Language acquisition and functioning in children with agenesis of

Language Acquisition and
Functioning in Children
with Agenesis of the
Corpus Callosum
Linda C. Badon. Ph.D.
Shalini Arehole, Ph.D.
John W. Oller, Ph.D.
Kayla O’Connor, McNair Scholar
University of Louisiana at Lafayette
1
What is ACC?
 A birth defect in which the
systems of nervous fibers that
connect the two hemispheres
of the brain (the corpus
callosum) are partially or
completely absent.
 Also for symptoms and
manifestations see the Travis
Research Institute and information
at
http://www.travisinstitute.org/neuro
science/agenesis.htm
SOURCE: healthlink.mcw.edu
2
Terminology
 The Corpus Callosum




The largest commissural system of bundles of nerve
fibers in the brain which
connects the right and left hemispheres of the brain
and which
is the main enabler of communication between the
hemispheres (in addition to the senses which permit
communication through the brain stem).
The critical pathway connecting holistic
impressions of the senses with the abstract
representations of thought, language, and social
understanding…
3
Paul, et al., 2007 assert:
“Generating a functional map of AgCC [agenesis of the
corpus callosum] brains will inform crucial questions
about cortical and subcortical reorganization: where are
particular functional regions (for example, specific visual
areas and areas involved in language) located? To what
extent do their locations differ from those in healthy
brains? Are there some functional regions whose
anatomical location remains relatively invariant, and are
there others that can shift location more variably? Such
questions have been much investigated in studies of
plasticity in animal brains; next to nothing is known about
this in the human brain” (p. 296).
4
The human corpus callosum
contains approximately 190
million axons… Fibres are
coloured according to their
projection areas: prefrontal
lobe (green), premotor and
supplementary motor areas
(light blue), primary motor
areas (dark blue), primary
sensory cortex (red), parietal
lobe (orange), occipital lobe
(yellow), and temporal lobe
(violet). c | In monkeys,
researchers have been able to
use chemical tracers to map
the organization of cortical
fibres passing through the
corpus callosum, providing a
level of detail currently
unavailable in humans.
BA23, Brodmann’s area; CC,
corpus callosum; SMA,
supplementary motor area.
Panel a modified, with permission, from REF. 145 © (2004) American Society of Neuroradiology. Panel b
reproduced, with permission, from REF. 144 © (2006) Elsevier Science. Panel c modified, with permission,
5
from REF. 146 © (2006) Oxford Univ. Press (Paul et al, 2007, p. 288).
Basic Neuroarchitecture
 Pragmatic mapping (per Oller, 1975, 2009) involves
the linguistic (abstract) representation of perceptual
and memorial information through signs (words or
other abstract signs) that are mapped onto things,
persons, and event sequences represented in images.
 As shown by Oller, Oller, & Badon (2010), the
dominant hemisphere manages words and sequences
of abstract signs (symbols); the right brain manages
holistic factual representations (icons of sensory
impressions, images, faces, and scenes); and the
corpus callosum enables the linking of them through
actions (indexes).
6
Roger Sperry, Nobel lecture of
1981 said of split-brain studies:
 “Each brain half . . . appeared to have its own,
largely separate, cognitive domain with its own
private perceptual, learning and memory
experiences, all of which were seemingly
oblivious of corresponding events in the other
hemisphere. . . . The speaking hemisphere [the
dominant one] in these patients could tell us
directly in its own words that it knew nothing of
the inner experience involved in test performances
correctly carried out by the mute partner
hemisphere [the minor one].”
7
Two Ways of Disturbing
Communication of the Hemispheres:
 (1) Hemispherectomy (or commissurotomy)
 (2) Complete failure to develop a corpus callosum
(agenesis) believed to be owed to genetic and/or epigenetic
developmental processes
 In both types of disruption of communication between the
hemispheres, we see similar symptoms manifested.
 Also we learn from both types that


either hemisphere can perform all the functions if the disruption
occurs at a very early age (Merrick, 2009; Sperry, 1981, A. Smith,
1966; A. Smith & Sugar, 1975);)
but that some corpus callosal interactions between the hemispheres
are essential to the development of abstract comprehension, e.g.,
8
comprehension of metaphor, sarcasm, humor, and abstractions.
Here Are Six Distinct Ways of Viewing the
Pragmatic Mapping Process: First, the most
abstract and simplest way (SπO)
 S = symbol, or sequence of them
 π = simple or complex indexical mapping (as in
pointing to a person named or an act referred to);
where one or many symbols are linked with a
factual context holistically represented in a given
perceptual scene, or a sequence of them that is
remembered, being experienced, or anticipated
 O = the holistic iconic representation, as in a still
shot or moving video record, of a dynamic factual
context as it exists and changes over time
9
Second, pragmatic mapping may be
viewed as a perceptual act:
Dominant hemisphere
function (abstract
symbolic representation)
Corpus callosal
function (indexical
association)
Subordinate
hemisphere function
(iconic, holistic
representation)
10
Third, pragmatic mapping may be
viewed as a signifying act:
Dominant hemisphere
function (abstract
symbolic representation)
Corpus callosal
function (indexical
association)
Subordinate
hemisphere function
(iconic, holistic
representation)
11
Fourth, pragmatic mapping may be viewed as
foundational to global neuroarchitecture.
WORDS
(3) Linguistic
(symbolic)
signs
L
(2) Motor
(indexical)
signs
Corpus Callosum
(1) Sensory
(iconic)
signs
Figure from Oller, Oller, & Badon (2010), p. 535.
FACTS
R
12
Fifth, pragmatic mapping serves as a
basis for classifying disorders showing
the role of the CC in the middle
Diagram from Oller, Oller, & Badon (2010), p. 517).
13
Sixth, it can be seen as the central
cycle in abstract sign development
Diagram from Oller, Oller, & Badon,
2006, p. 95.
1. Discrimination involves
discovering the boundaries and
characteristics of icons
(subordinate hemisphere, iconic,
holistic function)
2. Prescission involves the
displacement of a bounded
object relative to an observer
(corpus calossal function
involving both hemispheres in
noting indexical association)
2. Hypostasis involves the abstraction of a representation of whatever has been
discriminated and prescinded and the introduction of the newly formed
representation into the stream of experience, thereby enriching it, and enabling
higher level representations to be formed; involves both hemispheres and the corpus
callosum but especially depends on the dominant hemisphere)
14
With the foregoing in mind, what if the corpus
callosum does not develop at all?
 In the classic case studied by Saul and Sperry (1968; Sperry, 1968)
such an individual had “an above-average IQ” and motor speech
capacities about equally well formed in both of the hemispheres; good
at verbal tasks but performed comparatively less well on tasks
requiring holistic spatial processing normally assigned to the
subordinate hemisphere.
 Merrick (2009) reports a case of complete agenesis with “deficits in
problem solving, verbal fluency, and abstract reasoning (Paul et al.,
2007)…. [with] impairment in learning and memory, executive
functions, motor coordination, intellectual abilities (FSIQ 78),
academic achievement, language and perceptual reasoning” (p. 431;
retrieved November 13, 2009, from
http://acn.oxfordjournals.org/cgi/content/abstract/24/5/431).
 We must also keep in mind that genetic and developmental
15
problems are rarely focally exclusive with respect to damage.
Common Terms referring to callosal dysfunctions (from
ACC Network, 5749 Merrill Hall Room 337, University of Maine, Orono, ME 04469-5749 USA
Retrieved November 13, 2009 from http://www.umaine.edu/edhd/research/acc/ )
 ACC (Agenesis of the corpus callosum): all or a portion of the corpus

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

callosum is absent
AgCC (Agenesis of the corpus callosum): another abbreviation
sometimes used for ACC
c-ACC (Complete agenesis of the corpus callosum): the entire corpus
callosum is absent
p-ACC (Partial agenesis of corpus callosum): a portion of the corpus
callosum is absent
Dysgenesis of the corpus callosum: the corpus callosum is present, but
malformed in some way
Hypogenesis of the corpus callosum: another term used to describe pACC
Hypoplasia of the corpus callosum: the corpus callosum is present but
abnormally thin
16
The brain with (left) and without
(right) a corpus callosum.
From ACC Network, 5749 Merrill Hall Room 337,
University of Maine, Orono, ME 04469-5749 USA
Retrieved November 13, 2009 from
http://www.umaine.edu/edhd/research/acc/
17
http://www.mypacs.net/repos/mpv3_repo/viz/full/17036/851803.jpg
Elements of the Corpus Callosum
1. Rostrum of corpus callosum
2. Genu of corpus callosum
3. Body of corpus callosum
4. Splenium of corpus callosum
5. Paraterminal gyrus
From ACC Network, 5749 Merrill Hall Room 337,
University of Maine, Orono, ME 04469-5749 USA
Retrieved November 13, 2009 from
http://www.umaine.edu/edhd/research/acc/
http://www.mypacs.net/repos/mpv3_repo/viz/full/17036/851803.jpg
18
Historical Perspective of Agenesis of
the Corpus Callosum
•First case of complete ACC reported in 1812
•First case of complete agenesis reported in 1911
•By 1933, 81 cases were reported
•Presently, a search of the Web of Knowledge on
November 13, 2009 yields 756 hits on the phrase
“agenesis of the corpus callosum” … clearly a
problem of considerable interest.
19
An evolving conception
 18th century
Site of the soul
Early 20th century
preventing two
sides of the brain from collapsing


Mid 20th century with Myers and Sperry
INTERHEMISPHERIC COMMUNICATION
AND
COORDINATION OF COMPLEX ACTIONS
20
Incidence of agenesis or partial
agenesis is unknown…
 Many cases go undiagnosed (or are called by a half dozen or
more different names)
 Current estimates vary greatly suggesting that corpus
callosal abnormalities may be quite rare or may occur in as
many as 4 persons per 1,000 in the general population;
 Such abnormalities are known to co-exist more commonly
with developmental disabilities (estimated to occur in about
22-24 cases per 1,000).
 Also, it is certain that abnormalities tend toward comorbidity… one noted injury usually involves others… that
may not have been noted yet
21
Etiology
(http://www.umaine.edu/edhd/files/2009/05/acc-fact-sheet-final.doc
)
 Chromosome errors or inherited genetic factors
 Epigenetic interactions
 Prenatal infections
 Physical injuries owed to trauma
 Toxic exposures
 Systematic blockages (e.g. hyperplasias of various
sorts)
 Metabolic disorders
 Combinations of the above
 And, probably, other yet to be discovered factors
22
All four major classes of disorders and occur with agenesis or
dysgenesis of the CC (Moes, P., Schilmoeller, K., &
Schilmoeller, G., 2009; also, Oller, Oller, Badon et al, 2010)
1.
Bodily (Anatomical) Conditions Sensory Disorders
1.
2.
2.
Sensory Disorders
1.
2.
3.
4.
5.
3.
Visual
Auditory
Olfactory
Gustatory
Tactile
Sensory-Motor Dysfunctions
1.
2.
3.
4.
4.
Partial to complete absence of the corpus callosum
Absence or partial formation of other anatomical elements such as genitourinary components, gastro-intestinal defects (e.g., an imperforate anus),
cardiac anomalies, skeletal defects, etc.
Autonomic system disorders (e.g., of digestion or cardiac rhythms, etc.)
Movement disorders of volitional acts as in chewing, swallowing, and so on.
Gesture
Speech
Higher Level Emotional/Language/Cognitive Disorders
23
Dysgenesis of the CC goes by many different
names and symptoms are sometimes regarded
as the whole condition. It may be diagnosed as:
 Microcephaly (also, colpocephaly = enlargement of the occipital horns)
 Hydrocephalus
 Arnold-Chiari (or Chiari) malformation (with downward displacement of




the cerebellar tonsils and the medulla leading to hydrocephalus because of
blocking the flow of cerebrospinal fluid;
Tonsillar herniation (another name for Arnold-Chiari malformation )
Aicardi syndrome (partial or complete absence of the CC with retinal
abnormalities, and seizures during infancy)
Andermann syndrome (abnormal or absent reflexes, hypotonia,
amyotrophy, loss of sensation in the limbs, and tremors; gait problems,
joint contractures, and scoliosis); abnormal cranial nerve growth, facial
muscle weakness, drooping eyelids, gaze palsy. intellectual disability,
seizures, depression, anxiety, agitation, paranoia, and hallucinations.
Toriello-Carey syndrome with agenesis of the CC, telecanthus (increased
distance between the eyelids), short palpebral fissures (opening of the
eyelids), small nose with anteverted nares (extreme turned up nose),
retrognathia (extreme underbite), abnormal ears, laryngeal and cardiac 24
anomalies, brachydactyly (short fingers and toes), and hypotonia.
(different names or comorbid conditions
along with ACC or DCC continued)
 Hippocampal abnormalities (Donmez, et al., 2009)
 Phalangeal hypoplasia (abnormal bone growth in fingers and toes;

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
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Gillis, et al., 2009)
Ectopic grey matter (same source)
Brain stem abnormalities (same source)
Reduced volume of the ventral cingulum (Nakata, et al., 2009)
Calcified intraluminal meconium (abnormal hardened stool of newborn,
Puvabanditsin, et al., 2009)
Imperforate anus (same source)
Fronto-nasal dysplasia (Guion-Almeida, & Richieri-Costa, 2009)
Cleft lip/palate (same source)
Mental retardation (same source)
Lack of language acquisition(same source)
Hearing loss (Nagamani, et al., 2009)
25
Etc.
26
Paul, L. K., Brown, W. S., Adolphs, R., Tyszka, J. M., Richards, L. J., Mukherjee, P., &.
Sherr, E. H. (2007). Agenesis of the corpus callosum: genetic, developmental and
functional aspects of connectivity. Nature Reviews, Neuroscience, 8, 287-299.
27
Characteristics
)
(http://www.umaine.edu/edhd/files/2009/05/acc-fact-sheet-
final.doc
 Generally happy, pleasant disposition, enjoys being with

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
others
Developmental delays (e.g. late to crawl, walk, or talk,
toilet training)
Sensory issues (e.g. visual impairments, hearing deficits,
increased sensitivity to touch)
Low muscle tone
Clumsiness/poor motor coordination
Feeding/eating difficulties, gastric reflux
High tolerance to pain
Sleep-related difficulties (e.g. getting to sleep, nighttime
waking, bed-wetting)
28
Characteristics
)
(http://www.umaine.edu/edhd/files/2009/05/acc-fact-sheet-
final.doc
 Difficulties maintaining attention; restlessness or


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hyperactivity
Difficulty with complex tasks, abstract reasoning and
problem solving
Difficulty imagining the consequences of their own
behavior
Socially immature, lacks self-awareness, may have
difficulties with peer relationships
Very concrete in thought processes, difficulty with slang,
sarcasm or sophisticated humor (also metaphors)
Difficulty understanding social cues and expectations
29
How do these characteristics affect language?
Delayed language skills
Misinterpretation
of communication
cues
Misinterpretation
of social cues
30
ACC: Communication Symptoms
 Early speech and language delays (particularly with
expressive communication)
 Misinterpretation of the nonverbal communication of
others (i.e. their facial expressions or tone of voice)
 Difficulty understanding slang, sarcasm, and jokes
 Difficulty understanding others’ perspectives and emotions
31
Communication Symptoms
 Difficulty understanding abstract language/concepts
 Difficulties with complex tasks, abstract reasoning, problem
solving (such as managing money and schedules, responding
to novel situations)
 Communicating information that is untrue while perceiving
that it is true
 ACC leaves the affected person with certain shortcomings in
the handling of nonverbal information, or what in a general
theory of signs is termed iconic processing. (Saul & Sperry,
1968)
32
Targeted Skills
 Tasks requiring skills of both hemispheres will be the most
challenging and should be targeted.
 Left hemisphere: logic, sequencing, rationalizing, analyzing,
making objective assessments, and attending to details.
 Right hemisphere: intuition, processing, putting information
together, making subjective assessments, and looking at “the
whole”.
33
Variations
 Severity
 Childhood vs. Adolescence
 Possibly asymptomatic
 High- functioning vs. low functioning
34
Treatment
 Treat symptoms
 Callosal disorders are lifelong conditions.
 Early intervention services
 Supportive therapies
 Speech-Language Therapy
 Occupational Therapy
 Physical Therapy
 Musical Therapy
 Adult support services based on their individual needs
 Evaluations and therapies should begin early in life and
continue throughout childhood and into adult life..
35
References

ACC Network. (2009). What is agenesis of the corpus callosum (ACC)? Retrieved
November 13, 2009, from http://www.umaine.edu/edhd/research/acc/

Chiarello, C. (1980). A house divided? Cognitive functioning with callosal agenesis.
Brain and Language, 11, 128-158.

Donmez, F. Y., Yildirim, M., Erkek, N., Karacan, C. D., & Coskun, M. (2009).
Hippocampal abnormalities associated with various congenital malformations. Childs
Nervous System, 2(8), 933-939.

Gillis, J., Blaser, S., Miller, S., Li, C. M. (2009). Phalangeal hypoplasia, mental
retardation, agenesis of the corpus callosum, brainstem abnormalities, and ectopic grey
matter: unique case or newly recognized syndrome? Clinical Dysmorphology, 18(3), 160163.

Guion-Almeida, M. L., & Richieri-Costa, A. (2009). Frontonasal dysplasia, severe
neuropsychological delay, and midline central nervous system anomalies: Report of 10
Brazilian male patients. American Journal of Medical Genetics Part a, 1(5), 1006-1011.
36
References (continued)

Marszal, E.; Jamroz, E.; Pilch, J.; Kluczewska, E.; Jablecka-Deja; & Krawczyk, R. (2000).
Agenesis of Corpus Callosum: Clinical Description and Etiology. Journal of Child
Neurology, 15, 401-406.

Merrick, E. (2009). Case study: Neuropsychologic functioning and complete agenesis of
the corpus callosum. Archives of Clinical Neuropsychology, 24(5), 474.

Moes, P., Schilmoeller, K., & Schilmoeller, G. (2009). Physical, motor, sensory and
developmental features associated with agenesis of the corpus callosum. Child Care
Health and Development, 3(5), 656-672.

Nagamani, S. C., Erez, E., Eng, C., Ou, Z. S., Chinault, C., Workman, L., Coldwell, J.,
Stankiewicz, P., Patel, A., Lupski, J. R., & Cheung, S. W. (2009). Interstitial deletion of
6q25.2-q25.3: A novel microdeletion syndrome associated with microcephaly,
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
Nakata, Y., Barkovich, A. J.,, W.ahl, M., Strominger, Z., Jeremy, R. J., Wakahiro, M., 37
Mukherjee, P., & Sherr, E. H.. (2009). Diffusion abnormalities and reduced volume of the
References (continued)
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
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
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
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
Oller, J. W., Jr., Oller, S. D., & Badon, L. C. (2006). Milestones: Normal speech and
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
Paul, L. K., Brown, W. S., Adolphs, R., Tyszka, J. M., Richards, L. J., Mukherjee, P., &.
Sherr, E. H. (2007). Agenesis of the corpus callosum: genetic, developmental and
functional aspects of connectivity. Nature Reviews, Neuroscience, 8, 287-299.
38
References (continued)

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
Puvabanditsin S, Garrow Chinnakaruppan N, Bhatt M, Brandsma E (2009). Calcified
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
Temple, C.M., Jeeves, M.A. & Vilarroya, O. (1989). Rhyming skills in two children with
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
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
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39