Autism is a developmental disability that results in problems with social interaction and communication. Its features vary with individuals.
One person may have mild symptoms, whilst another may have serious ones. That is why healthcare providers consider autism a "spectrum" disorder, which includes an autistic disorder, Asperger syndrome, and pervasive developmental disorder (atypical autism).
Children who have an autistic disorder have major problems with language, social interaction and behaviour. Many also have learning problems and intelligence that is below average.
Children with Asperger syndrome have milder symptoms affecting social interaction and behaviour. Their language development is usually alright but they can have problems in certain aspects of language, for example, understanding humour. Their intelligence is usually above average. Some are skilful in memory, logic and creativity, eg in music, and pure sciences.
Children who have some, but not all of the features of autistic disorder and/or Asperger syndrome, are said to have a pervasive developmental disorder. Most have milder symptoms than autistic disorder but do not possess the good language and above average intelligence of Asperger syndrome.
Looking at the causes
Autistic spectrum disorder (ASD) can be due to primary or secondary factors. There is no medical condition in the former, which comprises 90 per cent of ASD. A medical condition is thought to be wholly or partially responsible for the latter, which comprises 10 per cent of ASD.
The conditions in secondary ASD are fragile X syndrome, tuberous sclerosis, and Rett syndrome.
Fragile X syndrome affects about one in every 3,600 boys and 6,000 girls, who have characteristic long faces, large ears and flexible joints. Tuberous sclerosis affects about one in 6,000 children, who have multiple, non-cancerous tumours all over the body. Rett syndrome affects about one in 20,000 girls who have ASD, and they have problems with physical movement and development.
Primary ASD is associated with genetic, environmental, neurological and psychological factors.
Although there is no specific gene identified, ASD is known to occur in families. If a child has ASD, there is about a 5 per cent chance that another child born to the same parents will have ASD. If an identical twin has ASD, the chance of the other twin developing the condition is 60 per cent.
The environmental factors associated with ASD are viral infection and maternal smoking during pregnancy, and the father's age. Pregnant women exposed to rubella have a 7 per cent chance of having an ASD child. The chance of pregnant women who smoke daily having a child with ASD is 40 per cent.
First time fathers above 40 years of age are six times more likely to father a child with ASD.
Studies on neurological factors have focused on the brain's amygdala, which acts like a switchbox between the cerebral cortex and the limbic system. The former processes sensory information and is responsible for all the brain's higher functions like thought, language, and problem-solving, while the latter controls a person's emotions.
The amygdala chooses the emotion to match the situation a person is in. Brain imaging studies suggest that connections between the cerebral cortex, amygdala and limbic system are altered in ASD.
Other studies have focused on mirror neurones which are thought to enable copying of the actions of others, eg an infant returns a mother's smile. As the child grows up, the mirror neurones may be involved in the brain's higher functions like language, learning, and recognition and understanding of others' emotions.
Brain imaging studies have found that the response of mirror neurones is altered in ASD. This mirror neurone dysfunction may be responsible for the problems with language, social interaction and some aspects of learning in ASD.
The focus of research on psychological factors is the concept of "theory of mind" (TOM). TOM refers to a person's ability to understand the mental states of others, ie the ability to see the world through another person's eyes. It is believed that most children understand TOM fully by about four years of age. Children with ASD have a limited or non-existent understanding of TOM, which may explain their problems with social interaction.
Although there are reports of links between vaccines and autism, none have held up to scientific scrutiny. There is no conclusive evidence that any part of a vaccine or combination of vaccines causes autism. There is also no evidence that any material used to make or preserve vaccines play a role in the causation of autism.
Symptoms of ASD
The features of autism involve communication, social interaction and behaviours. Communication can be verbal or non-verbal, eg eye contact, smiling, pointing. The social interactions include holding a conversation and understanding how others feel and think. The behaviours are repetitive, and include repeating actions or words, play and obsession with routines.
Some features may be typical of ASD while others may be a delay in the child's development.
Features are related to a child's development and may appear as early as six to 18 months when the baby may not follow a gaze nor appear to recognise or respond to a voice, but there is awareness of other sounds. The baby does not "babble" and appears expressionless. The baby has little interest in the surroundings or rarely makes gestures like pointing or waving.
The features are more obvious as the child becomes older. Language and social interaction problems become noticeable, together with unusual behaviours. Speech development may be delayed, or there is none at all. Speech can also be monotonous and repetitive.
The child does play in an imaginative but repetitive way. There is limited or no awareness of people in their surroundings. They may form friendships with other children only to behave inappropriately.
Many ASD children exhibit repetitive physical behaviours, eg rocking back and forth or licking objects. They prefer strict routines, which, if disrupted, would lead to temper tantrums or even attempts at self-harm. They often dislike certain foods.
There is usually an improvement as the child begins school. However, those with severe ASD may find school stressful, which may trigger disruptive behaviour.
Although most older children improve their language skills, specific difficulties may remain, eg repeating words in a "parrot" fashion, inability to understand humour, or sarcasm. Their lack of understanding of social interaction often hampers their friendships with other children of the same age. They need strict routines.
Children with Asperger syndrome do well with subjects involving facts, figures and logic, but they may have problems with subjects requiring abstract thought, eg literature.
A parent who is worried about a child's development would benefit from a consultation with his regular doctor who may carry out a brief screening test. This involves several questions and some assessment exercises with the child.
If the doctor suspects ASD, a referral will be made to a paediatrician, psychiatrist or psychologist who will carry out a detailed assessment, which would include a physical examination and other investigations.
When there is a diagnosis of ASD, it facilitates the parents understanding of their child's condition and plans can be then instituted to help the child.
Managing the problem
Managing the problem
There is no cure for autism; neither is there a single treatment for ASD. The objectives of management are to enhance learning and minimise its features.
There are several effective education and behavioural programmes. According to the American Academy of Paediatrics, "the principles and components of effective early childhood intervention in ASD include:
- Entry into intervention as soon as an ASD diagnosis is seriously considered rather than deferring until a definitive diagnosis is made;
- Provision of intensive intervention, with active engagement of the child at least 25 hours per week, 12 months per year, in systematically planned, developmentally appropriate educational activities designed to address identified objectives;
- Low student-to-teacher ratio to allow sufficient amounts of one-on-one time and small-group instruction to meet specific individualised goals;
- Inclusion of a family component (including parent training as indicated);
- Promotion of opportunities for interaction with typically developing peers to the extent that these opportunities are helpful in addressing specified educational goals;
- Ongoing measurement and documentation of the individual child's progress toward educational objectives, resulting in adjustments in programming when indicated;
- Incorporation of a high degree of structure through elements such as predictable routine, visual activity schedules, and clear physical boundaries to minimise distractions;
- Implementation of strategies to apply learned skills to new environments and situations (generalisation) and to maintain functional use of these skills; and
- Use of assessment-based curricula that address:
1. Functional, spontaneous communication;
2. Social skills, including joint attention, imitation, reciprocal interaction, initiation, and self-management;
3. Functional adaptive skills that prepare the child for increased responsibility and independence;
4. Reduction of disruptive or maladaptive behaviour by using empirically supported strategies, including functional assessment;
5. Cognitive skills, such as symbolic play and perspective taking; and
6. Traditional readiness skills and academic skills as developmentally indicated."
The management options include educational interventions, behavioural therapy and medicines.
The ideal educational intervention is to involve parents, teachers, psychologists and others to develop an individualised education plan that forms a structured framework for the child's school experience.
Studies have shown that ASD children benefit from visual information. Speech and language therapy improves language skills and the child's ability to interact socially. There are a variety of techniques that improve communication skills, eg listening and attention skills, as well as the ability to understand the social and/or emotional context of specific language and non-literal language.
Behaviour therapy reinforces appropriate behaviours and reduces inappropriate behaviours. Skills are broken down into small tasks and rewarded in a structured manner. Speech therapists, occupational therapists and physiotherapists have an important role in improving communication and interaction skills, adjusting tasks to match abilities and needs, and improving motor skills respectively.
There are no medicines that can cure ASD. But medicines are available to treat some of the symptoms, eg repetitive thoughts and behaviour, and aggressive behaviour. The selective serotonin reuptake inhibitors (SSRIs) - fluoxetine and paroxetine - which alter the brain levels of serotonin, a chemical which affects mood and behaviour, are used often.
Other medicines used include anti-psychotics, tricyclic compounds and anxiolytics. All these medicines are prescription items.
There is no evidence that complementary and alternative medicines are effective, and some may even be dangerous.
The outlook for ASD depends on its severity and the child's intelligence. Those with mild to moderate ASD and average or above average intelligence often grow up to be independent adults with jobs and family. Those with severe ASD and below average intelligence are unlikely to be independent adults and would require care and assistance for the rest of their lives.
Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with.