We are a little different, we volunteer with a group called St John's Ambulance, which I'm pretty sure is strictly Canadian, but I could be wrong on that. Our standards are much the same as other therapy groups. You want impeccable leash manners, amazing tolerance for other dogs. You want to start exposing your dog to ad devices like crutches, canes, walkers, wheel chairs, pulled oxygen tanks and the hoses that come with, colostomy bags, catheter tubes/bags, etc. Don't forget to expose them to a variety of people as well...some physical disabilities cause people to have a variety of physical difference than the 'average' person, and some other disabilities can leave people to be mute and distant, and that can really throw some dogs off. You also want to start exposing to a variety of noises, particularly loud unexpected ones. To start is absolutely acceptable, it's the recovery they are looking for. I have one resident we go visit that has advanced Alzheimer's and can be hugging Sulley, then yell a random profanity at a nurse very, very loudly and essentially right in Sulley's ear. It's important that they are able to cope with those sorts of situations.
The other thing to consider is your own ability to cope with those situations. I'll be the first to tell you it isn't easy, and it isn't for everyone. It can be emotionally difficult dealing with a person that has dementia and forgets a lot of things, or get disoriented or upset and you don't understand why. It also breaks my heart to visit some residents that are well in mind, but have no other visitors. They search for us every Saturday, just for someone to say hello to and chat with for a little bit. On the other hand, when a normally distant and mute person looks at your dog and smiles, then reaches out a hand for a small pet, it's an amazingly gratifying experience. It is really something very special, and that is the reason we go back after the less pleasant ones.
I'm hoping we can be tested to work with children and the mentally handicapped in a few months, so I'll let you know how that goes. That would allow us to enter into some group homes and participate in reading programs and the like.