"People who do puzzles and crosswords may stave off dementia longer,” according to BBC News. The website said that mentally stimulating activities may protect the brain from memory loss but also speed up mental decline once the disease takes hold.

The story is based on research that followed 1,157 elderly people to examine how mentally stimulating activity in old age affects the development of dementia. The results suggest that being mentally active slows down cognitive decline before the onset of dementia but leads to faster decline after dementia has set in. The authors suggest that mental activity may somehow allow the brain to initially tolerate the brain changes associated with Alzheimer’s, but that decline is swifter once brain changes reach a more advanced stage.

While it is interesting, the authors’ theory was not conclusively proven by this study and will need further testing. Mental activity is only one factor that may contribute to the risk for dementia, along with genetics, environment and education. The study did not specifically test brain-training games or puzzles, as some newspapers suggested.

Where did the story come from?

The study was carried out by researchers from Rush University Medical Center, Chicago, and was funded by the US National Institutes of Health.

The study was published in the peer-reviewed journal Neurology. It was widely reported by the media, whose coverage was generally fair but uncritical. Some newspapers focussed on the delays in dementia symptoms seen in those people who were most mentally active, while others concentrated on the swifter mental decline they exhibited once dementia eventually began.

The Daily Mirror’s claim that “thinking too hard may actually damage the brain of some older people” is misleading. The study did not specifically test the impact of brain-training games or mental puzzles, both of which were mentioned in press coverage.

What kind of research was this?

The researchers point out that more frequent cognitive activity has been associated with a reduced risk of cognitive decline and symptoms of dementia. However, it has not been associated with any reduction in the development of brain lesions associated with the condition.

Given that greater mental activity appears to protect brain function but not biology, the researchers argue that if cognitive activity before dementia were truly protective, it would also be associated with more rapid decline after the onset of dementia. In this cohort study, they tested this hypothesis, which implied that by delaying the onset of dementia, greater cognitive activity would “compress” the illness once it began, with the problem progressing more rapidly over a shorter time.

What did the research involve?

The researchers recruited 1,157 people aged over 65 who did not have dementia at the time of enrolment. Participants were selected at random from a larger study looking at risk factors for dementia. At their initial interview, they were asked to rate how frequently they took part in seven activities in which information-processing plays a central role. These included watching TV, reading, doing crosswords and visiting museums. Frequency was estimated using a five-point scale, ranging from every day (5 points) to once a year or less (1 point).

The researchers used these ratings to make an overall estimate of how often people participated in mentally stimulating activities. Participants were also given four validated cognitive performance tests to assess their cognitive abilities.

The participants were followed up for an average of 12 years. Every three years, different samples of the group underwent a comprehensive clinical evaluation, in which they were classified as having no cognitive impairment, mild cognitive impairment or Alzheimer’s disease. Participants underwent further brief cognitive testing at 3-yearly intervals to assess cognitive function. (Three waves of clinical evaluation were included in this ongoing study. The fifth wave is still underway).

The researchers used validated statistical methods to look at the possible associations between people’s levels of cognitive activity and their cognitive function and clinical outcomes.

What were the basic results?

Clinical evaluation over the course of the study found that 614 people had no cognitive impairment, 395 had mild cognitive impairment and 148 had Alzheimer’s disease. When the researchers analysed the data, they found that:

• In the group without cognitive impairment, the annual rate of cognitive decline was reduced by 52% for each additional point on the cognitive activity scale.
• In the group with mild cognitive impairment, the rate of cognitive decline was not associated with cognitive activity level.
• In the group with Alzheimer’s disease, the average annual rate of cognitive decline increased by 42% for each point of the cognitive activity scale.

Together, these results associate greater cognitive activity with slower decline in people without cognitive impairment and faster decline in those with Alzheimer’s disease.

How did the researchers interpret the results?

The researchers said their results suggest that cognitive activity enhances the brain’s ability to maintain relatively normal function despite neurological degeneration. This means that after the onset of dementia, the resulting decline is more rapid. They said that the benefit of delaying the initial appearance of cognitive impairment comes at the cost of a more rapid progression of dementia when it eventually arrives.

The researchers concluded that any mentally enriching interventions, such as puzzles or acting classes, may need to be started before the development of cognitive impairment, because many people with mild cognitive impairment already have substantial physiological signs of Alzheimer’s disease in the brain.

Conclusion

This study has some strengths, including the large number of patients followed and the long follow-up period. Furthermore, its clinical evaluations and assessments of cognitive function were based on validated measures. The participants also represent a broad spectrum of cognitive function, ranging from no impairment to dementia.

However, the study also has limitations.

• It did not make adjustments for other factors (called confounders) which might contribute to the development of Alzheiner’s. For example, certain educational, social and genetic factors may have differed between the groups, which were not accounted for in the researchers’ analyses.
• Importantly, the assessment of cognitive activity was based on a composite measure. Since only seven cognitive activities were assessed, they may not reflect people’s true levels of cognitive activity. The use of composite measures to assess cognitive function also means that specific deficits in memory, for example, were not tested for by themselves.
• Only two to three observations were recorded for each individual in the study. Therefore, when graphed, the rate of decline in cognitive function tended to appear as a straight line, whereas a more complex pattern may have been revealed if more than three data points had been available.

Overall, this study supports the authors’ theories about the development of Alzheimer’s. However, further research that adjusts for other known risk factors is needed before any practical recommendations can be made from the results.

Links To The Headlines

Doing puzzles ‘could speed up dementia’. Daily Mirror, September 2 2010

Brain teasers accelerate dementia – pick up a book instead. The Independent, September 2 2010

Keeping the mind active staves off dementia at first but speeds it up later. The Daily Telegraph, September 2 2010

Brain training may delay dementia. BBC News, September 2 2010

Links To Science

Wilson RS, Barnes LL, Aggarwal NT et al. Cognitive activity and the cognitive morbidity of Alzheimer disease. Neurology, [Published online before print] September 1 2010

“Newborn babies should not be given sugar as pain relief,” read the headline in The Guardian. The newspaper said the routine use of tiny amounts of sugar before minor medical procedures is common practice but “it does not work and may damage their brains”.

Current medical guidelines recommend that babies swallow sucrose (sugar) solution before minor hospital procedures, such as the newborn heel prick blood test, as sugar solution is safe and effective at reducing pain they will feel.

The conclusions of this small study (44 babies analysed from 59 recruited for the study) directly challenge existing medical practice, with the finding that sugar did not reduce pain measured by looking at brain activity in response to a heel prick. Previous studies had all looked for a change in the baby’s facial expression to know when the baby was in pain, rather than looking directly at brain activity. This method of measuring pain in babies may be more objective than interpretations of facial expressions, but more research is needed to prove this.

The study itself did not find that using sugar was associated with any ‘damage to newborn brains’, instead it explained that pain itself may affect a developing brain. If the lack of effect of sugar is confirmed in larger studies, then it can no longer be thought of as an effective pain relief drug for small babies.

Where did the story come from?

The study was carried out by a researcher from the Nuffield Department of Anaesthetics at the University of Oxford, along with colleagues from University College London and Great Ormond Street Hospital for Children. The study was supported by the Medical Research Council and published in the peer-reviewed medical journal The Lancet.

Several other newspapers including the Mail and the Mirror also covered this story and reported it fairly. They focused on the fact that pain may cause short or long-term adverse effects on the development of the infant brain and suggested that if sugar is merely a distraction then hugs or breastfeeding may work just as well.

What kind of research was this?

All babies have a heel prick blood test before they are eight days old to test for a variety of conditions. Currently, it is recommended that babies swallow sucrose (sugar) solution before the test to reduce any pain they may feel. Previous studies, including a systematic review of 44 studies, have suggested that sugar solution is safe and effective for reducing pain from minor hospital procedures.

In this double-blind, randomised controlled trial, the researchers wanted to find out if the sugar solution was actually reducing pain in the babies. The researchers explain that trials of pain relief in small babies are a challenge as the usual ways of reporting pain in clinical trials, such as asking for a description of the pain or using pain relief charts, cannot be used in babies. Usually in studies with babies, an observational pain score (premature infant pain profile – PIPP) is used. This combines video recordings made of the babies facial expressions (grimacing), as well as behavioural and physiological measures, such as oxygen use.

This study used an electroencephalography (EEG) cap to measure the electrical activity in the brain in response to pain as well as the usual PIPP response. The researchers monitored the brain activity of the babies during the heel prick test to look for a particular pattern of pain-specific brain activity, to see if the sugar solution caused a reduction in the pain response.

Care was taken to ensure no one involved in the study knew which babies had received which intervention.

What did the research involve?

The researchers carried out their study from February 2009 to March 2010. The participants were all healthy newborn infants born at 37–43 weeks of pregnancy and were less than eight days old when tested.

The researchers excluded babies from the study if they showed signs of tissue damage on the lower limbs, had previous surgery, serious illness or were born to diabetic mothers or opioid users. The babies were randomly assigned to receive either 0.5mL of a 24% of sucrose solution or an equivalent volume of sterile water on the tongue.

A non–painful control stimulus was used first in all babies. The heel prick device was placed on the heel but the blade did not puncture the skin. The solution was then placed on the tongue two minutes before the actual heel prick took place.

Recording electrodes were positioned on the scalp to record the EEG, using the EEG cap. The researchers also used videos to record the behaviour and the facial expressions of the infants along with heart rate and oxygen levels in the blood and reflex movements of the limbs during the heel prick.

The researchers analysed the results on 20 out of 29 from the sucrose group and 24 out of 30 allocated to the sterile water group. The dropouts were mainly due to technical failure of the EEG, for example because of excessive movement. Only one parent withdrew consent in the sterile water group.

What were the basic results?

The measure of brain activity after the painful heel prick did not differ significantly between infants who received sucrose: mean 0.1 (95% Confidence Interval [CI] 0.04 to 0.16) compared with those who received sterile water: mean 0.08 (95% CI 0.04 to 0.12) p=0.46.

The PIPP score, a combined measure of heart rate, oxygen levels and facial expression (grimacing) scored from the video, was significantly lower in infants given sucrose compared with those given sterile water. Furthermore, significantly more infants had no change in facial expression after sucrose administration, 7 of 20 given sterile water (35%) compared with none of 24 given sucrose (p<0.0001).

How did the researchers interpret the results?

The researchers say that oral sucrose does not significantly affect activity in neonatal brain or spinal cord pain circuits, and therefore might not be an effective pain reliever.

They say that the ability of sucrose to reduce the PIPP scores observed in newborn infants after a painful event should not be interpreted as pain relief.

Conclusion

This study has used objective measures of pain in a small sample of infants and used careful blinding and randomisation to reduce bias. There are a few limitations due to the study size, but the conclusions are likely to challenge the currently held belief that sugar is an effective treatment for the pain of minor procedures in infants. The limitations mentioned by the researchers were:

• The small sample size of 44 infants analysed, which could mean that this study was not powered to observe subtle effects that sucrose might have on the brain processes used for pain.
• A measure of pain in infants is necessarily indirect (because they cannot describe the sensation), and so even though the electrophysiological measures reported in this study are more objective it is not clear that they are measuring the conscious pain experience of the newborn infant.
• The significant reduction of PIPP scores with sucrose confirm the results of the systematic review that looked at this as their main outcome. 
• The drop out of 15 infants (25% of those recruited) may have affected the reliability of the results.

The study itself had not identified harms associated with the use of sugar and it is an extrapolation to suggest that the use of sucrose for newborn pain relief ‘may damage their brains’. This may be particularly alarming for parents or doctors to read and is not a finding of this study. There is growing evidence that some newborns’ experience of pain may have lasting adverse effects on their neurodevelopment but to state this in a way that suggests that a study has shown that using sugar causes damage to newborn brains is unhelpful.

The researchers suggest that this single-centre trial should be repeated in a larger sample of infants, and that the new EEG measurement method should be used to test the effect of other known pharmacological analgesic drugs, such as morphine. This seems like sensible advice.

Links To The Headlines

Newborn babies should not be given sugar as pain relief, says study. The Guardian, September 2 2010

Pain relief is not so sweet for babies. Daily Mirror, September 2 2010

A hug, the sugar-free way to ease baby’s pain. Daily Mail, September 2 2010

Links To Science

Slater R, Cornelissen L, Fabrizi L et al. Oral sucrose as an analgesic drug for procedural pain in newborn infants: a randomised controlled trial. The Lancet, [Early Online Publication] September 1 2010

Stevens B, Yamada J, Ohlsson A. Sucrose for analgesia in newborn infants undergoing painful procedures. Cochrane Database of Systematic Reviews 2010, Issue 1

Shah PS, Aliwalas LL, Shah VS. Breastfeeding or breast milk for procedural pain in neonates. Cochrane Database of Systematic Reviews 2006, Issue 3