Ashleyk,
We too have psychosis and cognitive and memory issues. I very recently stumbled across a line of research using DBS for dementias including Alz and PDD. It is a very new idea, and one you might consult with your wife's neuro about. What I have found so far is that the procedure itself is safe and tolerated by patients with dementia, and that it can improve memory and some facets of QOL for some patients; however those benefits seem to wane about a year after the procedure, and from what I have read, were not that robust (and definitely not enough to transform someone who needed a caregiver into someone who could live alone). While the improvement wasn't huge, in my book, any improvement is still improvement

Unfortunately, I can't see our insurance company (or Medicare/Medicaid, depending on your situation) being willing to pay for DBS without a lot more research showing that the majority of patients not only improve, but improve enough to justify the risks and costs of the surgery. Just thought I would mention this. I believe the neuro heading up a lot of this research is Lozano, if you're interested.