Autism in children may be may soon be diagnosed by health professionals analysing the way in which a child talks.

Scientists have discovered that those affected by autism have a 'unique vocal signature,' which could be used to identify the condition before the traditional symptoms become apparent.

Experts believe a quicker diagnosis would allow parents to organise remedial treatment, which works best if started early. Researchers said they believed autism could be diagnosed as early as 18 months, compared to the current age of diagnosis, which in the United States is 5.7 years.

The new method uses a computer program to analyse recordings of the speech sounds made by young children. Scientists tested the method on 232 children aged between 10 months and four years, who had all been previously diagnosed with autism or language delay. Using the technology, scientists were able to identify those with autism with 86 per cent accuracy.

The research indicated that one of the biggest differences was how a child with autism forms syllables. This usually requires rapid movement of the jaw and tongue, a skill usually learnt in the first months of life, but children with autism were much slower to develop the skill than others of the same age.

Those working in speech and language therapy jobs will be interested to learn that the analysis is based on sound pattern, rather than words - which means the method can be used with young speakers of any language.

Steven Warren, a professor of applied behavioural science at the University of Kansas, told The Independent: "This technology could help paediatricians to screen children for autism spectrum disorders to determine if a referral to a specialist for a full diagnosis is required and get those children into earlier and more effective treatments."