title: Assessing new dimensions of attentional functions in children prenatally exposed to environmental contaminants using an adapted Posner paradigm.
abstract: Chronic exposure to methylmercury (MeHg), lead (Pb) and polychlorinated biphenyls (PCBs) has been associated with a range of attention deficits in children, but it is not known whether selective spatial attention is also altered. We modified the classic Posner paradigm, which assesses visuospatial attention, to also assess vigilance and impulsivity. This paradigm is based on the well-documented findings that a target will be detected more quickly if a visual cue indicates beforehand where it will appear, and more slowly if the cue indicates a false spatial location. In our task, visual distractors were introduced, in addition to the classic Posner trials, to assess impulsivity, and a central smiley face, whose eye-movement cued the location of the targets, to measure spatial attention. This task was administered to 27 school-age Inuit children (mean age = 11.2 years) from Nunavik (Arctic Quebec, Canada), in which pre- and postnatal exposures to environmental contaminants had been documented from birth. After controlling for the impact of confounding variables, multivariable regressions revealed that prenatal exposures to PCBs and Pb were significantly associated with greater inattention and impulsivity, respectively, while current exposure to Pb was significantly associated with longer reaction times. Although a significant correlation was observed between cord blood PCB concentration and decreased visuospatial performance, no significant association was found after adjustment for confounders. No effect was found for Hg exposures. These results suggest that our adapted Posner paradigm is sensitive in detecting a range of attention deficits in children exposed to environmental contaminants; implications for future studies are discussed.
authors.affiliation: Centre de recherche, CHU Sainte-Justine, 3175, Chemin de la Côte Sainte-Catherine, Montréal, Québec H3T 1C5, Canada.
authors.forename: Audrey-Anne
authors.initials: AA
authors.lastname: Ethier
authors.affiliation: École de psychologie, Université Laval, Pavillon Félix-Antoine-Savard, 2325, rue des Bibliothèques Québec G1V 0A6, Canada.
authors.forename: Gina
authors.initials: G
authors.lastname: Muckle
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, Wayne State University, 3901 Chrysler Drive, Suite 2-C, Detroit, MI 48201, United States.
authors.forename: Sandra W
authors.initials: SW
authors.lastname: Jacobson
authors.affiliation: Axe santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, 2875 boul. Laurier, Québec, Québec G1V 2M2, Canada; Département de médecine sociale et préventive, Faculté de Médecine, 1050, avenue de la Médecine, Pavillon Ferdinand-Vandry, Université Laval, Québec, Québec G1V 0A6, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Ayotte
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, Wayne State University, 3901 Chrysler Drive, Suite 2-C, Detroit, MI 48201, United States.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Jacobson
authors.affiliation: Centre de recherche, CHU Sainte-Justine, 3175, Chemin de la Côte Sainte-Catherine, Montréal, Québec H3T 1C5, Canada; Département de psychologie, Université du Québec à Montréal, 100 rue Sherbrooke Ouest, Montréal, Pavillon Adrien Pinard, Montréal, Québec H2X 3P2, Canada. Electronic address: saint-amour.dave@uqam.ca.
authors.forename: Dave
authors.initials: D
authors.lastname: Saint-Amour
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000139:chemically induced* / Q000175:diagnosis*; D002170:Canada; D002648:Child; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D007854:Lead / Q000633:toxicity; D008137:Longitudinal Studies; D008297:Male; D008628:Mercury / Q000097:blood / Q000633:toxicity; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011078:Polychlorinated Biphenyls / Q000097:blood / Q000633:toxicity; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000503:physiopathology*; D012189:Retrospective Studies; D014796:Visual Perception / Q000502:physiology
chemical_list: D004785:Environmental Pollutants; D007854:Lead; D011078:Polychlorinated Biphenyls; D008628:Mercury
keywords: Development; Human neurotoxicity; Impulsivity; Lead; Methylmercury; Polychlorinated biphenyls; Vigilance; Visuospatial attention