title: [Psychometric properties of the Autism-Checklist (ACL) in adults with intellectual disability].
abstract: OBJECTIVE
  To determine the validity of the Autism-Checklist (ACL) in adults with intellectual disability (ID) who are suspected of having autism spectrum disorder.
  
  
  METHODS
  In 154 adults with ID the results of the ACL were compared to the results of the final diagnostic classification obtained by a multiprofessional case conference for autism. Psychometric properties of the ACL were evaluated.
  
  
  RESULTS
  The internal consistency as indicated by Cronbach's alpha was 0.81. The ACL sum score highly correlated with established screening measures such as the Social Communication Questionnaire (SCQ: Spearman's rho = 0.620) and the Pervasive Developmental Disorder in Mental Retardation Scale (PDD-MRS: Spearman's rho = 0.490). ROC Analysis revealed an area under the curve of 0.859. The ACL classification complied with the final diagnostic classification in 80.5 % and Cohen's kappa revealed a moderate agreement of 0.596. Sensitivity/specificity of the ACL were 90.7 %/67.6 %, respectively. Interrater-intertime reliability was good (Cohen's kappa = 0.702; Spearman = 0.549; n = 53). In 19 patients (22 %) a diagnosis of ASD had been given prior to referral.
  
  
  CONCLUSIONS
  The ACL is a suitable measure for adults with ID and suspicion of autism spectrum disorders.
authors.affiliation: Abteilung für Psychiatrie, Psychotherapie und Psychosomatik, Evangelisches Krankenhaus Königin Elisabeth Herzberge, Berlin.
authors.forename: Tanja
authors.initials: T
authors.lastname: Sappok
authors.affiliation: Abteilung für Psychiatrie, Psychotherapie und Psychosomatik, Evangelisches Krankenhaus Königin Elisabeth Herzberge, Berlin.
authors.forename: Manuel
authors.initials: M
authors.lastname: Heinrich
authors.affiliation: Abteilung für Psychiatrie, Psychotherapie und Psychosomatik, Evangelisches Krankenhaus Königin Elisabeth Herzberge, Berlin.
authors.forename: Albert
authors.initials: A
authors.lastname: Diefenbacher
mesh_terms: D000328:Adult; D057189:Checklist / Q000706:statistics & numerical data*; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis* / Q000523:psychology; D015897:Comorbidity; D003299:Cooperative Behavior; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis* / Q000523:psychology; D033183:Interdisciplinary Communication; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012189:Retrospective Studies