Professor Lorraine Tyler, Cambridge Centre for Ageing and Neuroscience
Ben - On average in the western world, we live longer now than we have ever lived before. But a longer life doesn’t necessarily mean a healthier life. So, lots of this scientific research in this area aims to increase not life span but actually increase health span.
It’s quite well-known that even with normal healthy ageing, we do seem to see a decline in our cognitive functions over time – that’s the ability with language, memory, attention, etc. – and the Cambridge’s Centre for Ageing and Neuroscience or Cam-CAN was setup to try and understand how this happens and to find ways to extend our cognitive functions into old age.
We’re joined by Professor Lorraine Tyler who heads up Cam-CAN. Lorraine, thank you ever so much for joining us. Is it a simple case that no matter what we do, we’re going to lose cognitive function as we get old?
Lorraine - It’s quite clearly not the case. One of the things that we do know is the variability in both the cognitive functions that decline and their rate of decline, and also the fact that lots of people show variability in the extent to which their cognitive functions decline. So, one of the things that we’re trying to understand and that will be especially possible if we can make the Cam-CAN into a longitudinal study, is exactly what it is about those individuals who show preserved cognition across their life span.
Ben - So, when we’re talking about cognitive decline – I mentioned language, memory and attention – what are we really talking about? What are the symptoms that we see?
Lorraine - Well, I think that lots of people would say that they see the effects of memory decline as they age. People think that they have problems with language when they have word-finding problems, but in fact, language comprehension remains intact throughout the life span. I mean, people can talk to each other and understand each other throughout their lives. Attention is supposed to wander, but I think the thing that people notice most of all is memory loss. This is not true for everyone and the other thing is that the extent to which we notice what we think of as being declines is affected very strongly indeed by our stereotypes of ageing.
Ben - So, if we expect that we are getting doddery, that we’re having senior moments then we’re actually more likely to at least see that in ourselves if not, others.
Lorraine - Absolutely, yes. Also, the negative stereotypes of ageing also affect our own physical health.
Ben - So, almost a placebo effect and because we expect to be losing our memory, we actually start to lose it.
Lorraine - Yes.
Ben - That’s quite remarkable. But when do this sort of thing start to kick in? I understand some of it is actually something I should be worried about. I'm in my early 30s and already, I could be seeing a decline.
Lorraine - Well, I think that people more strongly notice declines after about 50, but I think that’s to a certain extent because once again, we expect to see it. So, when younger people forget their keys, you know how forgetful younger people are, but we don’t think that they're suffering age-related declines.
Ben - So, when we’re actually talking about the decline that we do see, so when we have somebody who’s come in with a sort of pathological decline to the point where it’s become a hazard, do we see a certain pattern in brain activities or a brain basis for the decline that we do see?
Lorraine - We work on healthy ageing, so at the moment, we’re not looking at pathological ageing and if we do make this a longitudinal study then we’ll be able to uniquely chart the trajectory from a healthy to pathological ageing. But in terms of healthy ageing and people noticing declines, it depends on what it is. Most noticeably I think, people notice decline in their memory. That’s the earliest thing that happens. This does not necessarily straightforwardly reflect brain changes which are happening throughout our lives. The changes that take place in the brain, the reduction of grey matter for example, the neurons in the brain, the cells, and the white matter tracts that connects cell assemblies, occur throughout our lives and at different rates.
Ben - We know that brain is actually quite plastic. It can adapt. If somebody loses use of a certain limb or part of their vision, we know actually the brain can adapt to make use of those neurons. So, it does seem a little bit odd that we would lose our cognitive ability.
Lorraine - Remember that I mentioned before that there's a lot of variability in the extent to which people lose or show decays in cognitive functions and one of the things that we know from a number of studies now is that, as you said, the brain remains plastic and this is revealed in studies using imaging techniques, which can show us how the brain is functioning as it is carrying out particular kinds of cognitive tests. And what we see is that good performance in older people is typically associated with enhanced activity in the brain and this is in the context of reduced neurons and white matter tracts. You see a greater uptake in activity in other regions of the brain than those regions which would’ve been activated in young people. And the argument is, and the evidence for it is, that this association between reduction in cells, in brain shrinkage, increases in activation, they're associated with preserved function.
Ben - So, are we in a position yet where we can say that in order to preserve this function, you need to do a certain set of things? I know there's been research recently that showed that older people with a more active and larger social network for example were more likely to live longer and retain their abilities for longer. Is that the sort of advice we need to be looking at?
Lorraine - Yes, I think that’s certainly one thing. Another thing for which we perhaps have the strongest evidence at the moment is exercise - cardiovascular exercise. There's quite a lot of evidence at the moment. It’s not watertight, but it’s emerging evidence that increased cardiovascular exercise helps to improve cognition, and there's also evidence that it’s associated with neurogenesis – the formation of new neurons in the brain.
Ben - And anecdotally, we’re told that if you make sure you keep doing your crosswords or perhaps learn a new language when you retire, these sort of things can also make sure that we retain those abilities later in life.
Lorraine - Yeah, I think there's less strong evidence for cognitive training effects, but I certainly think if it was me, well, I mean, it is me, I like doing crosswords and Sudoku and things like that, and I think one should set one’s self challenges and try to get out of one’s comfort zone.
Ben - Well, they do say that you never improve if you don’t get out of your comfort zone.
Lorraine - Absolutely.