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“Memory decline reversed in tests on monkeys,” reported The Daily Telegraph. The newspaper went on to say that “a cure for memory loss in middle and old age could be a step closer thanks to a drug which restores the brain to a more youthful state”.

This news story is based on research examining differences in the rate at which brain cells fired in monkeys of various ages. It then looked at the effect of several drugs on these rates. The researchers found that the rate of firing of specific brain cells decreased in older monkeys. After being given some of the drugs, the brain cell firing frequency in middle age and older adults increased.

The researchers say the continuous firing of these brain cells is needed for ‘working memory’; a type of memory essential for abstract thought and completing complicated tasks.

This was an interesting and well-conducted animal study that could have important implications for addressing age-related memory loss. However, much further research is needed before we can be confident that the results apply to humans and can be used as a treatment for memory loss.

 

Where did the story come from?

The study was carried out by researchers from Yale University in the US and was funded by the National Institute of Aging, a part of the US National Institutes of Health.

It was published in the peer-reviewed medical journal Nature.

The lead researcher and Yale University receive royalties from Shire Pharmaceuticals from the sales of extended-release guanfacine, a version of the drug used in this study.

Generally, the media reported the story accurately. Although much of the focus was on guanfacine, many other drugs were also included in the study.

 

What kind of research was this?

This was an animal study that examined the effect of a drug called guanfacine on working memory in middle aged and elderly monkeys. Working memory is responsible for retaining information that is no longer available. The ability to do this is essential for abstract thought and completing complicated tasks. The researchers say that tasks requiring working memory include summoning information from long-term memory, such as where you left your keys, or remembering a recent event, such as a new phone number.

This particular animal model was chosen because previous research has found that working memory starts to decline in middle age in both humans and monkeys.

The researchers looked at whether normal ageing alters the functioning of brain cells in a part of the brain called the prefrontal cortex, which is responsible for working memory. Successful working memory is believed to require continuous communication between brain cells in this region.

Changes in the chemical environment in this region can alter the number of times prefrontal cortex brain cells ‘fire’ (communicate with each other) by weakening the connections between the cells. It is thought that the less frequently these cells fire, the less reliable an individual’s working memory will be. Researchers believe that a particular molecule, called cAMP, keeps these brain cells from firing.

Animal studies are useful ways to conduct preliminarily research that could not be carried out in humans. Follow up clinical trials are needed before the results can be confirmed to apply to humans.

 

What did the research involve?

The researchers compared the frequency of brain cell firing in the prefrontal cortex during working memory tasks in young adult, middle age and elderly monkeys. They studied the performance of six monkeys: two young adults, two middle age, and two elderly monkeys, on working memory tasks which required them to remember the location of an object.

The researchers recorded the brain activity of each monkey during this task and measured the firing frequency in different types of brain cells. These measurements were used to compare the level of firing across the three age groups, and to establish a starting rate in each age group. Following this, the monkeys were treated with different drugs, and the firing rates were measured again and compared against these starting firing rates.

The researchers wanted to see whether treatment with the multiple drugs could increase the frequency with which the brain cells fired. They tested drugs that are known to decrease the action of cAMP, increase the action of cAMP, or attach to the parts of brain cells that cAMP acts on. The drugs were applied to the monkeys’ brains, and the same task was repeated while the researchers recorded the brain activity and measured the frequency with which the brain cells fired.

The researchers compared the firing frequency data from the first set of experiments to establish whether there were any differences between the different age groups. They then compared the data from the second set of experiments to data from the first set of experiments, to establish whether or not the drugs had any impact on brain cell activity while the monkeys were performing tasks that needed them to use working memory.

The working memory tasks used during this study are commonly used in both animal and human studies.

 

What were the basic results?

During the initial task, which required the monkeys to remember the physical location of an object, the researchers found that the older the monkey, the less frequently their brain cells fired. That is, the young adult monkeys’ brain cells fired the most frequently, and the elderly monkeys’ brain cells fired the least frequently. The change in firing rate was only found to occur in the brain cells that fire when the object was no longer present, as opposed to those brain cells that are responsible for recognising the presence of the object and therefore fire while the object was present.

When the same task was performed after the application of the different drugs, the researchers found that after being given the drugs that decrease the action of cAMP, the brain cell firing frequency in middle age and older adults increased. When drugs that increase the action of cAMP were used, the brain cell firing frequency decreased.

 

How did the researchers interpret the results?

The researchers say their results show a ‘physiological basis for age-related working memory decline in the primate brain’, and that this decline can be reversed through treatment of the brain’s chemical environment. They go on to say that ‘there is potential to restore at least some cognitive abilities in the elderly.’

 

Conclusion

This was a well-conducted animal study that examined the functional basis for a specific type of age-related memory loss. Research into memory and age-related memory loss is increasingly important as our society continues to age. However, results from animal studies, while promising, still need to be interpreted cautiously.

It is unclear at this point whether the drug used in this research will work the same way in humans. Well-designed clinical trials will be able to examine the impact of the drug on memory loss in humans. However, until the results of such trials are available, how much this study can apply to human memory loss is unclear.

Several other aspects of this study, and the interpretation of its results, are important to note:

• The study did not focus on comparing how well the monkeys actually performed the memory tasks, either between age groups or after the drugs were given. Rather, it focused on measuring brain activity, which is thought to be related to task performance. To get an accurate idea of the real effects of the drugs on monkeys of different ages, future studies will need to measure effects on task performance directly. Any such effects in monkeys may not carry over – or carry over safely – to humans. In short, there is a long way to go before this has a practical human application.
• The drug guanfacine mentioned in news reports, is not the only drug studied with beneficial effects. Other drugs that either decreased the action of cAMP, or blocked the specific part of the brain cell on which cAMP acts, also improved the firing frequency in older monkeys.
• In this study, the drugs were applied directly into the brain region, not taken in pill or injection form. This is clearly not feasible in humans, and whether or not the drug will have the same impact when delivered differently remains to be seen. However, the researchers do say that previous research has shown that guanfacine enhances working memory performance in animals when the subjects were given the drugs and it was not applied directly to the brain.
• The study only involved six monkeys, which makes the results and the differences found more difficult to interpret. However, as this was a preliminary study that aimed to examine the effect of the drug in principle, and the researchers plan to continue this study in humans in accordance with established clinical trial guidelines, the small sample size is less problematic.
• The type of memory loss examined in this study is a common characteristic of normal ageing, and includes things such as forgetfulness and distractibility. It is not the same as the memory loss seen in specific diseases such as Alzheimer’s disease.

Links To The Headlines

Forget-me-not: Memory loss could be reversible thanks to medical tweaks made to ‘mental sketch pad’. Daily Mail, July 28 2011

Memory decline reversed in tests on monkeys. The Daily Telegraph, July 28 2011

Links To Science

Wang M, Gamo NJ, Yang Y et al. Neuronal basis of age-related working memory decline. Nature, Published online July 27 2011

The Independent has today reported that scientists may have discovered the genetic cause of Proteus syndrome, the rare condition made famous by Joseph Merrick, whose life was portrayed in the film The Elephant Man. Born in 1862, Merrick had progressive facial and limb deformities that were characteristic of his condition.

Proteus syndrome, which affects less than one in a million people, causes overgrowth or enlargement of multiple tissues and organs, and raises the risk of a person developing tumours. It is thought that the growths are caused by genetic mutations arising within a cell in the body, which divides and grows into areas of mutated tissue.

This new research analysed the genetic make-up found within the cells of patients with Proteus syndrome, comparing how affected and unaffected areas differed. Researchers discovered that 90% of individuals with the condition had a specific mutation in the AKT1 gene in some of their cells.

The results from this study support the conclusion that a specific mutation in AKT1 gene causes Proteus syndrome. Ideally, other studies will confirm these results in a larger number of cases, as so far this study has examined 29 patients. However, as the disease is so rare, it is likely to be difficult to identify large numbers of patients. This work will help researchers to understand the biology of the disease better, and may help in the diagnosis of Proteus syndrome.

 

Where did the story come from?

The study was carried out by researchers from the US National Human Research Institute and other research institutes worldwide. It was funded by the Intramural research programme of the US National Human Genome Research Institute and the Proteus Syndrome Foundations in the United States and the United Kingdom. The study was published in the peer-reviewed New England Journal of Medicine.

The Independent covered this story accurately.

 

What kind of research was this?

This was a case-control study, which aimed to identify differences in the genetic make-up of cells from people with a rare condition called Proteus syndrome (cases) and people without the condition (controls). This is an appropriate study design for identifying genetic mutations that might be responsible for Proteus syndrome.

Proteus syndrome is a condition in which there are uneven areas of overgrowth or enlargement of multiple tissues and organs in the body, along with an increased susceptibility to the development of tumours. It is a rare disorder, with less than one person per million affected. It is thought to be caused by genetic mutation, with the mutation occuring soon after an embryo is formed (instead of being a hereditary mutation). This mutation is believed to occur in a somatic cell within the embryo: a somatic cell forms part of the body but is not one of the reproductive cells (in other words, it is not an egg or a sperm). Only this particular cell and the cells that arise from it will have this mutation, and other cells in the body will not carry it, which means that different cells within the same person will have different genetic sequences. Having different genetic sequences in different parts of the body causes individuals with Proteus syndrome to have “affected” and “unaffected” parts of their bodies.

 

What did the research involve?

The researchers obtained blood and tissue samples from 29 people with Proteus syndrome and people without the condition (controls). They then compared the genetic make-up of these samples.

The researchers took samples from both affected and unaffected areas of individuals with Proteus syndrome and analysed the sequences of all known genes in each sample. Affected areas were considered to be those that had visible signs of overgrowth or blood vessel anomalies, while unaffected samples were taken from areas of the body that did not have these signs. Unaffected tissue samples were sourced from areas that were as far from the affected areas as possible. This analysis was initially performed on DNA samples from six people with Proteus syndrome and six unaffected controls. The control samples were obtained from the parents and one unaffected twin of the individuals with Proteus syndrome.

The researchers compared the samples’ DNA sequences to look for genetic variations that were present in the affected tissues from people with Proteus syndrome but less often or not at all in their unaffected tissues, and not present in the DNA from unaffected controls. They focused on genetic variations that would affect the proteins produced by the cells.

The researchers then confirmed their initial observations by analysing more DNA samples. In total, they looked at 158 DNA samples from 29 patients with Proteus syndrome.

Once they identified a suitable candidate mutation, they also looked at how this mutation affected the protein made from the gene in question.

 

What were the basic results?

The researchers initially identified a mutation in the AKT1 gene that was present in the affected tissue samples, but not the unaffected tissue sample, from one individual with Proteus syndrome. This mutation would be expected to lead to an alteration of one of the amino acid “building blocks” that would be found within the AKT1 protein. This protein is involved in various processes, including the division process cells undergo to form new cells.

The researchers then looked for this mutation in cells and tissue samples from control individuals. None of the controls carried this AKT1 mutation. When the researchers analysed more cells and uncultured tissue samples from 29 patients with the Proteus syndrome, they found that 26 of the 29 patients (90%) carried the mutation in AKT1 in at least some of their tested cells and tissues.

However, three patients with typical Proteus syndrome did not carry the mutation. The researchers say that they only analysed between one and three samples from each of these patients, and that it was likely that these samples were negative by chance, as not every cell in an affected individual carries the mutation.

The researchers then demonstrated that this mutation causes the AKT1 protein to become “locked” in its active state; in other words, the form it would be found in when performing a function. They also note previous studies, which have found that mice genetically engineered to have an abnormally activated form of this protein display symptoms similar to Proteus syndrome.

Finally, they report that this mutation was previously found in the cells of some human cancers.

 

How did the researchers interpret the results?

The researchers concluded that some of the tissues of people with Proteus syndrome contain a mutation in the AKT1 gene that alters the activity of the AKT1 protein. They say that their findings, along with what is already known about AKT1, suggest that: “[constant] activation of the protein underlies the overgrowth and tumour susceptibility in these patients.”

 

Conclusion

This study has shown that mutations in the AKT1 gene are present in the affected tissues and cells from the majority of the patients tested, but are not present in samples from unaffected individuals. These results support the suggestion that the identified mutation in AKT1 could be causing the characteristic problems seen in Proteus syndrome.

So far, this study has examined 29 patients with the syndrome, and ideally other studies will confirm this result in a larger number of cases. However, given the rarity of the condition which affects fewer than one in every million people, it may be difficult to gather a larger sample population.

The knowledge gained from this study will help researchers to understand the biology of Proteus syndrome better, and may help in diagnosing it.

Links To The Headlines

Scientists discover genetic key to Elephant Man’s disfigurement. The Independent, July 28 2011

Links To Science

Lindhurst MJ, Sapp JC, Teer JK et al. A Mosaic Activating Mutation in AKT1 Associated with the Proteus Syndrome. NEJM, July 28 2011

“IVF children have bigger vocabulary than unplanned babies,” The Daily Telegraph has reported.

The news is based on a large study investigating how pregnancy planning, time taken to conceive and the use of infertility treatment (including IVF) influenced cognitive ability of children at ages three and five. Researchers found that unplanned children had lower cognitive ability scores than those who were planned, with, for example, differences in verbal ability at age five equating to a developmental delay of more than five months. However, once researchers considered the effect of factors such as socioeconomic status (parental wealth) this difference almost entirely disappeared, suggesting that pregnancy planning had virtually no direct influence.

The finding that pregnancy planning had little influence was not well documented in news coverage, and the greater implication of this study is that it highlights the strong influence that social and economic factors can have on the cognitive ability of children.

 

Where did the story come from?

The study was carried out by a collaboration of researchers from the University of Oxford, University of Essex and University College London. It was funded by a grant from the Medical Research Council.

The study was published in the peer-reviewed British Medical Journal.

The authors say that previous research shows children born after a prolonged time to conception and assisted reproduction are at greater risk of poor health, and some researchers have also reported lower cognitive scores in such children. They report that unplanned pregnancies also have poorer health outcomes in early childhood, but that there is little information on whether a child’s development is associated with pregnancy planning and intention to become pregnant.

The Daily Telegraph’s coverage was balanced overall. However, its headline emphasising differences between children conceived through IVF compared to those born after unplanned pregnancies was misleading. The study itself stated that these factors did not appear to influence cognitive development, as social and economic factors were likely to be behind the association.

 

What kind of research was this?

This study used data from the Millennium Cohort Study in the United Kingdom. The Millennium Cohort Study is a nationally representative prospective cohort study of 18,552 families across the UK. This study used a random sample of all enrolled infants born in 2000 to 2002 that were resident in the UK at nine months of age.

This study investigated how pregnancy planning, time taken to achieve planned conception and infertility treatment influenced cognitive development at ages three and five.

 

What did the research involve?

Parental interviews captured information on health and socioeconomic status as well as information about pregnancy planning and infertility treatment. Children’s cognitive abilities were tested at three and five years.

Mothers were asked if they had planned to conceive and how they felt when they discovered they were pregnant. Those for whom the pregnancy was planned were asked how long they took to conceive and if they received treatment to aid their conception. Women were then grouped into the following six categories:

• Unplanned (unexpected, unhappy about pregnancy)
• Mistimed (unexpected, happy about pregnancy)
• Planned (planned, time to conception <12months)
• Subfertile (planned,time to conception ?12months)
• Induced ovulation (planned, used drugs to induce ovulation)
• Assisted reproductive technologies (planned, used technologies such as in vitro fertilisation (IVF) or intracytoplasmic sperm injection).

The researchers used a measure called British Ability Scales (BAS II) to assess three elements of cognitive ability in the children. At age three children completed a naming vocabulary component, which assessed verbal ability.  This was repeated at age five, together with measures of non-verbal and spatial abilities. The results of the BAS II are adjusted for age and so indicated how a child’s cognitive abilities have developed relative to their peers.

In total 18,114 children were resident in the UK and eligible for the study. Of these, 11,790 (65%) completed cognitive tests and provided data on socioeconomic status at age three years. A similar number of children completed the verbal, non-verbal and spatial tests at age five.

The analysis was restricted to singletons (only children). The researchers first looked at the simple (unadjusted) relationship between pregnancy planning and children’s cognitive ability. They then assessed this relationship to take into account a range of other influencing factors, including age, smoking habits in pregnancy, socioeconomic status, family income and alcohol consumption. This gave the researchers an “adjusted” relationship, taking into account all these external influences.  This type of analysis is appropriate.

 

What were the basic results?

In total, 41% of children were born after an unexpected pregnancy – 15% of mothers who felt unhappy or ambivalent about the pregnancy (“unplanned pregnancy”) and 26% of mothers who were happy (“mistimed pregnancy”). Some 53%, of mothers reported a planned pregnancy conceived in less than 12 months. One per cent were born after assisted reproduction.

Pregnancy planning and cognitive ability score

In all unadjusted analysis, the unplanned children had lower cognitive ability scores than those who were planned. The difference between verbal ability score at age five, for instance, was equivalent to a developmental delay of more than five months.

However, after adjusting for other factors these differences almost entirely disappeared, equivalent to no developmental delay in cognitive ability. The authors say that socioeconomic status was the most important factor in the differences observed between the two groups and not pregnancy planning.

Subfertility, fertility treatment and cognitive ability score

The relationship between subfertility and fertility treatment and cognitive ability was less clear, as each group’s results differed across the three elements of cognitive ability assessed.

In unadjusted analysis, children who were born after assisted reproduction had better verbal ability scores than the planned children at ages three and five. These differences were equivalent to an average of three to four months difference in development between the groups. These differences were reduced after adjusting for other influencing factors.

Children born after fertility treatment had lower non-verbal ability scores than other children, equivalent to a developmental delay of two months on average. Spatial ability scores were also lower in children born after assisted reproduction equivalent to a delay of one and a half months. These results, however, were not statistically significant.

 

How did the researchers interpret the results?

The authors conclude that “pregnancy planning, subfertility or assisted reproduction do not adversely affect children’s cognitive development at ages three or five”. They state that the differences in the unadjusted analysis are almost entirely explained by differences in socioeconomic circumstances between the groups.

 

Conclusion

This was a large cohort study of singleton children that looked at how pregnancy planning, time to conception and infertility treatment influenced cognitive development at ages three and five.

This study provides good evidence that pregnancy planning, subfertility or assisted reproduction do not adversely affect children’s cognitive development at ages three and five, and that the cognitive differences found appeared to be due to social and economic factors rather than parental planning, unplanned pregnancy or the use of fertility treatment.

This conclusion is not surprising. Parents with improved socioeconomic circumstances are more likely to be able to choose or plan when pregnancies occur due to their greater economic means, which are  also likely to be associated with factors such as being more highly educated parents or being able to offer more parental involvement. These types of social and demographic factors are likely to have a large effect on cognitive ability during early childhood.

A few points to note:

• This study only looked at singletons (only children) so the findings may not be directly relevant to families of larger size.
• Cohort studies can suffer from bias if lots of information is missing on participants, particularly if they drop out as the study progresses. This study had only a small amount of missing data and so the conclusions of the study are unlikely to be affected.

Overall, this study highlights the strong influence of social and economic inequalities on cognitive ability in children rather than suggesting these are directly affected by the nature of a child’s conception.

Links To The Headlines

IVF children have bigger vocabulary than unplanned babies. The Daily Telegraph, July 28 2011

Links To Science

Carson C, Kelly Y, Kurinczuk et al. Effect of pregnancy planning and fertility treatment on cognitive outcomes in children at ages 3 and 5: longitudinal cohort study. BMJ 2011; 343:d4473

Many newspapers reported today that Ed Miliband, leader of the Labour party, has had successful surgery on his nose to correct a breathing problem. According to The Daily Telegraph, Miliband revealed in April that he has a condition called “sleep apnoea, which interrupts breathing during sleep, made worse by a deviated septum in his nose”. The Independent reported that the “hour-long NHS procedure took place at the Royal National Throat, Nose and Ear Hospital in central London”.

Obstructive sleep apnoea (OSA) is a relatively common condition that causes interrupted breathing during sleep. Most people with OSA snore loudly and their breathing may be noisy and laboured.

A deviated nasal septum occurs when the thin wall of cartilage between the two nasal cavities is slightly displaced to one side. If this displacement is significant it can obstruct breathing and cause snoring.

There are several treatments for sleep apnoea, depending on what is causing the breathing obstruction. Many cases can be treated by making lifestyle changes, such as losing weight, avoiding alcohol and quitting smoking.

Based on the news reports, Miliband’s sleep apnoea may have been caused or exacerbated by a deviated septum. One option for treating this is to have surgery called a septoplasty, which involves repositioning the septum with the aim of reducing snoring and disruption of the breathing pattern during sleep. It is important to note that not all people with OSA have a deviated nasal septum, and not all people with a deviated nasal septum have OSA or need surgery.

Anyone experiencing sleep disturbance or excessive snoring that is causing them concern should consult their doctor to discuss the best course of action for them.

Find more detailed information on sleep apnoea in Health A-Z.

Links To The Headlines

Ed Miliband’s nose operation proves a success. Daily Mirror, July 28 2011

Miliband nose goes under the knife in effort to stop snoring. The Independent, July 28 2011

Ed Miliband has nose job to get a good night’s sleep. Daily Express, July 28 2011

Ed Miliband undergoes successful nose operation. The Daily Telegraph, July 28 2011

Ed Miliband nose operation satisfies surgeons and Labour spin doctors. The Guardian, July 28 2011

“Calorie counts on menus prompt healthy choices,” BBC News has today reported, saying that US research has found it helps healthy eating “but only in a limited way”.

The research involved a survey of thousands of customers at 11 top fast food chains in New York City (NYC) before and after full implementation of regulations requiring chain restaurants’ menus to contain details of the calories in all menu items. The study aimed to assess the impact that labelling had upon customer choices, but found no overall difference in the total calories per purchase, though there were reductions at three fast food chains that accounted for 42% of all customers surveyed. Overall, 15% of customers reported that calorie labelling had informed their meal choice, and these people consumed fewer calories on average.

Although this study has value in being reportedly among the first to assess the effectiveness of a calorie-labelling regulation, there are some limitations. These findings are specific to fast food chains in New York, and a third of those surveyed came from impoverished neighbourhoods, therefore it cannot be assumed that displaying calorie information elsewhere and among other socioeconomic, cultural and ethnic groups will have the same effect. Also, the study cannot tell us what longer-term implications the regulations will have on health or obesity.

Research specifically looking at the effect of similar measures in the UK would be valuable.

 

Where did the story come from?

The study was carried out by researchers from institutions in New York and California and was funded by the City of New York and by the Robert Wood Johnson Foundation Healthy Eating Research Program. The study was published in the peer-reviewed British Medical Journal.

BBC News and The Guardian have accurately reflected the findings of this report in their main text, but their headlines take varying slants on the results. The BBC was more optimistic in suggesting that calorie information can aid healthy food choices, but The Guardian highlighted that it only influenced a relatively small proportion of customers.

 

What kind of research was this?

This research used cross-sectional customer surveys to asses the impact of regulations requiring chain restaurants in NYC to display details of the calorie content of all menu items. These surveys were given at several top fast food chains in spring 2007 and spring 2009, or before and after the implementation of the legislation. The study’s aim was to assess the impact that adding calorie labelling had upon customer choices.

This type of assessment is often the way that large public health programmes are assessed after they have been implemented. When interpreting the findings it is important to remember that factors other than the programme may be influencing any changes seen.

 

What did the research involve?

In 2006 a regulation was passed in NYC that required chain restaurants to display the calorific value for all items on menus and menu boards, as part of the US strategy to combat obesity. Following this step the city approved a second health code regulation in March 2008 requiring chain restaurants with 15 or more stores nationwide to list calorie information prominently on all menus, menu boards and item labels. When the policy was introduced, labelling the calories in fast food items was considered to be an innovative step and there was only limited data on the effectiveness the measure might have.

The study included a random sample of 275 food outlets from the total 1,625 that were said to be covered by the 2006 regulations.  The sample featured outlets belonging to 13 chains. These locations were assessed over nine weeks in spring 2007, and then followed in spring 2009 (but by this time 22 outlets had closed or did not allow further data collection).

The researchers say that in 2007 only one chain (Subway) provided calorie information, but only for a small number of items. However, by 2009 all chains included in the study were considered to be “largely in compliance with the new regulations”, although there were variations in the way the regulations were implemented, such as in the size and prominence of the information.

After excluding two coffee chains and their 109 outlets, the researchers were left with a sample from 168 outlets belonging to 11 fast food chains. They had set a goal to survey 55 customers at each outlet, aiming for an overall sample of at least 3,600 people in each sample year. From 12pm to 2pm on weekdays adult customers were approached as they entered the restaurant and asked to provide their register receipts when exiting and to complete a brief survey (which asked questions such as whether they saw calorie information and if this information affected their purchase).

The main outcomes the researchers examined were changes in average energy content (kcal) per purchase after regulation, and the average energy content of purchases made by customers who said that they used the calorie information when deciding what to order.

 

What were the basic results?

The final study sample across the 11 chains included 7,309 customers from the 2007 survey and 8,489
from the one in 2009. Overall, more than 80% of all customers were approached, of whom 60% responded. A third of receipts came from locations in very poor neighbourhoods, and McDonald’s and Subway together accounted for 58% of all receipts collected.

Overall, purchasing patterns were found to be similar in the two time periods, and average calories per purchase did not change (828 vs. 846 kcal), although slightly fewer customers purchased a drink in 2009 (54%, compared with 58% in 2007). There were reductions in average calories per purchase at three major chains, which accounted for 42% of customers surveyed (McDonald’s 829 kcal in 2007 vs. 785 in 2009, Au Bon Pain 555 vs. 475 and KFC 927 vs. 868). The average energy content increased at one chain (Subway 749 vs. 882 kcal).

In 2009, 15% of customers overall reported using the calorie information when deciding on their purchase for that day (18% of women and 13% of men). These 15% of customers purchased foods with  fewer calories on average (757 vs. 863). Customers in wealthier neighbourhoods were also more likely to use this information (19%) than customers in moderate-poverty (17%) or the poorest neighbourhoods (12%).

 

How did the researchers interpret the results?

The researchers concluded that, although there was no overall decline in calories purchased across the full sample, several major chains saw significant reductions between 2007 and 2009. After regulation, they say that one-in-six lunchtime customers used the calorie information provided, and these customers went on to make lower calorie choices.

 

Conclusion

Fast food intake has often been linked to higher overall calorie intake, but information on the fat, sugar and calorie content of the food in restaurants and takeaways is often unavailable. There is currently a great deal of discussion over how similar labelling schemes might be adopted and what benefits they might have to the public. This particular study surveyed a large number of customers in 11 fast food chains in New York, both before and after the adoption of new regulations requiring them to display calorie content on their menus.

The implications of this study’s results are themselves open to debate, as illustrated by the slightly different slants offered by BBC News and The Guardian. The BBC has positively highlighted the fact that around 15 % of customers reduced their calorie intake in response to the information, while The Guardian has focussed on the fact that it made no impact on most consumers.

In order to assess the implications of the study’s results it is important to look at the research in context:

• These findings are specific to fast food chains in NYC, and a third of those surveyed came from very poor neighbourhoods. It cannot be assumed that the effect of displaying calorie information elsewhere and among other socioeconomic, cultural and ethnic groups will be the same as in this particular case.
• Surveys found no overall difference in the calorific content of purchases across the 11 chains, though three individual fast food chains did demonstrate reductions in calories per purchase after the regulations. Although this study cannot confirm either way, it may be the case that the regulations have lead food vendors to reduce the calories in their food items, meaning that the regulations might have some impact beyond simply changing consumer’s eating habits.
• From this study it is not yet clear whether the regulations will have any longer term effects on people’s health or weight.
• While this study can tell us about the calories in individual portions it cannot provide important information such as how frequently these people were purchasing fast food, whether it made people avoid fast food altogether, or whether labelling affected their other dietary choices. It might be the case that people still buy the same products but reduce the frequency of their visits in response to calorie information, or choose less calorific options for their meals later in the day.
• The surveys were conducted at lunchtime on weekdays in NYC: it may be the case that lunch choice was dictated by necessities such as needing to quickly get lunch. The study does not tell us about how people might choose food at less busy times such as weekends or evenings, when people have more time to consider their choices.

Overall the study provides only a partial representation of how calorie labels on fast food might influence eating habits, and probably only represents the specific setting and legislation of New York. That said, it is nevertheless of value as a means of examining how similar programmes could be implemented, and is said to be among the first to assess the population-level effects of a calorie labelling regulation.

The authors of the report say that in UK, 28 organisations have pledged to implement similar labelling in 2011 as part of the Department of Health’s voluntary Responsibility Deal programme, and these include some food chains that have been required to provide calorie labels in NYC. Similar before-and-after studies in the UK would be valuable for understanding the impact of the scheme.

Links To The Headlines

Calorie counts on menus ‘prompt healthy choices’. BBC News, July 27 2011

Fast-food study finds calories count for little for most customers. The Guardian, July 27 2011

Links To Science

Dumanovsky T, Huang CY, Nonas CA et al. Changes in energy content of lunchtime purchases from fast food restaurants after introduction of calorie labelling: cross sectional customer surveys. BMJ 2011; 343:d4464

Scientists have revealed that “people have bigger brains the further north they hail from”, The Sun reported. However, it added, this has nothing to do with them being more intelligent than southerners, but because they have to cope with less light.

This research investigated whether there is an association between the size of eye sockets and the brainpan in the skulls of people from around the world and the distance to the equator. Those who came from places further from the equator seemed to have larger eyes and brains. The researchers thought that this physical difference would help people to detect the lower levels of light of these areas.

The finding needs confirmation in further research, as it only looked at 73 skulls, and it is not known if these skulls are representative of the native peoples of the areas that they were reported to come from.

As most newspapers reported, if this difference does exist, it doesn’t mean that people from more northerly areas are more intelligent. Also, this study compared the skulls of people from countries around the world, and averaged measurements and latitudes within countries. As such, it is not clear whether there are any differences between people in the south of the UK and the north. While the study is interesting and may add to our knowledge of human evolution, this study is unlikely to have any practical application to human health.

 

Where did the story come from?

The study was carried out by researchers from the University of Oxford. Funding was provided by the British Academy and the Boise Fund at the University of Oxford.

The study was published in the (peer-reviewed) medical journal Biology Letters.

Despite slightly misleading headlines, the media generally reported the story accurately. Most clarified that any increase in brain size was probably confined to areas responsible for processing visual information and not due to increased intelligence.

 

What kind of research was this?

This was a cross-sectional study that aimed to investigate whether there are any evolutionary associations between eye socket size, brain size and the person’s distance from the equator. The study was carried out using skulls housed in the Oxford University Museum of Natural History and the Duckworth Collection at the University of Cambridge.

Previous research in animals has shown that low light conditions (such as those found in regions further from the equator) are associated with larger eyes. Larger eyes have also been found to be associated with larger areas of the brain responsible for processing visual information in both animals and humans.

Cross-sectional studies are able to describe associations, but cannot provide causative explanations on their own.

 

What did the research involve?

Based on previous findings in both animal and human studies, the researchers had a theory that the further away from the equator a population lived, the larger their eyes and brains would be. This theory is based on the premise that these populations would have less daylight than those who lived closer to the equator, and so natural selection would result in a better ability of seeing and detecting detail in low light. This process would take place over tens of thousands of years, and result in larger eyes. Similarly, the regions of the brain that process visual information would be bigger.

To test this theory, the researchers compared the size of various parts of skulls from different countries around the world and the distance of that country to the equator. They measured the cranial capacity (volume of the space inside the skull), orbital volume (volume of the space inside the skull’s eye socket) and foramen magnum (size of the large hole at the base of the skull through which the brain connects to the spinal cord) in the skulls of 73 healthy adults. These skulls were drawn from 12 different native populations found at various distances from the equator. Cranial capacity was used as an approximation of brain size, orbital volume as an approximation of eye size, and foramen magnum dimensions as an approximation for overall body size. The researchers also analysed the genetic background of the skulls, and controlled for genetics in their analysis.

The researchers then found the average brain, eye and body size for each population, and analysed this data according to the distance from the equator the population lived. They also estimated the level of light and average temperature in each country. Average temperature information was collected in order to test the possibility that the larger eye socket provided more room for insulating fat needed to protect the eye at lower temperatures. During the data analysis, the temperature and foramen magnum measurement were used to account for any role that climate or body size might play in eye and brain size.

 

What were the basic results?

The researchers found that living further from the equator was associated with having larger eye sockets and cranial capacity. Neither average environmental temperature nor average body size explained this relationship, as the association held when both measurements were taken into account.

 

How did the researchers interpret the results?

The researchers say their results suggest that: “that there has been selection for larger eyeballs under progressively lower light conditions”. In other words, larger eyeballs are found in populations that live in regions with less light and shorter days. They further say that previous research has shown that as human eyeball size increases, increases are also seen in the brain regions responsible for processing visual information, which is likely to explain the associated increase in cranial capacity.

Based on these results, the researchers intend to conduct further research to examine whether ability to detect details is different in populations at varying latitudes.

 

Conclusion

This study found that the skulls of people who lived further from the equator had structural differences that suggested they had bigger brains and eyes than people living nearer the equator. Importantly, brain size as described in this study does not equate to intelligence. The researchers suggest that increases seen may be due to increases in visual processing areas of the brain. The researchers also propose that this may have come about through evolutionary processes, which are evident only on a population level, not an individual level. This means that differences between groups may only be seen if we look at population as a whole, and that these changes have occurred very gradually over time.

This research describes average differences across populations, which likely took tens of thousands of years to develop. It also looks at averages across the globe, not within any given country. Although The Sun and many of the newspapers reported that these differences would be evident between northerners and southerners, this research looked at people in different countries at different latitudes around the world, and did not compare people within this country. Therefore it does not tell us whether there are any differences between people living in the north and south of the UK.

There are a number of other points to note:

• The study measured total skull volume and eye socket volume. The assumption is that larger skull and eye socket volume is associated with larger brain and eye size, although it is not possible to say for sure whether this was the case. There are also hypotheses made about the cause of these differences being the lower light in northerly areas. With evolutionary biology, it is often difficult to prove why changes in the past occurred, and researchers make hypotheses to explain their observations, and adapt these as needed when new information becomes available.
• The study was relatively small – analysing data from 55 skulls. Ideally, larger studies would be needed to confirm the findings.
• A study of living individuals could use for example, brain scans and vision tests to obtain similar data for living individuals from different latitudes.

This study aimed to describe trends across populations, and to look at how different populations might adapt to different environmental conditions. While it adds to the knowledge of human evolution, it does not have much practical impact to human health.

Links To The Headlines

How dark winters meant bigger human brains and eyeballs. BBC News, July 27 2011

It’s grim up North… which gives the locals bigger brains. Daily Mail, July 27 2011

Northerners have bigger brains, scientists reveal. The Sun, July 27 2011

Northerners have bigger brains say scientists. Daily Mirror, July 27 2011

Why northerners have bigger brains. Daily Express, July 27 2011

Size does matter: Northerners have bigger brains than Southerners (to see clearly in lower light levels). Daily Mail, July 27 2011

People at darker, higher latitudes evolved bigger eyes and brains. The Guardian, July 27 2011

Links To Science

Pearce E and Dunbar R. Latitudinal variation in light levels drives human visual system size. Biology letter 2011, Published online before print July 27

The Daily Telegraph reported that, “women who drink cranberry juice to ease urinary tract infections would be better off sticking to a low dose of antibiotics.”

The news coverage is based on a trial of whether cranberry tablets are ‘as good as’ at preventing urinary tract infections (UTIs) in premenopausal women who are prone to recurrent infections. Women with recurrent UTI (three or more in a year) are often given antibiotics as a preventative.

This 12-month study found that, compared to antibiotics, cranberry tablets were of no benefit at preventing UTIs in these women. The study had some limitations, including a high drop out rate, and so doesn’t represent the last word in whether cranberry juice can help in this way.

Importantly, this study did not assess whether cranberries have a preventative effect relative to no treatment. A Cochrane Systematic Review found that cranberry products reduced the recurrence of UTIs after 12 months treatment compared to placebo. However, like the current study, it found that the trials had a large number of participants that dropped out and that the optimum dose was not known.

Further research to see whether there is an optimum dose of cranberry to prevent UTIs is warranted. Taking preventative antibiotics is not ideal, and can lead to antibiotic resistance occurring. This study highlights the need for continued research for new non-antibiotic treatments for recurrent UTIs.

 

Where did the story come from?

The research was conducted by researchers from various medical centres in The Netherlands. The study was funded by the Netherlands Organisation for Health Research and Development and was published in the peer reviewed medical journal Archives of Internal Medicine.

The Daily Telegraph report does not say that this was a preventative treatment for women who were prone to recurrent UTIs. Although it mentions that cranberry capsules were used in the article, the top section implies that cranberry juice was assessed for treatment of active infections, which was not the case.

 

What kind of research was this?

The aim of this study was to compare the effectiveness of antibiotics to cranberry extract at preventing UTIs in a group of premenopausal women who were prone to getting them.

This was a ‘non-inferiority trial’, meaning that it tested whether a new treatment (in this case the cranberry extract) is equivalent to an existing standard treatment (trimethoprim-sulfamethazole (TMP-SMX). TMP-SMX is a standard antibiotic used in the treatment of UTIs.

The participants, who all had at least three infections over one year, were given either the extract or the antibiotic for 12 months.

The researchers said that for premenopausal women who have three or more UTIs a year, low-dose preventative antibiotics are usually recommended. However, this has the risk of leading to drug resistance not only of the bacteria that cause the infection but also the normal bacteria that live in that area. Therefore, alternative methods are needed.

Cranberries have been used for the prevention of UTIs for many years but it has not been established how they work. The researchers therefore wanted to see whether a cranberry tablet would prevent UTIs to a similar extent to antibiotics.

Women are, in general, at higher risk of UTIs compared to men. This is due to the short urethra and the close proximity of the urethral opening to the anus (which can allow transfer of bacteria such as E. coli from the digestive tract). Activities such as sexual intercourse can increase the likelihood of bacterial transfer.

 

What did the research involve?

The researchers recruited 221 premenopausal women who were over 18 years of age, who had self-reported at least three symptomatic UTIs in the past year. The women were from the Netherlands and were recruited between January 2005 and August 2007. The study excluded women who had a UTI at the time of enrolment or who had taken antibiotics or cranberries in the past two weeks.

Women with allergies to the TMP-SMX antibiotic were excluded, as were women taking oral anticoagulants or those who had renal stones as taking cranberries may be contraindicated in these women. The study also excluded women who were pregnant or planning pregnancy, breastfeeding or had previously had a kidney transplant.

The women were randomised to either receive for 12 months:

• One tablet with 480mg TMP-SMX at night, and one placebo capsule twice daily (110 women)
• One capsule with 500mg cranberry extract (Cran-Max, Proprietary Nutritionals Inc, Kearny, New Jersey) twice daily, and one placebo capsule at night (111 women)
  Neither the participants nor the researchers knew which tablets the participants were taking. The participants were told not to use any other antibiotic or cranberry treatment alongside their study treatment for the course of the study.

The researchers collected demographic and clinical characteristics of the women at enrolment. The women were asked to collect a urine and faeces sample (to assess E Coli) just before starting the study treatments. They did this once a month for the 12-month test period and for another three months after they had stopped taking the study medication. During these times the women were also asked about any UTI symptoms, side effects, infections other than UTIs or whether they had taken antibiotics for any reason.

After 12 months (or earlier if women dropped out of the study) they were asked to guess which treatment they had received.

The researchers assessed the bacterial composition of the samples, the number of recurrences of UTIs the women experienced and whether the E. coli bacteria in the samples were resistant to TMP-SMX.

 

What were the basic results?

The researchers found that after 12 months, the cranberry group experienced on average more symptomatic UTIs than the TMP-SMX group. On average there were four infections in the cranberry group [95% confidence interval CI 2.3 to 5.6] compared to 1.8 in the antibiotics group [95% CI 0.8 to 2.7]).

The cranberry group also had a higher proportion of women who had experienced at least one symptomatic UTI (78.2% versus 71.1% in the antibiotic group). Women in the cranberry group had their first recurrence on average four months after starting treatment compared to eight months with the antibiotic group.

However, after one month of using TMP-SMX, resistance to this antibiotic had increased from around 21.1% – 27.8% to 72.5% – 90.5% in both the faeces and the urine samples. Three months after stopping treatment, the bacterial resistance had returned to the same levels as before treatment had started. Antibiotic resistance did not increase in the cranberry group.

In both groups, many people did not complete follow-up to 12 months. In the TMP-SMX group, only 57 out of 110 reached their 12-month assessment. In the cranberry group, 53 out of 111 had follow-up at 12 months. Reasons for not completing the study included, lack of efficiency of the treatment leading to withdrawal, burden of the study leading to withdrawal, and adverse events or losing participants to follow-up.

Cranberries and TMP-SMX were equally well tolerated with similar levels of mild adverse effects. At the end of the study the participants were not able to guess which treatment they had been on.

 

How did the researchers interpret the results?

The researchers said, ‘in premenopausal women, TMP-SMX, 480 mg once daily, is more effective than cranberry capsules, 500mg twice daily to prevent recurrent UTIs, at the expense of emerging antibiotic resistance’.

 

Conclusion

This was a well-conducted trial designed to see whether cranberry tablets were ‘as good as’ preventative antibiotic tablets at preventing recurrent UTIs in premenopausal women who were prone to UTI recurrence. Although the study showed that antibiotic treatments were more effective, it also found that antibiotic resistance became more prevalent in women taking them.

UTIs are common in women, and a single UTI is usually treated by a one-off three-day course of antibiotics. This study was specifically investigating women with recurrent UTI, which is usually defined as a woman who has three or more UTIs in one year. Such women are at higher risk of regular infections and they may be given preventative antibiotics. Therefore, no assumptions should be made from this study about the effect of cranberry tablets and antibiotics at treating UTIs in women who are not prone to recurrence in the general population.

There were high withdrawal rates in both groups, and any long-term preventative treatment needs people to keep on taking it. The researchers said that in the cranberry group, women experiencing higher recurrence were more likely to drop out, but that they had adjusted for these in the analysis. They also pointed out that they did not check whether people had taken the tablets, which may have meant that people did not take the complete course of treatment.

This study found that cranberry tablets (at that dose) were not beneficial compared to antibiotics for preventing UTI infections. However, taking prophylactic antibiotics is not ideal as this may lead to antibiotic resistance occurring. This study highlights the need for continued research for new non-antibiotic treatments for recurrent UTIs.

This study did not look at the effect of taking cranberry tablets compared to no treatment and it is not possible to say that cranberry products have no benefit based on this trial. A Cochrane review (updated in 2007) found that cranberry products taken as a preventative treatment reduced the recurrence of UTIs after 12 months treatment compared to placebo, but like the current study found that the trials had a large number of participants that dropped out. It was noted in the Cochrane review and the current study that the optimum dose of cranberry for the prevention of UTIs is not clear. A second Cochrane review (updated in 2010) assessed the evidence for cranberries to treat an active UTI, and the researchers concluded that there were a lack of published randomised controlled trials and so it was not possible to determine the effect of cranberries to treat UTIs.

Women are at higher risk of UTIs than men due to the short urethra and the close proximity of the urethral opening to the anus. Women who are experiencing regular UTIs should always consult their doctor.

 

Ways for all women to help prevent UTIs include:

• drinking plenty of water
• always urinating whenever you feel the need (not holding on)
• wiping front to back (to avoid transfer of bacteria from the anus to the urethra)
• avoiding using heavily scented shower gels or soaps or feminine hygiene sprays
• Activities such as sexual intercourse can increase the likelihood of bacterial transfer, and washing the genital area prior to having sex, or emptying the bladder after sex may help

Links To The Headlines

Drugs beat cranberry cure. The Daily Telegraph, July 16 2011

Links To Science

Beerepoot MAJ, ter Riet G, Nys S, et al. Cranberries vs Antibiotics to Prevent Urinary Tract Infections. Archives of Internal Medicine 2011; 171:1270-1278

 

“A continuous night’s uninterrupted sleep may be the essential requirement for a good memory,” The Independent has reported. The newspaper added that it isn’t just the amount of sleep that is important for memory formation, but also enjoying sleep that is not interrupted.

The news is based on research carried out using mice that were genetically modified so that a particular group of nerve cells in their brains could be stimulated using light. Periodically stimulating the cells with pulses of light made the mice wake up briefly and then quickly return to sleep. This technique was unique in that it allowed the researchers to study specifically the “fragmentation” of sleep ? in other words, the effect of interrupting a period of sleep but not altering the overall quality or length of the sleep.

The researchers then examined how fragmentation of sleep affected the mice’s ability to remember objects that they had previously seen. They found that, compared to ordinary mice, these mice showed less familiarity with the objects when subjected to fragmented sleep.

As with all animal studies, the results of this well-conducted research currently has limited implications in humans. It remains to be seen whether fragmented sleep can affect memory in humans and, if so, how often sleep would need to be disturbed over the course of the night for this to be the case.

 

Where did the story come from?

The study was carried out by researchers from Stanford University. No funding source was disclosed in its research paper. The study was published in the peer-reviewed scientific journal Proceedings of the National Academy of Science (PNAS).

The research was described well by the newspapers, All emphasised that the study was carried out in mice.

 

What kind of research was this?

This was an animal study that investigated the effect of disturbed sleep on memory in mice. The researchers say that sleep is characterised by several features, such as duration, intensity and continuity, but that previous techniques in sleep research were not able to manipulate single aspects of sleep without interrupting others. For example, most traditional methods of sleep deprivation used in experiments disrupted the composition of sleep by disturbing  individuals so that the proportion of sleep spent in the rapid-eye-movement (REM) phase is reduced, which inadvertently disrupts sleep quality, continuity and in most cases sleep duration. In this experiment, the researchers created genetically modified mice in which they could activate certain brain cells (neurones) that play a role in the waking process. By doing this they could “fragment” sleep in mice without affecting its overall amount or intensity. They then carried out memory tests in the mice.

This exploratory research has the advantage of being able to manipulate selectively just one aspect of sleep, which would be difficult to do in humans. However, as with all animal studies the direct relevance to humans may be limited without follow-up work to see how similar mice and human sleep and memory processes are.

 

What did the research involve?

The researchers used a technique called optogenetics, which allows certain genes to be switched on when they are stimulated with light. In this case, the researchers genetically engineered mice to possess a particular group of neurones that could be activated through light exposure. These genetically modified neurones are involved in regulating how much of a stimulus is needed for the mouse to be aroused from their sleep.

The first step was to develop a programme of light stimulation that would cause the genetically engineered mice to have fragmented sleep without affecting other features of sleep such as sleep time. The researchers recorded the mice’s sleep patterns by monitoring their brainwaves with an EEG and observing muscle twitches. Their programme disrupted sleep continuity but did not appear to have an effect on the amounts of non-REM or REM sleep or the length of time the mice were asleep for when compared to control mice. By looking at the brainwaves the researchers could also verify that sleep quality was not affected.

The researchers said that one of the problems with researching the effect sleep has on memory is that the research procedures may lead to stress, which may itself have an effect on memory. This could mean that the research would be measuring the effect of stress rather than absence of sleep on memory. They therefore compared the amount of the stress hormone corticosterone in the genetically modified mice compared with control mice. They also looked at the behaviour of the mice for signs of anxiety – anxious mice tend to spend more times at the boundaries of a pen and are reluctant to spend time in the centre.

To test their memory the researchers took advantage of the fact that mice tend to explore new objects more than familiar ones. The researchers allowed the mice to explore an object and 24 hours later placed a new object alongside the familiar one to measure how long the mouse spent with the new object relative to the familiar one. It is expected that if the mice remember the first object they will spend less time exploring it and more time with the novel object. In theory, if the mice do not remember the object from the training session they would spend a similar amount of time exploring each object.

 

What were the basic results?

The researchers found that the genetically modified mice were no more stressed than the control mice: they had similar corticosterone levels and showed similar levels of anxious behaviour.

Following “training” time spent with an object, the genetically modified and control mice were stimulated with a light shone into their brain every 60 seconds during their first four hours of sleep. When the mice were exposed to the familiar object and a novel object when they woke, the control mice spent a greater proportion of their time exploring the new object than the genetically modified mice did. This suggests the control mice had formed a greater memory of the object during training time.

The researchers found that decreasing the frequency of light stimulation to once every two minutes fragmented sleep to a lesser degree than the 60-second protocol they had used in earlier tests. Stimulation once every two minutes did not affect memory formation.

 

How did the researchers interpret the results?

The researchers said that their research methods were a “non-stressful, non-pharmacological means of manipulating a specific feature of animal sleep through the activation of its own arousal mechanisms”. They say that they have shown that sleep continuity, independent of the amount of sleep achieved, “is critical for learning and memory in mice”. They suggest that: “there is a minimum length of non-REM sleep necessary for memory consolidation”.

 

Conclusion

This animal research used an ingenious approach to disrupt one aspect of sleep to show that continuous sleep in mice improves the ability to consolidate memories. Although well-conducted research, this was an animal study and its current implications for humans is limited.

Several of the newspapers, although highlighting that the study was conducted in mice, related this research to human sleep conditions such as sleep apnoea, in which a temporary halt or disturbance in breathing pattern causes a person to wake up. However, although the current animal study has set a minimum length of uninterrupted sleep needed for memory formation in mice, this memory-formation threshold would need to be determined for humans. Although people with sleep apnoea are like to have fragmented sleep, without direct study of the issue we cannot tell whether this is sufficient to affect memory.

This mouse research warrants further follow-up, particularly using experimental designs that can quantify the degree of fragmented sleep in humans are needed to see if these findings relate to humans.

Links To The Headlines

Fragmented sleep ‘harms memory’. BBC News, July 26 2011

Undisturbed night’s sleep needed for good memory. The Independent, July 26 2011

Uninterrupted sleep may be better for your memory than quality and length of sleep. Daily Mirror, July 26 2011

Links To Science

Rollsa A, Colasb D, Adamantidis A et al. Optogenetic disruption of sleep continuity impairs memory consolidation. PNAS [Published online before print] July 25 2011