I located an article on fMRI on Winpedia. The only thing it said about the test and Alzheimer's was that Alzheimer's patients could not comply with being still for the 15 minutes to 2 hours that the testing currently going on requires.

I also discovered a paper written about this technique and Alzheimer's patients at Temple University Hospital in Philadelphia. They did find significant differences btween Alzheimer's patients and other test subjects during certain semantic tests. And they believe their tests can be used to diagnose early Alzheimer's. The paper was published in 2004.

I found a second paper dated in 2003 from the University of Pennsylvania, again in Philadelphia. These would be two different studies (both tiny) run by two different groups even though they probably all know one another.

It doesn't look like this test is actually available, but they certainly are studying it. I've found studies at Oxford, Utah and Pennsylvania. I know that if I had looked harder I'd have found even more of them. Of course you have to be able to take an MRI to do it. In my husband's case he can't do that. He has a pacemaker.

I found some more stuff too. My search words were "fMRI Alzheimer's" Mostly I found technical papers, but none of the Abstracts were that hard to follow. The test groups are TINY - 7 patients, 16 patients, etc. This is really early stuff. But if you are trying to figure out early onset dementia, or even just the early stages, you are going to be sorry this test isn't really available yet, because it looks like it is going to be good stuff. And since it sounds to me like this is a new way to use equipment already quite common, the test might be available sooner rather than later.