Objective: To compare risk of written language disorder (WLD) in children with and without speech-language impairment (S/LI) from a population-based cohort.
Methods: Subjects included all children born between 1976 and 1982 in Rochester, Minnesota, who remained in the community after age 5 years (n = 5718). Records from public and private schools, medical agencies, and tutoring services were abstracted. S/LI was determined based on eligibility criteria for an individualized education plan. Incident cases of WLD were identified by research criteria using regression-based discrepancy, non–regression-based discrepancy, and low-achievement formulas applied to cognitive and academic achievement tests. Incidence of WLD (with or without reading disorder [RD]) was compared between children with and without S/LI. Associations were summarized using hazard ratios.
Results: Cumulative incidence of WLD by age 19 years was significantly higher in children with S/LI than in children without S/LI. The magnitude of association between S/LI and WLD with RD was significantly higher for girls than for boys. This was not true for the association between S/LI and WLD without RD.
Conclusions: Risk for WLD is significantly increased among children with S/LI compared with children without S/LI based on this population-based cohort. Early identification and intervention for children at risk for WLD could potentially influence academic outcomes.