Placing Children in Special Education A Strategy for Equity (1982) / Chapter Skim
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Biological and Social Factors Contributing to Mild Mental Retardation
Biological and Social Factors Contributing to Mild Mental Retardation
Pages 133-181
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From page 133... ...
This paper provides an overview of recent research in areas directly relevant to these issues, formulates the current state of the art, and provides a framework for conceptualizing the available data in their imperfect form. In so doing, it attempts to specifically examine the contribution of biological and social factors to the disproportionate representation of minority students and males in education programs for the mildly mentally retarded.
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From page 134... ...
It is hardly necessary to emphasize that the high grade cases of the type now so frequently overlooked, are precisely the ones whose guardianship it is most important for the state to assume. Mildly retarded people were feared for their assumed tendencies toward immorality, delinquency, criminality, and the propagation of "defective"
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From page 135... ...
The Education Act of 1921 specifically addressed the needs of the mildly retarded by creating a category of mental defect restricted to children ages 7-16 and based on educational but not social deficiencies (Blanton, 1975~. At the turn of the century, when the French minister of education commissioned Alfred Binet to develop a test to facilitate the early identification of children who could not meet the demands of regular schooling, the die was cast and the classification of school children was irrevocably altered.
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From page 136... ...
mental retardation ushered in a new era of special education and laid the foundation for many of the modern concepts of specific learning disabilities. In 1953 a committee of the World Health Organization defined mental deficiency as incomplete or insufficient general development of the mental capacities secondary to biological factors and defined mental retardation as the same condition secondary to social factors.
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From page 137... ...
In its mild manifestations, it is less a vehicle for understanding those people whom it labels than a mirror of the society that determines its boundaries (Sarason and Doris, 1979~. In this context of uncertainty this paper explores the data regarding the biological and social roots of mild retardation.
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From page 138... ...
This paper focuses primarily on prevalence data, as these numbers are the most relevant for defining and planning intervention services. LIMITATIONS OF THE DATA The most fundamental dilemma is clearly related to the absence of a consistent definition of mild retardation.
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From page 139... ...
noted that the reported prevalence of mild mental retardation in the People's Republic of China is essentially zero; their technologically unsophisticated society places minimal value on individual achievement and maximal emphasis on social cohesion and mutual support. In Sweden, where industrial modernization and emphasis on achievement are more evident, the reported prevalence of mild retardation is also relatively low, in part because of social acceptance of educational mainstreaming of intellectually limited children (Grunewald, 1979~.
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From page 140... ...
When broken down by severity, the percentages of mild retardation within each group ranged from 63 to 92 percent, with a median of 80 percent. Clearly, the limitations of the available epidemiological data are formidable.
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From page 141... ...
Initial prevalence rates were obtained by ascertaining the number of children (ages 8-10) who were identified as subnormal by the local school authorities and placed in special programs based on evaluation of their social competence, school performance, medical status, and psychometric test scores.
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From page 142... ...
VARIATIONS RELATED TO POPULATION SUBGROUPS Despite the problems and disagreements described above, a number of strong relationships have consistently been reported regarding the relative prevalence rates of mild retardation among specific demographic subgroups. SOCIOECONOMIC DIFFERENCES In 1962, The Report to the President of the President's Panel on Mental Retardation noted (p.
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From page 143... ...
A recent analysis of data on more than 35,000 children from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke specifically looked at the relationship of race and socioeconomic status to the prevalence of mild retardation based on test scores of 50 to 69 on the (WISC-R at age 71. Rates for the white population were 3.34 percent for the lower socioeconomic group (bottom 25 percent)
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From page 144... ...
(1970) found an ever greater prevalence in the portion of the lowest socioeconomic classes living in large families in areas with particularly poor and overcrowded housing.
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From page 145... ...
Data from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, based on IQ scores (WISC-R) between 50 and 69, revealed a prevalence rate for mild retardation of 4.83 percent among blacks and 1.17 percent among whites, with a persistence of at least a twofold difference across all socioeconomic groups (Broman, unpublished data, 1981)
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Males are more susceptible to infectious diseases, including neonatal septicemia (Smith et al., 1956) and those that affect the central nervous system, such as meningitis and encephalitis (Carpenter and Petersdorf, 19623.
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Although it is generally said that mental retardation is more common in males than in females (Farber, 1968; Goodman et al., 1956; Kirk and Weiner, 1959) , the literature on sex differences in prevalence rates is actually somewhat equivocal.
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Careful analysis of the confounding influences of socioeconomic and ethnic factors has not been done, and the data in this regard are therefore inconclusive. AGE DIFFERENCE S One of the most consistent findings among epidemiological studies of mental retardation is the dramatic change in prevalence rates with age.
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From page 149... ...
This relationship between prevalence data and age confirms without question the fact that mild retardation is largely a creation of universal compulsory education. Despite all the definitional confusion and methodological variation, the data show a consistent tension between the demands of the school and the performance of poor, nonwhite children, especially boys.
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From page 150... ...
Optimal competence and performance for any child, however, are dependent on the interplay between intrinsic biological integrity and an environment that facilitates the development of skills and positive self-esteem. The relationship between mild retardation and lower socioeconomic and ethnic minority status as well as the greater prevalence of school failure among boys have been extensively analyzed from educational, sociological, and political perspectives.
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From page 151... ...
The relatively low incidence of these conditions (1/10,000 female births and 1/1,000 male births, respectively) , the low rate of intellectual impairment involved, and the absence of data to suggest disproportionate distribution among socioeconomic classes or ethnic minorities suggest that major chromosomal disorders do not contribute to the numbers of mildly retarded children in any appreciable way.
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From page 152... ...
Moreover, even if genetic differences did exist, their influence on outcome for the mildly retarded would be overshadowed by the effects of the suboptimal environments within which ethnic minorities and the poor reside. Demographic Risk Factors Pregnancies that involve factors that increase the likelihood of perinatal mortality, prematurity, low birth weight, or a wide variety of handicapping conditions, including mental retardation, are called "high risk." It has been estimated that such pregnancies account for more than half of all perinatal mortality and morbidity (Vaughan et al., 19791.
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From page 153... ...
and are more likely to result in the birth of a low birth weight infant, regardless of social class (American Academy of Pediatrics, 19791. Several investigators have suggested that the increased incidence of small neonates is related to the competition for nutrients between the fetus and the still-growing mother (Naeye, 1981~.
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From page 154... ...
, between 1 and 7 percent of all infants born in the United States may be infected with one of these chronic organisms, and prevalence is even greater among adolescent women from lower socioeconomic classes. Since CMV is the most common of these infections, it would be instructive to examine its impact in detail.
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Further analysis revealed significant differences in IQ scores between CMV-positive and control children from the lower socioeconomic families, with no significant IQ differences between those
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From page 156... ...
clearly contributes additional vulnerability. In summary, the current state of knowledge regarding the influence of asymptomatic congenital cytomegalovirus infection on the prevalence of mild retardation among school children is highly suggestive but far from conclusive.
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central nervous system dysfunction with varying degrees of mental retardation (Clarren and Smith, 1978~. A number of serious methodological deficiencies in the existing literature, however, compromise the reliability and validity of the available data.
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Most recently, Sameroff and Chandler (1975) offered the phrase "continuum of caretaking casualty" to highlight the transaction between biological risk factors and environmental variables that eventually determine developmental outcome.
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The report of the Select Panel for the Promotion of Child Health (1981) states that "it is generally agreed that very low birth weight is among the most significant predictors of later neurological abnormalities and various cognitive and behavioral deficits" (p.
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From page 160... ...
(1973) found that two thirds of low birth weight males and more than half of the total group of former small-for-gestational-age babies of both sexes had problems of sufficient magnitude to warrant a wide variety of special educational services (which were not well defined)
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From page 161... ...
The best predictor was a composite reflecting socioeconomic status, maternal educational level and performance IQ score, head circumference at birth, and, among whites, a clinical diagnosis of brain abnormality in the neonatal period (Broman, 19811. In this context it is useful to examine the demographic distribution of low birth weight babies.
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From page 162... ...
Moreover, the likelihood of a poor developmental outcome in a low birth weight or asphyxiated newborn is significantly increased for children in the lower socioeconomic classes. Further evidence suggests that although sex differences in IQ may not be significant, males may have a considerably higher incidence of subtle neurological and perceptual disabilities related to factors of perinatal stress that contribute to learning and behavioral profiles resulting in their disproportionate placement in special educational programs.
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From page 163... ...
In a review of seven studies, Chase (1973) reported significant deficits in test performance by malnourished children ages 2-14 in all but one report.
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stated that "in spite of many serious methodological shortcomings in the studies that have been made, the weight of evidence seems to indicate that early and severe malnutrition is an important factor in later intellectual development, above and beyond the effects of socio-familial influences." The extent to which the kinds of nutritional deficiencies commonly found in the United States may be sufficient to affect intellectual development in children was considered by Livingston et al.
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From page 165... ...
It was noted that poverty and race are associated with deficiencies in six of eight specific nutrients. Even if these data are all high estimates of the extent of the nutritional problems of poor and ethnic minority children in this country, the potential contribution of this factor to the prevalence of mild retardation could be substantial.
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From page 166... ...
Prevalence rates in low-income, inner-city areas range from 4 to 40 percent positive in community screening programs (Lin-Fu, 19721. Moreover, among comparable socioeconomic groups in the population, lead absorption has been reported to be greater for black than for white children (Lin-Fu, 1979~.
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From page 167... ...
Thus, although the answers are not yet in, one cannot completely disregard the potential contribution of low levels of lead to the preponderance of mild retardation among ethnic minorities and poor children. Family Resources, Child-Rearing Practices, and Individual Learning Styles Contemporary conceptualizations of the process of human development place great emphasis on the transaction between biological predispositions and environmental contingencies as mutual determinants of developmental outcome.
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versus control lower socioeconomic class children. Zajonc and Markus (1975)
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From page 169... ...
Its very nature has changed dramatically over time, and its contemporary definitions are highly influenced by differences among societies. Within the United States in the past 100 years, arbitrary shifts in diagnostic criteria have moved children in and out of the mildly retarded population.
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From page 170... ...
Despite the serious methodological problems inherent in epidemiological studies of mild retardation, the consistency of the disproportionate diagnosis of children from ethnic minorities and lower socioeconomic groups has been impressive. Because of their high degree of overlap, it has often been difficult to tease out the relative contributions of ethnicity and poverty.
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From page 171... ...
Intrauterine factors such as cytomegalovirus and alcohol, complications during the newborn period related to prematurity and/or low birth weight, and early childhood insults such as malnutrition and lead intoxication can all inflict damage on an immature brain resulting in significant impairment in later intellectual functioning. These threatening influences and many others exist with greater frequency among poor and minority populations.
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From page 172... ...
Most low birth weight babies do well developmentally. Of those children who were exposed to noxious agents during their prenatal or postnatal life, some will have impairment of their intelligence and others will appear to escape unharmed.
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Birch, H., and Gussow, J 1970 Disadvantaged Children: Health, Nutrition and School Failure.
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From page 174... ...
1970 Consequences of low birth weight. Developmental Psychology 3:363-383.
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1976 School failure and deafness after "silent" congenital cytomegalovirus infection. New England Journal of Medicine 295:468-470.
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American Journal of Mental Deficiency, Monograph Supplement 64(2)
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From page 177... ...
Pediatrics 48:902-906. National Center for Health Statistics 1980 Factors Associated with Low Birth Weight: United States, 1976.
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American Journal of Mental Deficiency 82:525-534.
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1974 Inapparent congenital cytomegalovirus infection with elevated cord IgM levelscausal relation with auditory and mental deficiency. New England Journal of Medicine 290:291-296.
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1973 Natural history of mental retardation: some aspects of epidemiology. American Journal of Mental Deficiency 77:369-379.
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From page 181... ...
B 1975 Birth order and intellectual development.
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