Using fixed interval-based prompting to increase a student’s initiation of the picture exchange communication system.

This report describes an AB case study in which a fixed interval-based prompting procedure was used to support a child’s spontaneous approach to a Picture Exchange Communication System (PECS) book for selecting icons to request preferred items. The participant was a 6-year-old student with autism spectrum disorder. Preferred items were determined through formal preference assessments prior to the onset of the study. Performance was monitored based on the percentage of spontaneous approaching and requesting behaviors emitted during 10-min intervals throughout each day. Results revealed an increase in requesting of preferred items from a mean of 12% during baseline to 43% during intervention and 83% at a 6-month follow-up.