Updated Developmental Scale
Developmental Characteristics in Children with Down Syndrome
Some fifty years ago, the life-span expectancy for individuals with Down syndrome (DS) was around 12 years. More recently, with deinstitutionalization and medical progress, life expectancy has reached 50 years or more and is expected to increase (Strauss & Eyman, 1996). Because individuals with DS are living longer, it is important that they learn the necessary social and cognitive skills to allow them to live independently and to be a productive members of society. Early education, such as full inclusion, can help to establish these skills.
Gibson (1981) has identified three mental age (MA) growth periods, with the first two being followed by temporary plateaus, and the third by a gradual decline. The first plateau is reached between four and six years of age and occurs with a MA of about 18 months. The second plateau is reached around eight to 11 years of age, with a MA of about 30 months. The third plateau is reached between 12 and 17 years of age and corresponds to a MA of approximately 48 months. Gibson reports that the majority of children with DS obtain a MA of 48 months; however, the third plateau is not always reached.
Social and Communication Issues
Play behavior, especially symbolic play, is considered to be one of the most significant cognitive developments in early childhood and is the precursor of representational thought and language. Generally speaking, children with imaginary play skills use more sophisticated language and better academic skills. Several investigations have focused on the play of children with DS, with the overwhelming conclusion that the play of children with DS follows a similar sequence, is as well organized, and is as consistent as that of cognitively matched typically developing children. In one study, Beeghly et al. (1990) found the symbolic play in the children with DS emerged in a delayed manner, but progressed through the typical stages of object and social play. In another study, Chuang and Layton (1992) assessed the play behaviors of a group of Chinese toddlers with DS and another group of typically developing children. Overall, the children with DS were found to be functioning at approximately the same stage as the typical child, but the children with DS exhibited more pre-symbolic behaviors during their early stages and fewer play behaviors at later stages. These results suggest that the children with DS acquire essentially the same level of play but use less sophisticated behaviors. It is important, therefore, that imaginary play be part of the everyday routine in the home: parents should help their children interact with imaginary toys, pretend to have tea parties, and learn to use objects for other purposes than their intent.
Early Parental Interaction
Several investigations of early parental interaction between mothers and their children with DS suggest that these mothers, like mothers of typically developing children, regulate their language and communicative strategies to fit the communication level of the child (Petersen & Sherrod, 1982). However, the mothers of children with DS tend to be more controlling and directive during conversations than do mothers of typical children (Cardoso-Martins & Mervis, 1985; Levy-Shiff, 1986). Research also suggests that the interactions between mothers and their children are more restrictive (i.e., lower responsiveness, less initiations, less eye contact, less preverbal vocalization) (Berger & Cunningham, 1983). Furthermore, Leifer and Lewis (1984) found that children with DS were significantly delayed in their conversational responses to maternal question types. Taken together, the above findings reveal a great deal of similarity in conversational response abilities of children with DS compared to typically developing children, although the results do reflect some across group variability for the children with DS. The early linguistic environment for children with DS appears to be supportive and does not contribute to the speech or language delays so common in this population.
Individual speech sounds are often inconsistent, such that the same child might produce a single sound three or four different ways during a conversation. This inconsistency, along with poor intelligibility, is not present among other children with mental retardation (Dodd & Leahy, 1989). The inconsistency also seems to be a persistent problem even after intense therapy (Dodd & Iacano, 1989). An overall impaired sequencing of fine-motor movements and difficulties in processing sequential lends support to this assumption. Early speech intervention is highly recommended along with early and continued work on oral-motor skills (Layton, 1998).
Exercises that help to strengthen the range of motion for the lip, tongue, and jaw are important to adequate oral-motor development and possible improvement of phonetic or speech production later on (Beckman, 1990). In addition, lip stretching exercises, proper chewing, introducing a variety of food textures, and proper breathing techniques are also important for improving oral-motor function. It is suggested that these exercises be ongoing beginning when the child is first introduced to semi-solid foods and continued on a regular schedule until the child is well into school.
Speech intelligiblity needs to be one of the primary goals with these children. Swift and Rosin (1990) suggest a three stage sequence for improving speech intelligibility: prelinguistic, early linguistic, and late linguistic. In the prelinguistic stage, activities should include use of amplification systems such as hearing aids, use of manual communication, oral-motor training, and parent training to facilitae communication. In the early linguistic stage, Swift and Rosin suggest such activities as structured sound play, drill, scripts, carrier phrases, augmentative comunication systems, computers, and oral-motor work. The late linguistic stage is characterized by drill, scripts, repair strategies, and pairing graphic symbols to the the verbal productions.
Kumin et al. (1995) have also suggested the use of pacing boards to facilitate speech intelligiblity. A pacing board consists of a series of dots (either black dots or color coded dots related to intial, medial, and final sounds) placed across a cardboard sheet. Depending upon the age and need of the child, there may be as few as three or as many as 10 dots placed across the board. The professional uses the board to help the child identify and produce initial and final sounds of simple words, syllables from bisyllable and trisyllable words, and later the production of different words from simple and complex sentences. For example, the child is taught to touch a dot each time he or she says a syllable in a multisyllabic word. The advantage of the pacing board is that it provides both a visual and a tactile cue. It also provides the child with structure and the necessary pacing for proper articulatory movements of sounds, syllables, and words in sentences.
It has been reported that over 75% of children with DS present frequent hearing losses due to otitis media or fluid in the middle ear space (Cooley & Graham, 1991). Since a mild conductive hearing loss can affect language and cognitive development (Telle, 1984), it is recommended that early detection and aggressive management to reduce middle ear pathology be followed. Otologic management for children with DS can be problemantic since otoscopic viewing is difficult and surgical placement of tubes are hard to insert in the ear canals of these children since they are smaller (Strome, 1981). Consequently, it is important to find an experienced specialists when seeking medical services for children with DS.
In addition to middle ear pathologies, sensorineural hearing losses are also more prevalent in children with DS than age-matched peers. Dahle and Baldwin (1992) recommend regular and systematic hearing evaluations for all children with DS. In fact, infants with DS should receive an audiologic evaluation within a few months of life and checked every 6-12 months thereafter.
Language and Syntax
Children with DS have consistently been shown to have unexplainable delays in their acquisition of language, especially in the area of syntax (Fowler, 1995; Miller, 1991). Research has documented that a large discrepancy occurs between measured language skills and expected levels according to mental age. Fowler (1990) has reviewed this literature and has summarized the findings into four areas.
Fowler (1995) has noted a dissociation between function and use of language among children with DS. She reports that children with DS evidence conversational skills beyond their expressive language levels. These children engage in imaginative play and use appropriate conversational rules, such as turn-taking, asking questions, and making repairs, that go far beyond their expected expressive language level (Baren-Cohen et al., 1992). Fowler suggests that one current explanation for this discrepancy is related to a basic difficulty in their ability to perceive speech and store incoming acoustic information into a representational format that can readily be retrieved.
In summary, the language skills of children with DS can be characterized into four areas. First, children with DS show language production that lags behind their expected abilities. This lag appears to widen as they get older. Second, language production skills in these children are inferior in relation to their cognitive abilities. Third, syntactic development in children with DS is characterized by periods of fairly rapid growth similar to typically developing children (Miller, 1988), with protracted plateaus which are not typical of normal development (Fowler, 1988). Fourth, vocabulary acquisition in these children exceeds their syntactic development. Children with DS appear to exhibit a specific deficit in language learning with particular difficulty in the production of language.
Currently, the approach to speech-language intervention for children with DS is the same as that for children who are cognitively normal but who are specific language impaired (SLI) (cf. Bricker, 1993). Typically, the approach includes a naturalistic, or social-interactive environment. The child, either individually or in a small group, is presented with opportunities to interact with his/her environment. The teacher (or speech-language pathologists) reinforces, shapes, and expands the utterances generated by the child. However, on occasion, the child is worked with directly on a speech or language skill, which subsequently is introduced back in the natural or social-interactive exchange. Children with DS are, however, slower than children with SLI to acquire and maintain new communicative skills. They also tend to plateau at around a six year language level (Fowler, 1988). Nevertheless, language intervention approaches used with SLI children are generally quite effective.
Several professionals have advocated the early introduction of manual communication (signing) for children with DS (Abrahamsen et al., 1985; Layton & Savino, 1990). The argument for using manual communication is that early communicative needs are not being met by these children because they do not have the oral expressive skills necessary for communication. They may understanding the meaning of words, but just can not produce them. First words typically do not emerge in children with DS until three-years of age or later, and many have such severe oral-motor difficulties that oral communication becomes a life-long struggle. Manual signing provides an early expressive opportunity and allows the child to communication his/her wants and needs.
An example of using manual signing was reported by Layton and Savino (1990). They introduced a manual communication system to a young male with Down syndrome. Bobby was two years 10 months old when he was first seen. At that time he had poor verbal imitative skills, poor oral-motor control, had not gone through the typical babbling stage, had no consonant sounds but a few vowels, and was essentially nonverbal. An imitative oral-stimulation, naturalistic language intervention approach was introduced to Bobby, but was found to be unsuccessful. He neither would imitate nor attempt to produce any words. Signing was introduced as an assistive system so that Bobby could communicate with his parents and teachers. On the very first day, Bobby learned the sign for "french fry." He and his father then went to McDonald’s where Bobby generalized the sign and requested, by signing, an order of "french fries." When he arrived home, Bobby’s mother asked what he had done, and Bobby immediately signed "french fries."
Bobby’s sign vocabulary increased dramatically over the next few weeks. Oral words still did not develop in spite of a strong Total Communication approach: Bobby was encouraged continuously to speak and sign his wants, needs, labels, questions, etc. Bobby achieved a sign vocabulary of approximately 150 words. At this time, he acquired an oral-expressive vocabulary of about 12 words. Still, the number of oral words did not increase until his expressive sign vocabulary had reached approximately 400. At that time, his oral vocabulary increased dramatically, with his signs dropping out almost completely. Bobby became a totally verbal child. Bobby had received therapy for five university terms or approximately two years. He returned to the clinic two years after his last session, when he was seven-years old, for a follow-up evaluation. The only sign Bobby could remember was the "name sign" for this author. At time of the follow-up, Bobby’s expressive language was nearly age appropriate. Clearly, Bobby’s early sign training provided him with an initial communication system. It also helped to facilitate oral communication later on. It is possible that Bobby may have learned to talk without ever being exposed to signs, but that initial opportunity to communicate would not have been there if he had not learned to sign.
Reading and Literacy
The literature surrounding reading skills and reading instruction among children and young adults with DS is extremely sparse. In general, it has been suggested that reading typically can not be achieved until a child has reached a cognitive level or language age of approximately six years. Since many individuals with DS never reach this level, it has been assumed learning to read was not possible for them; therefore, reading had not been recommended. However, in the past decade a trend toward more literacy related goals for children with DS has been met with some measurable success (cf. Stratford, 1985). Children with DS are now reading for pleasure and are able to write creative stories. Furthermore, preschool children with DS who are introduced to reading in regular programs (Lorenz et al., 1985) have been found to increase their expressive language skills. Being able to read, in other words, has increased the children’s words, expressive sentences, and their sounds. Buckley (1995) recommends introducing reading even before these children are beginning to produce oral words, or around three years of age.
Buckley (1995) and Oelwein (1995) have detailed several suggestions on how to teach reading to children with DS. Both of these authors present important guides. Buckley and her colleagues (Buckley et al.,1993) have also published a book that goes beyond reading and discusses the relationship of language and reading development among children with DS. All three sources are excellent references for parents and professionals and include clear steps on how to introduce reading to children with DS. Some general guidelines for teaching reading to young children with DS, adapted from these references, include:
Direct Learning and Rehearsal
Over the years working with children with DS has taught this author two important things: most children with DS need some direct training on a skill, and rehearsing old information is critical to maintaining acquired skills. Direct learning is an important step in the acquisition of most skills, whether it be learning to produce appropriate oral-motor skills, producing a new sound, learning a vocabulary word, a new linguistic concept, reading a new word, or practicing how to tell a story. Most of these children need some direct instruction on what is expected, including some drill and practice. We frequently do this initially out of the natural context, but immediately contextualize it back into social situations. Thus, the child learns what is expected and then is given the opportunity to practice it in meaningful contexts.
Maintaining already acquired skills requires rehearsal of what had been previously learned. Children with DS frequently forget skills that have not been fully established. Those skills that have not been fully mastered are susceptible to fading. Rehearsing, or going back over previously learned skills, helps to refresh what previously had been learned and helps to strengthen memory. For example, an older student with DS had difficulty discriminating the differences between a quarter and a nickel. He had the need to know the difference between coins for his job. To him the coins were visually the same. After several lessons he learned through visual and auditory strategies to differentiate between the two coins. He could consistently identify both coins in real-life experiences and in direct clinical activities. His consistency was highly accurate and continued for several weeks. However, after dropping the activity and going on to another needed area. After a couple of week later, he again confused them. Training was reintroduced and after a few trials his old strategies resurfaced and he successfully discriminated the two coins. Three weeks later, he again had trouble telling the two coins apart in a real-life situation. Thus, real-life and decontualized training were introduced. Currently, he has no difficulty discriminating between the two coins in all situations, but periodic rehearsal still continues.
In general, it is recommended that parents should verbally interact with their child at a young age and introduce the child to social-community experience. Teach the child songs, read to the child daily, and begin to introduce pictures of objects within the home at around two years of age. Parents should be aware of early oral-motor training, chewing exercises, and swallowing. Large and fine motor activities are encouraged, including drawing, writing, and tracing. Parents should also consider introducing manual signs early to their children, and encourage expressive oral-words as much as possible. Parents should not accept the way the child produces his/her words (or articulates the sounds), but encourage the child to say the sounds clearer and more consistent. These suggestions are not short-term goals, but in many cases are necessary for several years; however, with persistence and perseverance your child can become an excellent communicator, a good reader, and an independent member of the community.
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