In the EME project we worked with a quadraplegic individual with severe cerebral palsy to develop the hardware and software necessary for an individual with extremely limited movement to fully interpret�as a soloist in a live performance�his own music composed in Hyperscore. Our technological development has incorporated an adaptive input device and accompanying software to allow the user�s symptomatic movement to provide sufficient accuracy, precision, and expressivity for the demands of a performance. By working with the subject as a collaborator, we have designed an interface that not only meets his very specific physical needs, but also unveils novel insights into the design of expressive interfaces that can be customized and personalized for any user.