Now this is just cool: Optics Tests For Early Alzheimer's Diagnosis Make Significant Advances. It turns out that Alzheimer's isn't just a brain disease, but a systemic one. The same amyloid protein that clogs up the brains of Alzheimer's victims also collect at the edge of the lens of the eye. They already did a Phase I human trial, so it may be that in the not too distant future it will be possible to catch, and verify the diagnosis of, Alzheimer's earlier in the course of the disease.
This comes by way of ScienceDaily, which everyone should have in their syndication list (feed).