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VIDBE-Q Volume 64 Issue 2
have very little information on successful students who are dual-media
learners. Literacy is of the utmost importance and one of the major
educational goals is to establish literacy for all students, so it is imperative
that we correctly identify a student's best reading and writing media,
regardless of whether it is single media, just braille or print, or dual-media.
Constant Time Delay: An Effective Literacy Intervention
Given the imperative need for literacy instruction, evidence-based
interventions are needed and one great example of a solid literacy
intervention for students with visual impairments, and especially dual-media
learners, is constant time delay, or CTD. A research study was conducted
at Vanderbilt University to increase the percentage of correctly-identified
braille contractions through three demonstrations of effect and across four
participants; essentially, the research team used CTD to teach the braille
contractions to the students, and it was proven effective for all four
students, all of whom were dual-media learners making the transition from
print to braille (see Figures 1 and 2 for examples of the data from the
study). This research builds upon previous studies conducted by Hooper,
Ivy, and Hatton (2014), Ivy, Guerra, and Hatton (2017), Ivy and Hooper
(2015), and Wilcox (2014). All of these were studies that examined the
