title: Subgroups of children with autism by cluster analysis: a longitudinal examination.
abstract: OBJECTIVE
  A hierarchical cluster analysis was conducted using a sample of 138 school-age children with autism. The objective was to examine (1) the characteristics of resulting subgroups, (2) the relationship of these subgroups to subgroups of the same children determined at preschool age, and (3) preschool variables that best predicted school-age functioning.
  
  
  METHODS
  Ninety-five cases were analyzed.
  
  
  RESULTS
  Findings support the presence of 2 subgroups marked by different levels of social, language, and nonverbal ability, with the higher group showing essentially normal cognitive and behavioral scores. The relationship of high- and low-functioning subgroup membership to levels of functioning at preschool age was highly significant.
  
  
  CONCLUSIONS
  School-age functioning was strongly predicted by preschool cognitive functioning but was not strongly predicted by preschool social abnormality or severity of autistic symptoms. The differential outcome of the 2 groups shows that high IQ is necessary but not sufficient for optimal outcome in the presence of severe language impairment.
authors.affiliation: Department of Psychiatry, University of Connecticut Health Center, Farmington 06030-2103, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Stevens
authors.forename: D A
authors.initials: DA
authors.lastname: Fein
authors.forename: M
authors.initials: M
authors.lastname: Dunn
authors.forename: D
authors.initials: D
authors.lastname: Allen
authors.forename: L H
authors.initials: LH
authors.lastname: Waterhouse
authors.forename: C
authors.initials: C
authors.lastname: Feinstein
authors.forename: I
authors.initials: I
authors.lastname: Rapin
mesh_terms: D001321:Autistic Disorder / Q000145:classification* / Q000175:diagnosis / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007360:Intelligence; D008137:Longitudinal Studies; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011594:Psychometrics; D015203:Reproducibility of Results