Features of Cornelia de Lange Syndrome relevant to self-injury
Medical and physical features of Cornelia de Lange Syndrome relevant to self-injury
The physical characteristics of Cornelia de Lange Syndrome have been described by a number of researchers and clinicians 4, 5, 6, 7, 8, 9. The most prominent characteristics include:
- Low birth weight.
- Delayed growth.
- Distinctive facial features (prominent philtrum (this is between the nose and the upper lip), thin downturned lips, long eyelashes, confluent (joined) eyebrows)
- Excessive hair growth
- Small hands and feet with short digits.
- Severe limb abnormalities (present in 25- 30%).
Many health and medical problems are also associated with Cornelia de Lange Syndrome. Box 2.2 shows how common some of these problems are in children and adults with Cornelia de Lange Syndrome in comparison to other children and adults with intellectual disabilities of the same age and with the same degree of intellectual disability.
The graph shows the common health problems seen in Cornelia de Lange Syndrome in comparison to other individuals the same degree of intellectual disability of comparable age. Eye, ear, dental, gastro-intestinal and skin problems are significantly more commonly reported for individuals with Cornelia de Lange Syndrome.
For the purpose of understanding self-injurious behaviour in Cornelia de Lange Syndrome, this chapter will attend more closely to those physical characteristics and health or medical problems that may be associated with discomfort or pain. This is because a number of these problems are potentially relevant to self-injurious behaviour. These are described below together with an indication of why they might be associated with self-injury.
- Eye problems
- The primary eye problems associated with Cornelia de Lange Syndrome include the absence or reduction of tears, blocking of the tear duct and potential abnormalities of the eye that cause impaired vision. In many people who have intellectual disabilities discomfort, irritation or pain in the eye will lead to eye pressing, poking or rubbing. Additionally, if vision is impaired by damage to the eye but the optic tract (the nerve fibres that carry signals from the eye) is intact and the occipital lobe (this is the part of the brain that receives and interprets signals from the eye) is functioning normally, then this can lead to eye pressing or poking. The reason for this is that if no light can stimulate the nerves in the back of the eye then physical stimulation of these nerves by pressing or poking leads to bright flashes of light and light patterns. In the absence of any other stimulation this can be rewarding and cause the behaviour to occur again in the future (see Chapter 5). Another reason for pressing or poking the eye is that this can lead to the shape of the eye being temporarily changed and consequently focus is improved.
- Ear problems .
- The most commonly reported ear problem in Cornelia de Lange Syndrome is chronic otitis media (middle ear infection)
Approximately 50% of head-banging that is commonly seen in many children under the age of five, who do not have intellectual disabilities is associated with this problem 31. There is no reason to think that children with Cornelia de Lange Syndrome should respond any differently to this painful condition than children without intellectual disabilities.
- Bone and joint problems
- Although there has been limited research into bone and joint problems in Cornelia de Lange Syndrome the presence of scoliosis (curvature of the spine), difficulties with gait and restricted movement in certain joints such as the elbow have been reported. Abnormalities in the hip occur in approximately 5-10% of children and adults with the syndrome.
Some parents also indicate that their children often ‘pop’ their hips, knees and other joints out of place. However, research on this has not been carried out and at the moment these reports are anecdotal. It is not clear what sensation is gained from this behaviour but it is thought that perhaps it might help to relieve pain or discomfort in the joints.
- Gastro-intestinal disorders
- Gastro-intestinal problems are one of the most commonly reported problems in Cornelia de Lange Syndrome. Research suggests that as many as 71% of children with the syndrome have feeding difficulties that reflect these problems.
There are two main gastro-intestinal disorders that are common in children and adults who have Cornelia de Lange Syndrome. The first is gastroesophageal reflux. This is caused by the sphincter muscle at the top of the stomach not being sufficiently tight to keep the contents of the stomach from rising up into the oesophagus.
The contents of the stomach are acidic causing painful burning sensations in the chest and throat when reflux occurs. The second problem is malrotation of the intestine. This is a serious and life-threatening condition that leads to considerable discomfort and requires immediate attention.
- Sinuses
- Sinusitis has been reported to be a common problem for individuals with Cornelia de Lange Syndrome. It is caused by inflammation of the sinuses causing pain and discomfort to the individual. Sinus problems may be related to the depressed nasal bridge that is characteristic of individuals with the syndrome.
- Teeth
- There are two dental related medical problems that might be associated with self-injurious behaviour. The first is the crowding of teeth. This can lead to some discomfort as teeth erupt. The second problem is the thin layer of enamel on the teeth. This may mean that dental cavities are more likely to occur and that there is increased sensitivity to touch and temperature in the teeth. This is potentially relevant to gastroesophageal reflux as constant contact between the acidic fluid from the stomach and the already thin enamel on the teeth can hasten the development of cavities.
In addition to these two specific problems that are related to Cornelia de Lange Syndrome it should be noted that there will in any event be some physical discomfort around the time of tooth eruption just as there would for any child.
- Peripheral sensory neuropathy
- Dr. Tonie Kline has suggested that here is some evidence that children and adults who have Cornelia de Lange Syndrome might have a peripheral sensory neuropathy. This means that the peripheral nervous system, that part of the nervous system outside of the brain and spinal cord that is associated with pain and sensation amongst other things, might not be sending the right signals to the brain. Given that for many children and adults the upper limbs do not develop properly it would not be surprising if the peripheral nervous system in the arms had also not developed normally. Even if the hands and arms are well-formed it is entirely possible that a peripheral sensory neuropathy is still present.
This disorder can have two important effects that might be relevant to self-injury. First, pain may not be experienced in the ‘normal’ way. Painful stimuli may not be experienced as painful. Secondly, people may experience unusual sensations in their hands and arms. These sensations are described by some people as pins and needles (dysaesthesia) or a mild burning sensation.
Autism in Cornelia de Lange Syndrome
There are three core deficits that are currently used to diagnose the presence of autism:
- Impairment in reciprocal social interaction.
- Impairment in verbal and non-verbal communication.
- Presence of restricted and repetitive behaviours.
The diagnosis of autism will only be made if all three of these impairments are present.
Two instruments that measure the presence of these three impairments are the Gilliam Autism Rating Scale and the Childhood Autism Rating Scale.
According to this graph individuals with Cornelia de Lange Syndrome do not show significantly increased levels of impairment on communication, socialisation and the presence of repetitive behaviour compared to other individuals with intellectual disabilities. According to this, ‘levels of autism’ are no different between the two groups.
In contrast to Graph 1, this graph indicates that individuals with Cornelia de Lange Syndrome show significantly increased occurrence of severe autism compared to other individuals with intellectual disabilities. More research is needed to establish the relationship between autism and Cornelia de Lange Syndrome.
Psychological factors relevant to self-injury
As discussed in Chapter about CdLS, a number of cognitive and behavioural features, i.e. a behavioural phenotype, may be associated with Cornelia de Lange Syndrome. In order to help us to understand self-injurious behaviour in Cornelia de Lange Syndrome, it is important to consider the cognitive and behavioural features that might be related to the syndrome. The specific features of the behavioural phenotype, including those that are relevant to self-injury are described here, together with a brief indication of why they might be important to consider in relation to selfinjury. Chapter 5 provides further insight into why and how these features might be associated with self-injurious behaviour in Cornelia de Lange Syndrome.
Intellectual disability.
One of the main psychological factors that is relevant to self-injurious behaviour in Cornelia de Lange Syndrome is the associated degree of intellectual disability. Research has indicated that people with Cornelia de Lange Syndrome have an intellectual disability ranging from mild to profound degree of disability, with the majority of people having a severe disability 5, 7, 13, 14, 15, 16, 17. In our research project we found that 45.6 % of people with Cornelia de Lange Syndrome had a profound degree of intellectual disability and 30.43% had a severe degree of intellectual disability when we used a standardised measure of adaptive behaviour (see Box 2.3). Presence of self-injury is related to intellectual disability and research has suggested that individuals with a greater degree of disability are more likely to display self-injury 18, 19 (see Chapter 3).
The table below shows the percentage of individuals in each category of degree of intellectual disability in our study of 54 people with Cornelia de Lange Syndrome. Note that the many of individuals with Cornelia de Lange Syndrome have either profound or severe intellectual disabilities.
Percentage of individuals in each category of degree of intellectual disability
Profound | Severe | Moderate | Mild | Borderline | |
---|---|---|---|---|---|
CdLS | 45.65 | 40.43 | 15.22 | 8.70 | 0.0 |
Since discovery of genes, in combination with technology we see a increase of diagnosis for CdLS. These increased cases are typical less severe (mild). This means we advise you to also read Genotype versus Phenotype correlation
- Communication.
- Past research indicates that children and adults with Cornelia de Lange Syndrome have communication deficits with around 30-85% of individuals showing no verbal communication skills 15, 16, 18, 20, 21, 22, 23. It is thought that the main problem related to communication is a deficit in expressive communication (see Box 2.4). Although children and adults with Cornelia de Lange Syndrome may have difficulties with expressive communication, research has indicated that individuals with Cornelia de Lange Syndrome use a number of non-verbal strategies to communicate including, for example, approach, touch and pushing a person’s hand away 22. Whilst this problem of poor expressive communication is not unique to Cornelia de Lange Syndrome (it is also seen in both Cri du Chat and Angelman Syndrome for example) it does have a particular relevance to self injurious behaviour (see Chapters 3 and 5).
This indicates the presence of a significant difference between the Cornelia de Lange Syndrome group and the comparison group. The graph shows that individuals with Cornelia de Lange Syndrome have a particular deficit in expressive communication (ability to express information to others) compared to other individuals with intellectual disabilities. The graph also indicates that individuals with Cornelia de Lange Syndrome have significantly better receptive communication (ability to understand incoming information from others) than this comparison group.
- Self-injury and aggression.
- As mentioned in Chapter 1, self-injurious behaviour has been suggested to be associated with Cornelia de Lange Syndrome 14, 20, 22, 24, 25, 26, 27, 28. Initially it was reported that self-injury was a significant feature of the syndrome. However, our research has shown that the association is not as strong as was at first thought. This is discussed in more detail in chapter 4. In addition to self-injurious behaviour, children and adults with Cornelia de Lange Syndrome can show other problem behaviours including physical and verbal aggression towards others and destruction of the environment (see Box 2.5). Interestingly, whilst there is no significant difference between the percentage of children and adults with Cornelia de Lange Syndrome who show self-injurious behaviour or destruction of the environment, children and adults with Cornelia de Lange Syndrome show significantly less aggression than children and adults who have the same degree of intellectual disability.
The graph shows that whilst individuals with Cornelia de Lange Syndrome show high rates of self-injurious behaviour, other behaviours such as physical aggression and destruction of property are also common.However, it is important to note that children and adults with Cornelia de Lange Syndrome show significantly less physical aggression than others with intellectual disability.
- Compulsive behaviour.
- Our recent research shows that children and adults with Cornelia de Lange Syndrome show significantly more compulsive behaviours than children and adults with same degree of intellectual disability (see Box 'Compulsive beaviour'). This is potentially important and relevant to self-injurious behaviour because it has been suggested that compulsive behaviours are related to severe self-injury that the person finds difficult to control 33. A number of studies have suggested that self-injury in people with Cornelia de Lange Syndrome has a compulsive quality and is associated with compulsive behaviour 23, 27, 28. (This is discussed in detail in Chapter 5).
Compulsive behaviours have been defined as ‘repetitive, intentional behaviours that appear to follow certain rules’. According to some researchers as many as 87.5% of individuals with Cornelia de Lange Syndrome show at least one form of compulsive behaviour 23. The graph below shows that individuals with Cornelia de Lange Syndrome show significantly more compulsive behaviours than the comparison group. In particular, checking, ordering and ‘grooming’ are among the most common compulsive behaviours in individuals with the syndrome.
- Hyperactivity.
- In the past it has been suggested that hyperactivity is a feature of Cornelia de Lange Syndrome20, 29. In our recent research we could find no evidence that hyperactivity was more common in Cornelia de Lange Syndrome than in children and adults with the same degree of intellectual disability. This does not mean that it does not occur, only that it is no more common than we would expect by chance.
- Autism
- Autism and autistic type behaviour has also been reported to be associated with Cornelia de Lange Syndrome 20, 25.
However, in our survey of people with Cornelia de Lange Syndrome we found different results for autism depending on the measure that we used. One measure (Gilliam Autism Rating Scale) showed no difference between the two groups whilst a second measure (Childhood Autism Rating Scale) showed a statistically significant difference between the two groups with autism being more common in children and adults with Cornelia de Lange Syndrome (see Box 2.7). It is important to clarify this issue as autism has been identified as a risk marker for the development of self-injurious behaviour 30 (see Chapter 3).
- Stereotyped behaviour.
- Finally, the presence of stereotyped behaviours also warrants mention, since there is some suggestion that there is a link between these behaviours and self-injurious behaviour. Stereotyped behaviours can be defined as repetitive, apparently purposeless body movements or use of objects e.g. body rocking or spinning objects. There has been little research into stereotyped behaviour in Cornelia de Lange Syndrome, however studies that have been carried out suggest that between 57% - 78% of individuals with the syndrome show stereotyped behaviour 22, 24, 25. This is not thought to be significantly different from other individuals with intellectual disabilities and the most common forms of this behaviour in Cornelia de Lange Syndrome reported in previous studies include body rocking, bizarre body positioning and object spinning 22, 25.
In our recent observational study of children and adults with Cornelia de Lange Syndrome, we found that significantly more individuals with Cornelia de Lange Syndrome showed distinct rigid J or C-shaped hand posturing than individuals with the same intellectual disability but without Cornelia de Lange Syndrome.
Summary
Whilst there are many ways in which children and adults with Cornelia de Lange Syndrome are no different from other individuals both with and without intellectual disabilities, there are some ways in which they are significantly different. The most important differences with regard to self-injurious behaviour are probably the medical issues that can be associated with irritation, discomfort and pain, and the psychological issues such as the degree of disability that is associated with Cornelia de Lange Syndrome, the presence of compulsive behaviours, the possible association with autism and more specific characteristics such as poor expressive communication and the presence of hand posturing.