Autism is a lifelong developmental disability that affects the way a person communicates and relates to people around them. Almost 520,000 people in the UK are affected by autism, Asperger syndrome or other related conditions. Children and adults with autism have difficulty relating to others in a meaningful way. Their ability to develop friendships is generally limited as is their capacity to understand other people''s emotional expression.

People with autism can often have accompanying learning disabilities but everyone with the condition shares a difficulty in making sense of the world.

People with autism generally experience three main areas of difficulty; these are known as the triad of impairments.

Social interaction (difficulty with social relationships, for example appearing aloof and indifferent to other people).

Social communication (difficulty with verbal and non-verbal communication, for example not fully understanding gestures, facial expressions or tone of voice).

Imagination (difficulty in the development of interpersonal play and imagination, for example having a limited range of imaginative activities, possibly copied and pursued rigidly and repetitively).

In addition to this triad of impairments, repetitive behaviour patterns and resistance to changes in routine are often characteristic.

Asperger syndrome is a form of autism, which affects the way in which a person communicates and relates to others. It shares a number of the traits of classic autism, difficulty in communication, difficulty with social relationships, and lack of imagination and creative play.

Asperger syndrome is less easily diagnosed than classic autism because the symptoms are less defined, with the child often being of average, or above average intelligence.

Many characteristics are the same as for autism, but some are more typical of a person with Asperger syndrome.

Social Relationships - many people with Asperger syndrome try hard to be sociable, they do not dislike human contact, and are interested in the world around them. Some are aware that they are ''different'' to others. Many find it hard to understand non-verbal signs, or facial expressions.

Communication - many will speak fluently, but seem unaware of the reactions of the person to whom they are speaking. They may talk on and on  regardless of the listener''s interest or feelings. They may make inappropriate remarks in a specific situation. Speech may be over precise or over literal. Jokes, exaggerated language and metaphors can be confusing or frightening.

Imagination - many people with Asperger syndrome excel at learning facts and figures, but find it hard to use this knowledge imaginatively. Many find subjects like literature very difficult.

Interests - they often develop an almost obsessive interest in a hobby or collection. Interests usually involve arranging or memorising facts about a specialised subject.

Routine - to a person with Asperger syndrome routine is extremely important. Changes, such as alterations to the school timetable, or moving house, can be very upsetting. People with Asperger syndrome often like to order their day to a set routine, and any unexpected changes to this routine can cause them to become anxious or upset. 

Other features - people with Asperger syndrome seem to have difficulty with co-ordination, making them clumsy. They may also adopt odd postures, and indulge in repetitive movements such as rocking or swaying.

Children are usually first identified as having this disorder by the noticeable language development. Language starts to appear eventually, but there is often a severe impairment in understanding and using language and applying linguistic rules in conversation. Children affected by this disorder have difficulties in the area of the triad of impairments associated with the Autistic spectrum, however these autistic features are usually mild, but it is important to recognise these when supporting the child.

Children will typically sound odd and stilted in conversation, using memorised phrases inappropriately and out of context. The child will take language literally, and struggle to understand idioms such as "raining cats and dogs". Children with Semantic Pragmatic Disorder often fail to grasp the important points in a conversation, they will  have difficulty processing information, especially in new situations. It can be problematic for the child to generalise what they have learnt in one situation and transferring that knowledge to another situation.

Children with Semantic Pragmatic Disorder will often have poor body language, they may stand too close to other people, avoid eye contact, or may walk away in the middle of a conversation.

The term Pervasive Developmental Disorder is broadly used as the umbrella term for all autistic spectrum and related disorders. It is sometimes referred to as PDD-NOS which stands for Pervasive Developmental Disorder - Not Otherwise Specified. This term refers to people who have difficulties in more than one area but do not fulfil the diagnostic criteria for autism or Asperger syndrome. As the name suggests this term should only be used when all other possible diagnoses have been eliminated.

It is important to note that a person with autism will have Pervasive Developmental Disorder, but someone with Pervasive Developmental Disorder will not necessarily have autism.

The following information is adapted from an article by Mike Larcombe (Support Worker at Elliot House) which appeared in the National Autistic Society magazine "Communication" in 1998.

Typically parents are often the first to make the connection with the autistic spectrum and their child. Often they read or hear something through the media, or from someone they know, about autism.

If you think your child may have an autistic spectrum disorder you need to see an autism specialist. Your GP should refer your child to a local professional, typically a paediatrician, or a psychiatrist. If the local professional is unable to clearly identify why your child has difficulties, or you are not satisfied with the assessment you are entitled to a second opinion. Where you go for a second opinion is negotiable between you and your local specialist or GP.

Mike Larcombe offers the following guidelines for parents who suspect their child has an autistic spectrum disorder:

Find out from support groups who you should see. Other parents that have been through the diagnostic process may have valuable information.

If you are told your child has any form of autism (including Asperger Syndrome) he or she will need a written diagnosis. The diagnosis should include the words "autistic spectrum disorder" as these are the key words that can help you access help, support, and understanding. Do not accept the view of some professionals that they do not wish to label your child. A clear diagnosis can be a passport to the provision that your child needs. Likewise, do not accept a partial diagnosis of autistic tendencies, traits, features or behaviour. This can restrict access to help and support.

Do not necessarily tell the professional what condition you think your child has. Clearly and concisely explain your child''s difficulties. If your child has social difficulties, explain them to the professional, and ask if they agree. Once the professional understands how your child behaves, he or she may be able to make the connection between your child''s difficulties and the autistic spectrum.

Get other professionals to tell your specialist or GP about your child''s difficulties. If any professional (teacher, health visitor, social worker) has shared concerns with you, get them to put this in writing. Specialists often take more notice of other professionals than they do of parents.

Do not accept that your child''s learning difficulties are causing him or her to behave in an autistic way. Many autistic spectrum disorder children do have learning difficulties, others have average abilities, and some high intelligence. A child''s intelligence has nothing to do with whether they are within the autistic spectrum or not.

Do not accept an alternative diagnosis if you believe there is more to your child''s problems than the diagnosis suggests. Many children who have an autistic spectrum disorder have originally been diagnosed as having; chromosome abnormality, Down''s syndrome, ADHD, ADD, emotional and behavioural problems, obsessive compulsive disorder, challenging behaviour, and many more. This does not mean that all children with these disorders are on the autistic spectrum, but it is possible for a child to have more than one condition, and also, some conditions can be part of a child''s autistic spectrum disorder.

Accept that obtaining a clear diagnosis can take time. Take one step at a time and try to keep moving along the diagnostic road. If you come to a dead end and your child does not have a clear diagnosis, ask the professionals involved where they plan to send your child for a further diagnostic assessment.

Families usually benefit more when they work with a professional, rather than against him or her. It is better to become a persuasive diplomat than to demand or argue.

Do not give up and do not try to cope with the difficulty alone. Use support groups and keep knocking on doors until you achieve your objective. Trust your instincts and views because you know your child better than anyone else ever will.