There are some genuine reasons why diagnosticians have difficulties recognising A/S. While there are psychometric (paper and pencil) tests that demonstrate difficulties with understanding and perception, these are not sufficient for diagnosis. The child's development must also be studied. Since this is a developmental disorder, the Asperger child will definitely show abnormalities in his/her development. So, if you are a parent accompanying your child to a diagnosis session, you must be careful to give an accurate account and not be tempted to say what a wonderful baby he was, giving you no trouble! The more you come across as a coping and confident mother, the more inclined the diagnostician may be to decide the problem is one of general developmental delay.

The diagnostician will be looking at the child's social development and may ask questions to do with how responsive he was as a baby (did he point out objects of interest) and how he played (did he do pretend play, did he understand that other people have feelings?) The child's language development will also be examined. Was he slow to talk, did he engage in conversational exchange, did he learn his language through reading?

Since this is a syndrome, different A/S children are affected to different degrees. For this reason, many different health specialists may be involved in the initial assessment of autism, from health visitors and speech and language therapists to GPs, child psychiatrists and occupational therapists. Some familes pass through all these specialisms and more before reaching the diagnosis. Sometimes the diagnosis is not clear or there may be several competing diagnoses such as ADHD, social anxiety disorder or developmental coordination disorder. Usually by the age of 7 the lack of social competence is more apparent and the diagnosis more straightforward.

The diagnostician is looking for distinct evidence, for example behaviours that would be abnormal in any child (flapping, stimming, lack of eye contact). Please note, many A/S children do not exhibit these behaviours. He will also be looking for behaviours that are inappropriate for the child's age. For instance, all babies go through a brief stage of staring at their hands. If they are still doing this as toddlers, it is abnormal behaviour. In many A/S children, such signs of their disability appear more marked at particular ages. Many parents of A/S children recognise their child's 'autistic' behaviours and body language as an early and useful indication of stress for a child who may be unable to articulate his problem through speech.

Thus, diagnosis depends on taking a full developmental history of the child as well as testing him with formal and informal procedures. It is really important that he is assessed in different situations, for instance at school and at home, in a one-to-one situation and amongst his peers. Often he will be able to manage one of these situations better than another, to the extent that his problems may be made light of by the observer. If you, as a parent, feel your child's (lack of) diagnosis is down to the diagnostician's inadequate understanding of the necessary steps outlined here, you should ask for a second opinion and demand an expert who understands A/S.