Developmental Apraxia of Speech
What is DAS or DVD?
DAS is a speech disorder that interferes with a child's ability to correctlypronounce sounds, syllables and words. It is the loss of ability to consistently position the articulators (face, tongue, lips, jaw) for the production of speech sounds and for sequencing those sounds into syllables or words. Generally, there is nothing wrong with the muscles themselves. The child does not have difficulty with non-speech activities performed with the muscles such as coughing, chewing or swallowing. However, the area of the brain that tells the muscles how to move and what to do to make a particular sound or series of sounds is damaged or not fully developed. This makes retrieving the "motor plan" for saying a word difficult.
As a result, even though the child knows what he wants to say, he cannot say it correctly at that particular time.
Sometimes he cannot even begin. Either the wrong sound comes out, or many sounds are left out all together. At that particular time, the motor plan is not accessible. These errors are not under the child's voluntary control so he often cannot correct them, even when trying his hardest. Frequently, a child will be able to produce a sound or word at one time and not be able to say is again when he wants to. A parent may hear words when the child is playing alone or when he is angry, but when asked to say the same word, he can't. This can be very frustrating for both the child and the parents.
What Causes DAS?
DAS is a neurologically based speech disorder. It is caused by subtle brain impairment or malfunctioning. No one currently know exactly what this brain impairment is or what causes it. Theories range from supposing the impairment is a very specific small injury or difference in the speech area of the brain to saying that is a very diffuse change that is not possible to isolate.
Although some children with DAS have had specific birth or prenatal injuries or periods without oxygen, most DAS children have nothing in their birth or prenatal histories that would suggest a possible cause of the DAS. It is interesting that there are a great deal of similarities in the histories of children with DAS, however, it has not been shown that any one or any specific combination of factors is responsible for the DAS. At this time, we simply do not know what causes DAS.
What are some of the main characteristics of DAS?
For a young child with DAS, a limited speech sound repertoire is frequently the main characteristic of his speech. This simply means that the child has very few speech sounds that he can use automatically so he frequently uses a simple syllable (such as da) to stand for almost everything.
If the child has gotten to a level where he can use several different consonants and is actually talking, the main characteristic of the DAS is inconsistency. A child with DAS is likely to have inconsistent speech errors and speech capability. For instance, he may be able to say a /p/ sound at the beginning of words as long as the /p/ is followed by an /o/, yet, he may not be able to say it if followed by an /e/. Or, maybe he can only say a /p/ at the beginning of a word if the word also ends in a /p/ as in pop. Another example could be that the child can say a /p/ word just fine by itself, but if there is a /t/ word in front of it, the /p/ becomes a /t/( so two pan is said two tan).
Perhaps he can say short single words well, but as soon as he uses two or three words in a row, he drops all the ending sounds. These inconsistencies can easily lead to confusion on the part of both the child and the parent. The child learns that he cannot trust himself to communicate his ideas well, and the parent may wonder whether the child is just being careless or lazy.
The length of a phrase as an adverse effect on articulation. Generally, the longer the utterance, the worse the speech accuracy. A child may be able to say syllables and short words fairly well but be impossible to understand in phrases or sentences.
Apraxic children are usually better at imitating speech than at saying words spontaneously. If you ask a child to say a words right after you, he is likely to say it more accurately than if he said it without your model.
Anxiety may affect a child's ability to speak well. For all of us, performing is more difficult than talking. Under stress, the ability to retrieve motor plans becomes more challenging. A child may be able to say a word or phrase well in a relaxed setting but, when he is "put on display" and asked to " Tell Grandma...", the plan for saying that word or phrase is not accessible, and the child fails.
Children with DAS may also lose words. Parents frequently report that the child "used to say that, but doesn't anymore". This is another example of the motor plan for a word or phrase being unavailable to the child.
What other areas can be affected by DAS?
Children with DAS not only have difficulty retrieving the motor plans for speech, they also may experience accessing vocabulary. Between the ages of 2 yrs and 5 yrs., the number of words that a child understands increases from about 200 words to over 20,000 words. If the child has not organized these words into a "dictonary", he will have huge problems finding the words he wants to say quickly. This increases the effort of communicating.
In the young child, this problem may show up as a tendency to be aggressive with other children. If the child cannot think of words to use to enter into play with friends, he may choose to push them, hit them, or disrupt their play. In older children, difficulty finding the right words may show up as shyness or a tendency to rely on "I don't know" as a response to questions.
Some children may choose one topic to be very good at discussing. If you stay on their topic, they sound fine, however, if you change the topic, you find them quiet and unsure of their ability to communicate.
Many children with DAS also have difficulty learning how to put things in sequence or in the right order and then later remembering what the right order was. They already have trouble putting sounds in the right order for words. This difficulty may also be found later as they learn written language.
Many children with DAS have problems learning to read and spell. Often their difficulty with written language is similar to the problems they had with spoken language. They cannot retrieve the words from their memory and they cannot sequence the letters into words or the words into meaningful sentences. When we work with children with DAS, we need to watch for signs of reading and writing problems and refer the children for help if those problems occur.
In addition, a child may show the same motor planning difficulties with fine motor tasks such as cutting, coloring and writing. An Occupational Therapist can assess motor planning problems that are affecting fine motor skills.
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