[Rett syndrome and autism. Early comparative evaluation for signs of autism using family movies].

Rett's syndrome progresses in 4 stages: the first signs of the disorder appear after a period of 6 to 7 months, during which development is considered to be normal. This asymptomatic period is apparently an essential criterion of the diagnosis, but some parents have reported some prodromes. In stage II of the disease (before 3 years), signs common with autism dominate the clinical picture and the diagnosis of the latter was often formulated. Our working hypothesis is that the pedopsychiatric analysis of home movies of young girls with Rett's syndrome, taken by the parents before the age of 2, may be able to show early clinical signs. The present study involved examining home movies of children subsequently diagnosed as having Rett's syndrome (n = 9) in comparison to those of autistic (n = 9) and normal (n = 9) children, using semiological evaluation tools (IBSE, BFE). The persons scoring were not advised of the diagnosis. The observations were thus situated before the disorders and/or at the time of their appearance. The study confirms the asymptomatic interval between birth and the first signs of the disease, it defines the mode of onset and shows the disturbance of certain functions such as intent and imitation, more pronounced in Rett's syndrome children between 12 and 18 months. At this age, it also enables Rett's and autistic children to be differentiated on the basis of the different involvement of the "cognition" function and unusual posture, more pronounced in these girls. It does not, however, differentiate Rett's from autism between 6 and 12 months and it is thus not surprising that at this stage the diagnosis of rett's syndrome or autism may be a source of confusion.