The overall goal of this procedure is to provide a home-based method for the assessment of language comprehension in very young, typically developing children as well as those with special needs such as autism. This is accomplished by first making visual and auditory stimuli that are engaging and appropriate for children with short attention spans. The second step is to set up a portable, intermodal, preferential looking paradigm at the child's house.
Play the videos and record the child's face. Next, the film of the child's face is analyzed by a custom coding program and eye movements coded for direction and duration of gaze. The final step is to compare looking patterns during the baseline and test trials.
Changes in looking patterns during the test indicate that the language of the test audio was understood. Ultimately, portable intermodal, preferential looking can be used to show what nonverbal or less verbal children know about specific linguistic constructions and language learning principles. The main advantage of this technique over existing methods, which require children to talk or to point to pictures, is that portable IPL relies on children's eye movements, so what makes fewer demands on the child and so enables us to determine what they really know about language.
The implications of this technique extend towards the designing of therapy or intervention for children with autism because it reveals what the children do or do not know about specific aspects of language, thereby helping service providers design more targeted interventions. Though this method has been used primarily with typically developing children and those with autism, it can also be applied to children with other developmental disorders such as those with specific language impairment. Its portability allows it to be extended to children living in rural areas far from universities or hospitals.
The videos used in this protocol should be designed to be both interesting and attractive, but also non aversive to young children with autism spectrum disorders. Video stimuli can be created using commercial non-linear editing programs such as Final Cut Pro or Avid Media composer using four to eight second movie clips when animated characters are needed. Use animals rather than humans to make the scenes less socially and emotionally challenging for children with a SD, also use dynamic scenes with brightly colored objects to capture and hold attention.
A red blinking light during inter trial intervals will hold the child's attention while video screens are blank. Here the first two clips are arranged sequentially, alternating left and right, paired with the same familiarization or teaching audio. Produce the voice audio using speech that is exaggerated in both intonation and duration.
Look, tuin. See tuin The baseline trials come next. These present the test stimuli side by side, but are paired with non directing audio.
The test trials appear last paired with the test audio that distinguishes the two visuals. Look at Tuin. Where's Tuin?
Finally include a one kilohertz tone on the second audio channel coincident with each trial to provide designation to coders of the onset and offset of trials at the child's home. First, describe the study format in detail to the child's parent and sign the consent forms. Emphasize that the child should watch with minimal interaction with the parent and introduce the MP three player for the parent to use with the child sitting on the parent's lap.
Next, set up the IPL components in the designated room connecting all power sources using extension cords. Set up the big screen with its back to the major light source and place the speaker centered behind the screen. Adjust both volume knobs to halfway.
Place the camera on the tripod atop the tone adapter box centered in front of the screen and load media into the camera. Place the direct to edit device or DTE on the floor next to the camera. Set up the projector.
Stand seven to 10 feet away from the screen. Then place the projector on top. Finally, place the laptop next to the projector stand next, connect all IPL components.
Connect the laptop so that it sends video signal to the projector. Also, make sure that the laptop sends out two audio signals. The voice audio going to the speaker and the tone audio going to the camera.
Connect the camera so that it sends video and audio signal to the DTE. Once connected, power up all components. The DTE screen should show a VI type one on the left and counter below this.
Now load the first video on the laptop using QuickTime. Place a chair or pillow two and a half to three feet from the camera in front of the screen. Then invite the child to sit on the chair or on the parent's lap.
If the child will sit on the parent's lap, give the parent the MP three player and earphones. If the child sits alone, the parent may sit alongside, adjust the lighting in the room as needed. Next, ensure that the child's face is visible in the camcorder and recheck whenever the child moves around.
Write the child's pertinent information on a dry erase whiteboard. Then press record on the DTE and film the whiteboard for 10 seconds. Now, use the laptop to play the first video by clicking view, followed by enter full screen.
Children who become fidgety during the video may be encouraged in general terms to watch the movie. After the video is completed, press the stop button on the DTE once the video has completed. Reward the child for participating with a gift at the end of the visit.
After the session, check that the child's eye movements have been digitized on the DTE. Then import the film into a non-linear editing program. Convert to a BI format used by the custom coding program, and then export to secure storage code each video following its specific layout such as arrangement of familiarization or teaching baseline and test trials Tap through the child's film to find the frames in which the waveform of the one kilohertz tone is visible, indicating that a visual stimulus is being presented to the child.
Then begin coding during the inter trial interval before each target trial when the centering light is presented, tab ahead frame by frame recording each change of gaze as either to the left, to the right, to the center, or away for any other direction. The coding program will output columns of numbers indicating the timing and type of each code entered. For example, CT 3, 3, 4, 9 9 means that at the onset of the trial, 3.3499 seconds from the start of the video, the child looked to the center.
The coding arrays can be analyzed by a custom MATLAB analysis program, which accesses the specific layout of the video being which side is the match for each trial of the video. The analysis programs will then calculate the child's duration and direction of looking during each coded trial, the child's latency to first look at the matching stimulus and the number of times the child's switches attention during each coded trial. Finally, we then compare children's looking during the control or baseline versus test trials for the following duration of gaze to the matching image latency of first look to the matching image time course of looking to both images during the entire trial and the number of switches of attention tension.
An example of looking patterns from children tested using PIPL can be seen here. Viewing the noun bias video, typically developing children at 21 months looked longer at the matching image during test compared with baseline trials indicating they had mapped the novel words onto objects rather than actions. Children with a SD averaging 33 months of age behaved similarly with similar effect sizes.
This figure presents time course analysis of typically developing children, viewing a shape bias video in visits spanning 20 to 32 months. Blue lines indicate looking to the match. Notice that the height of the blue lines during the test trials increases with age showing increasing shape preferences.
Red lines indicate looking away. Notice that at 28 and 32 months, the red line plummets when the videos come on, indicating that the children are looking primarily at the videos rather than away. Here we see time course data for children with a SD averaging 41 months while viewing a syntactic bootstrapping video.
Notice they look longer at the non-matching image during the baseline trials, but then looking as directed more at the matching images during the second half of the test trials when they're asked to find the referent of the novel verb After its development. This technique paved the way for researchers in the field of child development and developmental disorders to explore audiovisual integration and language development. In typical children learning a variety of languages such as Japanese, Turkish, French, and Chinese, and also children with cerebral palsy, or those who have received cochlear implants.
Of course, working with young children, including those with developmental disorders, requires a lot of energy, patience, and sensitivity to their specific needs.
