I have been inspired to start working in this area when I helped organize and perform in Empathy Concerts for my piano school, where we performed 50s and 60s pop music on the piano to geriatric patients.
The results were impressive. Patients who could not even remember their own names were singing along to the lyrics of the song. However, this only worked for specific songs, and the process of picking them out was done through brute force and elimination.
I hypothesize that there is an algorithmic way to accurately predict songs that they will like, instead of brute-forcing through candidates.