Validation of Autism Screening Questionnaire or Social Communication Questinnaire, Lifetime version to Portuguese language

Background: The rate of pervasive developmental disorders (PDD) have been described as up to 1%. Although studies do not suggest any modification of this prevalence in relation of ethnical differences, there are no studies describing the prevalence of PDD in cultures different from the northern hemisphere. It´s important to have efficient and validated diagnostic instruments in order to know what is this prevalence.

Objectives: translation, retroversion, cultural adaptation and validation of Autism Screening Questionnaire or Social Communication Questinnaire, Lifetime version to Portuguese language for its use in Brasil.

Methods: a sample of  120 patients was divided in three distinct groups of 40 individuals each: PDD clinical diagnosis, Down syndrome and psychiatric diagnosis. The questionnaire was applied to the persons legally responsible for the patients according to the standards of a self-applicable questionnaire. Psychometric measures of the translated questionnaire in his final version were tested.

Results: Sensibility values of 92.9% and specificity of 95.5% were found, considering a cutoff point of 15 points. The internal validity for the total 40 questions was 0.895, with a variation of 0.6 to 0.8. The reliability values obtained from the test and re-test demonstrated high agreement for most of the questions.

Conclusions: The final version of the instrument translated and adapted to the Brazilian culture, presented fully satisfactory measurement properties, proving to be of easy application and a useful tool for the diagnostic screening of PDD individuals.