An innovative study conducted by MaryAnn Demchak, Ph.D., BCBA-D, professor of special education, in the College of Education & Human Development and Chevonne Sutter, Ph.D., BCBA-D, research assistant professor and project coordinator of the ÁùºÏ±¦µä Dual Sensory Impairment Project, explores how Constant Time Delay (CTD) can effectively teach sight word recognition to students who are deafblind.
This research sheds light on an instructional method that could help bridge the gap in evidence-based practices for students with dual sensory impairments. Deafblindness, a condition that affects both vision and hearing, presents unique challenges for educators, particularly in the area of literacy instruction.
The study focused on two students, one in elementary school and one in middle school, both of whom experience significant challenges in accessing visual and auditory information. Using CTD, a response-prompting technique that systematically fades prompts to promote independent responses, researchers sought to determine whether it could improve sight word recognition. The results were promising, with both students successfully mastering three different word lists.
The study addresses a critical gap in research surrounding educational practices for students with deafblindness. According to previous research, there is a “dire need” for literacy interventions tailored to this population, as students with dual sensory impairments face compounded difficulties in communication, learning and interaction with their environment. Vision and hearing are our primary senses for learning, and losing both can make traditional observational learning nearly impossible. In some cases, students who are deafblind continue to have some residual vision and hearing that can be used. However, learning is still impacted. This is especially true for students with additional disabilities, as 88% of children who are deafblind have other impairments, which further complicates their educational needs.
CTD, a widely researched response-prompting method, involves systematically delaying the prompt that helps a student achieve the correct response. Initially, the instructor provides a zero-second delay, offering the prompt immediately after the presentation of the target stimulus. Once the student demonstrates understanding with immediate support, the time between the target stimulus and the prompt is gradually increased, allowing the student more opportunities to respond independently. This method has been shown to reduce errors and promote faster learning.
In the study, students practiced recognizing sight words, which are essential for building reading fluency. By developing automatic recognition of these words, students can improve their reading comprehension and overall literacy skills. While previous research has shown that CTD is effective in teaching literacy skills to students with intellectual and developmental disabilities, this study is one of the few that specifically examines its use for students with deafblindness.
The study demonstrated a functional relation between CTD and improved sight word recognition in both students. While the middle school student also had multiple disabilities beyond deafblindness, the CTD method was still effective, suggesting that it can benefit a broader range of learners with complex educational needs.
The study’s results indicate that Constant Time Delay is an effective tool for teaching sight words to students with deafblindness, helping to expand the limited research base on literacy interventions for this population. The success of both participants in this study highlights the potential of CTD to be a valuable instructional method for students facing significant barriers to learning.
For educators working with students who are deafblind, this research underscores the need to continue exploring and implementing evidence-based practices that meet the complex needs of these learners.
