Expressive vocabulary intervention for four 2- to 3-year-old children with cerebral palsy and speech/language difficulties: A single-case A-B study

To evaluate a parent-delivered expressive vocabulary intervention using focused stimulation for young children with cerebral palsy (CP). A single case A-B design was used. Use of expressive target words was evaluated during the baseline (A) and intervention (B) phases. Untrained expressive words were used as control behaviour. Four 2- to 3-year-old boys with CP and their parents participated. All participants had an expressive vocabulary of less than 50 words at study intake. Following training, parents delivered the intervention daily at home for 5 weeks. Generalisation of the intervention was measured with a parent-rated vocabulary checklist. Two participants showed clear gains and one participant showed a smaller gain in target words. Two of these three participants did not improve on control words, but one participant increased his use of both target and control words. One participant did not increase his use of either control or target words. All participants improved on parent-reported expressive vocabulary, and for two children, improvements were large. Parent-delivered focused stimulation may lead to gains in expressive vocabulary in children with CP and speech and language difficulties. The intervention would be suitable for larger single-case studies with more experimental control.