Our work in Music, Mind, and Health has culminated in a recent PhD thesis, showing the technologies and perspectives required to build on the transformative nature of music to drive specific neurological, physical, and psychological change. A radically new "Personal Instrument" is currently being used by Dan Ellsey, a quadraplegic individual, who controls this interface to sculpt an expressive performance of music in real time. A three-month study of Ellsey's expressive behavior�its potential as well as its limits�resulted in an interface tailored just for him, enabling him to access expressive performance despite his physical disability. This new line of work highlights principles for future instruments and applications, where the impact is in the marriage of the interface and uniqueness of the person. In this way, we are pursuing new design philosophies, technologies, and collaborations within the scientific community, public performance, and clinical research.