Byline: by John Naish
SENIOR moments? Forget them. Now it's middle-aged muddle we must worry about. Scientists last week declared that our ability to remember everyday things such as names and numbers starts to go at the tender age of 45.
But before you resign yourself to spending the second half of your life as a mental basket-case, there is positive scientific news, too. For memory is a strange and complex thing, as this guide to the mind makes clear ...
FIRST THE BAD NEWS ...
LAST week's study of more than 7,000 civil servants in London revealed how our power of recall starts to decline earlier than previously thought. Men and women suffered the same 3.6 per cent loss in memory power between the ages of 45 and 49, revealed the ten-year study published online in the British Medical Journal.
Fears about age-related memory loss are hardly new. Plato wrote that when a man grows old, he 'can no more learn much than he can run much'. But evidence of problems in mid-life is worrying because these may be the first signs of a condition called Mild Cognitive Impairment (MCI). This is an accelerated loss of memory power that can, in about half of cases, turn out to be the first early sign of Alzheimer's. Scientists believe that Alzheimer's can begin in the brain two or three decades before serious symptoms appear.
Regardless of our Alzheimer's risk, though, we all seem to suffer some loss of mental capacity from a comparatively young age. Studies show
that the processing speed in our brains slows down from our 20s onwards. 'By mid-life, most of our brains show some fraying around the edges,' says Barbara Strauch, author of The Secret Life Of The Grown-Up Brain.
'People's names are often the first edge to go ragged,' she adds. 'But the names are not technically gone. For the most part, it's a problem of retrieval, not storage.'
This difficulty is not caused by a simple loss of brain cells. Scientists used to think that we lost 30 per cent of our brain cells through ageing.
But recent studies show that the loss is much smaller. Instead, advancing years can bring a drop in the levels of chemical messengers in our brain -- called neurotransmitters. As a result, memory-power can drop, and we can also find ourselves getting distracted more easily.
Research shows that much of what we learn is not missing; it just gets misplaced. Hence that frustrating sense of 'it's in there somewhere,' when names, facts and figures elude our grasp.
Frustratingly, too, we can also find ourselves able to build vivid memory pictures of events that occurred decades ago, but incapable of remembering what we had for breakfast. This is because the brain creates very different kinds of memories -- and in mid-life some of our memory systems can become weaker than others.
SO HOW DOES YOUR MEMORY WORK?
THERE are several memory systems at work in the brain. One memory system comes into operation if you try to remember a place name or a phone number. Remembering things that can be expressed in language is called 'explicit' memory. Another memory system covers things of which you may not be consciously aware, such as how to ride a bicycle. That is called 'implicit' memory.
There is also short-term or 'working' memory and long-term memory. Short-term memory would be remembering a phone number for five minutes; long-term involves recalling it in a year's time.
Such differences in memory types are all too familiar to Joshua Foer, an American writer and international memory champion who has honed his immediate short-term memory so well that he can recall details such as the order of a newly shuffled deck of cards.
But he admits memories that require a little more longevity are more problematic: only a few nights after he won the annual US Memory Championships in 2006, he forgot that he had driven his car into town to eat dinner. …