Cognitive Deficit in 7-year-old Children With Prenatal Exposure to Methylmercury

Neurotoxicol Teratol. Nov-Dec 1997;19(6):417-28. doi: 10.1016/s0892-0362(97)00097-4.

Abstract

A cohort of 1022 consecutive singleton births was generated during 1986-1987 in the Faroe Islands. Increased methylmercury exposure from maternal consumption of pilot whale meat was indicated by mercury concentrations in cord blood and maternal hair. At approximately 7 years of age, 917 of the children underwent detailed neurobehavioral examination. Neuropsychological tests included Finger Tapping; Hand-Eye Coordination; reaction time on a Continuous Performance Test; Wechsler Intelligence Scale for Children-Revised Digit Spans, Similarities, and Block Designs; Bender Visual Motor Gestalt Test; Boston Naming Test; and California Verbal Learning Test (Children). Clinical examination and neurophysiological testing did not reveal any clear-cut mercury-related abnormalities. However, mercury-related neuropsychological dysfunctions were most pronounced in the domains of language, attention, and memory, and to a lesser extent in visuospatial and motor functions. These associations remained after adjustment for covariates and after exclusion of children with maternal hair mercury concentrations above 10 microgram(s) (50 nmol/g). The effects on brain function associated with prenatal methylmercury exposure therefore appear widespread, and early dysfunction is detectable at exposure levels currently considered safe.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Behavior / drug effects
  • Child
  • Cognition Disorders / chemically induced*
  • Cognition Disorders / psychology
  • Diet
  • Evoked Potentials, Auditory, Brain Stem / drug effects
  • Evoked Potentials, Visual / physiology
  • Female
  • Humans
  • Intelligence Tests
  • Learning / drug effects
  • Methylmercury Compounds / poisoning*
  • Neuropsychological Tests
  • Posture / physiology
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Psychomotor Performance / drug effects

Substances

  • Methylmercury Compounds