David Llewlyn (University of Exeter) - Cognitive ageing and dementia: Known knowns, known unknowns, and unknown knowns

Dementia is no longer considered to be part of normal ageing, however the core concept and it’s varying clinical presentations remain poorly understood and disputed. An emerging yet fragmented body of scientific evidence has little direct relationship with current clinical practice or policy, which is underpinned by faith in clinical or expert judgement and political and financial considerations.

Dementia is now one of the most widely feared conditions, perhaps the most widely feared, and an important and costly public health priority. However, we should not assume that researchers and clinicians share a common vision, language, or even definition of dementia though. Should it be defined by pathology? What about those with considerable longstanding pathology who have no cognitive deficits? Is Alzheimer’s disease really the most common form of dementia? What about mixed dementia? Indeed, is Alzheimer’s disease a form of dementia at all? What about those with Alzheimer’s pathology with no clinical symptoms? Should Alzheimer’s disease be  reconceptualised as a risk factor for dementia like stroke? What causes dementia, and is what’s good for the heart necessarily good for the head? What about invasive cardiac surgery?

If time permits we can also question the rhetoric that dementia is not part of normal ageing using an ‘eternal cohort’ thought experiment. It is therefore timely to consider what we really know, what we know we don’t know, and what we think we know but don’t.

The Think-Tank seminar series is organised by Heather O’Mahen, Lorna Cook, Matthew Owens-Solari and Matthew Lomas (mdcadmin@exeter.ac.uk).