The Pharmaceutical Journal
Vol 279 No 7462 p108
28 July 2007

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Nothing like a good night’s sleep

Such stuff as dreams are made on

Dementia and taking to the road

Nothing like a good night’s sleep

An interesting sidelight upon the vexed question of the value of a child’s afternoon nap is cast in a commentary in the 30 June issue of New Scientist. If a child indulges in a brief nap during the afternoon it is often regarded as beneficial by the parents. Yet there are doubts concerning the value of such a habit by the child later on.

Studies have suggested that daytime napping in young children may result in poorer sleep and mental functioning compared with the effect of sleeping only at night. The question to be answered is whether napping impairs the value of nocturnal sleep or otherwise.

At a university in the US, parents of 738 children were questioned about their sleeping habits between the ages of two and 12 years. Those who indulged in long daytime naps fell asleep at night an average of 39 minutes later and slept later at weekends than those who took no such nap.

The effect was more marked in the older children, a quarter of whom took a nap between the ages of 10 and 12 years. During the following week, when the children were obliged to wake at set times in order to get to school or fit in with the schedules of their working parents, problems arose.

Napping children continued to stay up later and spent less time in bed at night than their counterparts. Not only did they find it more difficult in getting to bed, but they found it harder to fall asleep and also to get up in the morning. Another study in Japan compared children who attended all-day pre-schools where 90-minute naps were compulsory with others who napped only when they found it necessary.

Children who took obligatory naps, although they went to bed 30 minutes later than the others on average, were more likely to prove moody in the morning and resist going to school. This behaviour persisted even after the children moved on to an elementary school and ceased from taking their naps. Thus, napping produced a lasting effect on their sleep-wake cycles.

Mental performance was also affected, according to a University of Florida study of kindergarten children. These were asked to solve puzzles that measured planning and organisational skills. Children who took longer daytime naps completed fewer puzzles successfully, and the later they went to bed the less well they performed.

Such findings may indicate that children are getting less sleep at night because of their naps or that they are napping because they sleep less at night. In any event it seems that however much time is spent napping, it cannot become an alternative to night-time sleep.

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Such stuff as dreams are made on

Homer remarked that dreams are gifts from Jupiter. For ages there has been a belief that they impart some insight into the future of an individual. Many other philosophers have argued to the contrary, saying that dreams are mere delusions. They do not agree over their causes but allow some role for the processes of imagination in the dreamer.

Physicians in the distant past have connected them with the humours or vapours that affect individuals during their waking hours. Cicero thought that those who gave credit to their dreams were the victims of their own vanity and folly.

Dreams have been attributed to things seen or eaten during the previous day. Cicero tells us of a man who dreamed that an egg was concealed under his bed, and a soothsayer assured him that where he had visualised the egg a treasure lay hidden. On investigating he uncovered a hoard of silver and gold, and the soothsayer was indignant when he was given none of it as a reward. In recovering it the expert thought it necessary to read certain psalms to deter evil spirits from removing it.

Every dream, it was thought, is the outcome of a sensation that is initiated and then continued by a succession of phantasms. According to John Brand, the 18th century antiquary, physicians were the only persons who tried to interpret dreams. What a man saw and pondered over during the day determined what he dreamed of when he retired to bed. In the 17th century, Descartes attributed experienced emotions to fluid currents in the brain; sleep intervening when these escaped into the nerves rendering them flaccid.

In human sleep, dreaming is a distinctive mental state that punctuates regular sleep periods. Dreams may include hallucinations, delusions, abnormal cognition, intensified emotions and amnesia. Changes in taste and smell are minor and pain is rare, even when provoked by terrifying perceptions. Most dream thoughts are promptly forgotten. A disproportional part of sleep is spent in the rapid eye movement phase, with raised heart rate and blood pressure and raised and irregular breathing rate.

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Dementia and taking to the road

There is a review in the 30 June issue of the BMJ dealing with the tricky question of dementia as it affects the driving of cars.

Dementia is defined as the loss of mental faculties, generally due to organic or functional disease and is a type of degenerative insanity. There are some 12 types of dementia recognised, all characterised by cognitive and behavioural defects and distinguished from amentia in being feeble mindedness of variable degrees.

Alzheimer’s disease is one of the commonest types encountered and involves degeneration of the brain cortex with loss of memory, aphasia and paralysis.

Dementia is important when it comes to driving vehicles on the road. As it progresses, the ability to drive is eventually lost and this calls for the withdrawal of a driving licence. However, many people continue to place themselves and others at risk since so many social functions depend upon driving. Nevertheless, it has been shown that drivers over 80 years of age tend to become better and more prudent. There is, however, evidence that the risk of accident does increase with advancing age.

Within three years of the onset of dementia, most people stop driving, but short-term memory, disorientation and loss of insight and judgement indicate incapacity. When there is doubt, an expert assessment is essential.

It is not disputed that some patients with diagnosed dementia are capable of driving safely but the challenge to doctors and the licensing authorities is to balance mobility and safety in a growing population of older people.

Evidence from Scandinavia, Australia and the US suggests that mass screening of older motorists has negative impact on public health and more specific tests should be introduced in the interests of mobility and safety. Steps should be taken to increase individual awareness of incapacity, rather than relying on the screening of masses of individuals.

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