Determining Optimal Treatment Intensity for Children With Language Impairment

The purpose of this study is to determine the amount of speech-language intervention children with language impairment need to make vocabulary gains. The investigators hope to identify the optimal amount of intervention needed as well as the point at which adding more intervention is no longer beneficial. Participants will be randomly assigned (like a flip of a coin) to attend therapy either one time a week for 10 weeks (2 hours a session) or 4 times a week for 10 weeks (30 min per session). Each therapy session will follow a word learning intervention that is designed to increase children's word learning abilities using rich, robust word learning strategies within story book readings. The optimal amount of intervention relates to duration, dose, and frequency. Duration refers to how long the child is seen for (e.g., 10 weeks, 1 year). Dose represents the number of exposures to each new vocabulary word within a therapy session. Frequency represents the number of therapy sessions per week. The investigators will test the hypothesis that distributed learning leads to higher gains. The investigators propose that the greatest gains will be observed for children who receive high-frequency/low-dose or low-frequency/high-dose treatments as compared to children who receive high-frequency/high-dose or low-frequency/low-dose treatments. The investigators will test the hypothesis that for both low-frequency and high-frequency treatments, there is a point at which increases in treatment dose do not correspond to any additional gains in children's vocabulary skills during treatment. At the close of this four-year study, evidence concerning optimal treatment intensity of a word learning intervention will be instrumental for immediately informing speech-language pathologists in how much vocabulary treatment to prescribe as well as for designing additional clinical trials by our and other research teams.