Most Alzheimer's research is focused on understanding and eliminating amyloid plaque, although there's some evidence of late that the plaque itself may not be the best point of aim for potential therapies. Another line of investigation revolves around neurofibrillary tangles. From Forbes, news of progress on this front: "In tests with mice and fruit flies, an enzyme appeared to both eliminate the tangles and reduce the brain's decline. ... It's not clear if tangles hurt brain cells or are just a symptom of a dementia problem. ... The point is that they're totally correlated with neurodegeneration in Alzheimer's disease, and in a number of other dementias. ... In some forms of dementia, tangles are 'the whole story' because amyloid plaques aren't present. ... it will likely take years for a drug for humans to be developed ... research into tangles has lagged behind research into ways to combat amyloid plaques."