The term “iso principle” is unique to the field of music therapy. It was first introduced in the late 1940’s by Altshuler as a method of mood management in which the music therapist provides music that matches their client’s mood, then gradually changes the music to help the client shift to a different mood. While Altshuler’ original “iso principle” method involved a system of programmed classical music, the term has a much broader scope now. In its most basic sense, the iso principle means meeting your clients wherever they are at that current moment. If a music therapist is working with a hospice patient who is in a depressive state,…