This short set of notes offers a summary of current data in the field of ASD, such as the means of identification, incidence, and differentiation from other pervasive disabilities, but also highlights the variability among children with ASD in terms of the permutation and severity of symptoms.

There follows a mention of a study which appears to discount anxieties over the use of those vaccines containing thimerosal.

The last section refers to two recent presentations at a BPS conference concerning, respectively, common inadequacies in evaluations of interventions, and the frequency of low-level sensory deficits which might underlie later higher level perceptual and cognitive problems.

This first synopsis, covering the work of Hudson and Dixon (2003), provides an opportunity to take stock of thinking in the field of autism since, in itself, their paper is a summary of current findings and ongoing questions.

They begin by referring to the 12 to 16 % of children diagnosed with some form of developmental or behavioural disorder within which autism is included.

Autism is listed in DSM-IV as one of the five pervasive developmental disorders which may be linked under the concept of an autistic spectrum. The others are Asperger Syndrome, Rett Syndrome, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder - not otherwise specified.

Asperger Syndrome may be seen as a less severe form of autism, with adequate language capacities, but with the same sustained impairment in social interaction and repetitive or restricted behaviours and activities.

Rett’s Syndrome involves a specific and distinctive pattern of developmental regression following a period of normal development during the first 5 or 6 months. The condition appears to apply only to females.

Childhood Integrative Disorder is marked by rapid regression in multiple areas of functioning following a period of at least 2 years of apparently normal development.

Pervasive but non-specified disorders describe severe impairments in the development of social interaction but the criteria for a given condition are not met.

While autistic disorder is more prevalent in males than in females ( a ratio of around 4:1), it is found that the milder forms of the condition are more commonly identified in males while females are usually more seriously affected and tend to have learning disabilities associated with their autism. No significant variation in prevalence has been found across racial, ethnic, or socio-economic groups.

They note that the rate of diagnosis of ASD has increased from around 5 children in 10,000 up to the mid-1980s to somewhere at least between 10 and 20 children per 10,000 now ( and some survey data would put the incidence much higher still ). They do not offer any explanation for this observation beyond a reference to the greater sensitivity towards ASD symptoms and to the broader definition of the condition.

With regard to initial diagnostic steps, an early cause for concern is some delay or failure in achieving developmental milestones, and a common feature is that of a range of communication and language deficits, both expressive and receptive, which may be attributed inappropriately in some cases to a hearing loss.

A formal diagnosis is usually made by the time the child is 3 years old ; but, with hindsight, parents frequently report some very early signs of non-responsiveness to greeting or contact, and limitations in the development of nonverbal interpersonal skills such as eye contact and facial expressiveness.

Speech and language delays are common along with an absence of social relationships … although some children may develop apparently good or even advanced speech but use it inappropriately within an echolalic or repetitive style. Tolerance of or a preference for sameness is typical, illustrated by an insistence upon clutching some "prop", or demanding to wear the same clothes or type of clothes all the time, or eating very few items of food. There is minimal imaginative play. The children are also frequently noted to engage in ritualistic and apparently purposeless motor actions.

Clumsiness and a degree of apraxia may be noted, along with poor muscle tone, toe-walking, and looseness of joints.

Early language deficits include no babbling or pointing by 12 months ; no single words by 16 months ; no 2-word spontaneous phrases by 24 months ; and a loss of language or social skills at any age.

A formal diagnosis involves differentiation of autism from the other pervasive conditions listed above, and also from selective mutism, language disorders, stereotypic movement disorder, Fragile-X syndrome, and attention deficit disorder.

The critical areas are those of social interactions and communication, atypical environmental responses, and specific behavioural problems.

When a diagnosis is made, the advice is that parents or carers need to be aware that Autism or ASD can vary in its severity from quite mild to severe, and that it may present alone or in addition to other problems such as learning difficulty, Tourette Syndrome, ADHD, or anxiety.

While the degree of eventual independence will depend upon the severity of the condition and the presence or absence of other disorders, early intervention can enhance the probability of positive progress in communication and adaptive skills.

Interventions may involve behavioural or occupational or language or physical therapies or a permutation thereof, and, with time, individual educational plans which may involve support in mainstream or access to more specialist facilities. Medication may also be indicated if problem symptoms, such as those relating to anxiety or to attentional disorders, are found to be inhibiting social or scholastic or occupational functioning.

Management style may change over time as the nature of presenting issues changes. For example, early childhood may be marked by hyperactivity and irritability. Later behaviours may include aggression and self-injurious behaviour ; and adolescence and adulthood may bring problems relating to depression or obsessive-compulsive behaviours.

In other words, the diagnosis of autism or ASD may be legitimately applied to individuals who share certain characteristics and symptoms but in whom the number, type, and severity of the symptoms cover a wide range.

A brief report of a study completed in Denmark ( Madsen et al 2003) focuses upon the concern lest the use of thimerosal in vaccines may be linked with neurodevelopmental abnormalities. ( Thimerosal is a mercury-based preservative. )

The findings showed, however, that when vaccines containing this substance were discontinued in that country in 1992, the apparent incidence of autism showed an increase.

This was taken as further evidence that such vaccines are safe, and as support for the view from health officials in the UK that these vaccines with thimerosal are not only unharmful but are actually more effective than those which do not contain this substance.

The study involved an analysis of epidemiological data from all children, aged between 2 years and 10 years, who were diagnosed with autism in Denmark between 1971 and 2000. The total number of cases was 965.

The incidence of autism remained stable during the time when the vaccine containing thimerosal was used, in contrast to the observable rise in incidence when these vaccines were discontinued.

The authors recognise that the observed increase in the incidence of autism is probably not causally linked to this change in vaccine, but that the use of alternative vaccines happened to overlap with the period from the 1990s onward when enhanced attention was being directed towards autism and ASD and when the diagnostic criteria became wider.

1. Early Intervention and evaluation

The paper from Williams and Wishart (2002) restates the view that the effectiveness of many of the currently available interventions for autism has yet to be thoroughly investigated.

One particular difficulty is that evaluative studies may be of a design which does not truly reflect how, precisely, the intervention is implemented in the real setting.

They go on to highlight the frequent absence of such prerequisites as clear profiles of the children who are the participants in a given intervention, data concerning the pattern of the intervention in terms of intensity and duration, and information about the level of training and experience of the therapist.

Reliability and validity of the emerging findings may, thus, be questionable ; and there may also be a problem in seeking to generalise the reported outcomes of one intervention to another intervention even if they are theoretically following a similar methodology.

2. Sensory Impairments

The paper presented by Nieto-Vizcaino and Leekam (2002) described the frequency with which self-reports among individuals with autism contain references to difficulties in the processing or integration of sensory information.

However, they argue that the extent of such difficulties has not been systematically investigated, and sought evidence from a study of a sample of children and young

people diagnosed with autism via the use of a diagnostic interview for social and communication disorders. This measure gathers information about abnormal responses to a wide range of visual, auditory, and proximal stimuli.

The findings indicated that the sample with autism differed significantly from what was observed among comparison groups with learning or language difficulties in terms of responses to proximal or visual stimuli. The differences were found for both high and low IQ groups, and for younger or older participants.

The authors concluded that specific low-level sensory difficulties may be found alongside higher-level cognitive and perceptual-integrative problems, and that such lower-level difficulties might underlie the later problems.

Hudson G. and Dixon D. 2003 Autism : challenges in diagnosis and treatment. Clinician Reviews 13(7) 45-52

Madsen K. et al 2003 Rise in autism cases after thimerosal vaccines discontinued. Conclusions reported in Medscape Health Information (September). Original article in Pediatrics 112 604-606

Nieto-Vizcaino C. and Leekam S. 2002 Sensory impairments in children with autism. Paper presented at the BPS Developmental Psychology Section, September 2002, University of Sussex. Reported in Proceedings of the British Psychological Society 11(2) August 2003

Williams K. and Wishart J. 2002 Early interventions for children with autism.

( Paper presented at the BPS Developmental Section Conference September 2002 )