The study took place at the preschool located in the Experimental Education Unit of the University of Washington.
The study began with 55 four- to six-year-old developmentally delayed preschool children. Five children were removed from the study due to high pretest scores or autism, and three children left the preschool, leaving a sample of 47 children. Of these children, 80% had significant language delays and some had additional disabilities (e.g., physical disabilities, mental retardation, or behavior disorders). Children were blocked by mean age and cognitive ability and then randomly assigned to one of four groups: blending, segmenting, rhyming, or a no-treatment comparison.
Results for the 22 children who had been randomly assigned to the blending or the comparison conditions are included in this report.
The blending intervention group participated in blending training that took place in two phases. Phase one of the training lasted three weeks, and phase two lasted four weeks. During phase one, the children focused on learning one specific blending task (e.g., blend two to three phonemes when presented as continuous sounds). During phase two, the children reviewed the task
learned in phase one and learned about other blending tasks (e.g., blend words with separated sounds and blend onset-rime). The children were taught in groups of three to five and met for 10
minutes four times a week. Results for phase two are not included in this report because the effects of the second condition cannot be separated from the effects of the first condition.
Comparison group children participated in routine preschool activities, such as listening to stories read by their teachers or “circle time” oral language activities. Additionally, the researcher met
twice with each child in the comparison group during phase two training to practice isolated sounds used in training.
The primary outcome domain was children’s phonological processing. Nine nonstandardized subtests measured phonological processing skills. There were three blending subtests, three segmenting subtests, and three rhyming subtests. The study also administered a phonological mastery test to the intervention group children to assess how well they learned tasks in the intervention they received, but it is not included in this review because the test was not administered to the comparison group children and was not considered in the impact analyses. (See Appendix A2.2 for more detailed descriptions of outcome measures.)
Support for implementation
Three graduate students with teaching experience provided instruction. The instructors met with the researcher each Monday to practice teaching formats for the week. Instructors were observed
during their sessions and received additional training as needed. Instructors alternated teaching the conditions described in O’Connor et al. (1993a, b, c).