Welcome! This page contains my own research for
the condition known as ACC. I am not an expert in the realm of medical
research nor do I claim to be an expert on anything. I am just a parent of
a child with ACC; and in my own struggle to understand my son's condition,
this page is the result of the information I found. Yet, as an educator, I
also researched the educational implications of ACC in the hope of finding
a 'magic key' to unlocking my son's learning potential through teaching strategies.
I did not find a magic key, but I did find some helpful guidelines that
do work for us. I was also gratified to learn that professional
research is ongoing so that perhaps the future will be much brighter for
our exceptional children. My hope is that by providing this information, I
can help others in their struggle to understand ACC too.
This page does contain a lot of medical terminology and
can be quite tough to wade through. Wherever possible, each term that
might be unknown to the viewer is linked to its definition in our
glossary. Just click the link, read the definition, and click the
"Back" button to return to this page.
Definition & Background:
Agenesis of Corpus Callosum is a rare disorder, which is classified as a congenital birth defect in the brain. It is characterized by a partial or complete absence [agenesis] of the corpus callosum, which connects the two cerebral hemispheres. This part of the brain is normally composed of transverse fibers
(National Organization for Rare Disorders [NORD], 1990). These fibers carry neural messages back and forth to allow the left hemisphere of the brain know what the right is doing and vice versa.
Disorders of the corpus callosum are not illnesses or diseases, but abnormalities of physical development. ACC occurs in utero during fetal brain development when an insult to the commissural plate interferes with the migration of cells that eventually form the corpus callosum. There is no single cause for the disruption of the brain's normal development. Instead, there are a variety of factors which can interfere & contribute to the condition.
Factors can include any of the following: 
A. Physical Insults occurring during the 5th to 16th week of pregnancy
Prenatal infections or viruses (for example, rubella or varicella-zoster)
Toxic-metabolic conditions (for example, Fetal Alcohol syndrome)
Blockage of growth of the corpus callosum (for example, cysts) ( NODCC, 2004 )
B. Genetic and Chromosomal
C. Metabolic Disorders
D. Syndromes
Classification types of ACC:
A. Type I
Neurologic Manifestations can include:
-
Normal intelligence to mild/moderate mental retardation.
-
Seizure disorder.
-
Impaired visual, motor, and/or bimanual coordination.
-
Mild impairment of crossed tactile localization and skills requiring matching patterns.
B. Type II
-
Associated with other migration, genetic, and chromosomal disorders.
-
Usually associated with severe neurologic manifestations.
Neurologic Manifestations can include:
-
Mental retardation
-
Seizure disorder
-
Hydrocephaly [fluid on brain] and/or Microcephaly [small
brain]
-
Hemiparesis [paralysis on one side of body]
-
Diplegia [paralysis of similar parts on both sides of
body]
-
Spasticity [increased muscle tone or rigidity]
-
Failure to thrive (Ped Base, 1994)
ACC is diagnosed in approximately 90% of patients during the first two years of life. An epileptic seizure or developmental delays are usually the initial symptoms that indicate that a child should be tested for a brain dysfunction. In the mildest cases, this disorder can be without apparent symptoms. A normal life span can be expected for people with ACC
(NORD, 1990).
As of 2004, I became aware of some significant changes in the definition or labels of people with ACC. These labels clarify the extent of the corpus callosum disorder.
Complete Agenesis of the Corpus Callosum
(C-ACC) Complete absence of the corpus callosum
Partial Agenesis of the Corpus Callosum
(P-ACC) Partial absence of the corpus callosum
Hypoplasia of the Corpus Callosum
Thin or underdeveloped corpus callosum
Dysgenesis of the Corpus Callosum
Malformation of the corpus callosum ( NODCC, 2004 )
Educational Implications and Recommended Teaching Strategies for Children with ACC:
Researcher Byron P. Rourke has found a striking correspondence between ACC and Nonverbal Learning Disabilities Syndrome [NLD], which is a subtype of learning disabilities whose neuropsychological assets and deficits have predictable academic and psychosocial outcomes. A few of his findings and strategies are listed below.
Academic Deficits:
-
Graphomotor: In the early school years, there is much difficulty with printing and cursive script. However, with practice, handwriting can become quite good.
-
Reading Comprehension: is poor compared to single-word reading [decoding].
-
Mechanical arithmetic and mathematics: Outstanding relative deficiencies and rarely exceeds grade level 5.
-
Science: Persistent difficulties in academic subjects involving problem solving and complex concept formation [e.g., physics] are prominent.
Teaching Strategies:
-
Teach in a systematic step by step fashion working from the concrete to more abstract concepts.
-
Encourage the generalization of learned strategies and concepts.
-
Facilitate structured peer interactions.
-
Promote, encourage, and monitor systematic explorative activities.
-
Teach the child to use age-appropriate aids to reach specific goals, such as calculators and digital watches.
-
Teach and emphasize reading comprehension skills as soon as the child has gained a functional appreciation of sound-symbol correspondence
(Rourke, 1995).
* It must be noted that the deficits and strategies above are just guidelines. Each child’s academic abilities will vary according to the type and severity of their individual neurologic manifestations.
References
National Organization for Rare Disorders, Inc. (1990) Agenesis of corpus callosum #355 [On-Line].
Available: http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Agenesis
of Corpus Callosum : Author
National Organization of Disorders of the Corpus Callosum. (2004) Definitions [On-Line].
Available: http://corpuscallosum.org/definitions.htm : Author
Ped Base. (May 1994) Agenesis of the corpus callosum. [On-Line]. Available:
http://www.icondata.com/health/pedbase/files/agenesis.htm
: Author
Rourke, Bryron P. (Ed). (1995) Syndrome of nonverbal learning disabilities: Neurodevelopmental manifestations. New York: The Guilford Press, 5, 499-506
Resources & Links:
-
Agenesis of the Corpus Callosum (ACC) Network
5749 Merrill Hall, Room 18
University of Maine
Orono, Maine, USA 04469-5749
(207) 581-3119
Fax: (207) 581-3120
E-mail: um-acc@maine.maine.edu
The ACC Network gathers and disseminates information concerning
Agenesis of the Corpus Callosum and related conditions to individuals
with ACC, their families, and service providers. It also provides a
directory and newsletter to foster communication among network
participants. In addition, ACC Network has a bibliography of books and
articles that are available to members and will provide referrals to
other providers and organizations.
The ACC Network publishes, The Callosal Connection newsletter on
an irregular basis at no cost. They offer a new parent packet that
includes a variety of information: a chapter from a book on ACC;
profiles of families with children that have ACC; newspaper articles
about individual children with ACC; a newsletter; a questionnaire and
accompanying consent form; a list of references; a list of resources;
and a list of syndromes and conditions associated with ACC.
National Organization of Disorders of the Corpus Callosum [NODCC] New
A non-profit corporation established by & for professionals, parents, and individuals with agenesis of the corpus callosum (ACC), other callosal conditions, and their families.NODCC works in collaboration with The ACC Network and several neuropsychological research programs.
Corpal
A Support Group for the families and caregivers of those with Agenesis of
the Corpus Callosum, and Aicardi Syndrome - based in the UK.
Yahoo!
Groups: Agenesis of Corpus Callosum
This online group is open to anyone interested in making friends,
sharing information and support with others affected by this disorder.
(You will need a Yahoo! ID to join and participate in this group.)
ANGELS AROUND THE WORLD
This page is dedicated to the children and adults around the world who
happened to be born with a rare condition known as..."Agenesis of the
Corpus Callosum."
Agenesis of the
Corpus Callosum: Online Continuing Medical Education
This site contains an online course about ACC and a self-evaluation quiz
to test your ACC knowledge (free of charge).
