I was an art therapist for many years, gradually combining it with music therapy (that part was self-taught mentoring with a musictherapist), and because of that, my facility changed my title to Sensory Therapist.
I worked in a nursing/rehabilition facility, with 99% of the residents having dementia as well as physical medical issues such as blindness, deafness, autism, people bedridden and breathing with trach machines... I did group programs as well as bedside programs, and let me tell you those residents see you as an angel sent down from heaven.
You'd study art theory, psychology, geriatrics, and you'd have access to their medical files to help you determine what their needs are. If you get a degree in Therapeutic Recreation, it covers all of these things. It's a very fulfilling and much needed line of work. I hope you go for it, you'll be making a tremendous difference in people's lives/
You can PM me if you need details of the programs I created and the techniques I used. I don't want to take over this thread!