Suzana Herculano-Houzel

Is it Alzheimer’s or isn’t it?

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Scientific meetings are often opportunities for researchers to exchange ideas and present to each other what they have just discovered or have begun to study but have not yet made public.

That’s why a recent meeting on Alzheimer’s disease was so extraordinary. Two private institutions, the international Alzheimer’s Association and Hong Kong’s Croucher Foundation, brought together around 30 renowned researchers specializing in the disease to spend three days in that city-state, locked in an auditorium – from where they only left for meals (delicious, by the way) – not to present their findings, but to assess the state of play and try to reach a consensus on what Alzheimer’s actually is, and what is known about its causes.

The problem is twofold. On the one hand, billions have been invested in research and drugs – but so far, there is no effective treatment, let alone recovery or cure. On the other hand, and perhaps one of the causes of the first problem: what doctors and researchers call “Alzheimer’s disease” used to be something very precise (early memory loss and dementia, with tau protein tangles found in the brain after death), but in recent decades it has come to embrace what others still call senile dementia and also non-hereditary forms of the disease, both early and late. Clinical examination shouldn’t be enough for a diagnosis, but in practice it’s often all that’s done.

The result: the name that used to designate a specific disease in middle-aged people, which in fact seems to have a clear diagnosis (although not yet exactly a defined mechanism), has become a bag of cats. Some researchers are still careful to define what they are referring to; but others, partly in their eagerness to have their efforts embraced by the abundant funding to study the disease, have contributed to clouding the diagnosis to the point of rendering it almost useless.

Useless and, frankly, worrying, both for science (which dilutes its efforts by mixing garlic and breadcrumbs) and for the families affected. Receiving a diagnosis of Alzheimer’s disease is devastating, and should only happen with complete certainty. The difference is that not all memory loss is a sign of Alzheimer’s – in the original sense, of rapid, extreme and early loss of memory and cognition. Stress, blows, strokes, vascular and metabolic problems and many other factors can lead to debilitating cognitive losses, yes – but not catastrophic ones, like the disease originally described by Dr. Alzheimer. When the diagnosis comes with a verdict, you can’t be too careful.

Originally published in Folha de São Paulo in April 2018.

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