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The Impact of Lead Poisoning on Learning and Behavior in School-Aged Children

This presentation aims to increase awareness of the effects of lead poisoning on children's learning and behavior, even at low levels. Strategies to support affected children and help families rid themselves of this toxin will also be discussed.

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The Impact of Lead Poisoning on Learning and Behavior in School-Aged Children

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  1. The Impact of Lead Poisoning on Learning and Behaviorof School-Aged Children November 4, 2016 Michigan Association of School Psychologists Annual Conference Grand Rapids, Michigan Carole Ann Beaman, Ph.D. LLP Certified School Psychologist, Clinical Therapist

  2. Goals of the Presentation • To increase awareness of the effects of lead poisoning • To increase awareness of the educational impact of lead poisoning even at low levels • To encourage the development and use of strategies to support the child whose learning may be impeded by elevated lead levels • To help schools be a vehicle of support for helping families rid themselves of this toxin

  3. Pathways of Poisoning • Lead enters the body through ingesting or inhaling lead particles or lead dust • Lead enters the body when it is metabolized • Absorption rate for children is 40-50% • Absorption rate for adults is 8% • A hungry child metabolizes 70% of the lead ingested. • Lead is fat soluble.

  4. Pathways through the Body • Lead enters the body and circulates through the blood • Lead is then deposited in the soft tissue (brain and other organs) • Lead finally resides in the teeth or bones until it is leached out for specific needs

  5. LEAD Alters Brain Function • LEAD crosses the blood/brain barrier • LEAD changes the production and transmission of neurotransmitters (mimics Calcium which fuels neurotransmission) • LEAD interferes with cell metabolism by immobilizing or mimicking calcium • LEAD modified synaptic communication between neurons (myelination issues)

  6. Major Functional Systems that depend upon Synaptic Strength • Sensory and perceptual systems • Auditory, visual, tactile and kinesthetic • Cognitive systems • Symbolic, linguistic Reading, Computing • Planning movements • Fine and gross motor actions and coordination • Learning and Memory • hippocampus • Social/Emotional systems • Limbic systems • Feedback and evaluation of actions • ExecutiveFunction: Decision Making

  7. Times of Greatest Risk for Lead Poisoning • In utero (body of undernourished mother will pull lead from her bones in seeking calcium to build her baby’s bones) or will ingest or inhale lead particles or dust that cross the placenta. • Children from ages 12 months to 3 years due to developmentally appropriate hand to mouth actions • Under seven years of age – due to rate of brain development

  8. Lead Induced Neuropathies • Death • Seizures • Mental Retardation • Behavioral Effects • Perceptual Motor Difficulties • Learning Deficiencies

  9. Historic Concerns about Lead Poisoning • 1971 CDC level of concern was 60 micrograms per deciliter • 1980 CDC level of concern was lowered to 25 micrograms per deciliter • 1991 CDC reduced the level of concern to 10 micrograms per deciliter • 2005 5 mg/dL

  10. Lead in Environment • Lead discovered at least 5000 years ago. • Lead is said to have contributed to the fall of the Roman Empire • Lead was removed from paint in 1978 • Lead was removed from gasoline in 1978 through 1987

  11. Lead Studies World Wide • Studies have been conducted all over the world. Published results from the following countries have added important information regarding the effects of lead on developing children: • USA, Australia, New Zealand, Greece, Italy, Denmark, Germany, China and Mexico • Studies were cross-sectional and retrospective cohort studies

  12. Effect on IQ and Achievement • Studies completed by Bellinger, Stiles, Needleman in 1992 determined that each increase of 10 micrograms per deciliter of blood lead there is a loss of 5 to 8 points in IQ Score and 8 – 9 points in Achievement Scores • Other studies have found similar relationships between blood lead and achievement and ability

  13. EBL and Word Reading • The relationship between the dentine levels at age 8 and the development of word recognition abilities: children with mildly elevated lead levels had mean scores which were consistently 3 points lower than children with negligible lead levels. This constant set back persisted to age 12 years. THERE WAS NO EVIDENCE OF A TENDENCY TO CATCH UP. Fergusson & Horwood, 1993

  14. Non Verbal Learning • To control for variations of verbal abilities across populations the focus on one study was to determine if elevated lead levels affected the fine motor abilities of young children. The following graphs indicates that there is an inverse relationship between blood lead levels and fine motor composite scores.

  15. Recent Studies • In a Cincinnati study using NHANES data 4,853 study subjects 6 – 16 using Arithmetic and Reading (WRAT) and Block Design and Digit Span (WISC-R) and adjusting for race/ethnicity, Poverty Index Ratio, Educational level of reference adult, serrum ferritin level, found

  16. Inverse relationship for Arithmetic and Reading with blood lead concentrations lower than 5.0 ug/dL. • Block Design was inversely associated with blood lead levels lower than 7.5 mg/dL • Digit Span was inversely associated with blood lead concentrations lower than 10mg/dL

  17. Authors state: The adverse effects of lead exposure on reading and other deficits in language based abilities are of particular importance because they are potent predictors of academic achievement and antisocial behavior. • Lanphear, Dietrich, Auinger and Cox, 2000

  18. Further Studies • Canfield, et all found that blood lead concentrations, even those below 10 mg/dL, are inversely associated with children’s IQ scores at three and five years of age, and associated with declines in IQ are greater at these concentrations than at higher concentrations. • The larger associations with IQ at lower lead concentrations may appear counterintuitive. Although it has not been part of any specific studies there is evidence that high concentrations of heavy metals may enhance cellular defense mechanisms and thereby lessen the rate at which additional damage occurs.

  19. Importance of Recent Findings • Findings that significant damage occurs below 10 mg/dL suggests that more U.S. children may be adversely affected by environmental lead than previously estimated.

  20. Study of Detroit Children – part of an intensive prospective study regarding prenatal cocaine/alcohol exposure and school outcomes. Children were given a battery of tests at age 6. Data used was from 277 children who were not exposed to cocaine or moderate to severe alcohol use. All were tested for blood lead levels

  21. Results: current whole blood lead level is a significant predictor of early reading abilities after controlling for the influence of confounding factors including socioeconomic status, maternal verbal intelligence, the home environment, cigarette exposure and maternal alcohol use. Significance on a test of early reading abilities found that blood lead levels as low as 4 mg/dL were significantly predictive of difficulties in acquiring early reading skills. Beaman, 2001

  22. Although the average deficit in IQ scores tend to be in the range of 4 points for individual children, it is not considered significant for individuals. However, an average decline of four points in normally distributed scores would result in 50 percent more children scoring one standard deviation or more below the mean!!!

  23. Behavioral Effects • A study with 2 to 5 year olds revealed that children with lead levels greater or equal to 15 mg/dL were 2.7 times more likely to have behavioral scores in the clinical range for: • Social withdrawal • Depression • Sleep Problems • Somatic Complaints • Aggression • Destructive Behavior • (Sciarillo, Allexander and Ferrell, 1992)

  24. Measures of Delinquency and Aggression • Lead exposure is associated with: • reduced verbal abilities • higher rates of reading disabilities • Lower threshold for frustration • Increased rates of academic failure • All of these are predictors of Delinquency and Aggression

  25. During a four year study Needleman and others found that parents and teachers periodically filled out questionnaires evaluating the children for aggression, delinquency and other behavioral problems. In addition the boys themselves were asked to report whether or not they had engaged in antisocial behavior.

  26. Results: • Only a slight association between lead levels and behavior was seen at age 7, but at age 11, the children with elevated lead levels were judged by both parents and teachers to be more aggressive, higher delinquency scores and have more somatic complaints than their low lead counterparts. The subjects themselves reported lead related increases in antisocial acts.

  27. Needleman and colleagues say their findings agree with clinical observations linking lead poisoning to disturbed behavior, and ‘extend the relationship downward in dose to asymptomatic youths with elevated body burdens. • These findings held true even when they controlled for nine different measures of maternal intelligence, socioeconomic status and quality of child rearing. (JAMA,Vol.275, No.5, Feb. 1996)

  28. Lead and Crime • Studies reviewed of prison populations have reveals two variables which are the same for inmates convicted for violent crimes: • Inability to read • Elevated levels of lead in their bones • Denno, 1994

  29. There is a seven fold increase in failure to graduate from high school regardless of the socioeconomic status of the family. • There is a clear connection between academic problems, behavioral problems and lead poisoning which becomes increasingly relevant when one attempts to understand why schools are failing.

  30. Response to Intervention for Studentswith Elevated Blood Lead Levels (EBL) • It is important to discover how learning goes wrong. Using an understanding of how the brain functions, it may be possible to determine if the problem is • How the information enters the brain (INPUT) • How the information is processed • How the information is stored (MEMORY) • How the information can be assessed (OUTPUT)

  31. PROBLEMS WITH LEARNING • Problems with INPUT of Information • Problems with PROCESSING information • Problems with MEMORY or RETRIEVAL of information • Problems with OUTPUT of information

  32. Problems with INPUT of Information • May be due to problems with auditory perception • May be due to problems with visual perception • May be due to lack of language especially vocabulary • May be due to poor attending skills and/or poor attention skills

  33. Strategies for INPUT problems • Multisensory experiences involve more areas of the brain to take in information • Multiple Intelligence Approach • Exploring differentiated learning • Use of Universal Design • Use Graphic Organizers or other devices to altar presentation of material • Provide opportunities for group work to reinform students of new material

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