Libby Kumin, Ph.D., CCC-SLP
Disability Solutions, November/December 2002, Volume 5, Issue 2
© Copyright 2003
|Printed with the permission of Joan E. Medlen, R.D., Editor
9220 S.W. Barbur Boulevard, #119-179
Portland OR 97219-5428
Fax: (503) 246-3869
Many children with Down syndrome
have difficulty producing consistently clear speech. At one time,
your child may call his sister by saying,
"Bonnie, come here," clearly and understandably.
At another time, he may reverse the
sounds in her name, leave out words or syllables
and say, "Nobbie, come." Another time,
he may grope and struggle and not be able to
say her name at all. Why can he say Bonnie
clearly one time, but not at other times? Why
does he have difficulty ordering a soda, but
then when the waitress asks moments
later, "ice or no ice," he very clearly says, "I don't
care." And, why does he have less difficulty
with a word in a short phrase than when the
same word is in a long string of words, even
though it's the same word. For example, he
can say "pop," but has difficulty saying "pop"
when it's part of "let's go get popcorn at the
store now." These difficulties and inconsistencies
are typical of a problem with motor
planning for speech, known as Developmental
Apraxia of Speech (DAS). DAS is one component
of your child's understandability
when he is speaking. Volume 5, Issue 1 of
Disability Solutions, defined and explored
speech intelligibility and all the contributing
factors affecting speech. This article
looks more closely at a specific aspect of
your child's understandability called DAS, a
commonly overlooked concern for people with Down syndrome.
Although many children with Down syndrome
show characteristics of DAS, it is a
term that has not been used to describe the
speech difficulties experienced by children
with Down syndrome. DAS describes difficulty
in voluntarily programming, combining,
organizing, sequencing and producing
consonant vowel combinations. DAS is a
descriptive label used when a child's speech
difficulty is due to planning the motor movements
and sequences of sounds for speech.
Currently there is great debate among
speech and language professionals regarding
apraxia in children. The term apraxia is
traditionally used to describe adults and
children who have speech before experiencing
a neurological event such as a stroke or
traumatic brain injury. The damage to the
brain because of the stroke or injury is what
causes a person to have difficulty processing
information and making sounds into
words. Therapy in this situation focuses on
regaining skills that were lost. However, the
term Developmental Apraxia of Speech is
used for children who have similar troubles
with motor planning for speech without a
specific event causing damage to the brain.
Children who have DAS are still in the process
of learning to speak. Instead of regaining
speech they lost, they are having difficulty
in developing speech for the first time.
There are a variety of other terms used
for DAS including: dyspraxia, developmental
dyspraxia, developmental verbal
apraxia, articulatory dyspraxia, childhood
verbal apraxia, childhood apraxia of
speech, and motor planning difficulties.
Health insurance companies often do not
cover treatment for DAS, because they see
it as a developmental problem; something a
child will eventually master as he grows and
matures. But DAS is not really developmental.
It does not go away as the child matures.
It requires specific treatment methods
to improve. DAS also does not appear to
be related to cognitive abilities. Children with
and without cognitive disabilities experience
Some professionals use the diagnostic label, pediatric or childhood verbal apraxia or childhood apraxia of speech to avoid being targeted as a developmental problem and, hopefully, increasing the chances for insurance coverage. In this article, I will use the term Developmental Apraxia of Speech, however these terms are all interchangeable. The diagnosis of DAS, or any other synonymous label, describes an inability of a child to voluntarily program, combine, organize, and sequence the movements needed for speech. Most children, learn the sounds for speech by listening to and watching adults and other children who are speaking to them and around them. Children imitate the sounds they hear others make and practice them when they speak. It seems very natural and effortless. In children with DAS, the skills needed to program and sequence the movements for speech must be taught and practiced deliberately and often. I believe this problem affects many children with Down syndrome, but it is rarely identified, evaluated or treated.
Historically, children with Down syndrome are not given a diagnosis of DAS. This is due, in part, to the original researchers who defined developmental apraxia of speech. In their studies they only included subjects who met the following criteria:
The results and definitions of DAS have not been generalized beyond the original subject groups, which leaves most, if not all, children with Down syndrome out of the screening process. This means assessment and treatment for DAS has not been provided for children with Down syndrome. In a recent study, seven children with Down syndrome, who had difficulty being understood, were tested using The Apraxia Profile. All seven subjects showed characteristics of developmental apraxia of speech. These findings suggest screening criteria for DAS must be revised in a way that does not overlook an important aspect to speech for children with Down syndrome.
Many children with Down syndrome appear
to have difficulties with motor planning
for speech. Should this difficulty with motor
planning be labeled DAS? I do not know.
Other professionals can work that out. I am
concerned about learning more about the
difficulties with speech children with Down
syndrome encounter so they get the help that
they need to speak as clearly as they can.
Preliminary results from a survey study
to determine whether developmental apraxia
of speech (DAS) is a widespread problem for
individuals with Down syndrome confirms
that children with Down syndrome are not
being diagnosed with DAS. With over 1300
families participating, only 16% of the parents
have been told that their child has
apraxia, whereas 61% of the families have
been told that their child has oral motor
problems such as low muscle tone in the
facial muscles. The survey also documents
that children with Down syndrome who have
apraxia tend to begin speaking at a later
age (average 5 years) and experience more
trouble with speech intelligibility than other
children with Down syndrome.
Although data has not been completely analyzed, it appears a higher percentage of children exhibit the signs and symptoms of DAS than we currently recognize. This means even when parents have not been told that their child has a diagnosis of DAS, many children with Down syndrome are exhibiting symptoms that are common in DAS and it is being overlooked. Speech intelligibility difficulties seen in children with Down syndrome are typically viewed, assessed and treated exclusively from an oral motor perspective. Therapy focuses on the low muscle tone, muscle strength, range of motion, and coordination. Hypotonia (low muscle tone), especially in the oral area, is a proven contributing factor to speech intelligibility. An oral motor approach addresses only one part of the issue if your child has DAS. It is important to improve your child's oral motor skills, but that does not address motor planning.
Developmental apraxia of speech is defined as a cluster of characteristics of speech. No one symptom must be present for a diagnosis, but the combination of several of these specific characteristics in speaking leads to the diagnosis. The most frequently reported symptoms of DAS are:
Many other symptoms of DAS can be observed in children with Down syndrome. The table below organizes the symptoms into categories to help you identify what you are observing in your child's speech patterns.
Although all children with DAS show some difficulty in the planning and sequencing of motor speech behaviors, they have a wide variety of error patterns, or mistakes that they make when they are speaking. Some children have a great deal of difficulty developing speech and are very delayed. Other children may not display any signs of difficulty until after they have developed speech, and only have difficulty when the task becomes more complex. Perhaps this is a reason why some children with DAS are not diagnosed right away. The signs can be subtle.
We do not know what causes Apraxia. One theory is that motor learning (learning how to make your body do something), including speech production skills are developed through experience and practice. Early movements such as those involved in crying, sucking and feeding are precursors to movements and skills needed in early speech production. Speech is a motor output system, but it is based on well functioning input systems, such as vision, hearing, tactile systems, and the ability to put all that information together correctly. If your child is not able to integrate all of the incoming sensory information, it is difficult to for him to organize and sequence the movements necessary for precise clear speech The theory is that listening to the sounds in your environment helps develop sound perception and that during early speech motor practice (such as cooing and babbling), templates in your child's brain are developed for producing the speech sounds. These templates serve as a quickly accessible recipe for the necessary movements to produce sounds and sound sequences, making the motor planning process almost automatic. Motor learning for speech depends on the development of strong templates (or motor plans) and those plans develop through experience. Children with Down syndrome have sensory (vision, hearing, touch) and motor deficits (low muscle tone, weak muscles) that would affect the ability to gain such experience. In addition, some children with Down syndrome have trouble integrating the information they receive from their senses properly. This is one reason sensory integration therapy is helpful for many children with Down syndrome.
When children have developed strong motor plans, they are able to produce rapid, precise, sequenced speech, almost automatically. Children who do not have adequate practice to develop these templates, will have a difficult time planning speech output. They may even need to consciously consider the many aspects of speech that would be automatic to typically developing speakers. You can help your child practice, in therapy and at home. (See Resources) Another theory is that developmental apraxia of speech results from neurological difficulties with messages traveling from speech sound input to speech sound output areas in the brain. The areas are not communicating well, resulting in difficulty with sequencing and producing speech sounds. Although a child with Down syndrome may have both oral motor and motor planning (DAS) difficulties, treatment techniques for oral motor difficulty and DAS are different. If your child has oral motor difficulties, the speech-language pathologist may use a muscle-strengthening program. Muscle strengthening can be practiced through feeding therapy and early sound play, so oral motor treatment techniques are often used earlier than DAS treatment techniques. When developmental apraxia is present, therapy approaches for teaching speech are different. (see DAS Treatment)
|Symptoms of Developmental Apraxia|
|Speech Development Patterns||Movement Characteristics||Speech Sound Production Characteristics||Over-all Verbal Production Patterns||Language Development|
If you think your child has developmental apraxia of speech, the first thing to do is have him evaluated to see if his speech is consistent with a diagnosis of DAS. There are no definitive guidelines for a complete evaluation that would lead to the diagnosis of DAS or motor planning problems. The diagnosis is made by a speech language pathologist using a combination of clinical observations, input from families, test batteries, and an analysis of a sample of a child's conversational speech. The results are analyzed to determine whether the characteristics seen in your child's speech and the test results indicate developmental apraxia of speech. Often, evaluation is not done until a child begins school, but if your child is unintelligible or is having noticeable difficulty with sounds, or noticeable difficulty developing speech, or has fewer than five understandable words approximations or no speech at all by age four, an evaluation can and should be done.
For children under four years old, or children
who are not yet speaking, the evaluation
may need to depend on parent questionnaires
and clinical observation of feeding
and eating so the therapist can compare
this information to his level of babbling and
vocal play. In this case, the diagnosis of
DAS may not be clear cut. If the results
appear to indicate DAS, a period of diagnostic
therapy to determine if the treatment
approaches for DAS are effective in helping
the child learn to speak, may be needed
and very helpful.
Testing for DAS is complicated by the inconsistent
nature of the errors that children
with DAS make. One time, your child may
say "elephant" perfectly. The next time, he
will struggle and grope for the sounds. A
third time he will reverse sounds and say
"efelant" for "elephant." This affects testing
and also affects intelligibility of conversation.
Inconsistent errors make it harder to understand
your child's speech. It is hard to translate
what your child says if the sound substitutions
that he makes change. If your child always said "th" for "s," your own mind would get used to translating th as s. When your
child said "thun," you would know he meant
"sun." But, if his substitutions are inconsistent,
it is harder for him as the word or
the sentence gets longer, or he makes vowel
distortions, sound reversals and sound additions
to words, it may be much more difficult
to understand your child's speech.
Children with DAS are highly inconsistent in speech. Research has shown that the results of articulation tests administered two weeks apart may be different not only in the number of sounds in error, but even the specific sounds that the child is having trouble with may be different from one testing session to another.
A complete evaluation would include different components which include a combination of:
A brief description of these evaluation components are listed below. Use these as a guide to understanding what your child's speech-language pathologist is seeking to learn. The more insight you have as a parent, the more helpful you can be when your child's speech patterns are inconsistent or variable.
Your child's speech language pathologist (SLP) will ask questions about your child's feeding and speech history. If you kept records, whether it is a baby book, journal, or photo album it is a good idea to bring it along. Anything that has dates to remind you what your child was doing at each stage. If your child with Down syndrome has DAS, some red flags appear early in development. For example, feeding difficulties are common; children with DAS may be slow to progress through textures or slow to tolerate baby food. Many parents report their children were quiet babies; they cooed or babbled very little. Understanding your child's early noise-making and feeding habits is an important part of the evaluation.
Your SLP will talk with you about your observations or ask you to complete a check-list. The observations of particular interest are whether your child has exhibited any of the speech characteristics listed above, including inconsistent speech errors, groping and struggle, sound and syllable reversals, and increased difficulty as a word or phrase gets longer.
An oral peripheral examination will be part of the speech evaluation. This is an examination of the structures for speech and how they function. Your speech-language pathologist will evaluate the lips, tongue, hard and soft palate and other oral cavity structures, and the movement patterns your child uses for articulation and for imitation of oral movements and speech. Typically, a child with developmental apraxia of speech will not have noticeable differences in the appearance of the structures. Children with Down syndrome may have difficulty moving the structures of the mouth such as the tongue, jaw, or lips for eating, due to low muscle tone, and may have difficulty with oral motor tasks, in addition to speech.
Your child will be asked to make specific movements with his lips or tongue such as blowing a kiss, smiling, or to make specific sounds such as oo and ee, or /s/ and /z/ or specific words. Sometimes these will be made on imitation, and at other times, they will be in response to labeling an object or picture. A child with DAS usually finds it difficult to imitate sounds or repeat words on request.
For children who are speaking and can identify pictures, an articulation test to sample your child's ability to produce each sound in English in different positions in words, may be conducted. Some widely used articulation tests are the Goldman-Fristoe Test of Articulation and the Photo Articulation Test (PAT). The results of these tests indicate which sounds your child can make correctly and which sounds he cannot make correctly. It is important to remember that because of the inconsistent nature of speech in children with DAS, articulation test results may not be reliable.
The purpose of a phonology test is to identify which phonological processes your child uses. For example, a phonology test will show if your child leaves out the final sound in words, saying "boo" for "book" and "soo" for "soup." Research shows the most frequent phonological processes used by younger children with Down syndrome ages 3 to 4.6 years are final consonant deletion (leaving out the last consonant in a word), initial cluster reduction (leaving out a consonant in a cluster of two or more at the beginning of a word such as spray or splash), and stopping. Stopping is replacing sounds such as fricatives with stop sounds (p, b,t,d,k,g) in which the air stream is stopped and then slightly exploded such as "toup" instead of "soup."
Your speech-language pathologist will be interested in hearing how your child sequences sounds in connected speech. This is usually observed by testing diadochokinetic rate. The diadochokinetic rate is the ability to make rapid speech movements using different parts of the oral facial structure. Your child's SLP is measuring how many times your child can say a syllable over and over in 5 seconds. She will observe the speed at which your child can transition from one sound to another and say a group of connected syllables. Your child will be asked to say things such as "pa" as in putt, "ta" as in tuck, and "ka" as in cut, and then combine them as in "pataka." Sometimes, real words, "buttercup," or "pretty kitty" will be used to test diadochokinetic rate. These words are used because they combine a sound made with the lips, a sound made with the tongue tip, and a sound made with the soft palate. The number of times that your child can repeat these syllables in five seconds will be calculated and compared to the results of other children. Keep in mind there are no norms available specifically for children with Down syndrome at this time.
If your child is older, your speech-language pathologist will talk with him about something he enjoys. She will record the conversation on audio or video tape to analyze later for different aspects of intelligibility and speech production (see Volume 5, Issue 1). This is difficult to do with young children who have Down syndrome, because they have limited speech output and often have short conversations.
The evaluation to determine whether a child shows characteristics of DAS usually depends primarily on clinical observation by your speech language pathologist and you. Until recently, there were no formal measures to use, but there now are several test batteries that can be used as part of the evaluation. However, for these tests to be used, children need to be able to speak. In the test batteries, children are required to repeat words, repeat phrases and sentences, and use spontaneous conversational speech. Until a child has sufficient speech to use these tests, evaluation depends on a combination of clinical and parent observations.
Recently, more in-depth tests have been developed to help identify whether a child's speech problem is DAS.
The Apraxia Profile consists of two versions, the Preschool Profile and the School-Age Profile. The same areas are assessed for both pro-files, but the Preschool Profile is shorter and less complex. Both include an oral motor exam, words, phrases and sentences, and connected speech. A checklist of common apraxia characteristics is used. The School-Age Profile includes rhymes, counting, and sentences with a rhythm that are imitated.
The Kaufman Speech Praxis Test for Children (KSPT) is a test appropriate for children with Down syndrome who are speaking. The KSPT is a standardized test. The test can be used initially and for retest purposes to chart progress. The Kaufman Speech Praxis Test includes subtests for oral movements, syllables, vowel sounds, syllables and conversation.
Another test that evaluates the motor speech system in children from 3-12 years is the Verbal Motor Production Assessment for Children (VMPAC). This test helps to identify the channels (auditory, visual, tactile) that would be helpful in treatment. It measures speech and non-speech skills at rest, at a vegetative level (chewing), and at a voluntary level.
The Verbal Dyspraxia Profile (Jelm) identifies children who demonstrate DAS. It is comprised of observation checklists to structure clinical observations. These checklists enable the speech language pathologist to compare your child's patterns of movement in feeding and speech.
Any thorough evaluation should deter-mine whether your child's speech difficulties are related to DAS. The goal of doing an evaluation is to develop an effective treatment plan, and to determine which therapy techniques will be most effective for your child.
Therapy for children with or without Down syndrome who have DAS is very focused and requires a great deal of practice and drill. Treatment plans for DAS progress in a slow methodical manner. Motor learning includes the need for many repetitions of speech movements, and for a systematic learning approach that moves from individual speech movements to sequences of movements, and from less complex to more complex movements.
I believe this type of therapy is most effective in individual therapy sessions in a quiet environment and should always include a home practice program. If your child is in preschool or elementary school, this means he may need to have what is called "pull out" service to effectively treat DAS. "Push in" therapy is very popular in inclusive settings and speech services in special education classrooms often occurs in the classroom, but if it is too loud or distracting for your child to hear and notice the subtleties of speech production, ask for this work to be done in a more quiet, separate, area.
Therapy for DAS in which practice only occurs in therapy sessions once or twice a week will not change speech motor planning skills. Frequent intensive therapy and daily practice at home are imperative for success. This involves short, frequent practice sessions. The frequency of the sessions is important. There are many treatment methods and some therapy approaches combine several methods. Treatment methods include:
Most treatment plans use practice, repetition, and drill as a primary component to the treatment plan. The idea is to heighten tactile and kinesthetic feedback, usually through using cueing. Programs also focus on placement and on what is needed for the production of sounds and sound sequences. Some treatment approaches combine gross motor movements, such as moving hands overhead, with speech soundmaking. The SLP will work with you to design an individual treatment program to meet your child's needs. Regular practice is critical to the success of DAS therapy, and the SLP should provide a home practice program for you and your child to work on together.
There are a number of things you can do at home to work with your child if he has DAS. The resource section has some ideas. In addition, the next issue of Disability Solutions will cover home activities in more depth. Here are a few ideas to get you started:
Developmental apraxia of speech complicates the speech and language development for many children with Down syndrome and makes learning speech more difficult. Therefore it is important to identify DAS as early as possible. This article outlines methods designed specifically for diagnosing DAS as well as methods that promote teaching speech to children with Down syndrome who have DAS. While it is easier to identify DAS in children who are already speaking, it is possible to identify DAS in children who are not yet speaking through observation of feeding development and other red flags such as groping or struggling when trying to speak.
The symptoms of DAS are often subtle and difficult for people who are not familiar with your child to see quickly. I hope the information in this article helps parents understand developmental apraxia of speech and identify whether or not it is something they should investigate in collaboration with a certified, experienced speech language pathologist.
You, as your child's best advocate, are critical to the process of identifying developmental apraxia of speech as well as designing and following through with treatment programs that will be helpful to your child. Your diligence will be rewarded.