New paper – Executive summary EHI expert conference

January 8th, 2016

Benton, D., Braun, H., Cobo, J.C., Edmonds, C., Elmadfa, I., El-Sharkawy, A., Feehally, J., Gellert, R., Holdsworth, J., Kapsokefalou, M., Kenney, W.L., Leiper, J.B., Macdonald, I.A., Maffeis, C., Maughan, R.J., Shirreffs, S.M., Toth-Heyn, P., Watson, P. (2015). Executive summary and conclusions from the European Hydration Institute expert conference on human hydration, health, and performance. Nutrition Reviews, 73 (S2), 148-150.

On April 7–8, 2014, the European Hydration Institute hosted a small group of experts at Castle Combe Manor House, United Kingdom, to discuss a range of issues related to human hydration, health, and performance. The meeting included 18 recognized experts who brought a wealth of experience and knowledge to the topics under review. Eight selected topics were addressed, with the key issues being briefly presented before an in-depth discussion. Presented here is the executive summary and conclusions from this meeting.

New paper – Developmental trajectories of grey and white matter in dyscalculia

October 15th, 2013

Developmental trajectories of grey and white matter in dyscalculia

Ranpura, A., Isaacs, E.B., Edmonds, C.J., Rogers, M., Lanigan, J., Singhal, A., … Butterworth, B.


Developmental dyscalculia is a significant neural deficit with broad social impact. A number of techniques have been used to identify the brain basis of dyscalculia, and many of these have highlighted the role of the intraparietal sulci and a left fronto-parietal network in the representation of core number skills. These studies offer conflicting explanations of the neurobiological deficits associated with dyscalculia, and to date few studies have elucidated the timeline of cortical changes involved. Here we report a volumetric study comparing well-characterized dyscalculic learners aged from 8 to 14 years with tightly matched controls. Using automated cortical parcellation of anatomical MRI, we show that the posterior parietal and fronto-parietal systems in dyscalculia may undergo abnormal development during the pre-teenage and teenage years. As a result, the present study more clearly characterizes the underlying neural basis of dyscalculia than previous studies have hitherto achieved.

New paper – Strategy modulates spatial perspective- taking: evidence for dissociable disembodied and embodied routes

October 15th, 2013

Strategy modulates spatial perspective- taking: evidence for dissociable disembodied and embodied routes

Gardner, M.R., Brazier, M., Edmonds, C.J., & Gronholm, P.


Previous research provides evidence for a dissociable embodied route to spatial perspective-taking that is under strategic control. The present experiment investigated further the influence of strategy on spatial perspective-taking by assessing whether participants may also elect to employ a separable “disembodied” route loading on inhibitory control mechanisms. Participants (N=92) undertook both the “own body transformation” (OBT) perspective-taking task, requiring speeded spatial judgments made from the perspective of an observed figure, and a control task measuring ability to inhibit spatially compatible responses in the absence of a figure. Perspective-taking performance was found to be related to performance on the response inhibition control task, in that participants who tended to take longer to adopt a new perspective also tended to show a greater elevation in response times when inhibiting spatially compatible responses. This relationship was restricted to those participants reporting that they adopted the perspective of another by reversing left and right whenever confronted with a front-view figure; it was absent in those participants who reported perspective-taking by mentally transforming their spatial orientation to align with that of the figure. Combined with previously published results, these findings complete a double dissociation between embodied and disembodied routes to spatial perspective-taking, implying that spatial perspective-taking is subject to modulation by strategy, and suggesting that embodied routes to perspective-taking may place minimal demands on domain general executive functions.

New paper – Subjective thirst moderates changes in speed of responding associated with water consumption

October 15th, 2013

Edmonds, C.J., Crombie, R., Gardner, M.R. (2013). Subjective thirst moderates changes in speed of responding associated with water consumption. Frontiers in Human Neuroscience; Nutritional influences on human neurocognitive functioning.

Participants (N=34) undertook a CANTAB battery on two separate occasions after fasting and abstaining from fluid intake since the previous evening. On one occasion they were offered 500 ml water shortly before testing, and on the other occasion no water was consumed prior to testing. Reaction times, as measured by Simple Reaction Time (SRT), were faster on the occasion on which they consumed water. Furthermore, subjective thirst was found to moderate the effect of water consumption on speed of responding. Response latencies in the SRT task were greater under the “no water” condition than under the “water” condition, but only for those participants with relatively high subjective thirst after abstaining from fluid intake overnight. For those participants with relatively low subjective thirst, latencies were unaffected by water consumption, and were similarly fast as those recorded for thirsty participants who had consumed water.  These results reveal the novel finding that subjective thirst moderates the positive effect of fluid consumption on speed of responding. The results also showed evidence that practice also affected task performance. These results imply that, for speed of responding at least, the positive effects of water supplementation may result from an attenuation of the central processing resources consumed by the subjective sensation of thirst that otherwise impair the execution of speeded cognitive processes.

New paper – Drink availability is associated with enhanced examination performance in adults

May 17th, 2013

Published in Psychology Teaching Review (2013), 19(1) 54-62

Chris Pawson (UEL), Mark Gardner (Westminster), Sarah Doherty (UEL), Laura Martin (UEL), Rute Soares (UEL) and Caroline Edmonds (UEL)


While dehydration has negative effects on memory and attention, few studies have investigated whether drinking water can enhance cognitive performance, and none have addressed this in a real-world setting. In this study we explored the potential benefits of the availability of water for undergraduates. The exam performance of students who brought drinks in to exams was compared with those that did not for three cohorts of undergraduates (n=447). We employed earlier coursework marks as a measure of underlying ability. Students who brought water to the exam achieved better grades than students who did not. When coursework marks were covaried, this effect remained statistically significant, suggesting that this finding was not simply due to more able students being more likely to bring in water. This implies that water consumption may facilitate performance in real world setting, and therefore, have specific implications for the assessment of undergraduate learners under examination conditions, but further research is required to evaluate this hypothesis.

New paper on water supplementation, expectancy and cognitive performance

January 22nd, 2013

Published in Appetite (2013), 60, 148-153

Water consumption, not expectancies about water consumption, affects cognitive performance in adults

Research has shown that water supplementation positively affects cognitive performance in children and adults. The present study considered whether this could be a result of expectancies that individuals have about the effects of water on cognition. Forty seven participants were recruited and told the study was examining the effects of repeated testing on cognitive performance. They were assigned either to a condition in which positive expectancies about the effects of drinking water were induced, or a control condition in which no expectancies were induced. Within these groups, approximately half were given a drink of water, while the remainder were not. Performance on a thirst scale, letter cancellation, digit span forwards and backwards and a simple reaction time task was assessed at baseline (before the drink) and 20 minutes and 40 minutes after water consumption. Effects of water, but not expectancy, were found on subjective thirst ratings and letter cancellation task performance, but not on digit span or reaction time. This suggests that water consumption effects on letter cancellation are due to the physiological effects of water, rather than expectancies about the effects of drinking water.


Water supplementation improves visual attention and fine motor skills in schoolchildren

September 20th, 2012

…otherwise known as, does having a drink help you Wii?  Our new paper out in Education and Health.

Water supplementation improved performance on letter cancellation and motor tasks in children aged 8 and 9 years. Paper link is here

Symposium Presentation 4 – Dehydration and brain imaging

April 19th, 2012

The use of Magnetic Resonance Imagery (MRI) in examining the effects of dehydration on brain structure and function in healthy humans

Marcus S Smith and Matthew J Kempton

Objectives: The ability to determine the effects of dehydration on brain structure and function has improved recently following advancements in magnetic resonance imaging (MRI) technology. Previous research reported reductions in total brain volume following 16-h fluid restriction and increases in ventricular volume.  Study 1 considered which image analysis was more sensitive to dehydration in adults. Study 2 considered whether dehydration effects on the brain were also observed in adolescents.

Design: The adult brain appears susceptible to dehydration; we examined whether similar changes occur in the developing adolescent brain.  A manual point counting technique (MEASURE) was compared to an automated voxelwise analysis (SIENA) of brain volume.

Methods:  In Study 1 seven adults (aged 23.8+4.1yr) and in Study 2 ten adolescents (aged 16.8+0.4yr) were scanned whilst hydrated and dehydrated. Dehydration was induced by cycling intermittently for 90-min whilst wearing impermeable plastic clothing. In Study 1, total brain volume was determined using MEASURE and SIENA. In Study 2, SIENA was accompanied by BOLD analysis of executive function.

Results: In Study 1, a 2.2+0.5% body mass decrease following dehydration showed ventricular expansion. SIENA was more sensitive than MEASURE.  In Study 2, a 1.6+0.3% body mass decrease showed lateral ventricular enlargement correlated with body mass reduction and inefficient use of brain metabolic activity following dehydration.

Conclusions: Brain structure changes were observed in adolescent and adult brains following acute dehydration. In adolescents, executive functions including planning and visuo-spatial processing were adversely affected.  Given these findings the effect of dehydration on school academic performance warrants future investigation.

Symposium Presentation 3 – expectancy, water consumption and cognition

April 19th, 2012

Expectancy and the water consumption effect

Caroline J Edmonds, Rosanna Crombie, Haiko Ballieux, Mark R Gardner and Lynne Dawkins


Objectives:  The positive effect of water consumption on letter cancellation task performance has been well established. The present study considered whether these effects are due to water consumption, or expectations about the effects of water consumption.

Design: Participants were told that the study would examine the effect of repeated testing over time. They were assigned to one of four conditions: Water, Expectancy; Water, No Expectancy; No Water, Expectancy; No Water, No Expectancy (water n = 24, after exclusions). Performance was assessed at baseline and Test.

Methods: Forty seven participants (aged 18 to 57 years) were recruited. Participants in the Expectancy groups were given the expectation that water positively affects cognition. All participants completed Thirst and Mood scales, Letter Cancellation, Forwards and Backwards Digit Span, and Simple Reaction Time tasks.

Results: Three participants were removed from analyses because they were in the Water group but did not drink. Difference scores were calculated by subtracting performance scores at baseline from those at Test. Those who drank water were significantly less thirsty, compared to those who did not have a drink. They also had a significantly greater improvement in Letter Cancellation performance, compared to those in the No Water condition. This water consumption effect did not interact with expectancy in the case of Letter Cancellation.

Conclusions: The effect of water consumption on Letter Cancellation performance appears to result from the physiological effects of water consumption, and not from expectancies about the effect of consumption.

Symposium Presentation 2 – Students who bring drinks into exams perform better

April 19th, 2012

Water consumption in exams and its effect on students’ performance

Chris Pawson, Mark R Gardner, Rute Soares, Sarah Doherty, Laura Martin and Caroline J Edmonds


Objectives: This study investigated the relationship between water consumption during exams and exam performance. A growing body of literature suggests that dehydration negatively affects cognition in adults. However, there is a relative paucity of enquiry exploring whether drinking water can aid cognition under normal conditions. The current study sought to address this by exploring the potential benefits of water consumption for adult learners.

Design: The study compared the exam performance of students who brought drinks in to exams and those that did not. It was predicted that students who brought drinks in to exams would perform better. In order to test the potential explanation that any group differences may be due to the increased likelihood of more capable students bringing in water, the analyses were conducted whilst covarying for general ability as measured by coursework marks.

Methods: Data were collected from three different cohorts of undergraduate study (n = 447). Researchers targeted a single exam amongst each cohort and noted which examinees had brought water into the exam. The marks attained by students in the target exams, and their coursework performance marks, were collated after the exam marking process.

Results: The results showed students who brought water to the exam performed better than students who did not. When coursework marks were covaried, this effect remained significant, suggesting that it was not simply that more able students chose to bring water.

Conclusions: This implies that water consumption may aid cognition in everyday settings, and therefore have specific implications for assessment procedures.

Symposium Presentation 1 – water and motor performance in children

April 19th, 2012

Water consumption positively affects motor and cognitive task performance in children

Paula Booth and Caroline J Edmonds


Objectives. Studies of adults show that dehydration negatively affects motors skills, cognitive performance and mood. Recent studies have shown that water consumption positively affects cognitive performance and mood in children.  This study investigated whether water consumption improves children’s performance on motor and cognitive tasks.

Design. Performance on two occasions was compared. On one occasion children were given an additional 250mls water to drink and on another they were not (Water vs No Water).  A series of cognitive and motor tests were conducted and performance compared in the two conditions and correlated with the amount of water drunk.

Methods.  Fifteen children aged 8 to 9 years old were assessed in the Water and No Water conditions. They participated in the following tasks; thirst scale, mood scale, letter cancellation, step ups, ball catching and “Raving Rabbid” Wii whack a mole style game.

Results. On average, children drank 169 mls water. Children rated themselves as less thirsty on the occasion on which they had a drink.  They also performed better on the letter cancellation task.  Task performance was better on all three motor tasks in the Water condition, but only significantly so in the case of “Raving Rabbids”. There were dose-response effects on “Raving Rabbids”, step up and ball catching tasks, with greater amounts of water drunk correlating with better performance.

Conclusions. Children’s cognitive and motor performance can be improved by having a drink of water. This has implications for policies on the availability of drinking water in schools.

Symposium on hydration and cognition at BPS Annual Conference

April 19th, 2012

On April 18th 2012 Dr Caroline Edmonds convened a symposium entitled “The effects of hydration on cognition: theory and applications” at the BPS conference in London. This is the overall abstract for the symposium.

There is a well established literature that demonstrates that dehydration has negative effects on cognitive performance, including memory, attention and motor skills. However, until very recently, there has been little attention paid to the complementary research question concerning the positive effects of water consumption on cognitive performance. There is also very little research on potential underlying cognitive and physiological mechanisms.  This symposium combines these two current strands of research.

The first two presentations report findings concerning the positive effects of hydration on cognitive performance. Booth et al discuss acute effects of water supplementation on cognitive measures in children. They report positive effects of water consumption on both cognitive and motor tasks. Pawson et al report an applied study that looks at the effect of water consumption on exam performance, suggesting that those students who bring water into examinations perform better, and argue that this is not a result of the more able students being more likely to bring in water.

The final two presentations consider factors underlying the observed benefits of water consumption on cognition.  Edmonds et al present data that suggest that it is the water, rather than expectations about water, that underlie the performance improvements associated with water consumption. Finally, Smith et al report two brain imaging studies that suggest that dehydration is associated with reductions in ventricular volume.

This symposium presents a timely overview of current studies in the area of hydration and cognition, and serves to focus future research objectives.

paper published – effects of caffeine and expectancy

September 9th, 2011

Dawkins, L., Shahzad, F-Z, Ahmed, S.S., Edmonds, C.J. et al (2011). Effects of caffeine and expectancy on mood and behaviour. Appetite, 57, 597-600.

We explored whether caffeine, and expectation of having consumed caffeine, affects attention, reward responsivity and mood using double-blinded methodology. 88 participants were randomly allocated to ‘drink-type’ (caffeinated/decaffeinated coffee) and ‘expectancy’ (told caffeinated/told decaffeinated coffee) manipulations. Both caffeine and expectation of having consumed caffeine improved attention and psychomotor speed. Expectation enhanced self-reported vigour and reward responsivity. Selfreported depression increased at post-drink for all participants, but less in those receiving or expecting caffeine. These results suggest caffeine expectation can affect mood and performance but do not support a synergistic effect.

paper published on long term effects of aluminium exposure from parenteral nutrition

September 9th, 2011

Fewtrell, M., Edmonds, C.J., Isaacs, E., Bishop, N. Lucas, A. (2011). Aluminium exposure from parenteral nutrition in preterm infants and later health outcomes. Proceedings of the Nutrition Society, 70 (3), 299-304.

Aluminium is the most common metallic element, but has no known biological role. It accumulates in the body when protective gastrointestinal mechanisms are bypassed, renal function is impaired, or exposure is high – all of which apply frequently to preterm infants. Recognised clinical manifestations of aluminium toxicity include dementia, anaemia and bone disease. Parenteral nutrition (PN) solutions are liable to contamination with aluminium, particularly from acidic solutions in glass vials, notably calcium gluconate. When fed parenterally, infants retain >75% of the aluminium, with high serum, urine and tissue levels. Later health effects of neonatal intravenous aluminium exposure were investigated in a randomised trial comparing standard PN solutions with solutions specially sourced for low aluminium content. Preterm infants exposed for >10 d to standard solutions had impaired neurologic development at 18 months. At 13–15 years, subjects randomised to standard PN had lower lumbar spine bone mass; and, in non-randomised analyses, those with neonatal aluminium intake above the median had lower hip bone mass. Given the sizeable number of infants undergoing intensive care and still exposed to aluminium via PN, these findings have contemporary relevance. Until recently, little progress had been made on reducing aluminium exposure, and meeting Food and Drug Administration recommendations (<5 μg/kg per d) has been impossible in patients <50 kg using available products. Recent advice from the UK Medicines and Healthcare regulatory Authority that calcium gluconate in small volume glass containers should not be used for repeated treatment in children <18 years, including preparation of PN, is an important step towards addressing this problem.

Caroline awarded research sabbatical

July 5th, 2011

Caroline has been awarded one of UEL’s research sabbaticals, which will take place in Semester A 2011-12 (September to December 2011).