Children and PCBs
How Behavioral
Effects Are Measured in Infants and Children
Hazardous
Substances and Public Health v.11, n.2, Summer01
Major sources of PCB exposure in children include eating contaminated food,
drinking contaminated water, and breathing contaminated air near some hazardous
waste sites or in buildings with old electrical appliances that use PCBs. PCBs
accumulate in pregnant womens' bodies and are released during pregnancy, passing
through the placenta, and thus exposing fetuses in utero. Infants may also be
exposed through nursing; because PCBs dissolve in fat, they can accumulate in
the mothers' breast milk and be transferred through breastfeeding.
Adverse effects in infants and children include
- low birth weight
- shorter gestational period
- smaller head size
- abnormal neurodevelopment (e.g., abnormal reflexes, motor immaturity,
permanent learning disabilities, mental retardation, impaired
cognitive skills, problems with memory, and depressed responsiveness)
- neurobehavioral deficits (e.g., increased hyperactivity)
- immunologic effects (e.g., less wheezing, fewer allergic reactions, higher
prevalence of recurrent middle ear infections, and higher prevalence of
chicken pox)
- problems with thyroid function
- facial abnormalities
- birth defects
How Behavioral Effects Are Measured in Infants and Children
Some of the tests used to measure infant/child behavioral effects are the Fagan
Test of Visual Recognition (also known as the Fagan Test of Infant
Intelligence), Bayley Scales of Infant Development, Wechsler Intelligence Scale
for Children-Revised (WISC-R), and Neonatal Behavioral Assessment Scale (NBAS).
- The Fagan test involves showing an infant or child two identical
photos of human faces for about 20 seconds, then changing one of the photos
for a new one and presenting the new combination of photos. Normal babies
spend more time looking at the photo of the new face. Children with memory
problems cannot remember the first two photos well enough to recognize
that the second two photos are different.
- The Bayley test is a standardized test gauging small children's
development
(children aged 1 month to 3.5 years). It includes a mental development index
(MDI) and a psychomotor development index (PDI). MDI measures memory, the
ability to solve simple problems, and language capabilities. PDI measures
body control, coordination, and fine motor movement. Both indexes are scaled
like a standard intelligence quotient (IQ) test.
- The Wechsler Intelligence Scales for Children-Revised (WISC-R)
measures verbal and nonverbal performance skills.
- The Neonatal Behavioral Assessment Scale measures behavioral
development. The scale evaluates 28 behavioral and 18 reflex items (e.g.,
assessing an infant's reactions to a variety of stimuli, such as a light in
the eyes, a rattle, or a moving ball).
Hazardous Substances & Public Health is a quarterly newsletter published by the Agency for Toxic Substances and Disease Registry (ATSDR). The contents are in the public domain and may be reproduced and distributed without permission, unless specified as copyrighted material from another source.
source: http://www.atsdr.cdc.gov/HEC/v11n2-3.html#Children%20and%20PCBs
16feb02
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