■ Diagnostic issues in young children and infants with autism
The average age of diagnosis of autism is 6 years [14,21]. Earlier diagnosis is preferable because children begin-ning intervention between the ages of 2 and 4 years are more likely to achieve developmental progress [20].
The diagnosis of autism in a young child is challeng-ing as their symptoms may be more restricted in com-parison to an older child [5,29].The levels oflanguage and cognitive maturity necessary to identify whether particular symptoms ofautism are present may be lack-ing in younger children. Consequently, not all criteria may be able to be assessed in very young children [10, 29,35].Nevertheless,there is evidence that a stable and reliable diagnosis ofautism can be made in children aged less than 3 years,although the expression of repet-itive behaviour is highly variable [31].