Download Down Syndrome: A Multidisciplinary Perspective

J Am Acad Audiol 6 : 39-46 (1995)
Down Syndrome :
A Multidisciplinary Perspective
Allan O. Diefendorf*
Marilyn J. Bull*
Debbie Casey-Harvey*
Richard T. Miyamoto*
Molly L. Pope*
Julia J. Renshaw*
Richard L. Schreiner*
Michelle Wagner-Escobar*
Abstract
Trisomy 21, a genetic disorder resulting from a chromosomal abnormality, is one of the most
common forms of mental disability in the United States . Individuals with Down syndrome frequently present with a constellation of medical problems including conductive hearing loss
and, to a lesser degree, sensorineural hearing loss . As part of a health care team, audiologists must be sensitive to and aware of medical conditions prior to establishing intervention
strategies . Medical conditions, by necessity, precede audiologic interventions and, therefore,
a close working relationship among team members is critical . Yet, audiologic and communication interventions should be established at the earliest possible time for maximizing an
individual's development potential . This article stresses the importance of a multidisciplinary
team in the provision of services so that prevention of further disabilities, improved outcomes
of medical interventions, and appropriate habilitative and educational planning may ensue.
Key Words:
Amplification, audiologic intervention, Down syndrome, hearing impairment
risomy 21, a genetic disorder resulting
from a chromosomal abnormality, is one
T of the common forms of mental disability in the United States, with an incidence
of approximately 1/700 live births . In 1866,
Langdon Down prepared the first adequate
description of this syndrome - hence, the
name, Down syndrome . The correct diagnosis
of Down syndrome can often be made at birth,
fostering early identification and immediate
habilitative planning .
Otolaryngologic and audiologic problems
are common in Down syndrome and constitute
potential additional disability. These topics are
the focus of this paper and emphasize the importance of early and regular re-evaluation of the
audiologic status of every child with Down syn'Indiana University School of Medicine, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana
Reprint requests : Allan O . Diefendorf, Indiana University School of Medicine, James Whitcomb Riley Hospital for Children, Indianapolis, IN 46202
drome. Skilled pediatric audiologic and otolaryngologic management in association with
appropriate communication intervention can
greatly enhance the social and cognitive function
of children with Down syndrome .
GENETIC CONSIDERATIONS
he genetic imbalance leading to Down synT drome can be represented by either Full
21 trisomy (nondisjunction), Partial 21 trisomy
(translocation), or mosaicism (postfertilization
nondisjunction) . When nondisjunction occurs
during the first meiotic division of reproductive
cells, both #21 chromosomes end up in one cell.
Instead of both cells having 23 chromosomes, one
cell has 24 chromosomes, and the other has 22 .
The loss of a #21 chromosome makes it highly
unlikely for an egg containing 22 chromosomes
to survive. However, the egg with 24 chromosomes can survive. Union with a cell containing
23 chromosomes results in a child with 47 chromosomes who has Down syndrome or trisomy 21 .
Journal of the American Academy of Audiology/ Volume 6, Number 1, January 1995
Paternal origin of the extra chromosome is estimated to occur in less than 5 percent of cases of
trisomy 21, with the remaining 95 percent to 97
percent being maternal in origin . In over 94
percent of the cases, Down syndrome is due to
nondisjunction (Cooley and Graham, 1991).
Translocation (approximately 4%) involves
the transfer of one portion of a chromosome to
a completely different chromosome . During
meiosis, the chromosomes are close together
for extended periods of time . They may touch,
stick to each other, and then separate . When
they separate, a segment of a chromosome might
be pulled off and lost (deletion) or attach itself
to another chromosome (translocation). As an
example, a part of the #21 chromosome might
attach itself to the #14 chromosome . If this
occurs during meiosis, one cell will then have
23 chromosomes, with one 21 and one #14/21
chromosome . Fertilization of the egg or sperm
containing the #14/21 translocated chromosome
will result in a child with 46 chromosomes,
including two #21 chromosomes and one #14/21
chromosome . This child, too, will have Down
syndrome because of the partial trisomy 21
caused by the translocation . If nondisjunction
happens after fertilization, mosaicism results.
For example, nondisjunction may take place
just after fertilization when four cells are dividing to form eight cells. If one of the four cells
divides unevenly, this leads to 47 chromosomes
on one daughter cell, 45 in another, and 46 in
the remaining six cells. The cell containing 45
chromosomes will die. If the 47-chromosome
cell contains a third #21 chromosome, all subsequent daughter cells of this cell will also have
47 chromosomes, or trisomy 21 . The end result
will be a child who will have about 80 percent
normal cells and 20 percent trisomic cells. The
child may look as though he has Down syndrome. However, the physical abnormalities
can be less obvious, and the mental disability
may be less severe . Mosaicism is rare and
accounts for fewer than 3 percent of all children
with Down syndrome .
Although the clinical diagnosis of Down
syndrome can often be made readily, diagnosis
in each child should be confirmed by chromosome
analysis . Chromosomal studies are useful in
the prenatal detection of the syndrome and for
recognizing women who may have an increased
risk of having a child with Down syndrome (i .e .,
those over 35 years or having previously borne
a child with Down syndrome). However, this
"at-risk" group accounts for only about one-third
of Down syndrome births .
40
OUTER AND MIDDLE EAR.
ANOMALIES
T
he communication handicap of Down syndrome children is well documented . However, the causative factors (see Table 1) underlying that problem are not well understood . It
is known that these children demonstrate a substantially higher prevalence of hearing impairment than the general population and that hearing loss is usually present in early infancy. Otologic findings and coexisting hearing losses are,
therefore, suspect in hindering their acquisition of language skills .
The craniofacial configuration of children
with Down syndrome is a contributory factor to
many of the otolaryngologic problems that occur.
Anatomically, diminished dimensions of the
external ear structures are characteristic of this
population . Aase et al (1973) have documented
that the longitudinal dimension of the pinna of
newborns with Down syndrome is more than two
standard deviations below that of normal newborns. Moreover, the pinna is usually low set. The
external auditory meatus is frequently narrow
or stenotic (1/z to ~/s the size of age-matched controls), predisposing to occlusion by even minimal
quantities of cerumen. Anomalies of the middle
ear that have been noted (Harada and Sando,
Table 1
Factors that Impact Language and
Speech Development
Medical Complications
Heart problems
Failure to thrive
Seizures
Frequent URls
Cognitive/Language-Speech Deficits
Language deficits
Speech production deficits
Memory and attention deficits
Hypotonia
Delayed acquisition of coordination movement (sitting,
crawling, standing, ambulating)
Poor oral motor skill development (feeding,
swallowing, tongue coordination, jaw stability)
Reduced speech production
Sensory Deficits
Hearing loss/auditory perceptual dysfunction
Visual deficits
Sensory integration deficits
Social Communication Difficulties
Complicated nurturing/lack of bonding
Stressed relationships
Reduced interaction patterns
Down Syndrome/Diefendorf et al
1981) include hypoplasia of the epitympanum,
varying amounts of mesenchymal tissue in the
middle ear including the round window niche,
a poorly developed and narrow round window
niche, ossicular abnormalities, and wide angle
of the facial genu . Congenital eustachian tube
abnormalities have been documented by Sando
and Haruo (1990) in a study of temporal bone
histopathology. Structural anomalies of the
eustachian tube exist, including a far more acute
angle of entry into the nasopharynx. This, coupled with diminished tube size, predisposes
these children to stasis of secretions, ascending
infection, and recurrent otitis media.
It has been suggested that the child with
Down syndrome may be more susceptible to
upper respiratory tract infection than the normal child because of peculiar nasopharynx development . In addition to an increase in the prevalence of otitis media with effusion, anatomic
considerations in nasopharyngeal development
are likely responsible for nasal obstructions and
subsequent rhinorrhea . Obstructive apnea is a
problem recently recognized to occur with significant frequency in persons with Down syndrome. Failure to treat in severe conditions may
result in failure to thrive, hypoxemia, and suboptimal mental function and progress to heart
disease secondary to disease of the lung .
Generalized muscular hypotonia is also
characteristic of Down syndrome . It is postulated
that this hypotonia might extend to the tensor
veli palatini muscle causing eustachian tube
dysfunction. This would result in poor middle ear
aeration and subsequent middle ear effusions
and infections . Moreover, the epithelium of the
middle ear may be roughened due to vitamin A
deficiency, increasing the chance of effusion
(Coleman et al, 1979).
Ossicular abnormalities include congenital
malformation and bony erosion from inflammation . It is difficult, if not impossible, to determine whether deformed ossicles represent congenital malformation or osseous remodeling by
chronic infection. Ossicular fixation also occurs
in Down syndrome and may result in a potentially correctable conductive hearing loss .
INNER EAR AND
RETROCOCHLEAR ANOMALIES
nner ear abnormalities are reported for both
cochlear and vestibular structures . Cochlear
abnormalities are more prevalent than vestibular abnormalities. When present, inner ear
abnormalities are generally mild . Igarashi et
al (1977) and Harada and Sando (1981) reported
that the length of the cochlear spirals are shorter
than that of normal controls . In a series of 12
temporal bones studied by Harada and Sando
(1981), the most frequently observed abnormality of the inner ear was endolymphatic
hydrops confined to the apical turn of the cochlea.
Although there are no reports of specific
abnormalities of the VIIIth nerve in Down
syndrome, central nervous system abnormalities are likely to be seen. Crome et al (1966)
and Crome and Stern (1972) reported that
the weight of the cerebellum and brain stem
is reduced when compared with normal subjects and may be consistent with the lack of
development in these structures . In addition,
Palo and Savolainen (1973) suggested that
there is a deficiency of the specific myelin
basic protein in Down syndrome . Banik et al
(1975) reported evidence of abnormal or incomplete myelination, which may reflect general
structural changes affecting neuronal growth
and synaptogenesis .
HEARING LOSS
T
he reported prevalence of hearing loss in
Down syndrome varies, depending on the
study population, age of the study group, criteria used to specify hearing loss, and procedural
variables, including the type of test administered.
Strome (1981) noted a prevalence of 42 percent
to 78 percent, verifying that the occurrence of
hearing loss is much more frequent in the Down
syndrome population than in the population at
large. Gerber (1977) has indicated that deafness is rare in this group. On the other hand,
studies utilizing developmentally appropriate
test techniques report that the majority of hearing impairments are mild to moderate in severity, varying 15 to 40 dB above normal threshold
(Greenberg et al, 1978 ; Balkany et al, 1979).
Glovski (1966), describing audiometric evaluation by air conduction of 38 children with
Down syndrome, found decreased hearing
sensitivity in over 70 percent. The type of hearing loss was not reported since sensorineural integrity was not evaluated via boneconduction audiometry. Brooks et al (1972)
found 77 percent of their subjects with Down
syndrome to have decreased hearing. Middle ear
pathologic conditions were reported in 60 percent of the patients, despite a mean age of 26
years for men and 24 years for women. Schwartz
and Schwartz (1978) reported that 67 percent
of their sample (39 children with a mean age of
Journal of the American Academy of Audiology/Volume 6, Number 1, January 1995
3 years) demonstrated otoscopic evidence of
pathologic ear conditions . Balkany et al (1979)
examined 107 patients with Down syndrome
(mean age of 12 years). Hearing loss was identified in 78 percent of their population . Additionally, among the 64 percent of ears identified
with binaural losses, 54 percent were of a conductive nature, 16 percent had sensorineural
loss, and 8 percent had mixed-type hearing
loss . According to Balkany et al (1979), about 40
percent of the children with conductive hearing
loss could not be explained by middle ear effusion or chronic otitis media. These patients had
normal-appearing otoscopic examinations, suggesting the presence of middle ear anomalies.
Surgical procedures on selected Down syndrome
patients revealed ossicular malformations and
destruction caused by inflammation due to
chronic infection.
These studies, coupled with surgical and
histopathologic findings, confirm that the majority of hearing losses appear to be conductive in
nature . Furthermore, in contrast to the natural
history of middle ear effusion in the normal
pediatric population, the prevalence of this condition tends to remain high in the Down syndrome population, regardless of age. It is recommended that individuals with Down syndrome and persistent conductive hearing loss be
treated aggressively from five perspectives :
to normalize hearing, to break the cycle of recurrent suppurative otitis media, to prevent chronic
ear disease, for early identification of longstanding hearing loss, and for provision of appropriate amplification.
Once the child who is at risk for longstanding hearing loss is identified, the nature of
the long-standing loss must be assessed . For
the Down syndrome population with stenotic
ear canals, wax accumulation, otitis media,
ossicular malformation, or adhesions, the audiology-otology team is critical . Even for the child
identified with a moderate sensorineural hearing loss, the potential of a conductive overlay
complicating the habilitation process is great. A
close working relationship with the otologist is
essential for the audiologist to know when the
timing is right to plan appropriate intervention
with amplification.
For many children, medical and surgical
management of a conductive hearing loss may
continue for months or years without complete
resolution of the hearing loss . This delay in
identification of a potentially unresolvable conductive hearing loss can be reduced by routine
postoperative audiograms and/or air- and bone42
conducted auditory evoked response testing as
well . Conversely, successful resolution and hearing improvement following medical management of a conductive hearing loss can camouflage an underlying mild sensorineural hearing
loss for years. Although hearing sensitivity and
responsiveness may be somewhat or even
greatly improved following medical management, a significant hearing loss may still exist.
Clearly, accurate post-treatment hearing assessment is critical in the early identification of
the child with Down syndrome with permanent
hearing impairment .
AUDIOLOGIC CONSIDERATIONS
A
udiometric evaluation of the Down syndrome population is an essential part of
their habilitative management . While conductive pathology is high, underlying sensorineural
hearing loss may be present. Therefore, the first
objective of audiologic testing is to obtain reliable auditory responses. Visual reinforcement
audiometry (VRA), conditioned play audiometry,
or conventional test procedures must be selected
based on the child's developmental age.
Greenberg et al (1978) reported the use of
VRA(Wilson et a1,1976; Wilson and Moore, 1978 ;
Thompson and Wilson, 1984; Wilson and Thompson, 1984) on 41 subjects with Down syndrome
between the ages of 6 months and 6 years. Thresholds, or minimum response levels, were obtained
on 81 percent of these subjects . Consistent with
other reports, there was higher than normal incidence of hearing loss among these children .
Thompson et al (1979) also found that subjects
with Down syndrome needed to be functioning
above a 10- to 12-month developmental age level
to be successfully tested using the VRAprocedure.
If clinicians are interested in predicting potential
success with the VRAprocedure for children with
Down syndrome, the Bayley Scales of Infant
Development (BSID) (Bayley, 1969) mental age
equivalent score provides the most distinct distribution between successful and unsuccessful
tests with the dividing point being a BSID mental age equivalent of at least 10 months .
In early studies, reliable hearing tests were
felt to be difficult to obtain due to the mental disability associated with Down syndrome . However, if clinicians consider test procedures suited
to the patient's mental age and developmental
level, audiometric data can be more easily
acquired . Play audiometry is usually very successful with older individuals with Down syndrome, even at full adult chronological age. The
Down Syndrome/Diefendorf et al
"eager to please" nature of children with Down
syndrome can lead to frequent false responses
when testing this population . Therefore, regardless of behavioral approach, stringent criteria
must be established and met to ensure conditioned responses to sound. Additionally, the use
of control trials must be implemented to monitor false responding behavior .
Speech audiometry is a very important tool
for the audiologist . Speech is familiar to young
children and will hold their attention. Beginning
measures may need to be completed in the
sound field due to typically poor headphone
acceptance and potential for collapsed ear
canals . Obtaining a soundfield speech reception threshold (SRT) followed by a bone-conducted SRT as an indicator of conductive
involvement may initially be of most diagnostic value. Individual ear SRTs can also be
obtained with insert phones to minimize the
complications of collapsed ear canals .
Audiologic testing of a child with Down
syndrome can be influenced by many variables . Use of familiar items, toys, or spondees
may often yield more reliable results. Establishing accurate audiometric results on a young
child with Down syndrome frequently requires
multiple test sessions . Therefore, keeping
things the same, or routine, will often help .
Consistent use of the same examiner, sound
suite, and toys and effective and consistent
praise and reinforcement can often facilitate
testing. Once children are comfortable and in
a "routine," progress can be made toward
obtaining reliable measures .
The high incidence of conductive hearing
loss makes acoustic immittance an essential
part of each hearing evaluation . For younger children, the effectiveness of tympanometry may be
compromised by narrow and stenotic ear canals,
wax accumulation, and patient cooperation.
However, Schwartz and Schwartz (1978) demonstrated the differential diagnostic value of tympanometry for children ages 2 weeks to 11 years
with Down syndrome by reporting: (1) the ability to complete tympanograms on 100 percent of
their sample ; and (2) the ability to differentiate
normal ears from ears with middle ear effusion
or suspected ossicular fixation . Of additional
significance was the high percentage of absent
or elevated acoustic stapedial reflex thresholds
found in their sample of children with Down
syndrome . Schwartz and Schwartz (1978) speculated that the absent acoustic reflexes may be
related to the generalized hypotonia that is common to children with Down syndrome . Loss of
tonicity may reduce the tension of the stapedius
muscle . Subsequently, greater sound intensity
may be necessary to achieve sufficient muscular contraction . In addition, it is also possible that
there may be certain subtle changes in the neuronal organization of the reflex arc in these children ; thus, these changes might preclude contraction of the stapedius muscle to acoustic stimulation. Each of these findings is potentially
relevant to understanding how children with
Down syndrome process auditory information.
Interpretation of patent pressure-equalization tubes can be difficult due to the unusually
small volume of the ear canal and middle ear
space in Down syndrome children . It is helpful
and recommended to compare pre- and postoperative volume readings to aid in the interpretation of tube patency.
To encourage early identification of hearing
loss, the utilization of the auditory brainstem
response (ABR) in the newborn nursery or in
early infancy for children with Down syndrome
is an accepted practice. Squires et al (1980) published one of the first comparative studies of
the ABR in individuals with Down syndrome . As
a group, the subjects showed shorter central
conduction times than a normal comparison
group. Additionally, absolute wave V latencies
for the subjects with Down syndrome tended to
be shorter, despite the fact that the investigators did not control for hearing loss . Folsom et
al (1983) also reported shorter wave V latencies
for their study group of children (12 months
and younger) with Down syndrome . The infants
with Down syndrome also showed a steeper
latency-intensity slope. Taken together, these
studies point out the necessity of establishing
latency curves across intensity that are specific
to children with Down syndrome . The reported
abnormalities in the cochlear and/or neural
structures in Down syndrome appear to be
reflected in their ABR latencies and, as such,
compromise the use of normal latency curves,
across intensity, as indices of hearing level.
Hearing levels in infants with Down syndrome,
particularly older than 6 months, that are determined solely by using the expected latency curves
for normal infants, rather than completing a
threshold search at decreasing intensity levels,
may underestimate the degree of hearing loss
and result in false negative findings .
Children with Down syndrome should be
given every opportunity to improve their hearing by appropriate amplification strategies . The
presence of any hearing loss may further complicate the known speech and language delays
Journal of the American Academy of Audiology/ Volume 6, Number 1, January 1995
and cognitive limitations that characterize these
children . Therefore, children with even minimal hearing loss should be considered candidates for amplification in an attempt to maximize opportunities for advancement.
Although an aggressive approach to fitting
amplification is stressed, the timing of this intervention must be viewed from a wide perspective .
Frequently, the recommendation for amplification will be delayed due to a history of fluctuating
conductive hearing loss . Further, many infants
and children with Down syndrome will experience prolonged hospitalizations, multiple surgeries, and other medical complications so that
hearing loss may not become a priority until
they become stable medically. It is appropriate
in these circumstances for the audiologist to
serve as a resource for the child and his family,
communicating with otologists, pediatricians,
and speech/language pathologists to ensure
eventual intervention with amplification as soon
as it is feasible .
As with all populations, it is essential to
consider the child's family agenda in terms of
their readiness and commitment to proceed with
amplification. In general, the earlier amplification can be introduced, the more easily it may
be incorporated into the child's daily routine
and the better the prognosis for long-term acceptance. Adjustment to and successful use of amplification is often more challenging when introduced to the older child with Down syndrome
because the child may resist the implementation
of a new routine. Regardless of the child's age,
ongoing and collaborative consultation with the
family is essential in determining the most
appropriate timing for intervention with amplification . Once a collaborative relationship with
the family is established, the audiologist may
also comfortably address important issues such
as anticipated benefits and limitations, concerns of family members and others working
with the amplification system, and special management considerations . For example, most children are initially amused and entertained by the
fact that they can make the hearing aid squeal
by putting their hand over the microphone . In
most cases, this behavior will last a few days and
then lose its charm and disappear. In the child
with Down syndrome, the ability to make the
hearing aid squeal may not extinguish quickly
and may become a behavior that continues long
after the fitting. "Feedback is fun" may become
a behavioral issue that is annoying to parents.
Another common behavioral complaint by parents is that they frequently find the hearing
44
aid turned off. It may be necessary to allow periods of time at home when the child doesn't wear
his hearing aids, in order to keep them on at
school. There are no easy answers in dealing with
these behavioral issues either for the parents or
the audiologist . Although reduced wearing time
may not be the best answer audiologically, it
may be the only solution to keep the family
working toward success.
The use of loaner amplification will not only
facilitate rapid delivery after a long-standing
hearing impairment is identified but will also
allow the audiologist to meet the demands of
changing circumstances such as fluctuant and/or
progressive hearing loss . For children with small
or stenotic ear canals, use of a bone-conduction
hearing aid with a stretch headband to hold the
bone oscillator in place may be the most effective amplification option until the child's ear
canals grow or can be surgically altered. If the
size of the child's ears are adequate to allow the
use of effective earmolds, conventional air-conduction hearing aids would be the instruments
of choice . Due to the power limitations of the bone
oscillator, effective amplification with boneconduction instruments is limited to those
patients with mild to moderate conductive
impairment. Although it is common practice to
fit children with bilateral hearing loss with binaural amplification, initially fitting one hearing
aid and later adding the second may often
increase the potential for eventual long-term
acceptance in this population . Given the high
incidence of chronic middle ear effusions, an
earmold for each ear is provided so the hearing
aid can be alternated between ears if necessary
during periods when one ear is draining .
This strategy promotes gradual and eventual
adjustment to amplification and reduces
the possibility of the child having to readjust
to amplification after long periods of time
without it .
LANGUAGE AND SPEECH PLANNING
C
hildren with Down syndrome are predisposed for language learning deficits . The
profile of language learning is quite different
when compared to the "normal developmental
profile" and when compared to the profiles of
other children with mental disability. The child
with Down syndrome demonstrates a decrease
in the rate of acquiring speech and language as
other cognitive skills increase with age (StoelGammon, 1990). Additionally, research has indicated that speech and language development for
Down Syndrome/Diefendorf et al
children with Down syndrome progresses in an
uneven pattern characterized by rapid spurts
and changes with long periods of plateau (Miller,
1987). Moreover, Miller and his colleagues (1989,
1990) have described various language learning
profiles that have been noted with Down syndrome children . Three profiles have been
described: (1) production and comprehension
skills that are commensurate with mental age;
(2) production skills that lag substantially behind
comprehension skills and mental age; and (3) production and comprehension skills that are behind.
Table 2
Goals for Enhancing Speech and
Language Learning
Medical Complications
It is important to have a pediatrician that leads a
multidisciplinary team and supports early intervention
for communication .
Cognitive/Language-Speech Deficits
Developing joint attention
Developing cognitive language skills (object
permanence, cause-effect, object concept)
Increasing initiated communication
Improving imitation skills
Expanding turn taking
Increasing functional interaction with objects
Developing vocabulary/concepts
Increasing mean length of utterance
Enhancing processing of language
Increasing flexible use of vocabulary
Developing pragmatic skills
Utilizing augmentative communication
(i .e ., sign language)
Expanding consonant/vowel variety
Increasing sequencing of syllable structures
(CV, VC CVC)
Improving phonologic skills
Decreasing rate of speech
Monitoring fluency
Motor Skill Deficits
Cotreatment with occupational and physical therapy
Movement and exploration of environment
Oral motor stimulation and feeding
Sensory Deficits
Otologic intervention
Audiologic intervention
Ophthalmologic intervention
Sensory integration programming
Enhancing visual/auditory attention
Social Communication Limitations
Parent education
Increasing initiated communication attempts
Increasing parent identification of communication
attempts
Following child's lead
Turn taking
Developing conversational formats
Developing repair strategies
The complexity of language development
patterns described demonstrates that children
with Down syndrome represent a heterogeneous
population . As such, factors that influence language development must be viewed carefully
for each child. From this analysis, goals (see
Table 2) to enhance language learning can be
developed.
Given that Down syndrome will most likely
continue to be a leading cause of mental disability, the challenge is to continue to improve
early intervention strategies . Goals for the future
should include close otologic management,
improved identification of the long-standing
hearing loss, earlier intervention with amplification, aggressive speech/language programming, and continued empowerment of the family striving to meet the needs of a child with
Down syndrome .
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