JOURNAL OF THE NATIONAL ACADEMY FOR CHILD DEVELOPMENT
1999, Volume 12, No. 1
Language Acquisition in Children with Down
Syndrome
The significance of auditory function and the developmental
costs of teaching signing or "Total Communication"
Robert J. Doman Jr.
In order to determine appropriate treatment
approaches for children with Down Syndrome (DS), one must
first, look at "normal" development, and then explore
how and why the DS population differs. When considering language
acquisition we encounter historic problems that are not dissimilar
from those of any of our special needs populations. The primary
problem is the overwhelming tendency among educators, therapists,
and caregivers to treat symptoms, when what is needed is a
neurodevelopmental approach. A neurodevelomental approach
involves identifying the developmental and neurological factors
involved in each area where "symptoms" imply delayed
or inappropriate function, and then determining how we can
intervene and make a significant impact on the issues that
created the problem in the first place.
Speech and Language
In this discussion we should first
make a distinction for parents between speech and language.
These terms are often used interchangeably, but they need
to be separated if we are to understand the components involved
in helping an individual to verbally articulate his or her
thoughts explicitly with good enunciation. Important lines
of distinction tend to get blurred in this discussion, because
of issues pertaining to word articulation. To be "articulate"
generally means to be able to speak effectively, which would
place the word squarely on the language side of the ledger.
But, we use the word "articulation" to refer to
the ability to enunciate, to pronounce a sound, a phoneme,
a word or a sentence clearly. Obviously this is an issue of
speech, not language. We want our child to speak with good
articulation and to be articulate; that is, we want both good
speech and language. For our purposes let us define speech,
as the neuro-motor function of pronouncing words clearly.
Language we will define as the neurodevelopmental ability
to use words, and to combine words so as to communicate. DS
children historically have both speech and language problems.
We will first look at language—because
you must first have words you want to say before we can be
concerned about how well you pronounce them! One quick insight
into what language is and where it comes from is to look at
the difference in language function between a child who hears
normally, a partially deaf child, and a totally deaf child.
A normal child develops normal language, a child with some
hearing may develop language, but if so it tends to be delayed
and limited as a reflection of the degree of hearing loss,
and the deaf child does not develop vocal language unless
significantly alternative means are employed. From this one
can infer an observation that has been demonstrated again
and again—the basis of language function is auditory
function. We must first have good hearing and processing of
sound. Therefore, our first concern in the acquisition of
language in DS children is auditory function and hearing.
Following our neurodevelopmental model,
we will look at the "normal" development of auditory
function and see what about DS is different and adversely
effects that development. To understand the significance of
hearing it is important to note that the auditory nerve, which
is the 8th Cranial nerve, is the most primitive nerve in the
body; the first nerve to develop in the fetus. This nerve
and the stimulation of this nerve are very critical to the
entire development of the child. The brain begins to learn
how to process sounds in utero. The child is not born with
the ability to process a full range of tones well, as a matter
of fact, many people never learn to process a full range of
tones well. The human ear can process tones throughout a huge
range, from 20 Hz. to 20,000 Hz. The brain must learn how
to process these tones, particularly the tones that are within
the language range. One can develop an understanding of tonal
processing by looking at the ability to hear and articulate
a foreign language. The child generally learns how to process
the tones in their native language during their first two
years of life; some tones are unique to specific languages
and absent in others. If the child has not learned to hear
those tones the child will not be able to articulate those
tones, and if enough of those tones are missing, the language,
which they are processing, is extremely garbled. An example
of a missing tone is the inability or difficulty of Japanese
speakers to hear or pronounce "R" sounds. To speak
a language you must be able to hear the specific tones in
that language.
Auditory Tonal Processing
Do children with DS have a more difficult
time learning to hear tones, and if so why? Many children
with DS do have a difficult time learning to process tones.
If the quality of the brain's auditory input is disrupted
or interfered with, auditory tonal processing development
will be delayed or permanently impaired, unless there is specific
and effective therapeutic intervention.
Generally, if language is delayed or
if there is some question about a child's hearing, hearing
tests will be conducted. These tests are either subjective
or objective. Subjective tests include the audiogram in which
the child is asked to respond in some manner to tones. Objective
tests include the auditory evoked response test, which measures
the brain's response to specific tones. These tests can generally
be relied upon to identify significant global hearing loss,
but they do not attempt to test more than a few sound frequencies.
Many tonal processing deficits escape detection. For example,
the inability of a native Japanese speaker to hear an "R"
will not show up in such testing. In these tests, typically
about 8 frequencies are tested across the 20,000 frequencies
that we should be able to hear. This is a very partial measure
of auditory tonal processing.
Auditory tonal processing problems
are very common. Physical problems that adversely effect auditory
tonal processing are not unusual; unfortunately, with our
DS children, they are more the norm than the exception. Fluid
or pressure in the middle ear is one of the most common problems
affecting the development of auditory tonal processing. In
our DS children this problem is almost universal. DS children
tend to have narrow Eustachian tubes. DS children also tend
to have low muscle tone. Coupled together, this makes it very
difficult for the middle ear to drain. This problem is compounded
by factors associated with a weak immune system, sinus congestion
and mouth breathing. A cursory look into the child's ears
is not going to identify these problems. I strongly encourage
the parents of every DS child under the age of five years
to work closely with an ENT (a physician specializing in treating
the Ears, Nose and Throat). Very regular visits to the ENT,
including a tympanogram test for fluid or pressure problems
in the middle ear, along with checks on the status of the
tonsils, adenoids, and sinuses are essential for all DS children.
Our DS children are predisposed to having problems which adversely
affect the structure and thus the function of the ears, throat,
sinuses, and oral cavity. These problems adversely affect
the quality of auditory input that the brain receives and
significantly impact the development of auditory tonal processing.
If our children are not developing
normal auditory tonal processing they will be unable to hear
tones well and are unable to process language well, thus creating
a problem with the development of language. Parents of "normal"
children often observe a problem in the child's language development
when their son or daughter has a middle ear fluid problem
or an ear infection. When these problems occur it is commonplace
to see regression in language function.
Remediation of tonal processing problems
has been one of my emphases for over twenty years. When I
first recognized the problem, I couldn't find an effective
treatment; I couldn't even find anyone else who understood
the problem! In the seventies I was doing some work in Spain
and heard of the work of a French ENT, Dr. Alfred Tomatis.
Dr. Tomatis trained professionals and treated patients using
special equipment he had designed to improve hearing. I flew
to Madrid and met with a physician trained by Tomatis and
was impressed with the results they were achieving. Upon returning
to the States I began referring some of my children to Paris
to work directly with Dr. Tomatis.
In the past twenty years there have
been many developments in the area of auditory training, all
of which are based on this original work by Dr. Tomatis. NACD
has utilized (and in most cases NACD staff has been directly
trained in) every major auditory training approach, always
in an attempt to find better technology and methodology. Even
the best of these programs have entailed accepting some trade-offs
in terms of their expense, convenience, and/or efficiency.
The best and most recent development is a home-based treatment
program developed by Applied Brain Technologies, which is
based on input from NACD. This collaborative program is not
only based on our experience but also that of leaders in Tomatis's
work and the field of psychoacoustics. Professional training
in ABT's "Listening Program" is presently being
conducted in Europe and the United States. Early research
results on this new program indicate that we now have a safe,
powerful tool that is easy to implement in the home and which
significantly improves auditory tonal processing.
Auditory Sequential Processing
The first step in providing a strong
foundation for speech and language is to develop good auditory
tonal processing. The second step in providing a strong foundation
for speech and language is establishing adequate auditory
sequential processing.
Auditory sequential processing is the
ability to take in bits or pieces of auditory input and to
process these pieces in a sequence. Initially, each individual
phoneme is a bit, then we learn to recognize a group of phonemes
together (a familiar word). Eventually a familiar couplet
or phrase is also recognized and processed as a single bit
of information. As the child develops the ability to sequence
more and more bits, her language ability grows. This language
progression grows from an initial sound, to an approximation,
to a word, to a couplet, to a three-word phrase, to a four-word
phrase, to a sentence and then strings of sentences. The function
that makes this possible is auditory sequential processing.
Normal auditory sequential development
occurs at the rate of one bit per year of development. Thus
a one-year-old child can process one piece, a two-year-old
two pieces and so on. Normal auditory sequential processing
for a child of seven years or older is considered to be seven
plus or minus two digits. Our perception is that anyone over
the age of seven with a digit span of less than seven has
a deficiency in auditory sequential processing. Auditory sequential
processing determines the ability to process language, to
think conceptually, and to express oneself in words.
Quality Auditory Input
The quality and quantity of specific
auditory input, which the child receives, determines the development
of auditory sequential processing. What constitutes quality
auditory input? Quality auditory input is sound in the form
of clear tones and words that are presently in an acoustically
friendly environment and which match or slightly exceed the
auditory processing skills of the listener.
What this means is that we need the
child to be in an environment as free of extraneous auditory
input as possible, void of noise if you will, and which is
organized with an understanding of the processing skills of
the listener. Extraneous auditory input noise is any sound
that isn't needed. I once heard a successful old farmer define
a weed as "any plant growing in the wrong place."
For our purposes, noise is any sound that appears in the wrong
place and time, usually because it is extraneous to the function
being performed. Auditory input that fits the listener is
input that matches or slightly exceeds the processing of the
listener. If we are cognizant of the auditory sequential processing
skills of the child, we can speak to the child in pieces that
the child can process and stretch them one step further so
that we are both communicating and helping to move the sequential
processing one step further. The optimal environment for this
quality auditory input is a quiet room with one child and
one adult.
The further we get from this model
the further we get from providing the child with optimal auditory
input. The more extraneous sound, the more noise, the more
voices, the poorer the quality of input. The child's problems
with auditory tonal processing further reduce the quality
of input. If we address the child without awareness of the
child's sequential processing capacities, the input will be
of even poorer quality. Anything that diminishes the quality,
quantity, or intensity of appropriate auditory input that
the child receives needs to be perceived as diminishing the
opportunities for the development of language.
Having evaluated accelerated and remediated
auditory sequential processing in some 20,000 children and
adults, we understand the significance of auditory sequential
processing, not just in the development of language, but in
the development of cognitive function and learning.
There is a direct correlation between
language development, cognitive development, academic development
and auditory sequential processing.
Language development is based upon
five major factors; the physical health of the child, the
opportunity to develop good auditory tonal processing, the
opportunity to develop good auditory sequential processing,
the opportunity to receive as much quality auditory input
as possible, and the child's need to speak to be understood.
The Value of Frustration and the Child's
Need To Speak
Before we move onto problems associated
with speech, I would be remiss if I did not offer some discussion
as to the child's need to speak. When we evaluate a child's
lack of language function, we evaluate the health, the tonal
processing, the sequential processing, the environmental opportunities
for quality input and the child's need to speak. This last
factor can have a very major impact on the development of
vocal language. Working with a full range of children has
many advantages, one of which is it makes it possible to identify
problems that on the surface have different origins, but which
on closer examination are in fact the same. In our work with
accelerating development in "normal" children, it
is not unusual to find a situation where we have a very motivated
attentive mom who is very attentive to her only child. In
many of these situations, the child's language skills are
superior as a reflection of the excellent opportunities the
child has received, but there are some exceptions. The exceptions
are children whose moms know what they want before the children
do or whose grunts are interpreted with almost psychic clarity.
These children have no need to speak, no need to work at learning
the "foreign language" that their mothers use. As
with most of us they take the easy road. In our DS population
we often have exactly the same experience we have with our
"normal" children, and sometimes it has a twist.
The twist is the use of an alternative means of communication.
Providing most children with an alternative
means of communication can eliminate the need to speak, or
the frustration that would be experienced at being unable
to communicate. This will generally delay the development
of language.
Distinguishing the Role of Neuro-Motor Factors
from Gaps in Tonal and Sequential Processing Development
Neuro-motor problems involving speech
are unfortunately very common among DS children. The origins
of these problems are the same as those in the development
of auditory tonal processing and sometimes are the reflection
of auditory tonal processing or sequential processing problems.
Health issues that effect the development of the sinuses,
mouth, and tongue are the culprits in the development of the
structures required for good articulation. The typical scenario
involves chronic problems that can originate with the ears,
throat, tonsils, adenoids, lungs or sinuses. Low tone coupled
with chronic problems that lead to mouth breathing, poor chewing,
poor tongue control and tongue thickening, inadequate sinus
development, high palates, enlarged tonsils and poor lung
capacity all create structural problems that impair speech.
These problems can be lumped together as oral motor problems.
In order to develop good speech, general health and oral motor
issues must be addressed. There are many oral motor techniques
and methodologies which can be employed, and which should
be included in the therapy program for these children.
Some speech problems are reflections
of auditory tonal issues rather than (or in addition to) neuro-motor
problems. If the child is unable to hear a tone properly he
will be unable to reproduce that tone properly. One of the
more common signs of auditory tonal processing problems that
should be noted are problems involving hypersensitivity or
hyper-acute hearing. These problems are universally a reflection
of an auditory tonal processing problem and one can infer
that in addition to the obvious hyper frequencies, there are
also other tones which are being underrepresented (or hypo).
No amount of oral motor work is going to correct a speech
problem that originates with an auditory tonal processing
problem.
Auditory sequential processing also
has a significant effect on speech. Children will generally
try to use more pieces that they can hold onto and will produce
what I call tonal approximations of the language. You can
liken this to humming the tune to a song for which you have
forgotten the words. If a child, for example, has the ability
to auditorially sequence two pieces, the child may come out
with what is almost a four or five word phrase which consists
of many of the vowel sounds and very few if any consonants.
If you already know what the child is talking about you may
be able to figure out what they are saying. We refer to this
process as "chunking," which means that rather than
isolating the pieces and articulating each phoneme, the child
is putting the whole phrase together as one chunk of information.
If a child is able to reproduce individual sounds and articulate
one or two syllable words well, but the articulation breaks
down if the child tries to say a longer phrase or sentence,
the problem is the auditory sequential processing.
Speech problems may be a reflection
of neuro-motor issues, auditory tonal processing or auditory
sequential processing problems. Comprehensive intervention
must address the specific problems that adversely affect the
specific child.
Why Do I Rarely Recommend Signing or Total
Communication Approaches
A significant controversy exists today
as to whether children with DS should be taught to sign. I
have watched the development of this trend with anxiety. Resorting
to sign language is a reflection of symptomatic intervention.
This trend is a reflection of understandable frustration and
a lack of understanding of the components of speech and language
and how to successfully remediate such language acquisition
problems. Signing and total communication approaches are rarely
the best option for DS individuals.
Most children with DS who have speech
and language problems are not receiving the necessary healthcare
intervention they need to facilitate good oral structure and
function. Most are not receiving good oral motor intervention,
most are not having their auditory tonal or sequential processing
issues addressed; therefore, most are in trouble.
Teaching sign language is a very understandable
impulse. If I were responsible for helping a DS child learn
to communicate and I did not understand the developmental
components involved in speech and language or the intervention
that is necessary for language to develop, I might resort
to signing as well. It seems harmless enough. It can help
relieve the child's frustration at not being able to communicate.
It is done with the best of intentions. At least it should
not hurt anyone. I understand the logic. Many children never
even obtain communication at all. Signing is better than nothing.
After all, once there is communication, we do gain new levels
of access to the uniqueness and beauty of the child.
But my experience has been that it
almost universally does hurt. Part of the problem revolves
around the perception of potential. Those who have seen very
few DS children learn to speak and communicate well are often
happy to accept less and are pleased with the results that
are achieved. My goal is always to achieve normal function.
I often object to traditional physical therapy approaches
because they are aimed at achieving any kind of "walking",
rather than normal walking. It is ok to forget about developing
normal muscle tone, normal muscle balance, or taking the child
through the normal developmental steps if the only goal is
"walking". But if you want the child to walk "normally",
you had better put all of the pieces together properly. The
same is true of speech and language. When you take developmental
short-cuts, you are cutting your developmental throat. Your
short-term solutions can destroy your long-term goals.
Signing or Whole Word approaches adversely
affect normal development. The primary input that drives the
development of auditory tonal and sequential development is
the processing of language. Listening to and trying to process
speech is the primary input that drives a child's development
of auditory tonal and sequential processing. If we establish
a means of primarily visual communication, the child will
"tune out" spoken language, and lose this very critical
input. It is argued that with a Total Communication approach
the child is hearing the word as well as seeing the sign.
The reality is that all young children are primarily visual
learners, not just DS children, and that everyone concentrates
on whatever works best. When you simultaneously sign and speak,
the visual input far outweighs the auditory. This dramatically
reduces the intensity of the auditory input, thus decreasing
its effect upon the brain. One future complication involves
the development of the articulation. A child who is intently
trying to understand what you are saying will closely watch
your mouth and will often mimic your actual tongue and lip
movements. If a child is watching your hands, they are not
watching your mouth. And if they are communicating via signing,
they are not so frustrated anymore. But frustration is what
drives development.
All theory aside, I have worked with
many thousands of DS children over many years. The families
that I work with come to me having utilized all manners of
treatments. I have no vested interest in using or not using
signs or any other technique for that matter. We use and recommend
thousands of techniques. My interest is only in finding out
what works and preferably what works best.
My experience has been that those children
who use signs, particularly those who go beyond a very few
rudimentary ones, are significantly more delayed in their
language function than children with similar basic function
who do not use signs. I have also seen that some children's
auditory tonal processing, auditory sequential processing,
speech and language development are irretrievably harmed.
But, the primary concern and dialogue should not be directed
toward signs or no signs, but toward putting the necessary
pieces together so as to accelerate the language development
in our DS children and avoid the need for such alternative
means of communication.
The rate at which a specific child's
speech and language develop is determined by a combination
of factors. Slow or delayed development does not reflect low
potential. However, we must address the specific neuro-motor
and neurodevelopmental needs of the child. Otherwise the child
will probably not get the opportunity to develop fully and
realize his or her potential.
We have learned a tremendous amount
in the last few years about the development of speech and
language. In just the past year, some very significant tools
have been created which will have a dramatic impact on our
children. Do not compromise. Work hard to provide the children
with every possible advantage. "Normal" is not an
unrealistic goal.
Reprinted from the Journal
of the National
Academy for Child Development
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