Audiologic Issues in CHARGE Syndrome
CHARGE is a syndrome that many audiologists have not
encountered. It is rare (1 in 15,000 births) and complex.
Audiologic evaluation of individuals with CHARGE syndrome can be
challenging as a result of characteristics that are unique to
this population. However, some of the characteristics seen in
individuals with CHARGE can also be seen in other populations,
such as those with severe developmental delays, autism spectrum
disorders, and auditory neuropathy/dyssynchrony.
"CHARGE" is the acronym created by R. A. Pagon and
her coworkers in 1981 (Pagon, Graham, Zozana, & Yong, 1981)
to describe six features of a complex genetic disorder. Since
1981, the diagnostic criteria have been revised, and they will
continue to be revised. At present, the criteria include more
than 20 physical anomalies, deficits in
sensory modalities, and a behavioral phenotype that is unique. At
present, diagnosis is based on clinical evaluation of the
presence of certain major and minor features (Blake et al., 1998)
and/or the presence of microdeletions in the CHD7 gene on
chromosome 8 (Vissers et al., 2004). The vast majority of genetic
mutations are sporadic rather than familial.
Though there may be deficits in every sensory modality, for
educational purposes, CHARGE is considered to be a deaf-blind
syndrome. Complete deafness and blindness are very rare. The most
common finding is partial loss of hearing and vision. However,
the combination of these two sensory deficits almost always
results in overall challenges that are much greater than would be
expected from the sum of the two. With multiple sensory deficits,
the effects are often subtle and may manifest themselves as
unique challenges in communication, learning, and behavior.
Within individuals, each of the 20+ possible anomalies may be
absent or present (varying in degree of expression from mild to
severe). Thelin and Swanson (2006) have given a description of
the most important anomalies. As a result of this complexity,
each individual may have a unique set of physical disorders, a
unique combination of sensory deficits, and a unique pattern of
behavior. The challenge to the clinician is to determine how best
to interface with that individual, recognizing the
individual's specific abilities, to obtain diagnostic
information and to provide needed treatment. As a result of very
significant sensory deprivation in all modalities, a substantial
percentage of individuals with CHARGE do not develop symbolic
communication. Some may use gestures to communicate, while others
may rely on more primitive forms of expression.
Approximately half of individuals with CHARGE have
severe-to-profound hearing loss. Many of these individuals are
very difficult to evaluate audiologically. However, the
documentation of hearing loss that enables either the fitting of
appropriate amplification (i.e. hearing aids or cochlear
implants) or a better understanding of the individual's
communication needs may result in the development of the primary
means for communication and learning. In the most extreme cases,
individuals with CHARGE who have virtually no channels of
meaningful sensory input may resort to destructive behaviors and
self-mutilation as their only means of communication. In some
cases, these behaviors have ceased after
that ended the individual's isolation. A more general
observation has been that the acquisition of symbolic
communication is highly correlated with
successful audiologic intervention
-regardless of the degree of hearing loss.
Individuals with CHARGE syndrome are typically delayed in
development-motorically, intellectually, and physically. Some
individuals do not reach puberty until 20 years of age. The most
common report from parents is that their child has reached some
developmental milestone well beyond the expected age of
acquisition and after the parents had lost hope that the
milestone would ever be reached. Parents are keenly sensitive to
this issue and discount the advice of clinicians who
underestimate their child's potential. It is critical for the
clinician to recognize this and to proceed and plan as if goals
that may seem unattainable may eventually be attained.
Structural Anomalies and Hearing Loss
In CHARGE, nearly every set of structures in the auditory
system may be involved.
typically are malformed and have patterns of malformation that
are so distinctive that preemptive diagnoses of CHARGE can be
made on the basis of unusually shaped, asymmetrical pinnae. The
anomalous pinnae rarely cause hearing loss, but they are often so
soft and floppy that they may not support a behind-the-ear
hearing aid. Ear canals are often stenotic but rarely
typically have ossicular malformations that result in conductive
losses that are greatest in the low frequencies but can be
present at all frequencies. Average conductive losses as great as
70 dB have been reported with normal tympanograms. Eustachian
tube dysfunction is almost universal, with most children
requiring several sets of tympanostomy tubes. When the eustachian
tube dysfunction is caused by craniofacial anomalies, middle ear
fluid and otitis media may persist into adulthood.
Cochleas and vestibular mechanisms
often are dysplastic or aplastic. Many different forms of
structural anomalies have been reported, including Mondini's
dysplasia, which includes dwarf cochleas and incomplete formation
of the semicircular canals. The semicircular canals of the
vestibular system are often missing. As a result, individuals
with CHARGE may have difficulty walking and performing acts that
require balance-related skills, but they rarely have any
complaints related to dizziness.
Auditory neural structures
may be involved as well. The auditory nerve may be reduced in
diameter or absent. Recent evidence suggests that the anatomical
assessment of the auditory nerve is best accomplished with
magnetic resonance images that are supplemented with information
obtained by computerized tomography. Radiographic studies have
shown instances of dysgenesis or agenesis of the corpus callosum.
In cases with relatively normal hearing, evidence of
retrocochlear involvement has been documented using auditory
evoked response testing.
There is no characteristic hearing loss in CHARGE syndrome.
The most common features are asymmetrical mixed losses that are
severe-to-profound in degree. Conductive components, which are
due to a combination of ossicular anomalies and middle ear
effusion, are often asymmetrical and fluctuating in nature;
cochlear hearing loss, often due to cochlear malformations, is
typically greater in the high frequencies. Three examples of
hearing loss in CHARGE are shown below. Hearing results were
specified using the audiometric standard in effect when the
audiograms were obtained.
Audiogram 1 (58-year-old female)
This audiogram was selected to illustrate asymmetry of hearing
loss between the ears, which is common in CHARGE syndrome. In
this case, there is asymmetry in both the conductive and cochlear
components and in the overall degree of hearing loss in the two
ears. Tympanometry was normal in both ears, indicating that the
middle ear losses are due to ossicular anomalies.
This is a rare case of familial CHARGE syndrome that includes
the woman whose audiogram is shown, her mother, her brother (one
of her four siblings), and three of her nine children (Thelin,
Mitchell, Hefner, & Davenport, 1986). Among these
individuals, auditory anomalies were found for every individual,
but hearing levels ranged from normal to profound hearing
Audiogram 2 (21-year-old female)
This audiogram was selected because it illustrates (a)
asymmetrical hearing loss and (b) bilateral mixed loss with
significant cochlear loss that is difficult to treat. In the
right ear, there is a mild conductive loss through 1500 Hz
falling to a profound mixed loss in the higher frequencies. In
the left ear, there is a severe-to-profound mixed loss. This
young woman has chronic middle-ear disease and has had many
surgeries in both ears. Middle-ear effusion and drainage into the
ear canals are still a persistent problem. The conductive
component of her hearing loss is probably due to a combination of
ossicular anomalies and effusion.
A unique aspect of this individual's auditory problems is
that even though the cochlear sensitivity in the left ear is in
the moderate to moderately severe hearing loss range, because of
the large conductive loss, the left ear is unaidable. She wears a
behind-the-ear hearing aid in the right ear, but when there is
effusion, her aided benefit is reduced. Under the best of
conditions, she receives most aided benefit at 2000 Hz and below.
With the large conductive loss in the right ear, if she is eating
or chewing gum, the internally generated noise is so great that
she cannot understand a person who is talking to her. As a result
of these factors, her hearing problems are resolved only
intermittently. She communicates with both spoken and signed
Audiogram 3 (12-year-old male)
This audiogram was selected to illustrate the magnitude of
conductive loss that can be present in CHARGE syndrome. The
tympanograms were shallow but peaked at room pressure-indicating
that the conductive loss was not due to eustachian tube
dysfunction or middle-ear effusion but rather to ossicular
anomalies. Unmasked bone-conduction thresholds were measured only
on the right ear but are shown for the left ear with a dotted
The solid lines (labeled with an S) indicate the pure-tone
thresholds obtained with supra-aural earphones. It is our
interpretation that these thresholds were
"bone-conduction" thresholds because, at these signal
levels, the earphone cushion on the pinna begins to act as a bone
vibrator rather than as an acoustic sound source. The average
air-bone gap for the five test frequencies was 61 dB in the right
ear and 72 dB in the left ear.
It is our opinion that the thresholds with the supra-aural
earphones significantly underestimate the true degree of hearing
loss and that a better estimate of the air-conduction thresholds
is obtained with insert earphones (dashed lines labeled with an
I). The insert earphones may be generating bone-conducted
stimulation as well, but we suspect because of the coupling in
the external auditory canal and the reduced amount of sound power
required, the stimulation is likely to be acoustic. We believe
that thresholds obtained with the insert earphones more
accurately reflect the individual's hearing loss.
The average insert earphone threshold for the right ear was
103 dB HL (average air-bone gap = 77 dB), and for the left ear it
was 105 dB HL (average air-bone gap = 79 dB). These are very
large conductive components that are difficult to overcome with
conventional hearing aids without encountering feedback. This
individual's bone-conduction thresholds make him a candidate
for bone-conduction amplification or an auditory osseointegrated
Factors in Audiologic Assessment and Treatment
Individuals with CHARGE often have physical and sensory
disorders, limited communication ability, and behaviors that
provide challenges in the assessment of hearing and the treatment
of hearing loss. Listed below are factors to consider when
providing audiologic services.
A significant percentage of individuals with CHARGE have no
symbolic communication. For individuals with limited
communication abilities, the presence of an adult who understands
the individual's communication system is very helpful.
Adapting audiologic procedures is often necessary. For example,
the audiologic assessment of a 27-year-old male who was
profoundly intellectually challenged and who had very poor vision
was possible because this individual would respond to speech
stimuli with grunts, head banging, and rapid eye movements. He
responded consistently to speech in each ear at 60 dB HL and to
bone-conducted speech at 40 dB HL, indicating the presence of a
bilateral mixed hearing loss.
Individuals with CHARGE may exhibit tactile defensiveness,
attention deficit disorder, autistic-like behaviors,
self-stimulatory behaviors, and in extreme cases,
self-mutilation. These challenging behaviors are those by which
individuals with severe sensory deprivation deal with the world
that they encounter. For these individuals, their behavior may be
their only mode of communication. The challenge to the
audiologist is to work through these behaviors to obtain an
assessment of hearing and to develop a method of treatment. In
many cases, successful treatment of hearing loss opens up the
best channel of communication for the individual. To reach this
goal, it is often necessary to conduct the assessment in small
steps with specific, limited objectives over a series of patient
visits. Patience and perseverance are essential-and are greatly
appreciated by parents who typically rate hearing loss as their
child's most significant disability.
Mucus and Saliva
Children with CHARGE often have major breathing, swallowing, and
feeding problems. Many are fed with a gastrostomy tube. Frequent
breaks may be needed in managing the child and keeping him or her
comfortable during assessment.
Audiologic assessment under sedation is often a desirable option.
However, there are two concerns. First, in some cases, the
individuals with CHARGE are medically fragile and have breathing
and swallowing difficulties that need to be taken into
consideration. Second, some individuals with CHARGE have shown
resistance to sedation and do not respond to standard doses of
The characteristic ocular anomaly in CHARGE is coloboma. This is
evidenced as a keyhole slot at the bottom of the eye that creates
a triangular iris as well as a void on the retina and in the
optic nerve. This can create holes in the visual field that
prevent detection of visual images-especially from above the
individual. If visual reinforcement audiometry is used, the
individual may turn his or her head at an unusual angle to place
the image on a functioning part of the retina.
For many individuals with CHARGE, their combined auditory and
visual deficits are so significant that they have only a small
area in front of them in which they can communicate optimally.
This area has been called the "communication bubble."
The size of the bubble varies depending on the individual's
hearing and vision, on the presence of background noise, and on
lighting (sensitivity to bright light is common). When the
individual with CHARGE is unable to walk or move independently to
situate himself or herself for optimal communication, the
clinician will need to make these accommodations and place the
interaction within the communication bubble.
Amplification needs to be fitted as early as possible. Because
the pinnae are often very soft and misshapen, they will not
support conventional behind-the-ear hearing aids. Due to
permanent and long-standing conductive hearing losses,
individuals with CHARGE may be candidates for bone-conduction
hearing aids or auditory osseointegrated devices such as the
"Baha." Cochlear implantation is sometimes an option,
but there are often concerns about the reduced diameter of the
auditory nerve and stimulation of the facial nerve by the
Parents of Children with CHARGE
Parents of children with CHARGE have likely seen dozens of health
care providers before seeing an audiologist. These parents
realize that they must advocate for their child; they often take
and file notes on each visit to a professional; and they are
keenly aware of who understands their child's problems and
who does not. Many have accessed the 250+ page manual titled
CHARGE Syndrome: A Manual for Parents
Foundation Web site. The manual is free to parents and professionals alike. The
professionals who are most appreciated are those who acknowledge
that they have not encountered CHARGE before but are willing to
acquire the information. Also, audiologists and speech-language
pathologists should understand that parents of children with
CHARGE are eternally hopeful about their child's prospects
for the future and appreciate the professional who will encourage
them even when the challenges are great.
The typical child with CHARGE has had 10 major surgeries
before 3 years of age. Once the survival of the child is assured,
parents shift their focus to development, communication, and
learning. Our data indicate that there is a significant
relationship between development of symbolic communication
(spoken or signed language) and early intervention (before 3
years of age) by audiologists and speech-language pathologists.
As a result, audiologists and speech-language pathologists have a
great opportunity to improve the quality of life for individuals
with this complex and multifaceted disorder.
James W. Thelin, PhD, CCC-A and Sarah E. Krivenki
Department of Audiology and Speech Pathology
University of Tennessee, Knoxville
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CHARGE Syndrome Web Resources
About the Authors
James W. Thelin is an audiologist who teaches graduate
students and conducts auditory and vestibular research at the
University of Tennessee. He has worked with parents of children
with CHARGE syndrome and individuals with CHARGE syndrome for 25
years. He is currently the vice president of the CHARGE Syndrome
Sarah E. Krivenki is a doctor of audiology student at the
University of Tennessee who is conducting research on the
vestibulo-ocular reflex in CHARGE syndrome.
This article first appeared in the Vol. 7, No. 3, May/June
2008 issue of