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The grey matter of the brain contains high levels of the essential nutrient DHA. Although the role of DHA in the developing brain and in dementia has attracted attention, its influence on the brain of the healthy adult has been little considered. A total of 285 young adult females took 400 mg of DHA, in a double-blind, placebo-controlled trial, for 50 d. After 50 d, recently acquired information was more likely to be forgotten by those who had consumed DHA. No significant differences in mood, reaction times, vigilance or visual acuity were found.

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AIMS: Optimal care for out-of hospital cardiac arrest (OHCA) patients may depend on the underlying aetiology of OHCA. Specifically chest compression only bystander CPR may provide greater benefit among those with cardiac aetiology and chest compressions plus rescue breathing may provide greater benefit among those with non-cardiac aetiology. The aim of this study was to generate a simple predictor model to identify OHCA patients with non-cardiac aetiology in order to accurately allocate rescue breathing. METHODS: We used two independent cohorts of OHCA patients from a randomized pre-hospital trial and a prospective hospital registry (total n=3086) to assess whether the characteristics of age, gender and arrest location (private versus public) could sufficiently discriminate non-cardiac aetiology. We used logistic regression models to generate a receiver operator curve and likelihood ratios. RESULTS: Overall, 965/3086 (31%) had a final diagnosis of a non-cardiac cause. Using 8 exclusive groups according to age, gender, and location, the frequency of non-cardiac aetiology varied from a low of 16% (55/351) among men >age 50 in a public location up to 58% (199/346) among women <60 in a private location. Although each characteristic was predictive in the logistic regression model, the area under the curve in the receiver operating curve was only 0.66. The associated positive likelihood ratios ranged from 1 to 3 and the negative likelihood ratios ranged from 1 to 0.4. CONCLUSION: The results highlight the challenge of accurately identifying non-cardiac aetiology by characteristics that could be consistently used to allocate bystander rescue breathing.

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BACKGROUND: Cardiopulmonary resuscitation (CPR) is an essential part of the chain of survival, with early administration directly affecting the patient's chance of survival. Pre-arrival telephone CPR instructions provide callers who have no CPR training on how to undertake this intervention. With the emergency medical dispatcher unable to see the caller or the patient, it is possible that problems will arise, presenting barriers, that stop the caller undertaking effective CPR. OBJECTIVE: To examine how commonly barriers to telephone CPR occur and whether this affects the time it takes to perform the intervention. METHOD: A retrospective quantitative analysis was undertaken using a convenience sample of 100 emergency calls. Calls were identified in the emergency control room as cardiac arrests and confirmed by the responding paramedics as cardiac arrests. The calls were listened to, established if CPR instructions were given, if the instructions were followed, if anything hindered the instructions undertaken, and the time taken to reach key points. FINDINGS: 18 cases had bystander CPR administered. An additional 56 of cases had CPR instructions provided but "barriers" in 49% (n = 27) hindered the effectiveness of these. The median time to recognition of cardiac arrest was 40 seconds, with time to first ventilation being 4 min 10 s and time to first compression 5 min 30 s. These times were notably higher in those cases where a barrier to effective telephone CPR existed. CONCLUSIONS: Barriers to undertaking telephone CPR occurred with a high degree of frequency. These barriers affect the ability of the caller to perform rapid and effective telephone CPR.

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Although there are reports that breakfast influences both mood and memory, there has been no attempt to consider whether a subsequent snack is beneficial. One hundred and fifty young female adults either fasted or consumed breakfasts of either 10 or 50 g of carbohydrate (corn flakes). Half received a further 25 g of carbohydrate in the form of corn flakes after 1 1/2 h (snack). Predictably, those who ate breakfast, and/or a snack, reported feeling less hungry. The larger the caloric intake, the less subjects reported hunger. Those who consumed a snack reported a better mood. Eating a larger breakfast was associated with poorer mood later in the morning, an effect reversed by eating a snack. Memory for the word lists was not influenced by eating breakfast, however, 20 but not 60 min after a midmorning snack, more words were recalled. Those who had eaten breakfast, as opposed to fasting, did, however, spend longer trying to recall the words. This finding was interpreted as evidence that eating breakfast was associated with better motivation. On a number of occasions, better memory was associated with lower blood glucose levels. These findings support previous observations that better glucose tolerance was associated with better memory.

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There have been previous reports that supplements of phosphatidylserine (PS) blunted the release of cortisol in response to exercise stress and that it improved mood. The present study extended these observations by considering whether PS supplementation influenced subjective feelings of stress and the change in heart rate when a stressful mental arithmetic task was performed. In young adults, with neuroticism scores above rather than below the median, the taking of 300mg PS each day for a month was associated with feeling less stressed and having a better mood. The study for the first time reports an improvement in mood following PS supplementation in a sub-group of young healthy adults.

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The hypothesis that the ability to control blood glucose levels influence memory and other aspects of cognition was considered. Individual differences in the ability to control blood glucose were measured by giving a glucose tolerance test (GTT) to 46 young adult females. A factor analysis of a series of measures of glucose tolerance produced four dimensions. A week later, having eaten their normal breakfast, they took tests of memory, reaction times and vigilance. The speed with which blood glucose increased, having its lowest point in the GTT, was associated with memory measured a week later. While performing the tests those with higher levels of blood glucose on arrival in the laboratory had quicker reaction times when monitoring eight but not four, two or one lamps. The finding was interpreted as demonstrating that higher levels of blood glucose specially influence tasks placing higher demands on the brain.

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A recent major theory was that a meal high in carbohydrate increased the rate that tryptophan enters the brain, leading to an increase in the level of the neurotransmitter serotonin that modulates mood. Although such a mechanism may be important under laboratory conditions it is unlikely to be of significance following the eating of any typical meal. As little as 2-4% of the calories of a meal as protein will prevent an increased availability of tryptophan. Arguably the food with the greatest impact on mood is chocolate. Those who crave chocolate tend to do so when they feel emotionally low. There have been a series of suggestions that chocolate's mood elevating properties reflect 'drug-like' constituents including anandamines, caffeine, phenylethylamine and magnesium. However, the levels of these substances are so low as to preclude such influences. As all palatable foods stimulate endorphin release in the brain this is the most likely mechanism to account for the elevation of mood. A deficiency of many vitamins is associated with psychological symptoms. In some elderly patients folate deficiency is associated with depression. In four double-blind studies an improvement in thiamine status was associated with improved mood. Iron deficiency anaemia is common, particularly in women, and is associated with apathy, depression and rapid fatigue when exercising.

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RATIONALE: It is traditionally assumed that under normal conditions the brain is well supplied with glucose, its basic fuel. However, given the limited stores of glucose in the brain and its dependence on a continual peripheral supply of glucose, it was considered whether the availability of glucose, and the ability to efficiently utilise glucose, affects cognitive functioning. OBJECTIVE: There is increasing evidence that the provision of blood glucose influences memory. To date, the impact of blood glucose on non-memory task performance has received little attention. The present study investigated whether the performance of non-memory tasks was susceptible to the level of blood glucose. Two studies are reported in which the influence of a glucose containing drink on six cognitive tests was considered. RESULTS: The consumption of a glucose containing drink resulted in faster performance on the Porteus Maze and greater Verbal Fluency. Higher levels of blood glucose on arrival at the laboratory were associated with better performance on the Water Jars test. With both the Porteus Maze and Block Design tests, after taking a glucose drink, poor performance was associated with blood glucose that remained at higher levels. CONCLUSION: It was suggested that we should consider two physiological mechanisms, firstly, that an equilibrium develops between plasma and brain glucose, such that those with higher levels of blood glucose could be expected to have higher levels of brain glucose and secondly, whether there are individual differences in the efficiency with which glucose is taken from the blood; those with poor glucose control perform some cognitive tasks more poorly.

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There is a series of reports that failing levels of blood glucose are associated with enhanced cognitive functioning. The hypothesis was examined that declining blood glucose levels are associated with enhanced memory only when individuals are subjected to cognitive demand. Subjects consumed either a placebo or a glucose containing drink, and then either sat quietly for 20 min, or performed a vigilance task. All subjects then attempted to recall a list of words. In those who performed the vigilance task, and consumed a glucose drink, memory was better when blood glucose levels fell more markedly. Those whose blood glucose levels fell more markedly also produced fewer errors while performing the vigilance task. In no instance did a fall in blood glucose predict the memory of those who had not performed the demanding vigilance test.

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