In healthcare settings, medical professionals' nonverbal behavior impacts patients' satisfaction and long-term physical, cognitive, and emotional well-being. The purpose of this research was to determine the effects of a music therapist's nonverbal behavior, affect and proximity, on participation and affect of 38 individuals with Alzheimer's disease and other related dementia (ADRD) during movement-to-music, singing, and instrument playing. Data indicated 62% of the individuals evinced positive affect when the therapist utilized affect and proximity combined, followed by the affect only condition (53%), proximity only condition (30%), and no affect or proximity condition (28%). A Friedman analysis indicated a significant difference in individuals' affect according to treatment conditions, chi(2)(r) (3, 4) = 34.05, p = .001. Nonverbal behavior also impacted individuals' accuracy of participation, with participation at 79% for both affect and proximity combined, 75% for affect only, 71% for no affect or proximity, and 70% for proximity only. A significant difference occurred for participation by treatment conditions, F (3, 111) = 4.05, p = .009, eta(2) = .10. Clinical implications are discussed.