Rett Syndrome: Speech and Language Development
First, let's look at the usual steps in the development of language and communication in infants and children, compared to children who have Rett Syndrome
It is important to understand the differences between some of the terms used to describe communication processes, so that intervention can address the right areas of need, to assist people with Rett syndrome to develop their skills.
Communication is a system for sending (expressing) and receiving (understanding) messages, by any method that results in the exchange of thoughts, feelings, information, or attitudes. Language is the ability to understand and use symbols, particularly verbal symbols (words) in thinking, and as a form of communication. A symbol is something that can stand for or represent something else. For example, the written or spoken word chair, or a photograph, or a line drawing, or a miniature, all represent the idea or concept of a chair. There is a developmental hierarchy to the understanding of symbols. A concept is an inner awareness of an object or an idea, which can be maintained when the object is not present. There can be no meaningful symbol until there is something in the person's concept formation for the symbol to represent. The earliest stage of concept formation begins with object permanence. Infants learn about object permanence by handling different materials and toys; turning them over in their hands, finding them under a blanket, putting them inside containers.
Most early learning is dependent on adequate play skills that facilitate the development of such cognitive skills. Even as young infants, children with Rett syndrome do not seem to use their hands to play in a normal fashion, and do not have the ability to interact with their environment by physically manipulating objects to find out about their properties. However, it is possible that children with Rett Syndrome develop some concepts just by watching others.
Speech is the result of a complex series of motor acts, which most people carry out automatically. Babies pass through several distinct phases in their development of speech. To develop these skills, the baby must have normal hearing, and gain a high degree of control of the co-ordination of muscles used to produce an intelligible signal. Because of dyspraxia, which affects all of their motor movement, individuals with Rett syndrome do not usually use speech to communicate. As speech is so seldom accessed by people with Rett syndrome, the comments below, about developmental stages, are confined to language development.
Stages in Language Development
The following descriptions, which
outline the first five stages of normal language development, include notes
about what the child with Rett syndrome might be doing during these periods of
development, compared to the non-Rett child. In these descriptions, reference
is made to the four stages of Rett syndrome.
· The pre-linguistic stage, which occurs during the first year of life.
From 0 to 3 months, the infant's behaviour is entirely reflexive. The infant can cry (when hungry or uncomfortable), grunt, sigh, and gurgle (when comfortable), and can make some vowel sounds when the tongue is positioned low in the mouth. The infant can be calmed by a familiar voice, and will startle at loud noises. In the first three months of life, the baby with Rett syndrome may cry less than other babies, and with hindsight, they are often described as model, i.e. quiet, babies.
From 3 to 6 months, behaviour starts to come under the infant's control. The infant can make differentiated cries for pain, discomfort and hunger, and a familiar caregiver is able to discriminate between these cries. The infant can make different vowel sounds, and will take turns in a vocal conversation. Infants turn their heads to locate sound, and will startle or cry to loud noises. They can discriminate voices with different intonation or tone, e.g. enjoy a parent's or caregiver's quiet calm voice, and be frightened by harsh tones. Infants with Rett syndrome may be different in the way they use their voices, and the quality of their cry sounds. The infant’s ability to be comforted through listening is likely similar to other babies.
From 6 to 9 months, the infant’s
control for speech becomes more refined. The infant will babble or play with
making sounds, sometimes to attract attention, and will look for the source of
a familiar sound, such as the washing machine. The infant can listen to speech
and other noises; enjoy toys that make noises; and respond to intonation
patterns indicating warmth, anger or negation in others' utterances. Language
games are often part of the baby's routines, e.g. "Peek a Boo" and
"Where's baby?" at nappy change time, or clapping games such as pat a
cake. Up to
this point, i.e. the first 9 months of life, most babies with Rett syndrome are
said to be developing normally, and seem to be meeting the milestones of
development. But, as we now know, Rett syndrome is not something that suddenly
appears at 6 months, or ten months. It
has been present from the time of conception, and certainly has affected the
way in which the baby’s brains grows and develop during pregnancy and in the
first few months of life. There will likely be many differences in the early
pre-linguistic stages for babies with Rett syndrome compared to babies who do
not have Rett syndrome, but there are no studies on this.
· Stage 1 of language development occurs from age 9-18 months
From 9 to 12 months, the infant demonstrates increased skills with sound production; these strings of speech sounds with intonation patterns are called "jargon"; it sounds as if the infant is talking in sentences. The infant will readily imitate sounds, especially non-verbal sounds such as coughing; gesture will develop, for example, shaking the head for yes and no, and pointing to things he or she wants. This marks the emergence of intentional communication. Infants will respond to sounds in the environment, such as their name, or the telephone ringing, and may respond to simple familiar requests or routines when accompanied by gesture; they can recognize the names of common objects and people, and shows an interest in looking at pictures named in books. By this age, most infants with Rett syndrome are entering stage I of RS, and are showing definite signs of difficulty in their development. Some infants with Rett syndrome may show signs of regression before this stage is reached; others continue their development of apparently following normal milestones, including the development of first words.
From 12 to 18 months, true
expressive language emerges. At the end of the first year the average infant
will express 4-20 words in addition to continuing to babble; by eighteen
months, the infant may use up to 50 single words. The use of one word may
correspond to a sentence, and the meaning of the utterance is conveyed by
changing the intonation pattern ("ball" may mean, "That
is a ball", or "Where is the ball?” or "Will you play ball with
me?"). Infants understand many more words than they can say, and
understand simple and familiar phrases and commands, respond by shaking their
heads for yes/no answers to simple questions, move rhythmically to music, and
enjoy listening to simple rhymes and songs. Most children with Rett syndrome do not reach the
milestone of having expressive vocabulary. If they do, their words will be used
to name objects and actions. Some children with Rett syndrome may have
progressed to the stage of having 20 or more words, before regression occurs,
but then lose their language.
· Stage 2 of language development occurs between 18 to 24 months
By 18 to 24 months, the child can
use two-word combinations (such as "Daddy gone", "more
milk", "go car"). The child has an expanding vocabulary
knowledge, from 20-50 words at 18 months to 300 words at 24 months, and can be
understood about 25% of the time. The
child brings objects on request, points to some body parts, understands simple
questions, and recognizes pictures of things he or she cannot yet name. At this age, most children
with Rett syndrome are in stage II of the disorder, which includes social
withdrawal, and loss of acquired language skills. We do not know if this loss
is total, or only for expressive skills; there are no studies that define what
actually happens to the language skills. It is not known if, or how many,
children with Rett syndrome reach this stage of language development. Symbolic
play, which is important in the development of language, is dependent on the
ability to manipulate toys and objects. By stage II, children with Rett
syndrome are having difficulty with functional use of their hands, and may not
develop these more advanced play skills. The lack of play skills may hamper
· Stage 3 of normal language development occurs between ages 24 to 36 months
By 24 to 30 months, the normal child will no longer use jargon. Children of this age will be able to repeat words and phrases, use questioning intonation, use 2-3 word combinations, will have a vocabulary of three to five hundred words, ask for things they want, and can use 2-word negative phrases ("No more", "not go"). The child will be able to select one named item from a group of five, follow simple instructions, enjoy listening to simple stories, and begin to understand personal pronouns (you and me). By this age, stage II of Rett syndrome is usually well established, and the child may be at the most withdrawn stage socially.
From 30 to 36 months, vocabulary
increases dramatically to as many as 900 words. The child will begin asking
questions, speak in 3-5 word sentences which are less telegraphic and more like
those of adults, begin to use grammatical markers on verbs (I goed, I
running) and make plurals and add possessive markers on nouns (shoes,
Mark's), begin to say I instead of me, and name 1-2 colours. It is not known if children
with Rett syndrome develop their receptive language skills to this level. There
are a few recorded cases of individuals with Rett syndrome who have retained
some of their expressive language and speech skills, e.g., Zappella's 3 cases
and at least some of the girls in this research were said to use short phrases
· Stage 4 of language development occurs between ages 3 to 11 years
The normal child of 3 to 4 years can give name, age, and sex; use simple present and past tense, be 75-90% intelligible, and often talks aloud during play activities. The child will understand simple stories, categorize objects into simple groups (food, clothes, toys), know several colours, some opposites, and can follow 2 related directions (Get a spoon out of the drawer and eat your lunch.). The child may have some concept of time and money, and may begin to recognize the correspondence between spoken and written words. From 4 years onwards, language becomes further refined, and is used in the social context of home and school. At this chronological age, the child with Rett syndrome is moving from stage II to stage III. For the child with Rett syndrome, entry into school may mean joining a segregated or an integrated classroom. Language stimulation will come from the teacher, aide, and other students, as well as continuing in the home environment.
Research and the Literature about Speech and Language Development in Rett Syndrome
There has been very little research carried out about speech, language, and communication development in Rett syndrome. Some of the researchers (Budden; Perry; Woodyatt) found that girls with Rett syndrome do not appear to develop beyond early sensory-motor levels, and have cognitive levels that plateau around 10-18 months. The researchers have noted that this apparent stagnation continues from childhood into adolescence and longer.
So far the research has not addressed any of the following questions:
Do children with Rett Syndrome really plateau at early levels of cognition and intellectual development, or are they just unable to show their inner knowledge
Do they develop language receptively in the normal expected sequence, but are unable to show those language skills expressively?
What ways of communicating are available to children with Rett Syndrome?
It is important to know that in most of this research, no modifications were made to the test procedures to allow for the dyspraxia or motor disabilities that occur in Rett syndrome, even though the researchers were aware of the problems. The results have been interpreted as evidence of delayed cognitive and linguistic development, and as evidence that the children’s level of intentional communication is consistent with their level of cognition. It is more probable that the level of intentional communication and interaction that the children can demonstrate is consistent with their level of motor development, is hampered by their disability, and is not indicative of their cognitive or internal thought and linguistic development.
To find out what a person understands, both cognitively and linguistically, it is common practice to ask the individual to manipulate objects or toys to specific instructions, or to point to pictures to identify vocabulary items. ("Show me the car", "Pick up the ball", “Put the doll on the chair”.) These activities require that the individual being tested should have control of his or her motor responses, especially the hands. In Rett syndrome, a predominant feature is dyspraxia: the inability to carry out purposive movement. The children may also have pervasive hand stereotypies, changing muscle tone, spasticity that increases with age, and problems with delayed responses, either because of dyspraxia, or because of processing difficulties. These difficulties were not taken into account in the research.
Children with Rett syndrome will have difficulty demonstrating that they understand as they cannot interact with the environment to manipulate toys or objects on command because of their neurologically based problems. Until more research is carried out, utilizing modified assessment techniques, the situation remains controversial. Assessment using standardized testing is inappropriate for individuals with RS unless modifications are made to the procedures to allow for increased processing time, or delayed reactions, or changes are made to the materials and equipment to allow for alternative methods of indicating responses.
It is important to acknowledge apparent comprehension, even as a remote possibility, because what we believe about an individual affects the way we interact with them. If we think a person does not understand, we may not talk to that person at all. If we think a person is profoundly delayed, we may talk to them as if they are a baby or a child, irrespective of their chronological age. If the communication partners of people with Rett syndrome believe the research findings, (that individuals with Rett syndrome are "profoundly retarded" and do not understand what is said to them) they may not talk to the individual at all. How will these children learn language?