Claims

CL001: Patient remembers to do the task, Part of UC001: Daily todo list
The main difficulty of people with dementia is remembering daily tasks, so the robot reminding the users to do their tasks can help them remember and the music can help reinforce the connection to the daily tasks.

CL002: User is happy because they completed a task, Part of UC001: Daily todo list
Even if they are reminded to do the task and do not remember on their own, the patients still feel the satisfaction of having accomplished the task themselves (since the robot only reminds them and does not help accomplish the task).

CL003: Patient is happy to interact with others, Part of UC002: Visit from the care giver or loved ones
Most elderly (disregarding whether or not they suffer from dementia) are eager to interact with their family, care givers, and even with people in general [citation?]. Thus, besides the benefit of updating the todo list to suit their preferences, the users also get to interact with others.

CL004: Patient is eager to be reminded of the newly added tasks or hear the newly selected music, Part of UC002: Visit from the care giver or loved ones
After having updated the todo list, the patients will be happy when they remember new tasks they would have otherwise forgotten about. Likewise, while changing the music associated might take some time to get used to, the users will be happier while listening to music they like more or music they feel like "fits" better with the task itself.