A test to detect autism early in a child's life is on the anvil, say scientists who claim that signs of the disorder can be identified in babies as young as six months, by measuring their brain activity.

A team, led by Prof Mark Johnson of Birkbeck College, University of London, says that the breakthrough may pave the way for "coaxing" the brain of a child to develop in different ways to counter problems caused by the condition.

It would also allow parents to alter the way they raise their children sooner, say the scientists.

In their research, the scientists analysed patterns of brain activity in 54 "at risk" children, all aged between six to 10 months and with a sibling affected by the disorder, as well as 50 infants whose older siblings were not affected, the 'Daily Mail' reported.

The team placed sensors placed on the scalps of the children to measure brain activity via electrical signals as they were shown faces that switched from looking at them or away from them.

The intensity of the electrical activity in certain areas was diminished in children at risk of autism. This suggested they were already registering unusual patterns of eye contact and social interaction.

The scientists found that 17 children in the "at risk" group were diagnosed with autism at the age of three.

Prof Johnson said: "Our findings demonstrate, for the first time, that direct measures of brain functioning during the first year of life associate with a later diagnosis of autism, well before behavioural symptoms.

"Differences in the use of eye gaze to regulate social interaction are a well-recognised early feature in many children with autism from the second year of life. At present, it is these that will alert parents and professionals."

He added: "The brain's plastic at an early age, it should be easier to coax different pathways into doing something that leads to children having the kind of social interactions which come more naturally to other people."

However, the scientists said that further research was needed to refine the testing. "It would also be important to assess why some children at high risk who showed early signs of unusual responses did not develop autism," Prof Johnson said.