Parent-implemented language intervention

The study utilized a single-case multiple-probe design across three mother/child dyads (Gast, Lloyd, & Ledford, 2014). In this design, probe data are collected intermittently during baseline in place of the continuous measurement of baseline data. The design requires that baselines for all participants begin at the same point in time and that at least three consecutive baseline sessions be collected prior to the introduction of the intervention for each participant. Following a stable baseline, participants had staggered entry into the intervention phase of the study in which data were collected continuously for 12 weeks. Further, staggered entry into the intervention phase was determined based on a set number of days (Gast et al., 2013), with each dyad entering the intervention phase after the previous dyad completed 3 weeks of intervention. Thus, Dyads 1, 2, and 3 completed 5, 7, and 9 baseline sessions, respectively. At the conclusion of baseline, each mother was individually presented with 2 hours of parent training consisting of a PowerPoint™ presentation, with embedded video clips that provided examples of the targeted intervention strategies. The clinician guided the mother through the PowerPoint™ presentation via Skype™. During these parent education sessions, the clinician and mother discussed each strategy in detail and addressed any questions the mother may have had.

A speech-language pathologist served as the primary interventionist. The intervention phase of the study consisted of four types of weekly sessions: (1) coaching, (2) homework, (3) parent–clinician feedback, and (4) data collection. Coaching sessions lasted for approximately one hour during which mothers received in-vivo guidance and feedback from the clinician as they used the targeted intervention strategies while interacting with their child. Guidance and feedback provided by the clinician to the mother consisted of models (i.e., the clinician providing an example of how to use a strategy, such as “What is Duck wearing?”) and prompts (i.e., the clinician telling the mom to use a strategy without providing a specific example, such as “Let’s try asking a question”). Further, the clinician would provide general feedback to the mother (such as prompting her to turn the page) or to reinforce the mother’s spontaneous use of strategies. Lastly, the clinician would provide guidance to the mothers on how to manage challenging behaviors as they arose. Mothers received this feedback in real time via a Bluetooth earpiece. To track fidelity of treatment implementation during coaching, a trained observer reviewed each coaching session and coded the frequency of clinician coaching behaviors across each strategy, as well as the parent’s response to the clinician and their spontaneous use of the intervention strategies (see Table 2).

Average frequency and percent agreement for clinician coaching behaviors and parent response to coaching across dyads.

Following each coaching session, dyads were asked to independently engage in the story-telling activity once again using the strategies practiced during coaching. This session was called the homework session and lasted approximately 15 minutes. The homework session was independently recorded by the mother on the laptop using Photo Booth™ software and transmitted to study staff via cloud-based data sharing software (Dropbox™). The mothers were not given instructions regarding the duration of the homework interaction, only that they should repeat the same book used during coaching and practice using strategies that were coached by the clinician. Upon receipt of the homework session, the clinician reviewed the video and then provided additional guidance to each parent during a distance-based feedback session. During this feedback session, the clinician would review video clips from the homework with the mother, highlighting aspects of the session that showed proficiency in strategy use and also highlighting areas for improvement. This session lasted for approximately one hour and did not involve the child.

The final weekly session was a data collection session during which the parent and child again completed the shared story-telling activity. Data collection sessions lasted for approximately 15 minutes. The clinician observed and recorded this session, but did not provide feedback.

The four session types (coaching, homework, feedback, and data collection) were repeated weekly for 12 weeks and a new book was used each week.

The expressive language sampling procedures were again administered after the completion of the intervention to provide post-intervention measures of generalization. At two months’ post-intervention, dyads completed three follow-up data collection sessions as a measure of intervention maintenance. These sessions consisted of a shared book-reading interaction between the mother and child using a previously unseen set of wordless books. Parent and child outcome variables were averaged across the three novel wordless books.

The context for the intervention was a shared story-telling interaction between the child and mother using wordless picture books that had been digitized and loaded onto the family iPad. Written text was removed from all of the stories and page length was edited such that each book ranged from 14 to 16 pages. Books were selected based on developmental appropriateness and story structure. Stories were organized into sets of three books based on a common character or theme to increase repetition and familiarity for the child. Mothers were sent story descriptions for nine book sets and were instructed to select four sets of books for use during the intervention sessions (see Table 3). The selected book sets were used during baseline and intervention sessions. For baseline sessions, mothers were instructed to complete the book sharing activity with their child, interacting as they usually would, using 1 of the 12 study books of their choosing. A different book was selected for each baseline session. During the intervention phase, mothers would put three book icons on a choice strip and have the child select which book they would like to read. Mothers were instructed to complete two of the three books from a given set before moving onto the next book set. Upon completing two books from each set (i.e., after eight sessions), the mothers were instructed to put the remaining four books (one from each set) on a choice strip such that their child could select one book from these four books prior to the remaining four coaching sessions. A script was provided as a guide for each book and could be used during coaching, homework, and data collection sessions. Scripts were not used during baselines or follow-up sessions. A set of three novel books was used during the two-month follow-up assessment and the same three books were used by all dyads. Mothers were instructed to put the icons for the final three books on a choice strip from which the child selected when doing the follow-up questions, but each book was only used once.

Wordless picture books used for shared story-telling.

Mothers received training on four language facilitation strategies that were designed to (a) increase the amount of verbally responsive language they provided to their children during the shared story-telling interactions and (b) prompt the child to verbally or gesturally participate in the story-telling interaction. The four language facilitation strategies were.

Mothers were encouraged to use verbal language to describe the important details and sequence of the story. The goal of story-related talking was to provide models of nouns, verbs, adjectives, adverbs, and function words to the child in addition to models of more advanced grammatical constructions. Mothers were given a written script for each story to provide them with some ideas about the kinds of language they could use while telling the story. Mothers were encouraged to go beyond the script and use their own ideas while interacting with their child.

Mothers were encouraged to add new semantic or grammatical information to the story-telling interaction in a way that was contingent upon child comments about the story; for example, if the child said “castle,” the mom could expand this utterance by saying “Pete built a sand castle.” The goal of expansions was to provide models of vocabulary and grammar that related to the core meaning of the child’s immediately preceding utterance.

Mothers were encouraged to ask their child open-ended questions that related to the content/topic of story, for example, “What are duck and sheep doing?” This strategy was important for prompting the child to use on-topic utterances that related to the story content and to assess comprehension of important story details.

The mothers were taught to provide the beginning of an utterance and use expectant waiting to prompt the child to complete the utterance by using a word or words they might not be able to use independently, for example, “Charlie’s new friend is a ——.”