The live music intervention was presented in the activities room of each senior center and included a classical violin for the performer (a classically trained violinist with experience arranging and playing pop music), a second violin for participant engagement, and a computer speaker for digital sound output (Dell, Inc.). The live music intervention sessions included multiple active engagement components, such as music adjustment (e.g., lowering the tempo, changing to an upbeat piece) to match participants' apparent mood, verbal interaction, physical engagement (e.g., encouraging dancing, on-beat clapping), and singing along.

The virtual intervention followed identical procedures as the live intervention and involved similar active engagement components, with the music being delivered to the same cohort via video conference (Zoom Communications, Inc.).

The live music intervention was presented in the activities room of each senior center and included a classical violin for the performer (a classically trained violinist with experience arranging and playing pop music), a second violin for participant engagement, and a computer speaker for digital sound output (Dell, Inc.). The live music intervention sessions included multiple active engagement components, such as music adjustment (e.g., lowering the tempo, changing to an upbeat piece) to match participants' apparent mood, verbal interaction, physical engagement (e.g., encouraging dancing, on-beat clapping), and singing along.

The self-reported stress survey was adapted and modified from Levenstein et al. (1993), with question wording modified to reduce the reading level. The stress-assessment survey was condensed to a total of 10 questions, each rated on a 4-level Likert scale from strongly disagree (0) to strongly agree (3). To maintain consistency, the rating on 4 items indicating lack of stress was reversed, so that 0 corresponded to 3 points. The total score was calculated by adding the individual scores for each question (score range, 0 to 30, where a higher rating corresponds to greater stress).

Registered nurses at each assisted living facility measured and recorded each participant's heart rate (HR) using an oxygen saturation monitor (Oxiline, Inc.). The monitor was placed on each participants' finger and the heart rate was recorded for a 1-minute interval 15 minutes before and after each music-based session.

Systolic blood pressure was measured using a sphygmomanometer (Curaplex, Inc.) immediately after the heart rate measurement