Accessibility

As part of the Accessibility course taught by Professor Jeff Bigham at Carnegie Mellon, my team collaborated with a client with cerebral palsy (CP) to enhance the usability of her augmentative and alternative communication (AAC) device system. Our goal was to improve communication support for individuals with complex communication needs (CCNs) by addressing both technical and user-experience challenges.

Observational Study

Non-verbal communication plays a vital role in face-to-face interactions, yet AAC devices often struggle to replicate these critical social cues. To address this gap, I helped design an observational study to better understand:

  • The dynamics of face-to-face interactions between AAC users and their caregivers.

  • Strategies caregivers use to support effective communication.

Case Study

Improving Usability of AAC Device for an Individual with CP

The study aimed to uncover ways to incorporate non-verbal social cues into AAC systems, improving engagement and autonomy for users. The findings provided insights for designing assistive technologies and social agents that foster richer communication experiences.

We worked closely with a client with CP to address usability challenges in her AAC device. Individuals with CP often face motor skill deficits, such as limited range of motion and coordination issues, which can hinder their ability to communicate effectively (Pennington, Goldbart, & Marshall, 2004; Koester & Arthanat, 2017). AAC technologies are crucial in bridging this gap, enhancing quality of life for individuals with CCNs.

Design Principles

To guide our design, we conducted extensive research in:

  • Physical therapy techniques.

  • Ergonomic handle design and joystick optimization.

  • Addressing the physical constraints of AAC devices.

Our research included studies on how joystick handle size and gain affect performance and physical load, applying insights to improve device ergonomics and user interaction.

Prototyping Process

Fig. 1: Our initial meeting with our client

Fig. 1: Our initial meeting with our client

Prototyping process: Applying research to solutions

Using the insights from our research and observational study, we developed low-fidelity prototypes to explore:

  • Ergonomic improvements to joystick handles.

  • Interface adjustments for ease of use and reduced physical strain.

  • Strategies for integrating social cues and enhancing non-verbal communication.

These prototypes were iteratively tested with the client, refining the design to better meet her needs and improve her overall experience.

Fig. 2: Initial Prototyping

Fig. 2: Initial Prototyping

Initial brainstorming and solutions

The initial prototypes, 3D modeled in Autodesk Fusion and printed with PLA material, were tested with the client to gather feedback on dimensions, shape, and grip. Early solutions focused on improving comfort and accessibility, including: adding an angled platform as an armrest, repositioning the joystick and buttons for easier access, and relocating the keyboard on the AAC device to minimize the distance for character selection.

User Testing

For the next round of user testing, we used qualitative research methods to evaluate prototype usability, fatigue reduction, and durability. Metrics were assessed through observations and client feedback, including Likert scale ratings for fit, grip, typing fatigue, and overall preference, as well as qualitative questions about size and shape.

The client typed sentences of varying difficulty ("easy," "medium," and "hard") using each prototype, with her original joystick serving as a baseline. After typing, she provided feedback on each prototype’s performance. Testing was structured to minimize fatigue by focusing on one sentence per prototype and collecting detailed feedback after each session. This approach allowed us to compare and refine designs based on both quantitative and qualitative insights.

Fig. 3: Design with client’s measurements from our prototyping session results

Fig. 3: Design with client’s measurements from our prototyping session results

Solution Design

User testing revealed that the client preferred the cylindrical joystick model, rating it highest for fit, least fatigue, and best grip. To enhance durability, we redesigned the final prototype to be solid rather than hollow, ensuring it could withstand her strong grip. Future iterations will incorporate a rubber or silicone coating for added comfort.

This project highlights the critical role of user-centered design in assistive technologies. By addressing physical constraints and improving usability, our work contributes to creating more accessible and empowering solutions for AAC users with complex communication needs.

Our future efforts would aim to scale these insights for broader impact and further refine AAC systems.

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