Robbie, who is autistic, is eight years old. He used to talk to his mother but he has become increasingly isolated. When he is difficult at school, he is made to sit on the naughty chair. It gets to the stage where if anyone says anything that distresses him, he will go there of his own accord, holding himself by the ear. He then hits himself and screams inconsol-ably. A number of interventions have been tried to help him, to no avail. It is only when his mother tries answering his sounds — using low and soft tones — that he quietens down. Then within a few weeks, he is talking to his mother again. What is happening here?

With one child in 97 born on the autistic spectrum many of us nowadays will have lives touched by the condition — if not directly we will know someone who knows someone ... Just like the rest of us, children with autism will possess all levels of skills or disability, few will have exceptional talent. Because of their autism, many will require support throughout their lives.

A child or adult with serious autism is often seen as unresponsive, “living in their own little world” and as having occasional or frequent outbursts of apparently unpredictable self-harm or aggression. Parents are desperate to communicate. The first thing they ask is, “When will he/she talk?”

So how can we get in touch with people who are totally absorbed in repetitive behaviours? Why do these children sit in a corner flapping their hands, or screaming and biting themselves? How can we help them feel at home in the world we share?

Before we can communicate, we need to reflect on what it is like to be autistic. The problem lies in how incoming information is processed. Although the eyes and ears of those on the autistic spectrum may function normally, they have difficulty organising the information they receive and putting it into context. This is particularly marked with speech.

The brain also finds it difficult to switch off, so a sound may continue in the brain long after its source has discontinued. It is as if you are living in a turning kaleidoscope where the pattern never settles. They are easily sensorily overloaded and when this happens sounds boom and shut down, visual images swirl and break up. Balance swirls. Internal sensations may result in feeling that they are being attacked, triggering the body’s self-defence system. It is said that that the brain is like a dial-up modem instead of a cable modem — when it is fed too much data it crashes. Added to all this, the brain may not be getting strong enough messages from the muscles and joints, so autistic children may have little idea of what they are doing. All this can be extremely frightening and painful.

To escape this sensory chaos, children and adults with autism focus on physical sensations, such as finger scratching, hand flapping, flicking switches, tearing paper — on sounds such as their own breathing or on a particular DVD. These predictable fixations allow them to exclude those stimuli that overload the brain. In all the chaos, they find coherence: now they do know what they are doing.

This sensory confusion can be bypassed by using their body language to communicate instead of words, an approach introduced by the psychologist, Geraint Ephraim in the 1980s, and eventually named Intensive Interaction. Ephraim was my supervisor for four years and from him I learned to look at what my conversation partner was doing — and particularly, how they were doing it. Are he or she calm or getting upset? I learnt to use his or her activity as a language out of which to build affective and empathetic conversations that tuned in to how he or she was feeling, promoting emotional engagement.

These conversations are based on early infant-mother interactions, in which the infant initiates a sound or movement, the mother responds and, when the infant feels sufficiently confirmed, it moves on to some other sound or movement. We can use this, looking at what physical feedback our partners are giving and responding accordingly. If they are making a sound, I will answer their sound. While not mimicking or copying it, I will use it as part of my response, perhaps varying the tempo, pitch or intonation. If they are tapping, I will tap back with a slightly different rhythm. Or I may tap back the rhythm of a sound on their shoulder. In practice, one can think of Intensive Interaction as being like jazz, where you extemporise on a theme, building variations. There is increasing academic evidence that using body language to communicate promotes eye contact, the desire to move closer and increased social responsiveness.

One of the many problems for people with autism seems to be that they get stuck in the stage of needing a mother or motherfigure’s confirmation before they can move on. By using language familiar to their brains, we shift attention from their inner closed-off world to a source outside themselves — from solitary self-stimulation to shared activity. In the film Autism and Intensive Interaction (see end of article), we see how children whom I have never met before quickly start to be interested in the world outside and interact with people.

To return to the schoolchild Robbie, he is drowning under an avalanche of sensory input that causes him real pain. It is only when he hears sounds that his brain recognises that do not add to his confusion, that he is able to find meaning.

Intensive Interaction is easy to learn. In our infancy we have all of us been involved in it and we can all of us adapt to using it. After watching the film of my methods, the mother of an autistic child threw up her hands and said: “I can go home and do this now!” We learn the language from our partners, we do not need to be experts to get a response: all parents of children with autism need to share her confidence.

Although Intensive Interaction can be used across the non-verbal levels of disability and not just for autism, I have worked particularly with children and adults on the severe end of the autistic spectrum. It is not a cure, but helps to bring calm and the joy of relationship to their lives. Reducing the sensory overload, enables their brains to work more effectively.

Phoebe Caldwell has just been presented with the Times/Sternberg Active Life Award for her pioneering treatment. Applications for the 2010 award will open later in the year.

Phoebe Caldwell’s DVD, Autism and Intensive Interaction is published by Jessica Kingsley Publishers. www.jkp.com