Katelyn, posting on Life Without Memories (http://alzheimersadvocacy.com/2006/11/29/electric-blankets-are-a-safety-concern-for-alzheimers-patients/) mentions a very real danger when we’re caring for Alzheimer’s patients…letting them use an electric blanket.  She refers to an article that tells of an elderly Alzheimer’s patient experiencing burns, apparently by turning the electric blanket to “high” while her caregiver husband was sleeping. 
As an Alzheimer’s patient becomes more incapable, remembering how to use an electric blanket…and even what it’s for can become a challenge.  It falls under the same concern we have about letting this person operate an electric stove.