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Cochlear Implantation in Children With CHARGE Association
Paul W. Bauer, MD;
Franz J. Wippold II, MD;
Jenifer Goldin, MS, CCC-A;
Rodney P. Lusk, MD
Arch Otolaryngol Head Neck Surg. 2002;128:1013-1017.
ABSTRACT
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Objective To explore the anomalies of the temporal bone found on radiologic examination,
technical challenges in cochlear implantation, and audiologic benefit derived
from cochlear implantation in a series of children with CHARGE association.
Design Case series report.
Setting Tertiary referral children's hospital pediatric cochlear implant program.
Patients Six children with CHARGE association and sensorineural hearing loss.
Intervention All patients were evaluated and followed up by the cochlear implant
team. Cochlear implantation was attempted in all 6 children.
Main Outcome Measures Computed tomographic scans and cochlear implantation operative records
were reviewed, and their findings were correlated. Audiometric and speech
perception data before and after cochlear implantation were compared.
Results Five children with CHARGE association received implants. A sixth child
did not because of an aberrant course to the facial nerve. The 5 children
receiving implants obtained varying degrees of measurable benefit from their
implants. All 6 children had temporal bone abnormalities seen on their computed
tomographic scans and documented at the time of surgery.
Conclusions Variations in the temporal bone anatomy of patients with CHARGE association
can lead to increased technical challenges and risk to the facial nerve during
cochlear implantation. Individual outcomes after implantation may vary; our
patients receiving implants obtained benefit. Parents should be counseled
thoroughly and have appropriate expectations before proceeding with implantation.
INTRODUCTION
THE CRITERIA defining appropriate candidates for pediatric cochlear
implantation have expanded significantly as professionals have learned of
the benefits implants provide to children with deafness. Although these criteria
now include very young children and children with more residual hearing, some
controversy remains about whether children with deafness who have significant
cognitive, developmental, and physical comorbidities should undergo cochlear
implantation. Traditionally, these children have not been considered for cochlear
implantation because of questionable benefit from implantation.
One such group of children includes those with CHARGE association, a
mnemonic that refers to patients with ocular coloboma and/or choanal atresia
and manifestations of at least 4 of the 7 most common findings of the association
(coloboma, congenital heart disease, atresia choanae, postnatal retarded growth,
retarded development and/or central nervous system anomalies, genital hypoplasia
or hypogonadism, and ear anomalies or deafness).1
Findings that are seen less often include micrognathia, cleft palate, facial
palsy, swallowing difficulty, tracheoesophageal fistula, DiGeorge syndrome,
renal anomalies, and rib anomalies.1-2
These patients may have otologic manifestations involving the external, middle,
and inner ear that contribute to profound deafness.2-4
The incidence of severe to profound sensorineural hearing loss has been reported
to range from 34% to 38%, with as many as 75% of patients with CHARGE association
having some degree of sensorineural hearing loss.3, 5
Treatment of patients with CHARGE association present multiple challenges.
The original description of CHARGE association by Pagon et al1
includes 54 patients. All but 1 of these patients had some degree of mental
retardation or developmental delay. Establishing the diagnosis of mental retardation
in children with CHARGE association is complicated by the presence of visual
(coloboma) and auditory deficits. It is difficult to predict before implantation
how the addition of an auditory stimulus to a child with CHARGE association
will effect his or her cognitive development and performance.
In considering cochlear implantation for patients with CHARGE association,
attention must be given to the varied temporal bone anomalies that may be
encountered.2-5
Variations in the anatomic course of the facial nerve place these children
at increased risk of nerve injury during implantation surgery.
This study explores the anomalies of the temporal bone found on radiologic
examination, technical challenges in performing cochlear implantation in these
patients, and audiologic benefit that pediatric patients with manifestations
of the CHARGE association receive from cochlear implantation.
PATIENTS AND METHODS
A query of the St Louis Children's Hospital Cochlear Implant Program
patient database identified 6 patients with manifestations of CHARGE association
who had undergone evaluation and surgery for cochlear implantation. The radiologic,
medical, and audiologic records of the 6 children were reviewed. The Washington
University in St Louis, School of Medicine, Human Studies Committee approved
the study.
As part of the standard evaluation for cochlear implantation, patients
underwent computed tomography of the temporal bone. High resolution scans
were obtained in the axial plane using the following parameters: 0° to
–1.5° gantry angulation, slice thickness of 1.0 mm (5 patients)
and 2.0 mm (1 patient), 160 to 410 milliamperage seconds, and 120 kV. A neuroradiologist
(F.J.W.) who was blinded to the surgical findings reviewed the computed tomographic
scans of each patient. Radiologic and intraoperative findings were correlated.
Operative reports were examined to ascertain intraoperative morphologic
middle ear and temporal bone findings, degree of difficulty in performing
the implantation, and complications during surgery.
Audiometric test results before and after implantation were reviewed
to determine the benefit derived from implantation. Data sources included
routine audiometric testing, speech perception testing, and parental questionnaires.
Before implantation, ear-specific unaided pure-tone thresholds were
obtained. Aided sound-field testing using the patients' hearing aids was also
done. In addition, auditory brainstem response testing was performed for all
patients who were unable to complete or had no responses on behavioral tests.
After implantation, aided sound-field thresholds were obtained using the patients'
cochlear implants. All speech perception testing was completed at 70-dB sound
pressure level using monitored live voice.
The Early Speech Perception test was used to assess closed-set word
recognition abilities. Based on the results, a child's speech perception abilities
are categorized as (1) no speech perception, (2) pattern perception, (3) some
word identification, or (4) consistent word identification. The chance score
for each of the subtests is 25%.6
The Glendonald Auditory Screening Procedure (GASP) was used to assess
open-set speech perception abilities. The test consists of 12 words (GASP-W)
and 10 questions (GASP-S) presented through listening alone. The child is
required to repeat the word and answer the questions presented. The chance
score is 0%.7
The Meaningful Auditory Integration Scale (MAIS) or Infant Toddler–MAIS
(IT-MAIS) was used to evaluate the child's ability to make meaningful use
of sound in everyday situations. The parental questionnaires assess 3 major
areas: (1) how well the child has adjusted to his or her amplification device,
(2) how well the child responds to sound, and (3) the ability of the child
to derive meaning from auditory phenomena. A score of 0 indicates the inability
of the child to make use of sounds in his or her everyday environment, and
a score of 40 indicates that the child can consistently make use of and comprehend
sounds.8-9
RESULTS
The clinical manifestations of CHARGE association differed among the
patients. Individual patient characteristics are outlined in Table 1. Data from the most recent evaluation, including age at
time of implantation, duration of implant use, ear receiving the implant,
device implanted, electrode insertion depth, communication mode, and years
of implant use, are detailed in Table 2.
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Table 1. Occurrence of CHARGE Anomalies*
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All 6 patients had abnormalities on review of their temporal bone computed
tomography scans (Table 3, Figure 1, and Figure 2). The internal auditory canals were small bilaterally in
3 patients and unilaterally in 1 patient. Four patients had abnormally large
vestibular aqueducts. All patients had malformed or absent semicircular canals
and bilaterally malformed vestibules. The apical turn of the cochlea was hypoplastic
or dysplastic in 3 patients. Middle ear anomalies were less prevalent. One
patient had bilaterally partially fused ossicles. Unilateral effusions were
seen in 2 patients. In all patients, the facial nerves coursed over the promontory
bilaterally.
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Table 3. Temporal Bone Computed Tomographic Findings
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Figure 1. Patient 6. A, Axial computed tomographic
scan of the left ear demonstrating a small internal auditory canal (large
arrow), a dysplastic vestibule (small arrow), and an aberrantly positioned
facial nerve (white arrowhead). The semicircular canals are absent. The apical
turn of the cochlea is hypoplastic (black arrowhead). B, Image slice inferior
to A, illustrating the hypoplastic apical turn of the cochlea (arrow) and
the aberrantly positioned facial nerve (arrowhead).
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Figure 2. Patient 5. A, Axial computed tomographic
scan of the right ear showing a dysplastic vestibule (arrowhead) and partially
fused ossicles (arrow). B, Image slice inferior to A demonstrating the high
jugular bulb (arrow). The position of the round window niche is shown (small
arrowhead). A small amount of fluid is in the right mastoid air cell (large
arrowhead).
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A review of the operative records revealed no abnormal findings documented
intraoperatively in patient 1. In patient 2, the facial nerve passed lateral
to the oval window. In patient 3, the lateral semicircular canal was absent,
the incus appeared hypoplastic, and the cochlear promontory appeared flattened.
In patient 4, the incus was hypoplastic, there was a hypoplastic remnant of
the stapes superstructure, and the cochlear promontory appeared flattened.
In patient 5, the lateral semicircular canal was absent, the incus was hypoplastic
with a remnant of the stapes superstructure not attached to the footplate,
and the facial nerve was dehiscent for almost 360° as it passed lateral
to the oval window. In addition, a perilymphatic gusher was encountered after
drilling the cochleostomy, and a 4 x 6-mm area of temporal parietal
skull was dehiscent with exposed dura. In patient 6, the lateral semicircular
canal was absent, the incus was hypoplastic with a remnant of the stapes superstructure
not attached to the footplate, and the stapedial tendon attached directly
to the long process of the incus. The stapedial muscle was lateral to the
facial nerve. His facial nerve appeared to have a bifid course, with the superior
branch passing lateral to the oval window and the inferior branch passing
directly over the cochlear promontory. Intraoperative facial nerve stimulation
confirmed these observations. Because of the location of his facial nerve,
a cochleostomy could not be safely created, and the procedure was aborted.
A full insertion of all active electrodes was achieved in patients 1 through
5.
According to the audiometric data before implantation, a pure-tone threshold
response was obtained only at 0.5 kHz for patients 1, 2, and 4; no response
was obtained at the other pure-tone frequencies. Patients 3 and 5 had no measurable
responses at the maximum output limits of the audiometer to speech or tones.
After implantation, patients 1 through 4 had thresholds in the mild hearing
loss range. Frequency-specific thresholds after implantation were not consistently
obtained for patient 5; however, a speech awareness threshold was obtained
through behavioral observation at the 45-dB hearing level (Figure 3). Patient 6 did not receive an implant; therefore, the
audiometric data are not included.
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Figure 3. Hearing aid thresholds before
(dotted lines) and after (solid lines) implantation. Patient 3 had no aided
responses before implantation. Patient 4 had no aided response at 250 or 500
Hz.
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Speech perception scores after implantation, defined using the Early
Speech Perception test categories, improved for 3 of the 5 patients receiving
implants. Because of the variation in follow-up duration for the patients,
results of the most recent examinations after implantation are reported (Figure 4).
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Figure 4. Early Speech Perception (ESP)
test results from the most recent postoperative examination. Patient 1 at
4 years after implantation; patient 2 at 18 months; patient 3 at 6 months;
patient 4 at 1 year (did not cooperate during the ESP test but completed 9
of 20 key words on the Mr Potato Head Test); and patient 5 at 6 months.
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Speech perception scores on the GASP after implantation were available
for patient 1. Before implantation, patient 1 scored 0% correct on the GASP-W
and the GASP-S. One year after implantation, the scores were 8% correct on
the GASP-W and 0% correct on the GASP-S; at 2 years, 17% correct on the GASP-W
and 20% correct on the GASP-S; and at 4 years, 50% correct on the GASP-W and
50% correct on the GASP-S. Results were not obtained on patients 3 and 4 because
of their young age and were incomplete on patients 2 and 5 because of insufficient
language development.
Parental questionnaires revealed that patient 3 scored 3 on the IT-MAIS
before implantation and 31 at 6 months after implantation. Meaningful Auditory
Integration Scale scores for patient 5 were 3 before implantation and 6 at
6 months after implantation. Meaningful Auditory Integration Scale and IT-MAIS
data are not reported for patients 1, 2, and 4 because this questionnaire
was not used as part of the St Louis Children's Hospital standard evaluation
battery until after these patients had received their implants.
COMMENT
Most of our patients with CHARGE association benefited from successful
implantation. The decision to perform implantation in these children remains
controversial. Some implant programs choose not to perform implantation in
children with deafness who have multiple comorbidities because of potentially
poor results. Other programs perform implantation in these children in anticipation
of some benefit from long-term acoustic input.
Imaging provides a useful tool for preoperative evaluation of these
patients. The internal cochlear structure, vestibular aqueduct, and internal
auditory canals are especially well suited for imaging analysis. Although
current high-resolution scans provide exquisite detail, fine structures such
as the insertion point of the stapedial tendon may not be reliably demonstrated.
Coronal imaging may improve imaging accuracy.
Approaching the middle ear through the mastoid and facial recess can
be technically challenging in performing cochlear implantation. The absence
of the lateral semicircular canal and ossicular anomalies can deprive the
surgeon of important anatomic landmarks for identifying the facial nerve.
In patients 5 and 6, we removed the incus buttress to improve exposure to
the epitympanum and provide a wider field of view, through which we were able
to follow the facial nerve from the cochleariform process into the mastoid
segment. In some patients, the additional removal of the incus after disarticulation
from the stapes further improves access; however, in patients 5 and 6, the
incus was hypoplastic, with a remnant of the stapes superstructure not attached
to the footplate. Therefore, removal of the incus in these patients would
not have improved our field of view. In these patients, the exposure provided
by removing the incus buttress allowed us to identify the dehiscent and aberrant
course of the facial nerve. An aberrant or bifid course to the facial nerve
may predispose to inadvertent nerve injury. The course of the facial nerve
can also prevent successful cochlear implantation, as demonstrated in patient
6. Preoperative computed tomographic scans may not adequately demonstrate
the course of the facial nerve.
In patient 6, the option of implantation in the contralateral ear was
discussed with the patient's parents. They elected not to pursue cochlear
implantation further at this time.
Another concern in a child with CHARGE association, and which may lead
to a delay in implantation, is the need for other surgical procedures. Children
with cardiac anomalies, choanal atresia, micrognathia, cleft palate, or tracheoesophageal
fistula frequently require multiple surgical procedures. Unipolar electrocautery
is contraindicated after implantation and may complicate the completion of
these procedures. Careful consideration should be given to the timing of cochlear
implantation relative to other potential surgical procedures a child may need.
Results on speech perception tests improved in patients 1, 2, and 4.
Patient 3 has significantly improved in responsiveness and use of sound, as
measured by the IT-MAIS. Although patient 5 has shown no measurable benefit
with the test battery used in this study, his parents report that he has an
improved quality of life and is more curious about the world around him. This
is an important point. Benefit denotes something
that promotes well-being (ie, a useful aid). Our current battery of audiologic
and perceptual testing provides the basis to demonstrate objective benefit
from cochlear implantation. However, in children with significant cognitive,
developmental, and physical comorbidities, our current standard test battery
limits our ability to demonstrate objective benefit in these children. More
subjective measures reported by parents and other caregivers often serve as
early indicators of benefit.
Follow-up for most of our patients was short, limiting demonstration
of objective benefit to our patients. Prior studies10-11
show that children with motor or cognitive delays develop improved speech
perception more slowly than other children receiving implants; however, they
progress in their speech and auditory skills over time. In support of this
observation, patient 1 developed no open-set speech recognition after 1 year
and only minimal recognition after 2 years. Four years after implantation,
this patient showed significant improvement in open-set speech recognition.
We anticipate that the other children evaluated in this study will continue
to make progress over time.
CONCLUSIONS
Cochlear implantation in patients with CHARGE association is feasible.
Variations in temporal bone anatomy can lead to increased technical challenges.
Surgeons planning cochlear implantation in these patients should be knowledgeable
about the potential variations to avoid inadvertent facial nerve injury. Parents
need to be aware of the increased risks, particularly to the facial nerve,
and the possibility of no or partial electrode implantation. Although individual
outcomes may vary, all but 1 of the children in our series obtained measurable
benefit. Because of variations in the degree of benefit these patients achieved
after implantation, it is important to ensure that parents are counseled thoroughly
and have appropriate expectations before proceeding with implantation.
AUTHOR INFORMATION
Accepted for publication February 13, 2002.
This study was presented at the American Society of Pediatric Otolaryngology
16th Annual Meeting, Scottsdale, Ariz, May 10, 2001.
The opinions and assertions contained herein are the private views of
the authors and are not to be construed as official or as reflecting the views
of the US Department of Defense.
Corresponding author and reprints: Paul W. Bauer, MD, Division of
Pediatric Otolaryngology, Department of Otolaryngology–Head and Neck
Surgery, The University of Texas Southwestern Medical Center, 5323 Harry Hines
Blvd, Dallas, TX 75390-9035 (e-mail: paul.bauer{at}utsouthwestern.edu).
From Washington University in St Louis, School of Medicine (Drs Bauer
and Lusk); the Division of Pediatric Otolaryngology (Drs Bauer and Lusk),
Departments of Radiology (Dr Wippold) and Audiology (Cochlear Implant Program)
(Ms Goldin), St Louis Children's Hospital; and Mallinckrodt Institute of Radiology,
Washington University Medical Center (Dr Wippold), St Louis, Mo; and F. Edward
Hébert School of Medicine, Uniformed Services University of the Health
Sciences, Bethesda, Md (Dr Wippold). Dr Bauer is now with the Division of
Pediatric Otolaryngology, Department of Otolaryngology–Head and Neck
Surgery, The University of Texas Southwestern Medical Center, Dallas.
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