From Autistic characters wiki

Director Michael Bergmann is father to Daniel Bergmann, an nonspeaking autistic man who learned to communicate with a letter board. Daniel was taught with the rapid prompting method (RPM), by RPM's founder Soma Mukhopadhyay.[1] Daniel is also credited as a technical advisor for Influence.

RPM and related methods like Spelling to Communicate are considered to lack scientific validity by many professional organizations such as the American Speech-Language-Hearing Association[2] and the American Association on Intellectual and Developmental Disabilities.[3] This because there is insufficient evidence that the messages produced via these methods originate from the disabled person, and not from the facilitator.