Table 1. Initial examples of categories and behavioural expressions of engagement.

	Category	Definition	Behaviour expression of engagement	Examples of the feedback (s)	No. of participants commenting on the categories
1	Facial expression	Noticeable changes on the PWD’s face during the intervention	Mouth and lip movement	“mouth moving, mumbling the song”	2
			Eyebrows movement (e.g. closed their eyes or raise their eyebrow)	“The person’s eyebrows were raising when the music was playing”	1
			Facial changes (e.g. neutral look, smile)	“I can see that the person (PWD) face looked different … like she was smiling) “The person face looked very neutral without much facial expression, but you can feel that she was enjoying the music, as if she was thinking about it.”	6
2	Bodily movement and verbal articulations	Large or small bodily movements and response during the intervention	Large and subtitle bodily movement (e.g. hands and feet taping, nodding, clapping, moving with music)	“Hand clapping and feet tapping” “There was one person who tapped his hands on his lap”	6
			Verbally responding (e.g. singing, talking, mouth mumbling)	“One of the elderly was moving her mouth.”	2
			Interacting with instruments (touching the instrument, playing with the instruments, making music)	“Hitting the African drum and the hand drum” “Playing with the drum stick”	3
3	Attention and awareness of activity	Being focus and attend to a stimulate that is in context with the intervention	Attention to stimulus (musician, other participants) undistracted eye contact	“there’s a lot of duplication. Because when they would said to you, “okay, this man has been accepted, could you please do a referral”, and we are all using information on the same system. So we end up doing the same thing again” “We’re having these discussions with psychology in the pod meeting they’re quite often quite like in-depth, which is great, but then if they’re accepted there and then in the meeting for psychology, the clinician, like the care coordinator then has to go away and type out the conversation. But we’ve already had the conversation with psychology, so could the referral not just be accepted there and then, without the paper part being done?”	4
			Playing an instrument	“Playing and focusing on the instruments in front of her”
			Moving along with music	“Her feet was tapping (along with the music)”
4	Emotional response	Participant’s “positive” and “negative” emotions in relations to the intervention	Pleasure and enjoyment	“I don’t really know what’s going on down here”	4
			At ease look (looks as if s/he was relaxed)	“She closed her eyes, but it looks like she was enjoying the music.” “Looking up but thinking about things but she seemed relaxed”	2
			Sad or anxious look (appear agitated, e.g., eyes down casted like in moment of unhappiness; tapping his/her fingers as in people who are anxious)	“I can see that the elderly was sad…but it does not mean she was not enjoying the music right? Maybe it made her remember something” “But I suppose negative emotions like looked anxious and sad can mean that the person is (PWD) is engaging with the therapy (intervention) right ?)”	2

PWD, person with dementia.