Learn more about the ORCA measure

This week we are highlighting two newly published, FAST-funded publications on the Observer-Reported Communication Ability (ORCA) measure for individuals living with Angelman syndrome. Communication is essential to daily functioning and has been identified by caregivers as a top priority to focus on for treatment efficacy in clinical trials.

Given that many individuals living with AS do not generally speak any words vocally, but have many other ways of communicating, including gestures, word approximations, and using symbol systems, or an AAC system, it is difficult to capture their true communication ability through standardized measures. Nearly all existing measures do not take into account all of the ways individuals with AS communicate, and we all know that this is most appreciated by those that know them best, their caregiver(s). In recognizing this limitation, Drs. Bryce Reeve and Christina Zigler at Duke University, were tasked by FAST to design and validate a new communication tool that is tailored specifically for the AS community called the Observer-Reported Communication Ability (ORCA) measure. This outcome measure, or tool that is designed to measure change in a clinical trial, was funded by FAST after some guidance by individuals at the FDA.  Members of the FAST team were very involved in its development to ensure this tool was reflective of the communication abilities of all individuals living with Angelman syndrome.  

The ORCA is a caregiver-reported measure dividing communication into 3 main concepts: expressive, receptive and pragmatic communication. The ORCA team defines expressive communication as interactions where the individual living with AS is communicating something to their communication partner, receptive communication as the process of understanding a message expressed by a communication partner, and pragmatic communication as appropriate communication in social settings. The team first interviewed 22 caregivers of AS individuals of all genotypes to understand the types of communication functions observed. Within expressive communication functions such as requesting objects, places, or entertainment were common. Individuals living with AS were also able to seek attention from caregivers, request more of something, and refuse items. Caregivers reported that individuals with AS could comment, defined as remarks expressing opinions or reactions, with simple behaviors like laughing or smiling to express happiness or excitement and low-pitched vocalizations when they were unhappy. Functions such as responding to names, yes/no questions, and directions were observed within the receptive communication category. Additionally, AS individuals were able to make choices such as picking a food preference and understanding isolated words indicated by response to familiar names and food. Finally, in terms of pragmatic communication, individuals living with AS were reported to have strengths including greetings, comfortability, and recognition of familiar games. To conclude the initial interview, the ORCA team asked what meaningful change in communication meant to each caregiver. Responses included having a more complex communication ability, initiating communication, and the ability to more easily communicate with individuals outside of their immediate family.

From this first study of caretaker interviews, the team at Duke then drafted a preliminary version of the ORCA and tested it with additional caregivers. It was important to ensure that this measure was able to capture the communication abilities of all individuals with AS. Responses to the ORCA transitioned into “No, only once”, “Sometimes”, and “Yes, almost all the time” to indicate skills development and mastery. From these changes the team at Duke was able to create a finalized version of the ORCA measure that they then tested in 249 families of kids with all genotypes ranging in age from 2 to 39 years. From the data collected in this study, they observed that the ORCA was sensitive enough to measure nuanced AS communication abilities in all individuals tested, and no individual fell off the bell curve, as they do in most other standardized tests of communication abilities. This was a very exciting finding.  This measure is now being utilized in all of the active clinical trials for Angelman syndrome, as the first endpoint or outcome measure developed specifically for Angelman syndrome. In addition, since this project started, the FDA gave this same team at Duke a grant for over $2M to continue to develop the ORCA for 13 additional neurodevelopmental disorders, like Angelman syndrome, because it was clear that this was a large gap in standardized assessments that are being used in clinical trials for all neurodevelopmental disorders, and this was a really promising tool to fill that gap for Angelman syndrome and beyond.