When my daughter was first diagnosed, one of the characteristics of Williams syndrome (WS) that I found most facinating was their language and communication skills. Individuals with WS are known to be vocal- gifted with gab; often described as having the "cocktail party" personality. They have rich vocabularies and can talk your ear off so to speak about anything and everything. I had the pleasure of experiencing this gift when I attended the St. Louis WSA convention in summer of 2010. Kate was mearly one and we had never meet an adult with WS, as of yet. When we entered that hotel and was greated by the WSA gang (a group of WS adolescents and young adults), I was in for a treat. They congregated in the lobby and escorted guests up and down the elevators (which made it tricky to catch an open place to stand in one but it was comical all the same). Eventhough we were strangers, several individuals shook our hands as we entered the door, within minutes we had made friends. It was quite an amazing experience. My husband and I laughed on the last night of the convention when we learned that some poor soul was having a wedding in the same building. I expected they had quite the party along with some very happy crashers!
As a parent of a newborn, the diagnosis can be very overwhelming. It's devestating in the beginning and only natural to latch on to any and all hope that comes your way. One of those hopeful peices is the language factor. You hear or read that your child will have a mental disability, low IQ, may never live on their own and at times it's almost too much to take. But then you read about their beautiful language and you get a little seed of hope. In early childhood that little seed takes longer than you expect to sprout.
If you talk to any WS parent, most will admit that one of their first concerns was- when will that bubbly language appear?... preschool comes and your child is still doing baby talk. It can make a parent a little on edge. Good thing is that speech delay is typical for a child with WS. Delayed speech occurs across the board and there are mountains of research out there explaining why. In this section of the blog, I reached out of my comfort zone of basic anatomy and tackled the world of speech and language. It's not my strong point, so you'll have to bear with me. I write this section in homage to my daughter's lovely speech therapist who inspired me to learn more about the development of speech.
Early speech delay
Although many parents anticipate that first ma-ma or da-da around 6-10 months, parents of children with WS collectively have to wait much longer. Studies of young children with WS show that they all demonstrate a delay in speech. Researchers have linked this to a delay in two skills: delay in the ability to produce a rhythmic pattern, a motor skill called rhythmic development and the ability to pick specific words out of a string of speech.
Motor skills come first
In all children, language development typically follows development of major motor skills. Most children start to acquire a rich vocabulary and pick up more words after mastering crawling or walking. This is the pattern for normal development. In a young child, the brain has to train its neurons, or nerve cells, to communicate with muscles in order to get the desired effect- walking without falling, picking up food and putting it in the mouth and moving the tongue and lips to produce a sound. It's all something the brain has to learn to coordinate. It's no surprise then that if motor skills are delayed and/or a child has problems with low tone in their muscles (see the muscle section of this blog), they are going to have trouble producing language.
This picture shows a reflex arc. It's the nervous system pathway used to control the muscle. In simplified terms- Information comes from a sensory receptor (such as hearing speech) and it travels to the brain or spinal cord where it is interpreted. The central nervous system then sends information to the muscle to create speech.
In order to speak there are many muscles in the mouth that the brain must learn to control. In order to accomplish the task of language, the body must first figure out:
- How the nervous system will communcate properly with the muscles to create a muscle tone that allows it to produce the desired motion. Remember from the muscle section of this blog, tone is related to a constant state of contraction that a muscle is in that allows it to monitor the space that the body occupies and adjust contraction based on need for balance, coordination and general awareness of which way is up.
- The muscle itself must also have the proper strength so it doesn't get tired. This can also include the range of motion needed to produce a sound, the speed of the tongue or lips to develop a word or phrase, coordination of several muscles in the oral cavity and something called dissociation or the ability to move all the muscles independent of one another. Not a small task for a baby.
- On top of all this language is a complicated process of receiving sensory information- seeing your environment, hearing your parents say something and having to process that information, figure out what it means and how you want to respond and then eliciting the proper movements to speak coherently. All of this takes time to develop and for a child with WS it all starts in learning to move and coordinate the muscles.
Muscles of the head and neck used for speech and swallowing.
Several speech studies looked at the child's development of motor skills and tried to find a relationship between an acquired motor skill and the onset of language. The first language skill that most parents and researchers note is the ability to babble. In the speech and language world this is called canonical babbling. Canonical babbling is the repeatition of sounds such as ma ma, da da, ga ga, etc. It is considered a major speech milestone which usually occurs in typical children around 6-10 months of age but much later in those with WS. What the study found was that children with WS had to develop a gross motor skill related to rhythm before they began to babble. When they began to rhythmically nod their head (called head banging) or circle their arms (called occilated movements) their language development quickly followed. Once this skill was acquired (on average around 16 months old in children with WS) canonical babbling followed on average about 2 weeks later.
Followed by canonical babbling, babies with WS will usually say their first word around 20-21 months old. In all children in this study, the first word came 18 weeks following the canonical babbling (versus a typically developing child whose canonical babbling begins at 6-10 months and first word typically said 2-3 months later). The conclusion of this study stated that the delay of speech in williams syndrome is actually linked to a delay in motor development since babbling requires motor skills. Therefore, the delay of rhythmic hand banging results in the delay of the babbling which in turn delays their first words.
The complexity of babbling in WS has shown to be more variable than typically developing children and it also shows to be less complex. Young children with WS tend to babble by repeating one consonant versus using a variety of sounds like a typically developing child would. Studies also show that the more typical the babbling is for the children (meaning those WS children who make more complex sounds when they babble) tend to have better language skills when they age. Babbling is therefore a good indicator of language skills down the road.
It also has to do with interpretation...
Another delay in early speech in WS is the ability to pick words out of a conversation. When you converse with a child, they have to form meaning around all the words. Parents can easily see when a child understands sentences as they learn to follow directions- such as "Get the ball". As children develop their understanding of language, they typically learn words that start with a strong syllables and end with a weak one (such as ball) first. These words stand out in a sentence better than words that that have weak to strong syllables in the words (such as balloon). In williams syndrome, it is shown that they can pick up the strong to weak words when spoken to in sentences, but couldn't duplicate or pick out words with the weak to strong syllables. Additionally, if a weak to strong word is offered to them individually (not within a sentence) they can duplicate them. The research team found that many of the children with WS had a language delay in this area not because they couldn't learn these types of words but because of the method the words were presented to them (in a conversation rather than isolated). Therefore it's important when teaching your child vocabulary, that they learn what objects are in isolation of a conversation about them. Instead of telling the child "That is a balloon. The balloon floats." You should instead touch the object and simply say "balloon". This removes the "noise" from the label and the child will better understand.
How a young child with WS learns
In language, speechologists studied when the average child with WS was able to speak 100 words; which is a skill typical children develop around 18 months of age. This came at about 40 months on average for children with WS (ranging from 24 to 68 months), which is in the bottom 5% when compared to children overall. In the same study, the children were followed to see the rate of vocabulary development. The researchers found that some of the children's language development occured in spurts of new skills followed by times where little to no growth was noticed, similar to what a typical child would do when developing a new skill. These children tended to have more advanced language at 4 years old than those children in the study who slowly developed by progressively gaining skills with no lags in learning. The study didn't indicate which of these groups were "typical for WS". It just indicated that both types of growth were observed and resulted in different levels of vocabulary as they aged.
Studies of how young children with WS learn expressive language showed that it is highly linked to play based learning. If a child is shown something and told its name, they do not aquire the language as well as if they learn it through play, for example rolling a ball and learning it's a ball during the kinesthetic activity. In otherwords, they learn by doing. Other skills that were studied were the ability to sort objects into categories and the ability to call objects by name, called fast mapping. These two skills are linked cognitively and in WS, as in typical children, these skills are developed in sync (within less than 2 weeks of each other).
"Hey Mom, what's that?"- Pointing
Gestures are considered an early communication skill that often help children acquire a richer vocabulary. Typically children acquire the ability to point to an object by the age of one. Pointing is a child's way of learning labels. They point at something that is interesting to them and the parent follows the gesture and responds with a label. Children with WS, interestingly enough, don't develop the pointing skill until after language has began to develop. This is atypical in the developmental order for most children including those with Downs syndrome, autism, etc. The inability to point can further delay the development of their language. They also the have the inability to follow a point. Studies show that children with WS do much fewer gestures overall, than typical children and fewer than kids with Downs syndrome. Although, children with WS generally will test as having a larger vocabulary than children with Downs syndrome.
At preschool age, many children with WS will have acquired a large expressive language but lack skills in referential language. They'll have difficulty learning because they haven't developed the pointing skill. This skill cognitively shows that the child can pay attention to an object at the same time as they pay attention to the adult naming and communicating with them (i.e. listen to the teacher read a book while following their finger when they point to the objects or words in a story). When comparing non-verbal language of those with WS to typical children, children with WS have a strong non-verbal ability to express need and want but not to request names of objects for further learning or use pointing gestures.
The ability for a WS child to refer to an object to show want or need by pointing is significantly delayed in WS by 6 months up to a year. Children with WS will learn to request an object first but won't learn to point to it until much later. Few children in the study developed pointing before they were able to label objects using words. This skill is a milestone that many parents of those with WS celebrate because it is so noticably delayed. Researchers link some language delay to the delay in pointing because WS children will not point to objects they are interested in as a request to learn its name. This can further delay the acquision of new language. There are three methods parents can use to compensate for this. First, the parent should follow the gaze of the child if they are focused on an object and then name it for them. The parent can move an object in the direction of the gaze and then label it or the parent can tap on a object they are trying to label to gain their attention and then label it. It is important for parents to share the names of many objects since their child will not be able to communicate their curiosity of what objects are called.
Children with WS are often compared to those on the autism spectrum because of the absence of this skill, pointing. They can also have difficulty following a point when a person is trying to communicate something from across a room (another similar autism trait). At times they also demonstrate the inability to use eye contact in proper situations such as when a teacher is requesting attention in a classroom discussion or during conversation. They are delayed in skills such as giving and showing. Although the lack of these skills are found in children with autism, those with WS should not be labelled as autistic unless they display other autistic tendencies in addition to these (which can happen). These delays in communicative skills is considered a normal quality of WS, not a secondary diagnosis of autism.
Social Gaze
Another characteristic of children with WS is their fixation on faces. Studies have shown that a child with WS will place more attention on the face of the person working or playing with them, such as their teacher than the task at hand. This can make language acquision harder for them because they don't use joint fixation on the object that is being discussed. The fixation on the face can be even worse when it's a stranger. For example, if a teacher is working with a child with WS and trying to show them a ball, the child may fixate more on the teacher than the ball and miss the label.
School age
Although gestures are delayed in early childhood, when children with WS were reevaluated at a school age and compared to children with Downs syndrome and to typically developing children of the same age, gesture development becomes evident. In the early years, gestures are almost non-existant. When young children were compared to DS, they were found to have less gestures but more vocabulary words. But later in elementary ages, the gestures become a strength. Older children with WS are very expressive in both their vocabulary and gestures. This suggests that children with WS develop speech first and then develop gestures unlike what would be expected in the general population.
When children begin to vocalize concepts such as counting forward and backwards and putting together longer phrases and sentences, scientists have found that a child with WS tends to learn these skills in a different way than a typically developing child. Normally a child would learn a new word and relate it's context to something they already know. The brain is designed to work this way, building connections between something new with something old. This process is called association. This is why it's easier to learn something in depth when you are familiar with the background than if it's totally new and you can't relate. In WS, researchers have found that language development appears to take a somewhat different route. In WS, kids don't make as many associations, instead they rely more on their working verbal memory. They memorize the new information by hearing it (they are auditory learners). Theories as to why this happens stem from the development of the brain. Many think that in a child with WS, the language pathways are not only delayed but they develop in a different manner than a typical child's would. Therefore, they are going to approach learning in a different way as well. In fact, many studies that have tested working memory strength has found that adolescents with WS have a better verbal memory than thier typical peers. Meaning, if a person with WS listens to a sentence or paragraph they can repeat back the words more accurately than their typical peers can.
Measuring IQ
Belugi studied WS in the 1980's and made an observation that although those with WS couldn't show their knowledge on paper; for example through a drawing that depicts an object; they could describe it in detail using a complex vocabulary and dialogue. Her study showed that there is a definite disconnect between language abilities and intellectual cognitive ablities. Many other studies followed this one as it peeked interest in those outside of the WS research world. Research followed testing that the ability to speak fluently is independent of the ability to think intelligably. The research and data taken over the next 10 years was poor at most; having only small sample sizes and testing children who did not demonstrate classic WS deletions. Most described the children used in the sample study as having almost immeasurable IQ which we know today that this is an inaccurate portrayl of WS considering most have IQ that is midly below average.
In 2007, Dr. Mervis and Dr. Morris, in a joint study researched individuals with WS using a larger sample size than ever before and included only those with classic deletions who showed no signs of autistic tendencies. Dr. Mervis and Dr. Morris used a test called the Kaufman Brief intelligence test (KBIT) and determined that intelligence in WS lies on a spectrum. Just as the general population has a variety of IQ's; so does the population of those with Williams syndrome. The mean or middle IQ in their study was 69 which is considered at the high end of the mild mental disability range. However, there were people who scored in the 40's which is considered moderate intellectually disabled and those who scored around 112 which is considered average. More remarkable, when this study was matched up with the IQ ranges seen in the general population; the intelligence quotients are distributed in the same pattern just two standard deviations lower than for the general public (more in the middle; less on the outer scores) showing that in WS overall, the cognitive ability is what you'd expect to see in a typical person, just approximately 30 IQ points lower on the scale.
When your child's intelligence is evaluated by a school district it is important to ask them to use the KBIT test as mentioned above instead of the Differential ability scales test GBA. The later test looks at visual spatial abilities which are widely known to be a disability for those with WS. Therefore, using this test to evaluate IQ will inevidably show lower IQ levels than the KBIT test and it skews results.
Adolescence
In cognitive studies for adolescents, researchers test IQ and cognitive ability using a variety of measures. One of which is the person's ability to name objects that belong to a common category, such as "animal". In those with WS, they found that they will name more unique organisms when compared to typical adolescents. This skill first becomes evident between the ages of 11 to 19 and as the person ages within this range, the variety and uniqueness of the organisms they name only grows in magnitude. After the age of 19, this levels off. When compared to typical children of equal mental ability, those with WS scored equivalent to their peers in this area of semantics and in some categories scored equal with teens who had more advance mental abilities.
The most notable difficulty adolescents with WS have is their ability to describe an object in its space. When compared to teens with similar mental abilities, individuals with WS had a much harder time describing how an object is built or organized in relation to all of its parts. Theories are that those with WS have a disability in spatial language. Other researchers believe that they have trouble comprehending sequence in a sentence. This skill, called spatial memory, is demonstrated in a study where they showed adolescents with WS videos of motion, such as a box falling off a wall. Adolescents with WS could describe the action such as the box fell off, but couldn't describe where the box fell from (the wall). This shows that when they have to remember a series of events (two different places) their memory fails them.
Grammar
Traditionally, researchers have thought that individuals with WS tend to understand and use grammar better than would be expected. Much of this research is based on studies that compare individuals with WS to those with Downs syndrome. They show that those with WS consistently outperform their peers with Downs syndrome and often only score slightly below those individuals considered typical. Subsequent studies, however highlight that individuals with Downs syndrome tend to have a specific disability with grammatical speech and that the study was erroneous to compare those two groups.
How can you have a disability and a gift in the same area?
In brain studies, students with WS who have normal IQ's still show difficulites in spatial language in addition to quantitative language (like long vs short; over vs under, etc). The brain studies indicate that spatial language disabilities can be due to a structural abnormality in the intraparietal sulcus of the brain. The interparietal sulcus is a shallow dip that is formed by grey matter- the neural cells of the parietal lobe that are used to process or figure out sensory information . Scientists have identified that this area is used by people to understand numbers, particullary number order and comparing small numerical size to large. It is also used for some visual processing and eye movements used to judge visual- spatial information, maintaining visual attention span and interpreting social intent of others during a conversation, all obvious difficulties for individuals with WS.
The intraparietal sulcus is highlighted in red in this drawing.
Although, there are several studies that show there are enlarged areas in a WS brain, they cannot conclusively say that there are the same enlarged in all of those with WS because there has never been a sample size large enough to do so. Scientists have long attributed IQ to the amount of grey matter in the brain, which is used for critical thinking and white matter, which is used to transmit information quickly across the brain. Both of these are needed to analyze and interpret ones surroundings. Therefore, many feel that generally enlarged areas of the brain will positively correlate to a higher IQ and smaller areas lead to lower IQ's. Considering those with WS have both makes for a very interesting conflict. This is one of the many reasons why WS is such a fascinating disability for neuroscientists to study. (Look for a future blog post on more about brain studies.)
In sum... individuals with WS need speech therapy
Overall, studies have shown that individuals with WS do not have a verbal ability higher than what would be expected of their cognitive ability. But, they tend to have areas of speech that appear more typical (such as grammar, ability to repeat what they hear, and concrete vocabulary). Those language strengths often disguise their weaknesses (such as spatial vocabulary and their ability to explain sequence). Therefore, as an individual with WS reaches adolescence, they often lose therapy related to speech. Speech therapy is very important for a child with WS since their language in all areas will be delayed. As they age, therapy can be adjusted to the child's needs but it should not be denied in full because there are areas that will put the student at a disadvantage in school.
Sources:
Sources on brain studies:
http://www.ncbi.nlm.nih.gov/pubmed/18722146
http://www.ncbi.nlm.nih.gov/pubmed/17512756
http://www.annualreviews.org/doi/abs/10.1146/annurev.ne.12.030189.002113
http://www.sciencedirect.com/science/article/pii/0166223692903448
http://focus.psychiatryonline.org/article.aspx?articleid=50697
The brain studies have also shown that this structural abnormality of the intraparietal sulcus obstructs a nervous pathway to the later dorsal stream region. The dorsal stream region is a section of the brain in which a flow of sensory, particulary visual information sweeps down neural pathways and develops an overall awareness of spatial identity. It is found in the lower portion of the parietial lobe (which overall's function is to process and interpret sensory information) and sweeps across the occipital lobe (which interprets visual information) and across into the temporal lobe (which functions in many areas including memory).
These brain scans show overall volume of the brain. The WS brain is considered smaller by volume, by 15%, but some areas (indicated in light blue) are larger by comparison.
So, why do those with WS have relative strengths in language as well? By contrast, brain studies show that indivuals with WS have some regions of the brain, including the frontal lobes, the amygdala, and the cingulate gyrus that are of typical size or even enlarged in portions. Brain studies to investigate the social nature of WS indicate that there are enlarged areas in the temporal lobe, associated with memory and language centers, along with increased blood flow to the hippocampus region of the brain related to memory retrieval. In a psychiatry study, they found that there is a large amount of grey matter (cortex) in the WS brain, overall, especially in the Heschl's gyrus which is in the primary auditory area, explaining why those with WS are such great auditory learners. In this study, they could not explain why this thick cortex occurs but theories are that either the missing genes cause an issue with the regulation of the cell growth here, or that the neural pathways are overused in a WS brain compared to those of a typical indivdual.
This picture shows grey matter thickness in WS (on the left) compared to a typical adolescent (on the right). The red areas show the thickest areas of the grey matter.
In sum... individuals with WS need speech therapy
Overall, studies have shown that individuals with WS do not have a verbal ability higher than what would be expected of their cognitive ability. But, they tend to have areas of speech that appear more typical (such as grammar, ability to repeat what they hear, and concrete vocabulary). Those language strengths often disguise their weaknesses (such as spatial vocabulary and their ability to explain sequence). Therefore, as an individual with WS reaches adolescence, they often lose therapy related to speech. Speech therapy is very important for a child with WS since their language in all areas will be delayed. As they age, therapy can be adjusted to the child's needs but it should not be denied in full because there are areas that will put the student at a disadvantage in school.
Sources:
Information in the early childhood speech section was summarized mainly by the article above, by Dr. Mervis and partially by the following Masters thesis by Brittany Myatt: http://sdsu-dspace.calstate.edu/xmlui/bitstream/handle/10211.10/322/Myatt_Brittany.pdf?sequence=1
Sources on brain studies:
http://www.ncbi.nlm.nih.gov/pubmed/18722146
http://www.ncbi.nlm.nih.gov/pubmed/17512756
http://www.annualreviews.org/doi/abs/10.1146/annurev.ne.12.030189.002113
http://www.sciencedirect.com/science/article/pii/0166223692903448
http://focus.psychiatryonline.org/article.aspx?articleid=50697