Time Delay
What is a Time Delay?
Time delay is a teaching method used to help children with Autism Spectrum Disorder (ASD) learn new skills by gradually shifting the control from a prompt to a natural cue or instruction. Initially, the prompt and the instruction are given at the same time, which is called a zero-second (0-s) delay trial. Over time, the delay between the instruction and the prompt is increased, allowing the child more time to respond on their own before the prompt is given. This technique includes two structured methods: Constant Time Delay (CTD) and Progressive Time Delay (PTD). Time delay is helpful because it doesn’t require the child to imitate but focuses on skills like recognizing the prompt, waiting, following directions, and responding to tasks. It also works well because it builds on the child's existing skills and their experience with rewards (Walker, 2008).
Progressive Time Delay (Alzrayer et al., 2020)
Pre-session setup:
The instructor gathers materials needed for teaching the childs how to request preferred items using both low-tech (PECS communication book) and high-tech (iPad-based SGD) AAC systems.
Materials include preferred items identified through a preference assessment, the PECS communication book, and an iPad with the modified PECS Phase IV app installed.
Session set-up:
The instructor introduces the task of requesting items using either the PECS communication book or the iPad-based SGD.
The task involves creating multi-symbol messages (e.g., “I WANT + [preferred item]”) using the AAC systems.
Instructional Procedure:
The instructor presents the child with a choice of preferred items, displayed either on the PECS communication book or on the iPad screen.
The child is prompted to make a request for one of the items.
Prompting:
If the child does not make a request within the predetermined short time delay (initially 0 seconds, later up to 5 seconds), the instructor uses physical prompts (graduated guidance) to guide the child through the sequence of steps required to complete the request using the SGD or PECS.
Progressive Time Delay:
In later sessions, a progressive time delay is implemented where the child is given a set amount of time (e.g., 5 seconds) to make a vocal or SGD request before the instructor provides assistance.
Response:
The child makes a request using either the PECS communication book, the iPad-based SGD, or vocalization.
If the child makes a correct request before the time delay expires, the instructor provides immediate access to the requested item.
Feedback:
The instructor provides positive reinforcement (e.g., verbal praise, access to the requested item) for correct requests made independently or with minimal prompting.
For incorrect responses or lack of response, the instructor uses an error correction procedure: blocking access, modeling the correct response, and repeating the trial.
Increase Delay:
As the child demonstrates proficiency in making requests, the time delay before prompting is gradually increased, encouraging independent request-making.
The task is repeated across multiple trials and sessions to provide the child with numerous opportunities to practice making requests using both AAC modalities.
Monitoring:
The instructor continuously monitors the child’s progress, adjusting the level of prompting and the time delay as necessary to support learning and to encourage independent requesting.
The progressive time delay effectively supports the transition from prompted to independent requesting, allowing the child to practice and master the skills needed to use both low-tech and high-tech AAC systems.
Constant Time Delay (Chavers et al., 2021)
Session setup:
The instructor prepares the SGD and selects a set of preferred and non-preferred activities or snacks.
The instructor introduces the task by asking the child to select an activity or snack using the SGD.
Instructional Procedure:
The instructor administers a multistep requesting probe, asking the child, "What would you like to do?" and waits for the response.
Initial Waiting Period (Constant Time Delay):
The instructor waits for 3 seconds to allow the child to respond independently.
Verbal Prompt (If No Response): If the child does not respond within 3 seconds, the instructor provides a verbal prompt, e.g., "Can you tell me using your device?"
Gestural Prompt (If No Response after Verbal Prompt): If the child still does not respond after another 3 seconds, the instructor provides a gestural prompt by pointing to the SGD.
Physical Guidance (If No Response After Gestural Prompt): If the child does not respond within another 3 seconds, the instructor physically guides the child's hand to activate the correct icon on the SGD.
Reinforcement:
The instructor provides feedback based on the child's response. If the correct icon is activated, positive reinforcement is given (e.g., the preferred item is provided).
Practice and Monitoring:
The task is repeated with different requesting and small talk probes, with continuous monitoring and adjustment of prompts as needed.
References
Alzrayer, N. M. (2020). Transitioning from a low-to high-tech Augmentative and Alternative Communication (AAC) system: effects on augmented and vocal requesting. Augmentative and Alternative Communication, 36(3), 155-165. https://doi.org/10.1080/07434618.2020.1813196
Chavers, T. N., Morris, M., Schlosser, R. W., & Koul, R. (2021). Effects of a systematic augmentative and alternative communication intervention using a speech-generating device on multistep requesting and generic small talk for children with severe autism spectrum disorder. American Journal of Speech-LanguagePathology, 30(6),2476-2491. https://doi.org/10.1044/2021_AJSLP-20-00353
Walker, G. (2008). Constant and progressive time delay procedures for teaching children with autism: A literature review. Journal of Autism and Developmental Disorders, 38, 261-275