title: Failure to meet language milestones at two years of age is predictive of specific language impairment.
abstract: OBJECTIVE
  This study established predictive properties of single language milestones for specific language impairment (SLI) after the age of four, as these had not previously been reported in the literature.
  
  
  METHODS
  In this nested case-control study, children attending special needs schools for severe speech and language difficulties were matched with children attending mainstream schools. Data covering the ages of zero to four years were retrieved from well-child care clinics and the outcomes of 23 language milestones in the Dutch Developmental Instrument were analysed. The predictive properties were expressed as positive likelihood ratios, sensitivity and specificity.
  
  
  RESULTS
  We included 253 pairs of children with and without SLI, aged from four to 11 years. The mean age was eight years and three months, and 77% were boys. From the age of 18 months, cases and controls differed significantly on all milestones (p < 0.01). After 24 months, the language milestones had positive likelihood ratios that ranging from 6 to 108. In general, language milestones had a high specificity (range 77-100%), but the sensitivity was relatively low (range 0-68%).
  
  
  CONCLUSIONS
  Failure to meet language milestones from the age of 24 months was predictive of SLI, but the use of separate milestones had limited value due to low sensitivity.
authors.affiliation: Netherlands Organization for Applied Scientific Research TNO, Leiden, The Netherlands.
authors.forename: F Babette
authors.identifier: http://orcid.org/0000-0002-7718-4480
authors.initials: FB
authors.lastname: Diepeveen
authors.affiliation: Netherlands Organization for Applied Scientific Research TNO, Leiden, The Netherlands.|Department of Methodology and Statistics, Institute of Psychology, Leiden University, Leiden, The Netherlands.
authors.forename: Elise
authors.initials: E
authors.lastname: Dusseldorp
authors.affiliation: Department of Linguistics, University of Groningen, Groningen, The Netherlands.
authors.forename: Gerard W
authors.initials: GW
authors.lastname: Bol
authors.affiliation: Willem-Alexander Children's Hospital, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Oudesluys-Murphy
authors.affiliation: Netherlands Organization for Applied Scientific Research TNO, Leiden, The Netherlands.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Verkerk
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007804:Language Development; D007805:Language Development Disorders / Q000175:diagnosis*; D008297:Male; D011446:Prospective Studies
keywords: Developmental language disorder; Language milestones; Predictive properties; Specific language impairment; Validity