I heard about the good results achieved when pets visit nursing homes but I was glad to read this article
http://moderndogmagazine.com/articles/memory-assistance-dogs/65537
about dogs being trained to assist Alzheimer and dementia patients. This was first piloted in Israel and now in Scotland. Dogs have a 6 foot long leash and GPS navigation device in their collar. The main task for the dog is to bring his charge home when the command Home is given.