title: Diagnosis of severe developmental disorders in children under three years of age.
abstract: BACKGROUND
  Autism, intellectual disability, and specific language impairment (SLI) constitute three important forms of developmental disability that are often mistaken for each other, especially in very young children (under age 4). Diagnostic problems are caused by the fact that a fundamental problem in cognition, language, or behavior has secondary effects on the remaining areas, which makes it difficult to separate cause from effect. A wrong or absent diagnosis can be a major hindrance in providing properly targeted therapy for developmentally disabled children.
  
  
  METHODS
  From a population of 667 children referred to a specialized outpatient clinic for developmentally disabled children, we identified 35 children in whom the fundamental diagnosis of autism, intellectual disability, or SLI was unambiguous, and then analyzed these children's scores on 7 subtests from the Munich Functional Developmental Diagnosis, in order to identify specific features of each of the three syndromes.
  
  
  RESULTS
  The most reliable differentiating factor in our research group proved to be the MFDD subtest for self-reliance. A model was constructed to assist in analyzing the complex interactions of symptoms, which frequently overlap.
  
  
  CONCLUSIONS
  Cognitive and communicative limitations resulting from underlying perceptual dysfunctions can lead to inappropriate adaptive behavior in children with developmental disorders, such as autism, intellectual disability, and specific language impairment. Each of these syndromes has a specific profile in respect to measures of cognitive function, social skills, and verbal communication.
authors.affiliation: Department of Developmental Psychology and Neurolinguistics, Maria Curie-Skłodowska University, Lublin, Poland. k.markiew@wp.pl
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Markiewicz
authors.forename: Maria
authors.initials: M
authors.lastname: Pachalska
mesh_terms: D000367:Age Factors; D000554:Ambulatory Care Facilities; D001321:Autistic Disorder / Q000175:diagnosis; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis*; D002675:Child, Preschool; D003072:Cognition Disorders / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D007805:Language Development Disorders / Q000175:diagnosis; D008297:Male; D011044:Poland