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Article Excerpt
At times it seems as if those of us in the general field of child development and developmental disorders are like blind men looking at elephants: we are ostensibly studying the same pachyderm yet we often come up with quite different impressions or highlight quite disparate facets. Indeed, the study of the "exceptional child" is very broad in scope and diverse in disciplines, and exceptionalities can bridge both ends of the ability continuum. Because of this there has been an abundance of intellectual creativity and fine science, but unfortunately there has also been a lack of cohesion.
The purpose of this article is to stimulate some thinking about these exceptionalities, particularly the complexities and variations within and across people. The model we present is in reaction to a long-standing predilection in the field to talk of learning disabilities (LD) or abilities, and gifts or high-end exceptionalities, as if they were completely phenotypically, etiologically, and statistically independent. Traditional approaches have, over the years, led many "blind men" to look upon only limited aspects of the exceptional animal, culminating in an inability to resolve the great variation that exists or explain the larger beast in its entirety. Although there are a number of cognitive differences models that correctly advocate for an appreciation of profiles of strengths and weaknesses in exceptional children (see multiple intelligences or other approaches summarized in Gardner, 1999; Levine, 1992; Sternberg, 2000), there remains a need for a neuroscientific approach that can help us better understand and accommodate the twice-exceptional individual---one with developmental LD but also with high skills in the talent, creativity, or intellectual domains.
It is our proposal that we need to combine current approaches with some new ways of thinking. This will allow us to fully appreciate that the brain that produces developmental learning abilities across the spectrum must be viewed as an integrated and multifaceted organ that is more than a simple reflection of its separate parts or domain-specific symptoms. We will describe a thinking tool that focuses on developmental reading disability (RD) or dyslexia and the twice-exceptional individual. While we use RD as an exemplary disorder, what we will talk about may also be applicable to other developmental LDs as well.
THE NEED FOR A THINKING TOOL (1)
While the field of the study of learning disabilities, and particularly RD, has had a long and successful track record of sustained and focused neuroscientific research, the systematic study of giftedness and of populations of the twice-exceptional student (e.g., RD plus gifted; Craggs, Sanchez, Kibby, Gilger,& Hund, 2006; Kalbfleisch, 2004) is seriously lacking. (2) There are several key reasons why the neuroscience of the twice exceptional (TE) is limited.
First, the relative lack of empirical and neuroscientific study of the TE (or purely gifted) population is, in part, due to some long-standing traditions in the study of child development and the funding focus or preference that adopted the "disease model" of abnormal learning in certain populations of children. The concept of RD, for instance, grew out of a medical model and the people with a neurological, genetic, or remedial bent naturally approached poor readers as having unique etiologies and as being "disordered" or "diseased" (e.g., Clements & Peters, 1962; Orton, 1928; summarized Fletcher, Lyon, Fuchs, & Barnes, 2007). The major scientific machines and federal funding sources like NIH also favored a "disease model" approach, and money for the neuroscientific study of the "other end of the continuum" in and of itself, or along with an LD, is hard to find. (3) However, some federal and state funds have been available for the study of giftedness such as the Javitz monies and other resources, and these have yielded some prolific centers and involved nationally respected researchers. For examples see the National Research Center for Gifted and Talented at the University of Connecticut, the Belin-Blank Center for Gifted Education and Talent Development at the University of Iowa, and the Gifted Education Resource Institute at Purdue University.
Second, while it has been politically charged at times to define and study disordered populations as being biologically different than the rest of the people along the normal curve, it also has been difficult to talk about groups at the high end of the distribution as being different. A neuroscientific focus on the former group relative to the latter has been favored, however, because of what was seen as the obvious economic and emotional benefits of finding ways to treat people with a reading or learning disorder.
Third, the fairly limited empirical neuroscience research on the TE reflects the history of this field: it has been dominated by professionals less interested in cause and more interested in educational issues. Although the classification of TE is tied to special education, few basic neuroscience researchers live in the field and, instead, curriculum specialists and educational and clinician psychologists have tended to hold key posts and have chosen to focus more on treatment and identification. In other words, studies in the area of giftedness and of the TE student have tended to focus on curriculum, cognitive theory, learning styles, and definitional debates (e.g., McCoach, Kehle, Bray, & Siegle, 2004; Newman, 2004).
Finally, our historical and sometimes unconscious manner of approaching the study and understanding of the brain has helped limit basic research of the twice exceptional. Simply put, it has been difficult to reconcile TE brains with what we now know about the expression and causation of learning disabilities (see Footnote 2). For example, studies of RDs often are careful to control for ADHD, normal IQ, and psychiatric problems, but giftedness is not even considered as an important or potentially related variable. Learning disorders are explained as separate units with specialized neurological and genetic substrates, and to consider gifts in the same "disordered" brain is not part of these models. Indeed many fine-grained reading-specific neuropsychological and biological models have been proposed as have some models for giftedness in domains of cognition (e.g., Drmonet, Taylor, & Chaix, 2004; Fletcher et al., 2007; Mody, 2004; Nicolson & Fawcett, in press; Simonton, 2005). But as these models of ability evolve, it is implied that "disabilities" must have a different etiology than "gifts" and the two shall never meet! Our grasp of these apparent disparate conditions would be well served if there were a unifying model that would help organize and conceptualize the central research issues in the areas of giftedness, LD, and TE.
We are not the first to call for such work, although the yield of prior calls has been limited (Kalbfleisch, 2004). Among the first such calls was by Norman Geschwind and colleagues, who spoke about the relationships between giftedness and developmental reading disorders over 20 years ago (Geschwind & Galaburda, 1987). They proposed that genetics and in utero hormonal activity modified neurodevelopment and hemispheric specialization such that a person could be born with a brain wired to be at risk for RD and superior nonverbal abilities as well. They and others have proposed that the setting of the left hemisphere language areas to be prone to language-based impairments could in fact effect the growth of portions of the right hemisphere such that there might be an overrepresentation of nonverbal gifts in RD samples. In this way, the etiology of high and low abilities can be related at a basic biological level early in fetal development, and postnatal etiologic factors are considered less important (Craggs et al., 2006). Interested readers might also look at hormonal and immune system neurodevelopmental models that also attempt to explain high and low skills in the same person (Benbow, 1988; Butterworth, 2001; Schopler & Mesibov, 1992; Singh & Boyle, 2004). Still, these models tend to be domain specific and often deal with severely disabling conditions like autism and mental retardation (see Footnote 2), and all these models are in need of further validation.
Our purpose here is not to advocate for one model or another. We would say, however, that our understanding of what it is that makes someone TE (or gifted) is really paramount to our understanding of the etiology of the complete range of human abilities and no harm will come from grasping the neuroscience of the other side of the human continuum. More importantly to us is that there is a growing call for such research, be it directly or indirectly. For example, there is the fairly recent emphasis at the national level that our economic and intellectual future may lie in great part in the production of students in the science, technology, engineering, and mathematics (STEM) disciplines and the importance of identifying national talent in these areas, some of whom may be LD as well. Indeed, some federal funding agencies are responding to this need through programs tied to talent identification and STEM education (e.g., the Institute of Educational Sciences [IES]; and see the National Academies [n.d.] summary reports on this issue).
It is also becoming increasingly apparent that certain populations of children and adults are not well served by existing nosologies and models of special education for LD, TE, and giftedness (Eide & Eide, 2006; McCoach et al., 2004; Newman, 2004). Teachers, for instance, often are confused by conflicting abilities in the same child, and parents often are unable to get services for their child because the child does not fit any clear diagnostic scheme or qualification criteria. More well-designed neuroscientific study of the gifted and TE would help ameliorate some of these difficulties.
THE CONCEPT OF ATYPICAL BRAIN DEVELOPMENT APPLIED TO TWICE EXCEPTIONALITY: THE GIFTED RD INDIVIDUAL AS AN EXAMPLE
The Atypical Brain Development (ABD) model originally was designed in response to perceived needs in the field of LD, and especially RD (e.g., Bonifacci, 2004; Davis, 2004; Fadjukoff, Ahonen, & Lyytinen, 2001; Frith, 2001; Gilger & Kaplan, 2001; Gilger & Wilkins, 2008; Gilger & Wise, 2004; Goldstein & Schwebach, 2004; Jeffries & Everatt, 2004; Kaplan, Dewey, Crawford, & Wilson, 2001; Kaplan & Gilger, 2001; Kreuger & Markon, 2006; Lyon, Fletcher, & Barnes, 2003; Lyytinen et al., 2000; Missiuna, Gaines, & Pollock, 2002; Ping & Zu-wen, 2005; Rice & Brooks, 2004; Sonuga-Barke, 2003; Valtonen, Ahonen, P. Lyytinen, & H. Lyytinen, 2004; Zoia, Barnett, Wilson, & Hill, 2006). The ABD concept evolved primarily from thinking about the ecological validity of diagnostic categories. There also were issues being raised by ongoing genetic and neurological research at that time, especially in the area of RD, that were challenging to the assumptions behind the concept of a neurologically specific reading disability. The ABD approach was designed to provide some cohesion and reconcile research with some of the belief systems of many clinicians and educators who had extensive exposure to individuals with developmental problems like RD or other learning exceptionalities. Namely, practitioners were becoming dissatisfied with the practical utility of the dominant contemporary theories and guidelines, special education criteria, and how to deal with children who fail to fit molds constrained by these theories and related federal laws.
ABD Fundamentals
There are three fundamental assumptions behind the ABD concept. By and large the validity of assumption one is obvious. Assumptions two and three are likely also to be obvious, but some general references are provided (see Bartley, Jones, & Weinberger, 1997; J. W. Gilger, 1995; Pennington, 2002; Scerif & Karmiloff-Smith, 2005; P. Thompson, Cannon, & Toga, 2002; P. M. Thompson et al., 2001). The three assumptions are
1. The brain is the basis of behavior.
2. Individual differences in behavior are due to variable brain structure and function.
3. Ultimately, individual differences are the result of the complex effects of genes and the environment on the developing and learning brain.
It is important to realize that the...
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