Failure to meet language milestones at two years of age is predictive of specific language impairment.

AIM 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%). CONCLUSION 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.