Alzheimer's - closing in on early diagnosis

Doctor Thomas Insel discusses recent findings of structural changes in the brains of teenagers may be warning signs for the potential onset of Alzheimer's disease.

I think for Alzheimer’s we’re getting some really interesting leads. So there are really two observations; one that you can begin to image plaques and image amyloid. It’s very interesting because that could give us a biomarker that we didn’t have before. The other finding which doesn’t get much play but I think is one that is really intriguing is that if you look at people who have the APOE4 gene allele that greatly increases your risk for Alzheimer's, you can find changes in the brain; cortical thinning for instance, so structural changes very early in life, even in teenagers 30 to 40 years before you’ll have any of the signs or symptoms of Alzheimer's. Now that’s quite interesting because it says this is after all a brain disorder, we use behavioral changes to make the diagnosis. But increasingly we have to remember those behavioral changes are an end stage and we want to be able to use neuroimaging to diagnose a brain disorder much, much earlier. The analogy would be like saying we’re only going to diagnose coronary artery disease when someone develops the pain of a heart attack. Today we don’t do that, we get there much earlier. We use imaging, we use biomarkers, and we have a whole series of both family histories and genetics that helps us to suspect that someone’s at very, very high risk and we intervene early. But in dementia, in most neurological diseases, neurodegenerative diseases, and most mental disorders like schizophrenia and autism we’re getting there only when we have behavioral manifestations which are probably a very late stage in what’s been a very long process. Just one example: Parkinson’s emerges symptomatically when you’ve lost 80% of the cells in the substantia nigra; we don’t want to wait until 80% are gone, we want to know that’s going to happen at 20, 30, 40 percent or even before and intervene to make sure you never develop the signs and symptoms of Parkinson’s.