Abstract
The purpose of this investigation was to evaluate the efficacy of expansion points
(EXP) intervention with a modified criterion for preschool children with speech sound
disorders (SSD). Three preschool-aged children were enrolled in a single-subject multiple
baseline intervention study. Intervention took place over 16 sessions. Pre- and post-intervention
data are provided. Three outcome measures (generalization to probe words and gains
in percent consonants correct, PCC, in words and in conversation) were evaluated to
measure the effectiveness of the EXP intervention. All three of the participants demonstrated
gains by the end of the intervention phase when measuring PCC in single words. Two
of the three participants demonstrated gains in PCC in conversational speech. Progress
on individual phonemes was variable across participants. Utilizing the EXP approach,
two of the three children showed gains in all three outcome measures. One child showed
variable performance in one outcome measure, improvement in one, and a decrease in
one. Findings suggest that EXP should be further explored to evaluate intervention
efficacy.
Keywords
speech sound disorders - preschool - expansion points intervention - single subject
research design
