suggests that only part of the speech and language
outcome may be related to incomplete insertion. Only one adult had incomplete electrode
insertion, precluding meaningful statistical comparison (Table 4)
The post-operative speech and language scores in the present study are similar those
reported in other pediatric groups with cochlear abnormalities but lower than those with
normal cochlea and adult groups.2-4
One of the limitations of this study is the significant number of patients who did not have
complete post-operative speech perception and language testing. For example, 2 of the
patients with common cavities, 5 of those with IP-II + EVA and 2 of those with EVA alone
performed too poorly to test OSW. This may contribute to the failure of this study to show
performance differences between groups of different malformations. On the other hand,
the patients with these malformations who were tested performed well, underscoring the
wide range of outcomes that we observed within all groups of malformations
Conclusions
References
1. Sennaroglu L. Cochlear implantation in inner ear malformations--a review article. Cochlear Implants Int.
2010;1:4-41
2. Van Wermeskerken GKA, Dunnebier EA, Van Olphen AF, Van Zanten BA, Albers FW. Audiological
performance after cochlear implantation: a 2-year follow-up in children with inner ear malformations.
Acta Otolaryngol 2007;127:252–257.
3. Dowell RC, Dettman SJ, Blamey PJ, Barker EJ, Clark GM. Speech perception in children using cochlear
implants: prediction of long-term outcomes. Cochlear Implants Int 2002a;3:1–18.
4. Gleeson, T.G., Lacy, P.D., Bresnihan, M., et al. High resolution computed tomography and magnetic
resonance imaging in the pre-operative assessment of cochlear implant patients. J Laryngol Otol
2003;117, 692-695
5. SPSS Base 20 for Mac. IBM SPSS Statistics. 2011
! Implant performance cannot be reliably predicted based on the type of radiographic
cochlear malformation in either children or adults.
! Implant recipients with a shorter period of profound hearing loss have significantly
better implant performance.
! Intra-operative gushers and the incomplete insertions are associated with worse
implant performance