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Krzeczkowski JE, Hall M, Saint-Amour D, Oulhote Y, McGuckin T, Goodman CV, Green R, Muckle G, Lanphear B, Till C. Prenatal fluoride exposure, offspring visual acuity and autonomic nervous system function in 6-month-old infants. ENVIRONMENT INTERNATIONAL 2024; 183:108336. [PMID: 38064923 PMCID: PMC10981044 DOI: 10.1016/j.envint.2023.108336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/10/2023] [Accepted: 11/17/2023] [Indexed: 01/25/2024]
Abstract
BACKGROUND Prenatal fluoride exposure can have adverse effects on children's development; however, associations with visual and cardiac autonomic nervous system functioning are unknown. We examined associations between prenatal fluoride exposure and visual acuity and heart rate variability (HRV) in 6-month-old infants. METHODS We used data from Canadian mother-infant pairs participating in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. We estimated prenatal fluoride exposure using: i) fluoride concentration in drinking water (mg/L), ii) maternal urinary fluoride adjusted for specific gravity (MUFSG; mg/L) and averaged across pregnancy, and iii) maternal fluoride intake (µg/kg/day) from consumption of water, tea, and coffee, adjusted for maternal body weight (kg). We used multivariable linear regression to examine associations between each measure of fluoride exposure and Teller Acuity Card visual acuity scores (n = 435) and assessed HRV (n = 400) using two measures: root mean square of successive differences (RMSSD) and the standard deviation of N-N intervals (SDNN) measured at 6-months of age. RESULTS Median (IQR) values for water fluoride, MUFSG, and daily fluoride intake were 0.20 (IQR: 0.13-0.56) mg/L; 0.44 (0.28-0.70) mg/L and 4.82 (2.58-10.83) µg/kg/day, respectively. After adjustment for confounding variables, water fluoride concentration was associated with poorer infant visual acuity (B = -1.51; 95 % CI: -2.14,-0.88) and HRV as indicated by lower RMSSD (B = -1.60; 95 % CI: -2.74,-0.46) but not SDNN. Maternal fluoride intake was also associated with poorer visual acuity (B = -0.82; 95 % CI: -1.35,-0.29) and lower RMSSD (B = -1.22; 95 % CI: -2.15,-0.30). No significant associations were observed between MUFSG and visual acuity or HRV. CONCLUSION Fluoride in drinking water was associated with reduced visual acuity and alterations in cardiac autonomic function in infancy, adding to the growing body of evidence suggesting fluoride's developmental neurotoxicity.
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Affiliation(s)
- John E Krzeczkowski
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada.
| | - Meaghan Hall
- Department of Psychology, York University, Toronto, Ontario, Canada
| | - Dave Saint-Amour
- Faculté de médecine - Département d'ophtalmologie, Université de Montréal, Montréal, Québec, Canada
| | - Youssef Oulhote
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sina, New York, NY, USA
| | - Taylor McGuckin
- Department of Psychology, York University, Toronto, Ontario, Canada
| | - Carly V Goodman
- Department of Psychology, York University, Toronto, Ontario, Canada
| | - Rivka Green
- Department of Psychology, York University, Toronto, Ontario, Canada
| | - Gina Muckle
- Centre de recherche du CHU de Québec-Université Laval, Québec, Canada; École de Psychologie, Université Laval, Québec, Québec, Canada
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Christine Till
- Department of Psychology, York University, Toronto, Ontario, Canada
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Kabdebon C, Fló A, de Heering A, Aslin R. The power of rhythms: how steady-state evoked responses reveal early neurocognitive development. Neuroimage 2022; 254:119150. [PMID: 35351649 PMCID: PMC9294992 DOI: 10.1016/j.neuroimage.2022.119150] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 12/17/2022] Open
Abstract
Electroencephalography (EEG) is a non-invasive and painless recording of cerebral activity, particularly well-suited for studying young infants, allowing the inspection of cerebral responses in a constellation of different ways. Of particular interest for developmental cognitive neuroscientists is the use of rhythmic stimulation, and the analysis of steady-state evoked potentials (SS-EPs) - an approach also known as frequency tagging. In this paper we rely on the existing SS-EP early developmental literature to illustrate the important advantages of SS-EPs for studying the developing brain. We argue that (1) the technique is both objective and predictive: the response is expected at the stimulation frequency (and/or higher harmonics), (2) its high spectral specificity makes the computed responses particularly robust to artifacts, and (3) the technique allows for short and efficient recordings, compatible with infants' limited attentional spans. We additionally provide an overview of some recent inspiring use of the SS-EP technique in adult research, in order to argue that (4) the SS-EP approach can be implemented creatively to target a wide range of cognitive and neural processes. For all these reasons, we expect SS-EPs to play an increasing role in the understanding of early cognitive processes. Finally, we provide practical guidelines for implementing and analyzing SS-EP studies.
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Affiliation(s)
- Claire Kabdebon
- Laboratoire de Sciences Cognitives et Psycholinguistique, Département d'études cognitives, ENS, EHESS, CNRS, PSL University, Paris, France; Haskins Laboratories, New Haven, CT, USA.
| | - Ana Fló
- Cognitive Neuroimaging Unit, CNRS ERL 9003, INSERM U992, CEA, Université Paris-Saclay, NeuroSpin Center, Gif/Yvette, France
| | - Adélaïde de Heering
- Center for Research in Cognition & Neuroscience (CRCN), Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Richard Aslin
- Haskins Laboratories, New Haven, CT, USA; Department of Psychology, Yale University, New Haven, CT, USA
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Vrabič N, Juroš B, Tekavčič Pompe M. Automated Visual Acuity Evaluation Based on Preferential Looking Technique and Controlled with Remote Eye Tracking. Ophthalmic Res 2020; 64:389-397. [PMID: 33080607 DOI: 10.1159/000512395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 10/17/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To establish an automated visual acuity test (AVAT) for infants, based on preferential looking technique and controlled with remote eye tracking. To validate the AVAT in a group of healthy children. To compare AVAT visual acuity (VA) values with corresponding VA values acquired with standard tests (ST). METHODS ST, adapted for age (Keeler Acuity Cards in preverbal children and LEA symbols in verbal children), was performed to obtain monocular VA in a group of 36 healthy children. During AVAT, 9 different stimuli with grating circles that matched spatial frequencies of 9 Keeler Acuity Cards (ranging between 0.29 and 14.5 cycles per degree) were projected on a screen. Three repetitions of each stimulus were shown during 9-s intervals, interchanging with an attention grabber. The remote eye tracker was used to evaluate the proportion of time a child spent looking at each grating circle compared to a homogeneous gray background that matched the grating stimuli in average luminance. From this proportion of time, child's binocular VA was evaluated. RESULTS Ninety-seven percent (35/36) of healthy children successfully completed ST and AVAT. There was an agreement between the results of an ST and AVAT, with Lin's concordance coefficient being 0.53 (95% CI = 0.31-0.72). A tendency was observed toward VA overestimation on AVAT for children with VA >0.4 logMAR on ST and toward VA underestimation on AVAT for children with VA ≤0.4 logMAR on ST. CONCLUSIONS AVAT requires a minimally skilled investigator. The evaluation of better eye monocular VA on ST and binocular VA on AVAT was comparable for healthy children.
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Affiliation(s)
- Nika Vrabič
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Manca Tekavčič Pompe
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia, .,University Eye Clinic, University Medical Centre Ljubljana, Ljubljana, Slovenia,
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Hamilton R, Bach M, Heinrich SP, Hoffmann MB, Odom JV, McCulloch DL, Thompson DA. VEP estimation of visual acuity: a systematic review. Doc Ophthalmol 2020; 142:25-74. [PMID: 32488810 PMCID: PMC7907051 DOI: 10.1007/s10633-020-09770-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 05/05/2020] [Indexed: 01/23/2023]
Abstract
Purpose Visual evoked potentials (VEPs) can be used to measure visual resolution via a spatial frequency (SF) limit as an objective estimate of visual acuity. The aim of this systematic review is to collate descriptions of the VEP SF limit in humans, healthy and disordered, and to assess how accurately and precisely VEP SF limits reflect visual acuity. Methods The protocol methodology followed the PRISMA statement. Multiple databases were searched using “VEP” and “acuity” and associated terms, plus hand search: titles, abstracts or full text were reviewed for eligibility. Data extracted included VEP SF limits, stimulus protocols, VEP recording and analysis techniques and correspondence with behavioural acuity for normally sighted healthy adults, typically developing infants and children, healthy adults with artificially degraded vision and patients with ophthalmic or neurological conditions. Results A total of 155 studies are included. Commonly used stimulus, recording and analysis techniques are summarised. Average healthy adult VEP SF limits vary from 15 to 40 cpd, depend on stimulus, recording and analysis techniques and are often, but not always, poorer than behavioural acuity measured either psychophysically with an identical stimulus or with a clinical acuity test. The difference between VEP SF limit and behavioural acuity is variable and strongly dependent on the VEP stimulus and choice of acuity test. VEP SF limits mature rapidly, from 1.5 to 9 cpd by the end of the first month of life to 12–20 cpd by 8–12 months, with slower improvement to 20–40 cpd by 3–5 years. VEP SF limits are much better than behavioural thresholds in the youngest, typically developing infants. This difference lessens with age and reaches equivalence between 1 and 2 years; from around 3–5 years, behavioural acuity is better than the VEP SF limit, as for adults. Healthy, artificially blurred adults had slightly better behavioural acuity than VEP SF limits across a wide range of acuities, while adults with heterogeneous ophthalmic or neurological pathologies causing reduced acuity showed a much wider and less consistent relationship. For refractive error, ocular media opacity or pathology primarily affecting the retina, VEP SF limits and behavioural acuity had a fairly consistent relationship across a wide range of acuity. This relationship was much less consistent or close for primarily macular, optic nerve or neurological conditions such as amblyopia. VEP SF limits were almost always normal in patients with non-organic visual acuity loss. Conclusions The VEP SF limit has great utility as an objective acuity estimator, especially in pre-verbal children or patients of any age with motor or learning impairments which prevent reliable measurement of behavioural acuity. Its diagnostic power depends heavily on adequate, age-stratified, reference data, age-stratified empirical calibration with behavioural acuity, and interpretation in the light of other electrophysiological and clinical findings. Future developments could encompass faster, more objective and robust techniques such as real-time, adaptive control. Registration International prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), registration number CRD42018085666.
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Affiliation(s)
- Ruth Hamilton
- Department of Clinical Physics and Bioengineering, Royal Hospital for Children, NHS Greater Glasgow and Clyde, Glasgow, UK. .,College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Michael Bach
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sven P Heinrich
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - J Vernon Odom
- Departments of Ophthalmology and Neuroscience, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Daphne L McCulloch
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Dorothy A Thompson
- The Department of Clinical and Academic Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,University College London Great Ormond Street Institute of Child Health, London, UK
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Polevoy C, Arbuckle TE, Oulhote Y, Lanphear BP, Cockell KA, Muckle G, Saint-Amour D. Prenatal exposure to legacy contaminants and visual acuity in Canadian infants: a maternal-infant research on environmental chemicals study (MIREC-ID). Environ Health 2020; 19:14. [PMID: 32028962 PMCID: PMC7006412 DOI: 10.1186/s12940-020-0567-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 01/22/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND Prenatal exposure to environmental contaminants can have deleterious effects on child development. While psychomotor, cognitive and behavioural outcomes have been investigated in relation to chronic exposure, the associations with visual functions remains unclear. The present study's aim was to assess the associations of prenatal exposure to legacy persistent organic pollutants and heavy metals with visual acuity in Canadian infants. The potential protective effects of selenium against mercury toxicity were also examined. METHODS Participants (mean corrected age = 6.6 months) were part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), lead and mercury were measured in maternal blood during pregnancy, as well as in the cord blood. The Teller acuity card test (TAC) (n = 429) and the visual evoked potentials in a sub-group (n = 63) were used to estimate behavioural and electrophysiological visual acuity, respectively. Multivariable linear regression models were used to investigate the relationship between exposure to each contaminant and visual acuity measures, while controlling for potential confounders. Breastmilk selenium, which was available for about half of the TAC and VEP samples, was also taken into account in the mercury models as exploratory analyses. RESULTS We observed no significant associations between exposure to any contaminants and TAC. Analyses revealed a negative trend (p values < 0.1) between cord blood lead and mercury and electrophysiological visual acuity, whereas PCB and PBDE showed no association. When adding breastmilk selenium concentration to the mercury models, this association became statistically significant for cord concentrations (β = - 3.41, 95% CI = - 5.96,-0.86), but also for blood levels at 1st and 3rd trimesters of pregnancy (β = - 3.29, 95% CI = - 5.69,-0.88). However, further regression models suggested that this change in estimates might not be due to adjustment for selenium, but instead to a change in the study sample. CONCLUSIONS Our results suggest that subtle, but detectable alterations of infant electrophysiological visual acuity can be identified in a population prenatally exposed to low mercury concentrations. Compared to behavioural visual acuity testing, electrophysiological assessment may more sensitive in detecting visual neurotoxicity in relation with prenatal exposure to mercury.
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Affiliation(s)
- C Polevoy
- Centre de recherche, CHU Sainte-Justine, QC, Montréal, Canada
- Département de psychologie, Université du Québec à Montréal, QC, Montréal, Canada
| | - T E Arbuckle
- Population Studies Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Y Oulhote
- Department of Biostatistics and Epidemiology, School of Public health and health Sciences, University of Massachusetts at Amherst, Amherst, MA, USA
| | - B P Lanphear
- BC Children's Hospital, Simon Fraser University, Burnaby, Canada
| | - K A Cockell
- Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - G Muckle
- École de psychologie, Université Laval and Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - D Saint-Amour
- Centre de recherche, CHU Sainte-Justine, QC, Montréal, Canada.
- Département de psychologie, Université du Québec à Montréal, QC, Montréal, Canada.
- Département d'ophtalmologie, Université de Montréal, QC, Montréal, Canada.
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Abstract
This paper argues that investigators should consider replacing the popular practice of comparing individuals varying in gender, social class, and/or ethnicity on one or more continuous measures with a search for kinds of individuals defined by patterns of properties that include not only their values on outcome measures but also their gender, social class, and ethnicity. Investigators who believe that a particular predictor contributes to an outcome independent of the gender, class, or ethnicity of the participants often implement statistical procedures that promise to remove the contributions of the above categories. These analyses lead to misleading conclusions when the controlled category is correlated with the dependent measures. The final sections summarize the properties of genders, classes, and ethnic groups that make distinctive contributions to many psychological outcomes. The paper ends by noting that a society's ethical beliefs constitute a defensible basis for ignoring the biological properties associated with these categories in order to allow members of these groups access to whatever educational or occupational goals they desire.
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