Dementia - it's all in the mind

JOHN ELDER
Last updated 05:00 21/04/2014

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Is it possible, from a scientific point of view, that former New South Wales premier Barry O'Farrell had a ''senior moment'' when he forgot about the $3000 bottle of wine he received as a gift? Kind of.

At 56, O'Farrell is deep into middle-age, and - according to a 2012 study published in the British Medical Journal - cognitive decline begins at about 45, not at 60 as it was once thought.

Already O'Farrell is experiencing some level of age-related memory loss and a slowing down of his reasoning processes. So there's that.

Further, memory loss is exacerbated by stress. As Harvard Medical School's neuroscience newsletter On The Brain noted last year in an article on the middle-aged brain, the hormone cortisol - released during the ''fight-or-flight'' response to stress - can prevent the brain from laying down new memories, or from accessing memories that already exist.

Worse, it can damage the hippocampus, the part of the brain most associated with memory storage.

''Excess cortisol can make it difficult to respond to stimuli or retrieve the stored memories needed to guide us in certain situations, a condition that may account for our being bewildered when stressful situations arise,'' On The Brain advises.

Well, who wouldn't want to flee - and who wouldn't be bewildered by - the spotlight of a corruption inquiry?

So let's leave O'Farrell with that comforting thought and turn the spotlight upon all middle-aged folk, the multiple fronts where their lives have become a form of combat, including the occasional nagging worry that they are losing their minds.

Who doesn't want to flee reality when your teenage kids are carrying on like emperors at the Colosseum, your ageing parents are on the telephone again with a fresh grey crisis, your divorce is in train, your job may not survive the next round of redundancies, your doctor is rabbiting on about diabetes, your prostate, your lower bowel, your weight, your eyes are demanding reading glasses, and ... well, where are the bloody car keys so I can get the hell out of here?

They're not in my pockets and ... why am I not wearing underwear?

The overworked, overcrowded middle-aged mind can be forgiven a few memory lapses.

So take a few calming breaths and tell yourself: ''Damned cortisol, that's all it is.''

Except it's not.

Let's delicately backtrack to the question - or shall we call it the threat? - of age-related memory loss.

While it can be galling to realise you can't run or lift heavy objects with the ease you knew as a 20-year-old, it's actually a little frightening sometimes when you walk from one room to another, full of beans and purpose, only to find yourself standing without a clue as to what task you were in the middle of.

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Especially if only the other day you left your keys overnight in the front door? And so on.

There was a time you'd laugh it off and be grateful the keys weren't stolen. Now, in your 40s and 50s, there's a nagging worry that these lapses are the first signs of dementia - that one day too soon you're going to look in the mirror and wonder who is that naked person wearing a bowl of porridge as a hat staring back at you.

After all, dementia - and, of course, the dark lord of dementia, Alzheimer's disease - reached epidemic proportions in Australia five years ago, according to an Access Economics study commissioned by Alzheimer's Australia.

Last year, The Facing the Health of Australians survey of 5000 people aged 32 to 55, commissioned by the Australian Medicines Industry, found that dementia is second only to cancer as our greatest health concern, more feared than diabetes, obesity or depression.

For the ageing baby boomers and Gen Xers, the epidemic devastating their parent's generation today looms as their own plague of tomorrow.

And maybe, with that seemingly awful moment where you forget why you came into a certain room, and what it was you were meant to be doing, it's happening right now.

Professor Peter Schofield is executive director of Neuroscience Research Australia (NeuRA). He says that the fear and anxiety that middle-aged people harbour about dementia isn't unreasonable - ''It's true that age is the biggest single contributor to developing dementia'' - but it's overblown.

''Yes, as we age our brains shrink. Yes, they slow down a bit. We begin to lose neurons and they aren't replaced at the rate they once were. And so in some measure we are not as sharp or quick as we once were. But in the vast majority of the population aged in their 40s, 50s and 60s, that lack of sharpness is more a function of the complexity of what their brains are dealing with ... it's more a matter of selective attention than a measure of clinical pathology.''

However, because dementia is a high-profile issue ''many people are much more anxious about it. Every time they can't find their keys is an impending sign of dementia. Losing your keys is an anxiety issue, not a cognitive one.''

Schofield says that people ''attribute too much to middle age'' as a time of mental decline.

''It's when you're 70 and 80 years old having a senior moment that you're more likely experiencing mild cognitive impairment. Even then, generally, it's not enough to be lifestyle disabling.''

Kristyn Bates, research assistant professor in experimental and regenerative neuroscience at the University of Western Australia, says the prevalence of middle-aged and older people scaring themselves into wrongly thinking they're losing their minds is so high it has led to the creation of a whole new area of research: ''subjective memory complaint''.

''There is nothing wrong with their memory that we can measure. They perform normally. Because it's poorly defined, the prevalence of subjective memory complaint is between 20 to 50 per cent of the elderly population,'' Bates says.

The key issue here is that the healthily ageing brain doesn't lose memories, they just take longer to retrieve. As Marshall Dalton, a former research assistant at NeuRA, notes in a blog - written in part as a response to frequently asked questions at Rotary dinners where he was a guest speaker - ''age-related memory problems are the result of reduced efficiency in communication between brain cells, whereas memory problems in dementia are the result of cell death''.

In many instances when our brain seems to be malfunctioning, it's actually taking charge. In that moment when you walk into a room and forget what brought you there, Peter Schofield advises: ''perhaps the task was displaced by a more interesting thought or event. When you forget what you were doing, it's possibly because it wasn't so compelling. Most of us don't have hugely long attention spans.''

One of Schofield's research interests is in the genetics of brain function. And one of those functions is the ordering of information and giving priority to certain thoughts and events over others. This includes everything that we consciously see that's going on in the world - our eyes being a physical extension of the brain. The brain takes it all in, both focusing and editing what's happening in front of us.

This leads us to the unnerving issue of false memories: some researchers argue that every long-term memory we have is in some way false. This is because memory is a reconstruction, not a video recollection. When a new memory is acquired it goes through a number of different processes, firstly at the synaptic level (the junction where information is passed from one nerve cell to another), which takes hours; and then in the hippocampus, the part of the brain where new memories are laid down.

Each time we drag up a memory, it has been altered in some small way because of the circumstances we are in at the time, because of the motivation for recalling it or because new information has somehow mixed in with the original event. Why? It is thought largely to be a function of adaption, and the brain being efficient.

The net effect is that your memories - unless they have been planted by suggestion or manipulation - are true enough.

Schofield says it could be that memories are moved about, from one part of the brain to another, like a filing system being shuffled. ''The things you think about more are replayed more often. But there's a huge subjective element to this recollection ... in often replaying the memory, you form false recollections.''

Last year, researchers from the Massachusetts Institute of Technology successfully planted false memories in mice. This was hailed as having great potential for treating sufferers of post-traumatic stress disorder, where destructive memories could be edited into happier ones.

There are studies that show older adults are sometimes more likely than younger adults to remember events that never happened - but this may be a self-protective mechanism, akin to the gloomy German philosopher Nietzsche's idea that ''happiness is forgetting''.

A University of Virginia study from 2005, With Sadness Comes Accuracy; With Happiness, False Memory, found that happiness tends to generate false memories while unhappiness dredges up accurate ones.

This isn't to say that false memories generate the greater happiness and contentment that people 50 and over are routinely said to experience - but they may be both an expression and reinforcement of that happiness.

Harvard's On The Brain newsletter reported a study that found the middle-aged brain screens out negative emotions when confronted with negative images and is otherwise wired to accentuate the positive. It also noted that the brain in middle age may be more resilient than at any other time in life.

In fact, there is growing evidence that the middle-aged brain is more of a good news story than a sad one.

Kristyn Bates from the University of Western Australia says when she was an honours student in 2000, it was still thought that the brain stopped producing neurons past childhood. ''We now know that isn't true. Evidence came out last year that the hippocampi [we have a hippocampus in each hemisphere] each makes 700 new neurons every day.''

Bates says that while the middle-aged begin to lose synapses and there is an associated slowing of some functions, it's now understood that ''middle-aged people use their brain differently. Both sides of the brain are used to process information rather than just the one side.''

It's not yet understood if this is a natural offset to lost function, but the net result is better communication between both halves, and a greater ability to better judge situations and evaluate information.

''What we're seeing is the biological basis for wisdom that comes with ageing ... whereas younger people rely more on the immediate emotional response.''

The best news is that the decline of the brain can be slowed and even repaired, by doing the very same things that keep our hearts healthy: exercise, good diet, manage stress. The best exercise appears to be education.

Dr Margie Lachman, professor of psychology at Brandeis University, Massachusetts, who is conducting a massive study of brain function and behaviour in middle-aged Americans, found that poorly educated people who engaged in cognitive-based exercises enjoyed a significant lift in brain and memory function.

Kristyn Bates says: ''There's a dogma in neuroscience: the cells that fire together, wire together.''

In layman speak that's ''use it or lose it''.

Brainfood: how to slow mental decline

■ Cardiovascular exercise - what's good for the heart is great for brain.
■ Go back to school - short courses, esoteric lectures, learn a language, anything educational. 
■ Engage in brainteaser exercises (crosswords, Sudoku) in your spare time.
■ Get lots of sleep.
■ Take up meditation to help beat stress, a memory killer.
■ Take it easy with the booze - it really does kill brain cells.
■ Don't smoke.
■ Be happy - a positive attitude might generate false memories but it also aids focus and problem-solving.

- Sydney Morning Herald

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