into court in order to secure a verdict removing him from the control of his property on the ground of imbecility. Then the old man read to the jury his play
The Roman orator Cicero wrote: ‘Old men retain their mental faculties, provided their interest and application continue; and this is true, not only of men in exalted public station, but likewise of those in the quiet of private life.’ It is impressive to see how similar his views about how to age best are to current ones—keep mentally and physically active. To the objection that memory begins to fail in old age, he replies: ‘No doubt it does, if you don’t keep it in trim, or if you happen to have been born a trifle dull. I have never heard of any old man forgetting where he had buried his treasure: the old remember what is of real concern to them: their days in court, their debts, and their debtors.’
Those reaching 70 with some 14 years ahead will, on average, spend nearly two years in moderate or severe cognitive impairment. There is thus great concern, even fear, about the increase in dementia with age, especially Alzheimer’s disease. The Disconnected Mind team is conducting an extensive analysis on the contribution of lifelong demographic factors to the rate of brain ageing. Brain function at age 11 is the biggest indicator of brain function in later life; clever children make clever and mentally competent old adults.
There is not a significant loss of nerve cells with age, though several populations of nerve cells are lost in the old. As people age, peripheral nerves may conduct impulses more slowly, resulting in decreased sensation, slower reflexes, and often some clumsiness. Nerve conduction slows because myelin sheaths, the layers of cells around nerves that speed conduction of impulses, degenerate. Shrinkage of the brain is due to fluid loss as well as reduced branching of extensions from nerves. There is also a reduction in the size of the cell bodies and the accumulation of granular pigment and filament tangles and abnormal small structures. In about one third of old brains, there are abnormal deposits of amyloid, which are proteins that form insoluble fibrous protein aggregates and are common in the brains of those with Alzheimer’s disease, and this leads to damage of nerve cells. Late onset schizophrenia is rare.
Studies have revealed that separate brain regions that are involved in higher-order cognitive functions show less-coordinated activation with ageing. This reduced coordination of brain activity is associated with poor performance in several cognitive domains. Although neuronal loss is minimal in most regions of the normal ageing brain, changes in the connections between ageing neurons may contribute to altered brain function. More than 150 genes have been found to undergo age-dependent expression changes in the brain; some of these are more active with age in mice but less so with age in humans. The function of these genes and how they are turned on and off is not yet understood. Studies on mice have identified memory disturbances in the ageing brain as being due to certain genes associated with memory being turned off. There are also lower concentrations of neurotransmitters like dopamine, which has important roles in behaviour, cognition and voluntary movement. In the human brain, declining mitochondrial function may selectively affect neuronal populations with large energy demands, such as the neurons that degenerate in Alzheimer’s disease.
With mental activities, there is usually a much less dramatic decline with age than with physical activities. It varies a great deal, but the old can still be very productive. Politicians can continue to be active until rather old, some might say too old. Roman emperors ruled until they were of extreme old age. Augustus, who lived until the age of 76, remained in office until his death and didn’t stop visiting the Senate on a regular basis until he was 74. Winston Churchill was still prime minister at the age of 80.
Scientists usually do their best work when young, but there are important exceptions, such as Galileo writing
Writers, painters and sculptors do not lose their skills with age, and many have produced their finest works in the last fifteen or so years of a long life. At 97, Enrico Paoli, an Italian chess master, was the strongest active nonagenarian chess player in the world. He learnt chess when he was nine and started playing tournaments at 26. He won his last Italian championship title at the age of 60. Paoli was playing master-level chess at 96—in 2003 he played the international tournaments. Jose Raul Capablanca, the ‘Mozart of chess’, regarded Emanuel Lasker, who was world chess champion for 27 years, as the most dangerous player in the world in a single game, even as the latter neared 70. No other contemporary, he thought, surpassed him in his ability to evaluate a position and find the correct strategy.
The decline of memory with age depends on the specific nature of the memory, as there are different types. For example a patient with a particular brain damage cannot recollect personal experiences, but can learn new motor skills and lists of words. This is an implicit memory and involves recall of motor and academic skills without conscious awareness of previous experiences. It is distinct from explicit memory, which involves recall of previous experiences and information. Explicit or episodic memory involves the memory of autobiographical events, including recent events, such as times, places and associated emotions and is the most common memory loss with age. As the length and complexity of sentences increases, older adults have more difficulty understanding and recalling them. Yet factual knowledge does not decrease with age, though spatial memory, such as the layout of a museum recently visited, does decline.
It is common with old age to forget names of people or to lose a particular word—even though it is on the tip of the tongue. Usually the name or word is recalled later when one is thinking about something quite different. I have lost names, so too have many of my friends. I have also forgotten the faces of people whom I know quite well and have to ask them who they are when they greet me, and then I recall who they are. It is a bit embarrassing not to recall the name of someone you know when you meet them and need to introduce them to someone else. One also loses common objects, or as Edward Grey put it: ‘I am getting to an age when I can only enjoy the last sport left. It is called hunting for your spectacles.’
Jonathan Swift, the author of
Though there is no significant loss of knowledge with age, the elderly do not encode information into long- term memory as efficiently as the young. Forgetting to do something as one ages is common and worrying. Around 60 per cent of participants in a study of those aged 75 and older forgot to perform an action that they had previously been requested to carry out. A typical example of loss of a recent memory is the case of a distinguished but ageing TV presenter who went out to dinner on a Friday night. When he rang the hostess’s bell there was a delay, then she put her head out of an upper window and said hello. ‘Have I come on the wrong night?’ he asked. ‘No,’ she replied, ‘it was last Friday and you were here.’ All too familiar.
Complaints about memory are the most frequent cause for seeking medical advice about dementia. This is the result of episodic memory going wrong and leads to forgetting personal and family events and appointments; losing items round the house; repetitive questioning; inability to follow plots on TV or in films; forgetting past events and news items; and getting lost. The elderly have many more memories for events that occurred in adolescence and early adulthood than in midlife. Very few elderly show improved cognitive functioning in the evening, and unlike the young, their performance gets worse through the day. The herbal treatment ginkgo, used by
