C-BiLLT: Computer-Based Instrument for Low Motor Language Testing

The C-BiLLT is a psychometrically sound language comprehension assessment designed for children who are unintelligible or non-speaking due to motor impairment — most commonly cerebral palsy (CP). Items are presented orally by a test administrator and displayed visually on a computer, requiring minimal to no motor response from the child.

What makes the C-BiLLT unique is its flexibility. Children can respond using whatever alternative access method best suits their individual needs — eye gaze, switches, scanning, or other supports — allowing even children with the most severe motor impairments to respond reliably and unambiguously. The result is a rigorous, fair assessment of spoken language comprehension that doesn’t let a child’s physical limitations get in the way of what they know.

Integrating the C-BiLLT into The Bridge School’s practice.

A Bridge School speech-language pathologists discovered the C-BiLLT through a research article and reached out to its developer, Johanna Geytenbeek, in Fall 2021. Subsequently, our SLP team completed formal training and began using the assessment at The Bridge School in 2022. The results have been encouraging and the information gathered has improved our communication intervention plans.

Adapting the C-BiLLT for Students with Cortical Visual Impairment

Through our work with students, we identified a need for greater visual accommodation to support those with Cortical Visual Impairment (CVI). This feedback was shared with the development team and we have been working with them on adjustments to the assessment’s images and display settings to better serve individuals with visual impairments.

Developing a U.S. English Version

Currently, we are collaborating with Texas Children’s Hospital on a formal U.S. English version of the assessment. This collaboration has involved a careful review of the language and images used in the European version of the C-BiLLT to ensure they are appropriate and meaningful for children in the United States.

Updates include:

• Language revisions — Some concepts and phrasing have been adapted or retranslated for clarity and cultural relevance in American English.
• Image updates — We surveyed typically developing children across the U.S. to identify images that are more culturally representative and familiar.

These updates are being finalized by the development team and will be used in the norming study.

American English C-BiLLT Timeline

If you would like to participate in the norming study email mlseymo3@texaschildrens.org and Sruthi.Thomas@bcm.edu.