Augmentative and alternative communication design may impact performance

Children and young adults with Down syndrome often face communication challenges when they enter school or other vocational settings. In many cases, an individual's speech may be sufficient for communicating with familiar partners but is not sufficient when communicating with unfamiliar partners in these new settings.  

Many individuals with Down syndrome benefit from using augmentative and alternative communication (AAC) to supplement their existing speech which can be difficult for new communication partners to understand. AAC is any tool or device used to supplement speech such as a picture book, electronic tablet that presents the user with symbols or images, and sometimes text or synthesized voice output. 

One of the most common methods for using AAC is through a reach — pointing to the desired symbol using a finger or stylus. A new study led by Krista Wilkinson, distinguished professor of communication sciences and disorders at Penn State, examined how six individuals with Down syndrome and six individuals without a disability accessed a simulated AAC display, to evaluate how the organization of symbols on AAC displays affected the efficiency and quality of communication. 

 According to previous research, the organization of symbols relative to their color — red apples with red cherries in one corner — consistently positively influenced the speed and accuracy of identifying a target on an AAC display compared to a display that was randomly distributed.  

“Since the means of accessing AAC symbols for many people is the use of a finger point or press, it seemed possible that the non-optimal display might also negatively impact the motor reach used to access the display,” Wilkinson said. “If this was found to be true in our study, then in addition to the cognitive load during the visual search, inefficient motor behavior during reach would add another layer of effort and fatigue for users.” 

The study participants included six individuals with Down syndrome who self-identified as right-handed, and six individuals without disabilities who were matched on gender, hand preference, and age. The researchers used 16 line drawing picture symbols to show participants. Participants were shown a single symbol and were then tasked with identifying that symbol in the full array of 16 symbols.  

The researchers tested scenarios where symbols of the same color were grouped together and scenarios where the symbols were randomly distributed. Their findings showed that when the symbols were randomly distributed, participants took longer to initiate movement, had more reaches across the midline — using the right hand to reach for a symbol on the left side of the display, or vice versa — and had less accuracy in the final position of the movement. The negative effects were observed across all study participants but were larger for those with Down syndrome.  

“The impact of non-optimal AAC design appears to be universal, and this study suggests that it involves not just visual behavior, but motor behavior as well,” Wilkinson said. “Designing optimal AAC should reduce the challenges users face and promote desired outcomes like engagement in educational, social, vocational, and community settings.” 

Originally published in September 2025.