AERA, San Diego

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Natural Neurodevelopmental Variation and the
Twice Exceptional Student

• AERA, San Diego
• April, 2009
• Jeffrey W. Gilger
• Purdue University
• Email jgilger_at_purdue.edu

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Collaborators

• Tom Talavage
• Jason Craggs
• George Hynd
• Juliana Sanchez Bloom
• Olumide Olulade (Lewis)
• Others
• Funded in part by APA/Rosen Katz Foundation (PI
  Gilger) NICHD R01 26890-07 (PI Hynd) Purdue
  Bridge Funds

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Outline

• Brief Review of Genetic and Brain Studies of
  Developmental Reading Disorder (RD) and Spatial
  Abilities
• The Neurodevelopmental Paradox of the Twice
  Exceptional (TE) Person
• The Morphological Study of the MN Family
• The fMRI Study of the Twice Exceptional (2x)
• Closing Comment on Future Work and Implications

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Review Dyslexia (RD) is an unexplained inability
to learn to read (write, spell) in accordance
with age and/or IQ expectations
NIH/IDA working group J. Gilger, G. Eden,
H.Catts, E. Dickman, G.R. Lyon. S. Shaywitz, B.
Shaywitz, J. Fletcher. S. Brady, H. Tomey Lyon
et al., 2003, Annals of Dyslexia, 53
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Genetics
Chromosome 1 Chromosome 2 Chromosome 3 Chromosome
6 Chromosome 7 Chromosome 13 Chromosome
15 Chromosome 16 Chromosome 18 Chromosome
19 Chromosome X Gene associations to specific
cognitive traits
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Promising Gene Linkages and Gene Candidates
Chromosome 3 ROBO1 Axon guidance, across
midline and hemispheres Chromosome 6 DCDC2
Neuronal migration to cortex, expressed in
thalamus as well Chromosome 15 DYX1C1 Expressed
in brain
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Structural Imaging
Functional Imaging
Anatomical Studies
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Brain Pathology in Dyslexia

• An example from Galaburda et al. (1985) that
  shows a collection of neurons in Layer 1 of the
  cortex (cell free layer)
• These migration errors most likely occur in the 5
  7th month of fetal development

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Structural MRI
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Summary of Some Common Functional Findings
Demonet, J. F., Taylor, M. J., Chaix, Y.
(2004). Developmental dyslexia. Lancet, 363,
1451-1460.
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Four Well Accepted Conclusions About the Nature
of RD
Primarily a language-based disorder
(phonological awareness, processing)
Neurological in origin (left inferior frontal,
inferior temporal-occipital, temporal-parietal) I
n part, neurodevelopmental in origin
(disorganized neural pathways, atypical cortical
cell connection, gross and fine structural
formations different from controls, etc.) In
part genetic, with specific risk genes (moderate
h2, replicated linkages to specific genes or
chromosomal sites)
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Neurology is complex as is measurement
Nonverbal (spatial) abilities are those skills
that involve mental manipulation of objects,
forms or shapes, spatial coordination,
nonverbally mediated Gestalt processing, visual
memory, other

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• Practice effects
• Genetics, hormones
• Gender
• Culture
• Etc.

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Myths and Anecdotes Abound About Gifts and Twice
Exceptionality

• Misinterpretation of data
• Well intended bias
• Misrepresentation in literature
• Lack of Science!

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What We Are Not Talking About

• Rare and talented autistic, savant, or prodigy
  cases (Casanova et al., 2002 Cash, 1999
  Butterworth, 2001 Deutsch Joseph, 2003)
• What We Are Talking About
• Do dyslexics have a neurology that makes them
  more adept at NV tasks?
• Are NV gifted dyslexics neurologically like
  normal but gifted individuals?

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Reading (R) and Talent (T) Comorbidity
Common Etiology

ET1
R T
Etiologic Subtype

ET1
R

T
ET2
ET3
R T
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Normal Distribution of Learning Abilities or
Learning Brains
Expected Atypical Brain Development
Typical
?!
Medical Model
3-5
RD
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Continuum of Measured Abilities
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In-utero Effects on the Developing Brain How Can
Similar (Natural) Factors Miswire the Brain to
Have Both Deficits and Gifts?
Genetics
Environment
Neurology
RD
Risk
Interaction
Hi NVIQ
Nonverbal Abilities Over Verbal Abilities
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Even Gifted People Have issues
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1 Epidemiology As A Place To Start

• Base rate of RD 7 (7/100)
• Base rate of Gifted IQ 5 (5/100)
• Expected rates if the two conditions are
  independent .07 .05 .0035 (.35/100)
• Observed 3-5 (3 to 5/100)
• The observed rate is significantly higher than
  what we would expect by chance if the two
  conditions were unrelated!

Gilger, J., Hynd, G. (2008). Atypical Natural
Neurodevelopmental Variation as a Basis for
Thinking About the Gifted Dyslexic. Roeper
Review, 30, 214-228
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2 MN Family
Results The father and four sons of this
family demonstrated an unusual pattern of
giftedness in spatial/nonverbal reasoning as
measured by the PIQ on the WASI Average PIQ
130.8 Average split 29.2
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Line Responsible
V Verbal IQ P Performance IQ
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Normal Brain Development

• As can be seen the brain evolves from essentially
  smooth during early fetal development to a well
  defined gyral pattern at birth
• There is a significant increase in brain weight
  between the 24-26th weeks and a significant
  increase in gyrification between the 26-28th week

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Note Curved arrows indicate horizontal portion
of the planum temporale. Straight arrows indicate
the Post Central Sulcus (POCS) a. Steinmetz Type
I, b. Steinmetz Type II, c. Steinmetz Type III,
d. Steinmetz Type IV.
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Witelson, et al., Lancet, 1999
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Percent Gyral Typologies in the Nuclear Family
Members (normative sample in parenthesis)
Note Steinmetzs sample results are in
parentheses for comparison. Comparisons of
nuclear family to expected Rt and Lft ?2 p lt
.01
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Mathematical Spatial Processing
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Witelson, et al., Lancet, 1999
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Summary -30/35 family members tested had higher
PIQ than VIQ. -Notable tendency for careers to be
in traditionally nonverbal fields. -VIQ-PIQ
discrepancies and high PIQ are aggregating. -Morph
ology may reflect early developmental
events. -Initial support that the
Neurodevelopmental Paradox may have a
neurogenetic basis. -Next steps Ongoing fMRI,
genetic study including additional
subjects -Does this carry out to an unrelated
population? What is the functional aspect of such
morphology?
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3. Ongoing Study at Purdue Subjects Subjects
were the MN nuclear family (F 6) 10 NV gifted
(G 4) 10 RD and NV gifted (GRD 6) 10 RD only
(RD 6) 10 Controls (N 4)
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Methods Measures VIQ and PIQ via the Wechsler
Scales Measures of reading, orthographic
processing, phonological processing, rapid
naming, etc. Occupation/Pedigrees,
DNA Word-related MRI protocols courtesy of Ken
Pugh et al. Shepard-Metzler cubes adaptation for
the MRI MRI scans of the family members were
obtained with 3.0 Tessla magnet using a Horizon
LX GE Scanner
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Prelim Results

• Left hemisphere word processing
• Right hemisphere spatial processing

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Left Hemisphere Word Task
Red Areas active for real words only Blue Areas
active for non-words only Yellow Areas active
for both word and non-word tasks
N
RD
G
Under activation in RD Similar prefrontal
activation Fusiform gyrus/Brodmann 37/Inf tem
gyrus Increased intensity in gifted brains GRD
looks like G
GRD
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Right Hemisphere Spatial Task
Red Areas active for spatial stimuli requiring
rotation Blue Areas active for spatial stimuli
not needing rotation Yellow Areas active for
both types of spatial stimuli
G
N
RD
GRD
High activation for G and GRD Increased
activation for not the same stimuli in
RD Minimal activation for not the same in G and
GRD GRD looks like G Brodmann 17,18,19/Primary
vis cortex
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Axial Images Word Task (Left is Left)
Red Areas active for real words only Blue Areas
active for non-words only Yellow Areas active
for both word and non-word tasks
G
N
RD
Under activation in RD Similar prefrontal
activation Increased intensity in gifted
brains GRD looks like G but clearly not like N
GRD
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Axial Images Spatial Task (Left is Left)
Red Areas active for spatial stimuli requiring
rotation Blue Areas active for spatial stimuli
not needing rotation Yellow Areas active for
both types of spatial stimuli
G
N
RD
High activation for G and GRD Increased
activation for not the same stimuli in
RD Minimal activation for not the same in G and
GRD GRD looks like G RD look like G and GRD
while less specific to sameness
GRD
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Closing Comments
gtDo dyslexics have a neurology that makes them
more adept at NV tasks? gtAre NV gifted dyslexics
neurologically like normal but gifted
individuals? gtAre the same neurological
processes at work across different groups? Might
these be due to the same genetically mediated
neurodevelopment? gtImplications for practice (do
the brains process NV info differently, ID gifted
RD brains, does training on verbal modify NV as
well, etc.)

• gt Must complete study
• gt Do complete functional and structural analyses
• gt Other
• http//www.education.purdue.edu/ODFD/gilgerpres.ht
  ml

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Thank you! Jeffrey W. Gilger Purdue
University Beering Hall of Liberal Arts and
Education, Room 6114 100 N. University Street W.
Lafayette, IN 47907-2098 jgilger_at_purdue.edu http
//www.education.purdue.edu/ODFD/gilgerpres.html

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Some References (some on slides as well)
Craggs, J. Sanchez, J., Kibby, M.,
Gilger, J. Hynd, G. (2006). Brain morphological
and neuropsychological profiles of a family
displaying superior nonverbal intelligence and
dyslexia. Cortex, 42, 1107-1118. Rhee, S.,
Hewitt, J., Corley, R., Willicut, E.
Pennington, B. (2005). Testing hypotheses
regarding the causes of comorbidity Examining
the underlying deficits of comorbid disorders. J.
Abnormal Psychology, 114, 346-362. Ramus, F.
Neurobiology of dyslexia A reinterpretation of
the data. TINS, 27, 720-726. Smalley, S., Loo,
S., Yang, M. Cantor, R. (2004). Towards
localizing genes for cerebral asymmetry and
mental health. Am. J Medical Genetics
(Neuropsychiatric Genetics), 135, 79-84.
Gilger, J. Wilkins, M. (2008). Atypical
Neurodevelopmental Variation as a Basis for
Learning Disorders. In M. Mody E. Sillliman
(Eds.), Language Impairment and Reading
Disability Interactions Among Brain, Behavior,
and Experience. (Series on Challenges in Language
and Literacy). Guilford Press. Smith, S.D.
Gilger, J.W. (2007). Dyslexia and other
language/learning disorders. In Rimoin, Connor,
Pyeritz Korf (Eds. 5th edition), Emory and
Rimoin's Principles and Practices in Medical
Genetics. Livingstone Churchill NY. Gilger,
J.W. Kaplan, B. (2001). The neuropsychology of
dyslexia The concept of Atypical Brain
Development. Developmental Neuropsychology, 20
(2) 465-481. Gilger, J., Hynd, G. (2008).
Atypical Natural Neurodevelopmental Variation as
a Basis for Thinking About the Gifted Dyslexic.
Roeper Review, 30, 214-228
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