[Music therapy single case research--a qualitative approach].

A qualitative approach for describing music psychotherapy treatment is developed. For this purpose we employ the methodological principle of triangulation of perspectives (patient, therapist, independent observers, composers). Our approach is based on the concept of the resonator function describing the perceptive capacity of all participants for effective and relationship-referred significance of the work produced during the treatment. The qualitative method importing and extending the knowledge of the inner context of the case is illustrated by two musical improvisations from the treatment of a female patient suffering from chronic migraine.