WHAT IS AUTISM?

Autism is a disorder characterized by abnormal social interaction, poor communication skills and stereotyped behaviours (restricted, repetitive movements).

The disorder has varying degrees of severity and is also referred to as autistic spectrum disorder, which includes Asperger syndrome, Rett syndrome and pervasive developmental disorder, not otherwise specified.

HOW COMMON IS AUTISM?

The prevalence of autism has increased markedly over the past twenty years in both developed and developing countries.

Prevalence in the USA is now reckoned to be about 1% of the population. Much of this increase is likely to be due to the application of stricter diagnostic criteria and an increased public awareness of the condition, but some may be due to as yet unidentified environmental agents.

WHAT ARE THE CAUSES OF AUTISM?

In the majority of instances, a specific cause for autism cannot be identified.

There are some genetic conditions that are associated with autism (e.g. Fragile-X syndrome, tuberous sclerosis). Minor genetic deletions and duplications are also frequently found in children with autistic spectrum disorder.

Other possible causes include infections and exposure to toxins in the prenatal period, during birth and in the first few months of life.

It may be that autistic spectrum disorder results from exposure of genetically susceptible individuals to as yet undetermined adverse environmental agents.

PRESENTATION AND DIAGNOSIS

HOW DOES AUTISM PRESENT?

Autism becomes manifest in early childhood, before the age of 2 1/2 years. The child usually presents with delayed speech development associated with peculiar behaviours. Sometimes lanuage development seems normal at first and then regresses. There is difficulty in making eye contact with the child. Speech is often limited to repetition or echoing of what has been said or has been heard on a television or radio program. Requests are frequently ignored or misinterpreted or there may be a delayed response to them.

Parents of children with autism often report that by one year of age the child does not attempt, as would be expected, to obtain people’s attention by pointing to a desired toy or object. Their child does not engage in imaginative play e.g. lining up toy cars rather than driving them around. Children with autism tend not to join in interactive play with other children, preferring to play in parallel with them. They also prefer sameness in their environment and become very upset for instance when their toys are moved from the position in which they were originally placed.

Children with autism frequently engage in repetitive movements such as flapping of the hands, spinning, and head banging. Many children with autism also develop an attachment to unusual objects or parts of objects (e.g. wheels of a toy car) or a circumscribed interest in odd or specific topics. Others show a dislike or an abnormal need for certain sensations such as smell, taste, sound and touch.

HOW IS AUTISM DIAGNOSED?

The diagnosis of autism, as with other medical conditions, is based on the clinical history,physical examination and laboratory investigations where they are indicated.

Children suspect of having this diagnosis should be referred to a physician who has been trained in the administration of special diagnostic instruments used to detect this condition. These include the Childhood Autism Rating Scale (CARS); the Autism Diagnostic Observation Scale (ADOS); The Autism Diagnostic Interview-Revised (ADI-R) and the Diagnostic Interview for Social and Communicative Disorders (DISCO).

Screening Tests like the Modified Checklist for Autism in Toddlers (MCHAT) have also been developed for early detection of autism since earlier diagnosis will result in earlier intervention and therefore greater likelihood of improvement.

ALTERNATIVE DIAGNOSES

Other conditions that may present with delay in language development and behavioural problems include the following

  1. Hearing impairment: All children who have delayed speech should have formal hearing assessment
  2. Intellectual disability (previously known as mental retardation): Children at the severe end of the autistic spectrum disorder are frequently intellectually disabled as well
  3. Developmental speech delay: It may be that some children who were in the past diagnosed with this uncommon condition in fact had mild autistic disorder
  4. Childhood Disintegrative Disorder: This rare condition presents later in childhood with dramatic regression in language, social function and motor skills

HOW IS AUTISM TREATED?

Unfortunately there is as yet no specific treatment for autism.

Drugs such as Risperdone and Aripiprazole may be useful for control of aggression, agitation and self-injurious behaviour.

Methylphenidate (Ritalin; Concerta) may be helpful in the management of accompanying attention deficit hyperactivity disorder (ADHD).

Research is currently being carried out on drugs that may have a more specific action on the underlying brain dysfunction.

Special diets are effective when autism is a manifestation of metabolic disorders such as phenylketonuria.

The mainstay of treatment of autism is through early behavioural interventions (e.g. Applied Behavioural Analysis), which are still undergoing research as to their efficacy.

Advances in management have also been made through the use of computer technology.

Other approaches to treatment such as chelation, Vitamin B6-Magnesium, hyperbaric oxygen, megavitamin therapy, and sensory-motor integration programs have so far not been demonstrated to be efficacious in large, properly controlled studies

OTHER ASPECTS OF MANAGEMENT

Speech therapy for improvement of language skills

Placement in special education for improvement in social and language skills

Anti-epileptic drug therapy for control of seizures, which tend to be more prevalent in children with autistic spectrum disorder

Epilepsy surgery for tuberous sclerosis, one of the known genetic disorders that may cause autism