Although many different types of information are important to a complete science of learning disabilities, information about “alterable variables” is of particular value as we attempt to apply our science to helping children. This month's Topical Review addresses a set of environmental and diet variables that are clearly alterable and that may have an important impact on the way children think and learn. The studies reviewed here have employed advanced technology to assess the effects of these “alterable variables” on both brain functioning and cognitive performance. Although the subjects employed in the studies are not formally diagnosed as learning disabled, the implications of the findings for children who experience special learning problems are nevertheless quite clear.—JKT
Baird, H., John, E.R., Ahn, H., & Maisel, E.Neurometric evaluation of epileptic children who do well and poorly in school. Electroenceph. and Clin. Neurophysiol., 48:683–693, 1980.
3.
Benignus, V.A., Otto, D.A., Muller, K.E., & Seiple, K. J.Effects of age and body lead burden on CNS function in young children II: EEG spectra. Electroenceph. Clin. Neurophysiol., 52:240–248, 1981.
4.
Bibby, J.The general linear model—A cautionary tale. In C.A. O'Muricheartaigh and C. Payne (Eds.) The Analysis of Survey Data, Volume 2. Model Fitting. New York: John Wiley & Sons, pp. 51–58, 1977.
5.
Bremner, I & Campbell J.K.The influence of dietary copper intake on the toxicity of cadmium. In O.A. Levander & L. Cheng (Eds.), “Micronutrient interactions: Vitamins, minerals and hazardous elements,”Annuls of the New York Academy of Sciences, 1980, 355, 319–331.
6.
Buell, G.Some biological aspects of cadmium toxicology. Journal of Occupational Medicine, 1975, 17, 193.
7.
Cerklewski, F.L. & Forbes, R.M.Influence of dietary zinc on lead toxicity in the rat. 1976, B. 106, 689–696.
8.
Cohen, J. & Cohen, P.Applied Multiple Regression/Correlation Analysis for the Behavioral Sciences, Second Edition.Hillsdale, New Jersey: Lawrence Erlbaum Associates, pp. 320–325, 1983.
9.
Cleave, T.The Saccharine Disease. New Canaan, Connecticut: Keats Publishing, 1975, P. 89.
10.
Charney, E., Kessler, B., Farbel, M., & Jackson, D.Childhood lead poisoning. New England Journal of Medicine, 1983, 309, 1089–1093.
11.
Corridan, J.P.Head hair samples as indicators of environmental pollution. Environmental Research, 1974, 8, 12–16.
12.
Fishbein, D. and Thatcher, R.W.Nutrition and electrophysiological indices of maladaptive behavior. In: H. Lieberman and R.J. Wurtman (Eds.), Research Strategies for Assessing the Behavioral Effects of Food and Nutrients, Conference Proceedings. M.I.T.November 9, 1982.
13.
Fox, M.R.Effect of essential minerals on cadmium toxicity: A Review. Journal of 1974, 37, 321–324.
14.
Gordon, G.F.Lead Toxicity. Sacramento, California: American Academy of Med Preventics, 1976.
15.
Govoni, S.Memo, M., Spano, P.F. and Trabucchi, M.Chronic lead treatment differentially affects dopamine synthesis in various rat brain areas. Toxicology, 12:343–349, 1979.
16.
Goyer, R.A., & Mahaffey, K. R.Susceptibility to lead toxicity. Environmental Health Perspectives, 1972, 2, 73–80.
17.
Green, R.G.Reading disability, Canadian Medical Association Journal, 1969, 100, 586.
18.
Hambidge, M.K.Hair analysis: Worthless for vitamins, limited for minerals. American Journal of Clinical Nutrition, 1982, 36, 943–949.
19.
Holmes, H.N., Campbell, K. & Amberg. E.J.The effect of vitamin C on lead poisoning. Journal of Laboratory and Clinical Medicine, 24, 1119–1127, 1939.
20.
Horst, R.L., Thatcher, R.W., Lester, M.L. and McAlaster, R.Differential Effects of Age on sensory Evoked Potentials in Children. In A. Rothenberger (Ed.), Event Related Potentials in Children. Elsevier Biomedical Press. Holland, 1982.
21.
Jeejeebhoy, K.N., Chu, R.C., Marliss. E.B., Greenberg, G.R., & Bruce-Robertson, A.Chromium deficiency, glucose intolerance, and neuropathy reversed by chromium supplementation, in a patient receiving long-term total parental nutrition. American Journal of Clinical Nutrition, 1977, 30, 531–538.
22.
John, E.R.Functional Neuroscience. Vol. II, Clinical Applications of Neurometrics, E.R. John and R.W. Thatcher (Eds.), L. Erlbaum Assoc., Inc., N.J., 1977.
23.
John, E.R., Karmel, B.Z., Corning, W.C., Easton, P., Brown, D., Ahn, H., John, M., Harmony, T., Prichep, L., Toro, A., Gerson, I., Bartlett, F., Thatcher, R., Kaye, H., Valdes, P. & Schwartz, E.Neurometrics. Science, 1977, 196, 1393–1410.
24.
Johnson, D.E., Tillery, J.B., & Prevost, R. J.Trace metals in occupationally and nonoccupationally exposed individuals. Environmental Health Perspectives, 1975, 10, 151–158.
25.
Jones, H.S. & Fowler, B.A.Biological interactions of cadmium with calcium. In O.A. Levander & L. Cheng (Eds.), “Micronutrient interactions: Vitamins, minerals and hazardous elements,”Annuls of the New York Academy of Sciences, 1980, 355, 309–317.
26.
Karmel, B.Z., Kaye, H. & John, E.R.Developmental neurometrics: The use of quantitative analysis of brain electrical activity to probe mental function throughout the life span. In A. Collins (Ed.), Minnesota symposium on child psychology, Hillsdale, N.J.: Erlbaum. p. 141–198, 1978.
27.
Kimura M.Effects of cadmium on growth and bone metabolism. In J.O. Nriagu (Ed.) Cadmium in the Environment, Part II. Health Effects, New York: John Wiley & Sons, 1981, pp. 757–781.
28.
Kronick, D.A case history: Sugar, fried oysters, and zinc. Academic Therapy, 1975, 11, 119.
29.
Kubota, J., Lazar, B.S. and Losee, F.Cooper, zinc, cadmium and lead in human blood from 19 locations in the United States. Arch. Environ. Health, 16: 788–793, 1968.
30.
Latham, M.C., & Cobos, F.The effects of malnutrition on intellectual development and learning. American Journal of Public Health, 1971, 61, 1307–1324.
31.
Lester, M.L., Horst, R. & Thatcher, R.W.Protective effects of calcium and zinc against heavy metal impairment of cognitive function. (in preparation 1985).
32.
Lester, M.L.Thatcher, R.W. and Monroe-Lord, L.Refined Carbohydrate Intake, Hair Cadmium Levels and Cognitive Functioning in Children. Journal of Nutrition and Behavior, 1982, 1, 3–13.
33.
Lederer, L.G. & Bing, F.C.Effects of calcium and phosphorus on retention of lead by growing organismsJournal of the American Medical Association, 114, 2457–2461, 1940.
34.
Lin-Fu, J.S.The evolution of childhood lead poisoning as a public health problem. In J.J. Chisolm & D.M. O'Hare (Eds.), Lead Absorption in Children, Baltimore: Urban & Schwarzenberg, 1982, pp. 1–10.
35.
Lin-Fu, J.S.Children and lead. New England Journal of Medicine, 1983, 307, 615–616.
36.
Luckey, T.D. and Venugopal, B.Metal Toxicity in Mammals. Plenum Press, New York, 1977.
37.
Mahaffey, K.R.Nutritional factors in lead poisoning. Nutrition Reviews, 1981, 39, 353–362.
38.
Mitchell, D.G., & Aldous, K. M.Lead content of foodstuffs, Environmental Health Perspectives, 1974, 7, 59–64.
39.
Moynahan, E.J.Zinc deficiency and disturbances of mood and visual behavior. Lancet, 1976, 1, 91.
40.
Neathery, M.W.Metabolism and toxicity of cadmium in animals. In J.O. Nriagu (Ed.) Cadmium in the Environment, Part II. Health Effects, New York: John Wiley & Sons, 1981, pp. 553–581.
41.
Needleman, H.L.Lead and neuropsychological deficit: Finding a threshold. In H.L. Needleman (Ed.), Low Level Lead Exposure: The Clinical Implications of Curent Reserach. New York: Raven Press, 1980, pp 43–51.
42.
Nishiyama, K., & Nordberg, G. F.Adsorption and elution of cadmium on hair. Archives of Environmental Health, 1972, 25, 92–96.
43.
Nordberg, G.F., & Nishiyama, K.Whole body and hair retention of cadmium in mice. Archives of Environmental Health, 1972, 24, 209–214.
44.
Oleru, G.Kidney, liver, hair and lungs as indicators of cadmium absorption. American Industrial Hygiene Association Journal, 1976, 37, 617–621.
45.
Otto, D.A., Benignus, V.A., Muller, K.E., & Barton, C. N.Effects of age and body lead burden on CNS function in young children. Electroenceph. Clin. Neurophysiol., 52:229–239, 1981.
46.
Petering, H.G., Yeager, D.W. and Witherup, S.O.Trace metal content of hair. II. Cadmium and lead of human hair in relation to age and sex. Arch. Environ. Health, 27:327–330, 1973.
47.
Petering, H.G.Some observation on the interaction of zinc, copper and iron metabolism in lead and cadmium toxicity. Environmental Health Perspectives, 1978, 25, 141–145.
48.
Pihl, R.O. & Parkes, M.Hair element content in learning disabled children. Science, 1977, 198, 204–206.
49.
Powers, H.W.S.Dietary measures to improve behavior and achievement. Academic Therapy, 1973-1974, 9, 203–214.
50.
Powers, H. & Presley, J.Nutrition and Your Child's Behavior, New York: St. Martin's Press, 1978.
51.
Reeves, R.D., Jolley, K.W., & Buckley, P. D.Lead in human hair: Relation to age, sex, and environmental factors. Bulletin of Environmental Contamination & Toxicology, 1975, 14, 579–587.
52.
Rie, H.E. & Rie, E.D. (Eds.) Handbook of Minimal Brain Dysfunctions: A Critical Review. New York: John Wiley & Sons, 1980.
53.
Rutter, M. & Jones, R.R.Lead versus Health: Sources and Effects of Low Level Lead Exposure. New York: John Wiley & Sons, 1983.
54.
Schroeder, H.A.Losses of vitamins and trace minerals resulting from processing and preservation of foods. American Journal of Clinical Nutrition, 1971, 24, 562–573.
55.
Schroeder, H.A.The Trace Elements and Man, Old Greenwich, Connecticut: Delvin-Adair Company, 1973, Pp. 1–21.
56.
Settle, D.M, & Patterson, C.C.Lead in albacore: Guide to lead pollution in Americans. Science, 1980, 207, 1167–1176.
57.
Shakman, R.A.Nutritional influences on the toxicity of environmental pollutants. Archives of Environmental Health, 1974, 28, 105–113.
58.
Singhal, R.L., Merali, Z., and Hrdina, P.D.Aspects of the biochemical toxicology of cadmium. Aspects of Toxic Agents, 35:75–80, 1979.
59.
Six, K.M. & Goyer, R.A.Experimental enhancement of lead toxicity by low dietary calcium. Journal of Laboratory and Clinical Medicine, 1970, 76, 933–942.
60.
Six, K.M. & Goyer, R.A.The influence of iron deficiency on tissue content and toxicity of ingested lead in the rat. Journal of Laboratory and Clinical Medicine, 1972, 79, 128–136.
61.
Sorensen, J.R.J., Melby E.G., Nord, P.J. & Petering, H.G.Interferences in the determination of metallic elements in human hair. Archives of Environmental Health, 1973, 27, 36–39.
62.
Suzuki, T., & Yoshida, A.Long-term effectiveness of dietary iron and ascorbic acid in the prevention and cure of cadmium toxicity in rats. American Journal of Clinical Nutrition, 1978, 31, 1491–1498.
63.
Thatcher R.Neuroelectric techniques in clinical neurology. In: The Proceedings of the 17th Annual San Diego Biomedical Symposium, Academic Press, New York, 1977.
64.
Thatcher, R.W. and Cantor, D.S.Electrophysiological techniques in the assessment of malnutrition. In J. Brozek and B. Schurch (Eds.), Malnutrition and Behavior: Critical Assessment of Key Issues, Lausanne, Switzerland: Nestle Foundation Press, 1984, pp. 116–136.
65.
Thatcher, R.W., Lester, M.L., McAlaster, R., & Horst, R.Effects of low levels of cadmium and lead on cognitive functioning in children. Archives of Environmental Health, 1982a, 37, 159–166.
66.
Thatcher, R.W., Lester, M.L., McAlaster, R., Horst, R., and Ignasias, S.W.Intelligence and Lead Toxins in Rural Children. Journal of Learning Disabilities, 1983b, 16, 355–359.
67.
Thatcher, R.W., McAlaster, R, Horst, R.L. and Lester, M.L.Evoked Potential Correlates of Cognitive Functioning in Children. In A. Rothenberger (Ed.), Developments in Neurology, Vol. 6: Event Related Potentials in Children, Elsevier Biomedical Press, Holland, 1982b, pp. 337–344.
68.
Thatcher, R.W., McAlaster, R., and Lester, M.L.Evoked Potentials related to hair cadmium and lead. In: Brain and Information: Event Related Potentials, R. Karrer, D. Cohen and P. Tueting (Eds.), Annals of the New York Academy of Sciences, 1984a, 425, 421–423.
69.
Thatcher, R.W., McAlaster, R., Lester, M.L., and Cantor, D.S.Comparisons among Nutrition, EEG and Trace Elements in Predicting Reading Ability in Children. In: S.J. White & V. Teller (Eds.) Annals of the New York Academy of Sciences, Discourses in Reading and Linguistics. 1985, 433, 87–96.
70.
Thatcher R.W., McAlaster, R., Lester, M.L., Horst, R.L. and Cantor, D.S.Hemispheric EEG Asymmetries Related to Cognitive Functioning in Children. In A. Perecman (Ed.), Cognitive Processing in the Right Hemisphere, New York Academic Press, 1983a, pp. 125–146.
71.
Underwood, E.J.Trace Elements in Human and Animal Nutrition, New York: Academic Press, 1977.
72.
U.S. Environmental Protection Agency: Air Quality Criteria for Lead, Washington, D.C.: Office of Research and Development, December, 1977. (EPA 6008-77-017).
73.
Venugopal, B. & Luckey, T.D.Metal Toxicity in Mammals. Vol 2. New York: Plenum Press, 1980.
74.
Von Hilsheimer, G.Allergy, Toxins, and the Learning Disabled Child, San Rafael, California: Academic Therapy Publications. 1974.
75.
Vostal, J.J., Taves, E., Sayre, J.W., & Charney, E.Lead analysis of house dust: A method for the detection of another source of lead exposure in inner city children. Environmental Health Perspectives, May 1974, 91–97.
76.
Warren, H.V., & Delavault, R. E.Lead in some food crops and trees. Journal of the Science of Food and Agriculture, 1982, 13, 96–98.
