11 results
3 Fluoride Exposure and Hypothyroidism in Pregnant Women: A Potential Mechanism of Fluoride Neurotoxicity
- Meaghan Hall, Bruce Lanphear, Jonathan Chevrier, Richard Hornung, Rivka Green, Carly Goodman, Pierre Ayotte, E. Angeles Martinez-Mier, Christine Till
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 866-867
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Objective:
Fluoride exposure has been associated with thyroid dysfunction, but fluoride's impact on thyroid function in pregnancy is unclear, especially during early gestation when the fetus is dependent on maternal thyroid hormone. We examined the potential thyroid-disrupting effects of maternal fluoride exposure in pregnancy and tested whether thyroid disruption in pregnancy mediates the association between maternal fluoride exposure and child intelligence quotient (IQ) among Canadian mother-child dyads living in areas with optimal fluoridation.
Participants and Methods:We measured fluoride concentrations in drinking water and in spot urine samples collected in each trimester from pregnant women enrolled in the Maternal-Infant Research on Environmental Chemicals study. We also measured thyroid hormone (thyroid stimulating hormone [TSH], free thyroxine [FT4], and total thyroxine [TT4]) levels during the first trimester of pregnancy and categorized women as euthyroid (n=1301), subclinical hypothyroid (n=100), or primary hypothyroid (n=28). Those categorized as primary hypothyroid were combined with an additional 79 women who reported clinical diagnoses at time of study enrolment (total n=107). In a sample of 1508 women, we used logistic regression to estimate the association between fluoride exposure and risk of either subclinical or primary hypothyroidism, separately, and linear regression to estimate associations between fluoride exposure and women's thyroid hormone levels (TSH, FT4, TT4). We tested effect modification by child sex and thyroid peroxidase (TPO) antibody status. In a subsample of 439 mother-child pairs, we measured child Full-Scale IQ (FSIQ) at 3-4 years of age using the Wechsler Preschool and Primary Scale of Intelligence. We used linear regression to test associations between maternal hypothyroidism or thyroid hormone levels, and children's FSIQ scores. Finally, mediation analysis in the counterfactual framework was used to estimate the proportion of the effect of maternal fluoride exposure on child FSIQ mediated by maternal hypothyroidism, through evaluation of the natural direct (not through hypothyroidism) and indirect (through hypothyroidism) effects.
Results:Using categorical measures of thyroid status, a 0.5 mg/L increase in water fluoride concentration was associated with a 1.64 (95% confidence interval [CI], 1.04 to 2.58) increased odds of primary hypothyroidism. This association was stronger among women with normal TPO antibody levels (< 5.61 IU/mL) (odds ratio, 2.80; 95% CI, 1.24 to 6.36). In contrast, we did not find a significant association between maternal urinary fluoride and hypothyroidism. For continuous measures of thyroid hormone levels, a 1 mg/L increase in maternal urinary fluoride was associated with a 35% (p=0.01) increase in TSH among women pregnant with a female fetus. In our subsample analyses, children born to women with primary hypothyroidism had lower FSIQ than children of euthyroid women, especially among boys (B, 8.78; 95% CI, -16.78 to -0.79). In contrast, maternal TSH, FT4, and TT4 levels were not significantly associated with child FSIQ scores. Maternal primary hypothyroidism did not significantly mediate the relationship between maternal water fluoride concentration and child FSIQ (p natural indirect effect= .35).
Conclusions:Fluoride in drinking water may increase the risk of hypothyroidism in pregnancy. Thyroid dysfunction in pregnancy may be one mechanism underlying developmental neurotoxicity of fluoride.
45 A systematic review of cognitive correlates of fatigue in pediatric-onset multiple sclerosis
- Tracy L. Fabri, Serena Darking, Mansi Gulati, Brenda L. Banwell, Ruth Ann Marie, E. Ann Yeh, Christine Till
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- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 558-559
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Objective:
Fatigue is common in pediatric-onset multiple sclerosis (POMS), yet causal factors and correlates of fatigue are poorly understood in this population. A 2016 review suggested an association between fatigue and emotional difficulties, sleep disturbance, and reduced quality of life in POMS. Information regarding the potential association between fatigue and cognitive challenges is limited and mixed. Through this systematic review, we searched for relationships between fatigue, cognition, and mental health.
Participants and Methods:Systematic review methodology and PRISMA guidelines were followed. Five electronic databases were searched: Ovid: Medline, Ovid: EMBASE, Ovid: PsycInfo, Web of Science and CINAHL. Search terms were specific to each database. Reference lists of included studies were also hand-searched. We included empirical studies that were published in English after 2001, included a sample with confirmed diagnoses of POMS using McDonald criteria, and measured fatigue, cognition and clinical factors including mental health outcomes. Cognition had to be assessed using a standardized assessment tool and studies must have examined associations between outcomes of interest either descriptively or by assessing bivariate or multivariate relationships. Covidence was used to complete the screening, extraction, and quality assessment. Two independent researchers (i.e., T.L.F, and/or S.D, and/or M.G) reviewed each paper included in the title and abstract screen and full text review. S.D and M.G completed the extraction and quality assessments. Conflicts at all stages were resolved by the lead author (T.L.F). The University of Adelaide JBI critical appraisal checklist for analytical cross-sectional studies was used to ensure the scientific rigor of each included study. Sample characteristics and measures of fatigue, clinical and cognitive variables were extracted. A narrative synthesis was conducted.
Results:We identified 1025 abstracts through our initial search and retained 119 articles for full text review. One hundred and six of these studies were excluded during the full text review including six studies which did not examine the relationship between the outcomes of interest. Fifty-one additional studies were identified from hand-searching reference lists of included studies, of which 24 were retained for full text review. A total of 15 studies were extracted and analyzed. Overall, a positive relationship was found between fatigue and mental health outcomes (i.e., anxiety and depression), whereas results were mixed regarding the association between fatigue and performance-based measures of cognition as well as fatigue and other clinical characteristics (e.g., disease duration, EDSS, treatment with DMDs, relapse rate, age at disease onset). In some studies, fatigue and executive functioning performance were negatively related; the relationship was less clear in others (e.g., both fatigued and non-fatigued MS patients demonstrated cognitive challenges, an association between fatigue and executive functioning was identified at follow-up but not baseline). Eleven of the 15 included studies (73%) did not identify associations between fatigue and cognition.
Conclusions:While studies are mixed, fatigue in children has been associated with aspects of cognition. Understanding the relationship between fatigue, cognition, and mental health and identifying gaps in the existing literature, have implications for informing interventions for this clinical population.
2 Sex difference of Developmental Neurotoxicants on Intellectual Abilities: A Systematic Review and Meta-Analysis
- Carly V Goodman, Rivka Green, Allya DaCosta, David Flora, Bruce Lanphear, Christine Till
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 865-866
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Objective:
Early life exposures to lead, mercury, polychlorinated biphenyls (PCBs), polybromide diphenyl ethers (PBDEs), organophosphate pesticides (OPPs), and phthalates have been associated with diminished IQ scores in children. Some studies suggest that these neurotoxicants impact boys and girls differently. We conducted a systematic review and meta-analysis to identify and quantify sex differences in IQ deficits from pre- and post-natal exposures to these developmental neurotoxicants.
Participants and Methods:We used PubMed and PsychINFO to screen abstracts of articles published between January 1, 1950 and December 31, 2021 for empirical studies of six neurotoxicants [lead, mercury, PCBs, PBDEs, OPPs, and/or phthalates] that (1) used an individualized biomarker; (2) measured exposure during the prenatal period or within the first six years of life; and (3) provided different effect estimates on children's intellectual abilities by sex. We assessed each study for risk of bias using Navigation Guide (Woodruff & Sutton, 2014). For studies with combinable data, we performed separate random effects meta-analyses for boys and girls with subgroup analyses by neurotoxicant. To homogenize the magnitude of effect observed in each study, we recalculated results to be expressed as the absolute change in intellectual abilities for a relative change of 1.5 times (i.e., 50% increase) in the exposure variable.
Results:Of 3205 studies screened, 53 met inclusion criteria: 34 evaluated prenatal exposure, 11 postnatal exposure, and 8 both pre- and post-natal exposure. We generally rated these studies as "low" to "probably low" risk of bias. Among the studies examining prenatal exposure, 27 reported no significant differences between the sexes, 7 found negative associations in boys, 4 found negative associations in girls, 5 found negative nonsignificant associations in boys and positive nonsignificant associations in girls, and 3 found no clear pattern, where differences by sex depended on the specific phthalate compound or outcome measurement. Among the studies examining postnatal exposure, 14 reported no significant differences between the sexes, 1 found a negative association in boys, 2 found negative associations in girls, and 2 found positive associations for either boys or girls. In our meta-analysis of 16 studies (4 lead, 4 mercury, 2 PBDEs, 2 OPPs, 4 phthalates), we found that prenatal exposure to developmental neurotoxicants was associated with decreased full-scale intelligence in boys (B = -0.26; 95% CI: -0.45, -0.08), but not girls (B = 0.09; 95% CI: -0.14, 0.31). In subgroup analyses by neurotoxicant, prenatal exposure to lead (B = -1.07; 95% CI: -1.63, -0.52), and ZPBDEs (B = -0.57; 95% CI: -1.14, -0.01) were associated with decreased full-scale intelligence in boys, whereas the girls' effect sizes were consistently near zero.
Conclusions:During fetal development, boys appear to be more vulnerable than girls to IQ deficits from neurotoxic exposures, and especially from lead and PBDEs. More research is needed to examine the nuanced sex-specific effects found for postnatal exposures to toxic chemicals.
Symposium 15: Impact of Environmental Contaminants on Child Neurodevelopment
- Christine Till
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 863-864
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Children are exposed to toxic chemicals throughout development and the long-term consequences of this exposure can be profound. Despite decades of research documenting the vulnerability of the developing brain to environmental contaminants, there has been little progress in protecting against developmental neurotoxicity. This symposium will discuss recent research in developmental neurotoxicology using a "developmental origins of health and disease" (DOHaD) framework that examines the context in which environmental contaminants exert their effects. We will examine the timescale for developmental toxicity, windows of vulnerability, and the bases of individual differences in vulnerability, including sex-specific effects of chemical exposures. This symposium will feature new pregnancy and birth cohort studies that have implicated fluoride as a developmental neurotoxin and endocrine disruptor. In addition, we will discuss emerging issues in epidemiology, including how environmental contaminants may interact with non-chemical stressors and have lifelong impacts on cognition and behaviours. This symposium will be capped with a discussion of the public's knowledge, attitudes, and behaviours related to developmental toxicity and strategies to reduce exposure. All speakers will be asked to draw conclusions on research priorities, and discuss how to balance regulators' need for "ideal evidence" with a public health strategy that aims to protect the public from critical environmental hazards. The symposium will consist of the following five presentations, each 12 minutes in length, followed by a 15 minute discussion.
1. John Krzeckowski, PhD, York University, Toronto, Canada.
TITLE: Applying a Dimensional Framework to the Study of Developmental Neurotoxicity
2. Carly Goodman, PhD candidate, York University, Toronto, Canada
TITLE: Sex difference of Developmental Neurotoxicants on Intellectual abilities: A systematic review and meta-analysis
3. Meaghan Hall, PhD candidate, York University, Toronto, Canada.
TITLE: Fluoride Exposure and Hypothyroidism in Pregnant Women: A Potential Mechanism of Fluoride Neurotoxicity
4. Ashley Malin, PhD, University of Florida,
Florida, USA.
TITLE: Urinary Fluoride Levels and Metal Co-Exposures among Pregnant Women in Los Angeles, California
5. Rivka Green, PhD, The Hospital for Sick Children, Toronto, Canada.
TITLE: Translating developmental neurotoxicity for the public: A large, multi-country, randomized-control trial investigating children's environmental health literacy
5 Translating developmental neurotoxicity for the public: A large, international, randomized-control trial investigating children's environmental health literacy
- Rivka Green, Christine Till, Allya DaCosta, Jana El-Sabbagh, Carly Goodman, David Flora, Erica Phipps, Bruce Lanphear
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 868-869
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Objective:
Exposure to toxic chemicals during early brain development increases the risk of neurodevelopmental problems in children. Parents' and prospective parents' understanding of the impact of toxic chemicals on brain development and the efficacy of translation tools for children's environmental health literacy are poorly understood. We developed and validated a questionnaire, PRevention of Toxic chemicals in the Environment for Children Tool (PRoTECT) to assess knowledge of toxic chemicals and neurodevelopment, intentions to reduce exposures to toxic chemicals, and preferences for actions by government and industry to prevent neurodevelopmental disorders. Using PRoTECT, we surveyed people of child-bearing age across five countries (Canada, United States (US), United Kingdom (UK), India, and Australia) to identify general patterns of responses on this questionnaire by demographic characteristics, including country, age, gender, parental status, pregnancy status, and education. We also employed a randomized control design to examine the efficacy of a knowledge translation video to instill knowledge and prompt behavioral changes to reduce exposures to toxic chemicals immediately following its presentation and after a six-week follow-up period.
Participants and Methods:We recruited 15,594 participants, ages 18 to 45, via CloudResearch's Prime Panels between October-December 2021. After completing the PRoTECT survey, participants were randomly assigned to watch the video Little Things Matter: Impact of Toxic Chemicals on Brain Development (i.e., the experimental group) or to serve as the control group. Next, both groups answered a series of questions to assess their knowledge of toxic chemicals, their intentions to reduce exposures to toxic chemicals, and barriers to changing their behaviours. After six-weeks, we recontacted a subset (N=4,842) of participants to repeat PRoTECT and answer the same series of behavioural questions assessing whether they modified any of their behaviours to reduce exposure and why or why not.
Results:Most participants (i.e., 75-85%) agreed that toxic chemicals can impact brain development and endorsed preferences (∼85%) for allocating more resources to prevent neurodevelopmental disorders, especially people with higher education, parents and pregnant women, and people who lived in India. Despite this, a large proportion of participants (∼50%) trusted industry and believed that government effectively regulated toxic chemicals. After the six-week follow-up, experimental participants showed greater changes in scores on PRoTECT (i.e., between 5-15% change), indicating greater knowledge about harms posed by toxic chemicals, more intentions to reduce exposure, and stronger preferences for prevention as compared to the control group. Differences were larger among people from the US, those who were more highly educated, and people in their thirties. However, the differences between groups in making behavioural changes to reduce exposures were attenuated at the six-week follow up as compared to baseline. Significant barriers to reduce exposure to toxic chemicals were reported by both groups and included cost, inconvenience, and not knowing how to determine whether a product is non-toxic or where to purchase non-toxic products.
Conclusions:We observed greater knowledge and concerns about toxic chemicals among more affluent respondents, pregnant women and parents, and people living in India across both groups. While the video enhanced participants' knowledge about toxic chemicals and intentions to reduce exposure, they indicated that barriers hindered them from making behavioral changes.
Enhanced Recruitment During Executive Control Processing in Cognitively Preserved Patients With Pediatric-Onset MS
- Emily Barlow-Krelina, Gary R. Turner, Nadine Akbar, Brenda Banwell, Magdalena Lysenko, E. Ann Yeh, Sridar Narayanan, D. Louis Collins, Bérengère Aubert-Broche, Christine Till
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- Journal:
- Journal of the International Neuropsychological Society / Volume 25 / Issue 4 / April 2019
- Published online by Cambridge University Press:
- 28 February 2019, pp. 432-442
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Objectives: Youth and young adults with pediatric-onset multiple sclerosis (MS) are vulnerable to executive dysfunction; however, some patients do not demonstrate functional deficits despite showing abnormalities on structural magnetic resonance imaging (MRI). Cognitively intact adults with MS have shown enhanced activation patterns relative to healthy controls on working memory tasks. We aim to evaluate whether cognitively preserved pediatric-onset MS patients engage compensatory recruitment strategies to facilitate age-normative performance on a task of working memory. Methods: Twenty cognitively preserved patients (mean age=18.7±2.7 years; 15 female) and 20 age- and sex-matched controls (mean age=18.5±2.9 years; 15 female) underwent neuropsychological testing and 3.0 Tesla MRI, including structural and functional acquisitions. Patterns of activation during the Alphaspan task, a working memory paradigm with two levels of executive control demand, were examined via whole-brain and region of interest (ROI) analyses. Results: Across all participants, lower accuracy and greater activation of regions implicated in working memory were observed during the high demand condition. MS patients demonstrated 0.21 s longer response time than controls. ROI analyses revealed enhanced activation for pediatric-onset MS patients relative to controls in the right middle frontal, left paracingulate, right supramarginal, and left superior parietal gyri during the low executive demand condition, over and above differences in response time. MS patients also demonstrated heightened activation in the right supramarginal gyrus in the high executive demand condition. Conclusions: Our findings suggest that pediatric-onset MS patients may engage compensatory recruitment strategies during working memory processing. (JINS, 2019, 25, 432–442)
Cognitive and Behavioral Functioning in Childhood Acquired Demyelinating Syndromes
- Christine Till, Austin Noguera, Leonard H. Verhey, Julia O’Mahony, E. Ann Yeh, Jean K. Mah, Katia J. Sinopoli, Brian L. Brooks, Berengere Aubert-Broche, D. Louis Collins, Sridar Narayanan, Douglas L. Arnold, Brenda L. Banwell
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- Journal:
- Journal of the International Neuropsychological Society / Volume 22 / Issue 10 / November 2016
- Published online by Cambridge University Press:
- 01 December 2016, pp. 1050-1060
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Objectives: The aim of this study was to describe cognitive, academic, and psychosocial outcomes after an incident demyelinating event (acquired demyelinating syndromes, ADS) in childhood and to investigate the contribution of brain lesions and confirmed MS diagnosis on outcome. Methods: Thirty-six patients with ADS (mean age=12.2 years, SD=2.7, range: 7–16 years) underwent brain MRI scans at presentation and at 6-months follow-up. T2-weighted lesions on MRI were assessed using a binary classification. At 6-months follow-up, patients underwent neuropsychological evaluation and were compared with 42 healthy controls. Results: Cognitive, academic, and behavioral outcomes did not differ between the patients with ADS and controls. Three of 36 patients (8.3%) were identified with cognitive impairment, as determined by performance falling ≤1.5 SD below normative values on more than four independent tests in the battery. Poor performance on a visuomotor integration task was most common, observed among 6/32 patients, but this did not differ significantly from controls. Twelve of 36 patients received a diagnosis of MS within 3 years post-ADS. Patients with MS did not differ from children with monophasic ADS in terms of cognitive performance at the 6-months follow-up. Fatigue symptoms were reported in 50% of patients, irrespective of MS diagnosis. Presence of brain lesions at onset and 6 months post-incident demyelinating event did not associate with cognitive outcome. Conclusions: Children with ADS experience a favorable short-term neurocognitive outcome, even those confirmed to have MS. Longitudinal evaluations of children with monophasic ADS and MS are required to determine the possibility of late-emerging sequelae and their time course. (JINS, 2016, 22, 1050–1060)
Age of Onset as a Moderator of Cognitive Decline in Pediatric-Onset Multiple Sclerosis
- Banafsheh Hosseini, David B. Flora, Brenda L. Banwell, Christine Till
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- Journal of the International Neuropsychological Society / Volume 20 / Issue 8 / September 2014
- Published online by Cambridge University Press:
- 17 July 2014, pp. 796-804
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Cognitive impairment is often reported in pediatric-onset multiple sclerosis (MS). Using serial cognitive data from 35 individuals with pediatric-onset MS, this study examined how age at disease-onset and proxies of cognitive reserve may impact cognitive maturation over the course of childhood and adolescence. Neuropsychological evaluations were conducted at baseline and up to four more assessments. Of the 35 participants, 7 completed only one assessment, 5 completed two assessments, 13 completed three assessments, 10 completed four or more assessments. Growth curve modeling was used to assess longitudinal trajectories on the Trail Making Test-Part B (TMT-B) and the Symbol Digit Modalities (SDMT; oral version) and to examine how age at disease onset, baseline Full Scale IQ, and social status may moderate rate of change on these measures. Mean number of evaluations completed per patient was 2.8. Younger age at disease onset was associated with a greater likelihood of cognitive decline on both the TMT-B (p=.001) and SDMT (p=.005). Baseline IQ and parental social status did not moderate any of the cognitive trajectories. Findings suggest that younger age at disease-onset increases the vulnerability for disrupted performance on measures of information processing, visual scanning, perceptual/motor speed, and working memory. Proxies of cognitive reserve did not protect against the progression of decline on these measures. Young patients with MS should be advised to seek follow-up cognitive evaluation to assess cognitive maturation and to screen for the potential late emergence of cognitive deficits. (JINS, 2014, 20, 1–9)
Contributors
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- By Ted Abel, Antoine Adamantidis, Karla V. Allebrandt, Simon N. Archer, Amelie Baud, Michel Billiard, Carlos Blanco-Centurion, Diane B. Boivin, Ethan Buhr, Matthew E. Carter, Nicolas Cermakian, Jennifer H.K. Choi, S.Y. Christin Chong, Chiara Cirelli, Marc Cuesta, Thomas Curie, Yves Dauvilliers, Luis de Lecea, Derk-Jan Dijk, Stephane Dissel, Annette C. Fedson, Jonathan Flint, Marcos G. Frank, Paul Franken, Ying-Hui Fu, Thorarinn Gislason, David Gozal, Devon A. Grant, Hakon Hakonarson, Makoto Honda, Hyun Hor, Christer Hublin, Peng Jiang, Takashi Kanbayashi, Jaakko Kaprio, Andrew Kasarskis, Leila Kheirandish-Gozal, RodaRani Konadhode, Michael Lazarus, Meng Liu, Michael March, Mark F. Mehler, Keivan Kaveh Moghadam, Valérie Mongrain, Charles M. Morin, Benjamin M. Neale, Seiji Nishino, Allan I. Pack, Dheeraj Pelluru, Rosa Peraita-Adrados, Giuseppe Plazzi, David A. Prober, Louis J. Ptáček, Irfan A. Qureshi, David M. Raizen, John J. Renger, Till Roenneberg, Elizabeth J. Rossin, Takeshi Sakurai, Paul Salin, Karen D. Schilli, Eva C. Schulte, Laurent Seugnet, Paul J. Shaw, Priyattam J. Shiromani, Patrick Sleiman, Mehdi Tafti, Joseph S. Takahashi, Matthew S. Thimgan, Katsushi Tokunaga, Giulio Tononi, Fred W. Turek, Yoshihiro Urade, Hans P.A. Van Dongen, Juliane Winkelmann, Christopher J. Winrow
- Edited by Paul Shaw, Mehdi Tafti, Michael J. Thorpy
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- Book:
- The Genetic Basis of Sleep and Sleep Disorders
- Published online:
- 05 November 2013
- Print publication:
- 24 October 2013, pp xi-xiv
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Memory Performance and Normalized Regional Brain Volumes in Patients with Pediatric-Onset Multiple Sclerosis
- Amanda Fuentes, Donald Louis Collins, Daniel Garcia-Lorenzo, John G. Sled, Sridar Narayanan, Douglas L. Arnold, Brenda L. Banwell, Christine Till
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- Journal of the International Neuropsychological Society / Volume 18 / Issue 3 / May 2012
- Published online by Cambridge University Press:
- 10 February 2012, pp. 471-480
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Studies in adults with multiple sclerosis (MS) have associated regional brain abnormalities with memory impairment. While memory problems in children with MS are often reported, little is known about the neural correlates that may contribute to these difficulties. We measured verbal and nonverbal memory using the Test of Memory and Learning (TOMAL-2) in 32 children and adolescents with MS and 26 age- and sex-matched healthy controls. Memory performance was correlated with volumetric measures of the whole brain, hippocampus, amygdala, and thalamus. Brain volumes were normalized for age and sex using magnetic resonance imaging (MRI) data from the National Institutes of Health MRI Study of Normal Brain development. With the exception of story recall, performance on memory tests was similar to that of the control group. Relative to controls, patient with MS showed reduced volume in the whole brain (p < .001), amygdala (p < .005), and thalamus (p < .001), but not the hippocampus. In the patient group, word-list learning correlated with whole brain volume (r = .53) and hippocampal volume (r = .43), whereas visual recognition memory correlated with thalamic volume (r = .48). Findings are consistent with the well-established role of the hippocampus in learning and consolidation and also highlight the importance of diffuse brain pathology on memory function. (JINS, 2012, 18, 471–480)
16 - Integrating nitrogen fluxes at the European scale
- from Part III - Nitrogen flows and fate at multiple spatial scales
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- By Adrian Leip, European Commission Joint Research Centre, Beat Achermann, Federal Office for the Environment Air Pollution Control, Gilles Billen, University Pierre & Marie Curie, Albert Bleeker, Energy Research Centre of the Netherlands, Alexander F. Bouwman, Netherlands Environmental Assessment Agency, Wim de Vries, Wageningen University and Research Centre, Ulli Dragosits, Centre for Ecology and Hydrology, Ulrike Döring, European Commission Joint Research Centre, Dave Fernall, Food and Rural Affairs Kingspool, Markus Geupel, Federal Environment Agency, Germany, Jürg Herolstab, Penny Johnes, University of Reading, Anne Christine Le Gall, INERIS, France, Suvi Monni, European Commission Joint Research Centre, Rostislav Nevečeřal, Czech Hydrometeorological Institute, Lorenzo Orlandini, European Commission – DG AGRI, Michel Prud'homme, International Fertilizer Industry Association, Hannes I. Reuter, Gisxperts gbr, David Simpson, Norwegian Meteorological Institute, Guenther Seufert, European Commission Joint Research Centre, Till Spranger, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Mark A. Sutton, Centre for Ecology and Hydrology, John van Aardenne, European Commission Joint Research Center, Maren Voß, Leibniz-Institute of Baltic Sea Research Warnemuende, Wilfried Winiwarter, International Institute for Applied Systems Analysis
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 345-376
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Summary
Executive summary
Nature of the problem
Environmental problems related to nitrogen concern all economic sectors and impact all media: atmosphere, pedosphere, hydrosphere and anthroposphere.
Therefore, the integration of fluxes allows an overall coverage of problems related to reactive nitrogen (Nr) in the environment, which is not accessible from sectoral approaches or by focusing on specific media.
Approaches
This chapter presents a set of high resolution maps showing key elements of the N flux budget across Europe, including N2 and Nr fluxes.
Comparative nitrogen budgets are also presented for a range of European countries, highlighting the most efficient strategies for mitigating Nr problems at a national scale. A new European Nitrogen Budget (EU-27) is presented on the basis of state-of-the-art Europe-wide models and databases focusing on different segments of Europe's society.
Key findings
From c. 18 Tg Nr yr−1 input to agriculture in the EU-27, only about 7 Tg Nr yr−1 find their way to the consumer or are further processed by industry.
Some 3.7 Tg Nr yr−1 is released by the burning of fossil fuels in the EU-27, whereby the contribution of the industry and energy sectors is equal to that of the transport sector. More than 8 Tg Nr yr−1 are disposed of to the hydrosphere, while the EU-27 is a net exporter of reactive nitrogen through atmospheric transport of c. 2.3 Tg Nr yr−1.
The largest single sink for Nr appears to be denitrification to N2 in European coastal shelf regions (potentially as large as the input of mineral fertilizer, about 11 Tg N yr–1 for the EU-27); however, this sink is also the most uncertain, because of the uncertainty of Nr import from the open ocean.