[The Marburg Rating Scale for Asperger's Syndrome (MBAS)--a screening instrument for high-functioning autistic...

Asperger's Syndrome is a disorder of uncertain nosological validity, which is difficult to differentiate from high-functioning autism. Even today these disorders are unfortunately diagnosed very late, often in the wake of earlier, different diagnoses. The purpose of this study is to present a screening instrument (MBAS), which is sensitive to these disorders.

The instrument was tested among a total of 91 probands (44 of whom had been diagnosed as autistic, and 47 of whom had been diagnosed with a non-autistic disorder).

The items on the MBAS were of average difficulty; generally, the all item-total correlation was good. The total scale has an internal consistency of Cronbach's alpha = .91 and the convergent validity of the MBAS and the ADI-R reached r = .61 (p = .001). The total score of the questionnaire discriminated highly significantly between the group with autism and that without. At a sensitivity of 95.5% and a specificity of 95.7% the number of misclassifications is low. False negative classifications occurred only in the case of very young children.

The MBAS is a reliable and valid instrument for screening and generating tentative diagnoses of high-functioning autism. The questionnaire is well suited for the selection and generation of tentative diagnoses of autism on a high-functioning level.