Monday, August 31, 2009

Dyslexia and Autism are Opposites - Implications for Creativity, Late-Blooming / Precocity, and Savant Abilities

Structural studies from Michael Casanova and colleagues showed that the brains of dyslexic and autistic subjects had opposite findings. Microcolumns are repeating groups of neurons that share a common dendritic bundle. The microcolumnar hypothesis is the idea that the microcolumn is the basic unit in the cortex, not individual neurons.

"Dyslexia and autism are on opposite tails of the normal distribution of the width of minicolumns...Autistic individuals have increased number of smaller minicolumns and dyslexic children have decreased number of larger minicolumns..." When the depth of gyral depths were measured of dyslexics compared to controls, "mean gyral white matter depth was 3.05 mm (SD ± 0.30 mm) in dyslexic subjects and 1.63 mm (SD ± 0.15 mm) in the controls." Researchers speculated that longer connectivity in the brains of dyslexics could account for "a greater capacity for abstract, 'visionary' thinking", but also slower development (late blooming?) including a slower development of reading. Its information like this that should reinforce the idea that dyslexic children should have a differentiated educational program (fewer inappropriate demands at early ages) - and recognition of high creative potential and capacity for abstraction.

The changes in autism could also account for why some people with autism show extreme precocity with rote tasks, may have unusual gifts of rapid mathematical calculation, and superior abilities with certain tasks of visual discrimination (like Oliver Sack's account of two twins with autism who could rapid determine when 111 matches had fallen to the ground).


Structural differences between dyslexic and autistic brains
Microcolumns figure
Increased gyral depth in dyslexia (abstract only)
Savant numerosity pdf

16 comments:

  1. Anonymous9:34 AM

    I'm confused now, I thought it was quite common for people with Aspergers Syndrome to also be dyslexic?

    ReplyDelete
  2. They are quite different when at least from our perspective of neurological and neuropsychological assessment. The behaviors may overlap because kids with either condition may miss visual or auditory perceptual cues and have trouble with rapid back-and-forth social interactions, but from many other standpoints, they appear almost the complete opposite.

    ReplyDelete
  3. My own child has been diagnosed autistic (he is recovered now) as well as moderately dyslexic.

    ReplyDelete
  4. This comment has been removed by the author.

    ReplyDelete
  5. Many children diagnosed with both autism and dyslexia may find that by young adulthood the autism is 'recovered'. But we would argue that this children could have been distinguished from classic autism in their earlier years. Some children with autism are diagnosed with 'hyperlexia' but this is very different from classic dyslexia. I realize this all can be quite confusing, but it is an important finding - and psychometricians need to take into account biology - adapt their tests to take into account advances in neuroscientific research.

    ReplyDelete
  6. MMM... I too am confused. My son, age 16, has aspergers and dyslexia. With intensive orton gillingham he learned to read. However, he still struggles mightily with spelling and writing tasks. Due to these frustrations, his asperger traits seem more pronounced.

    ReplyDelete
  7. I am sorry but this makes no sense to me. My oldest had pdd-nos and was hyperlexic. He is now aspergers. Since autism and other LD issues are based upon neurological deficiency I do not see how these issues are opposites. Too many persons with autism have comorbid LD issues incuding dyslexia. How does one brain function at polar opposite levels at the same time?

    ReplyDelete
  8. I'm sorry, no one should make any conclusions on any individual children based on this type of general cohort-based research. If a child has a limited visual span he or she may have difficulty with reading as well as reading faces. When a study such as this looked at classically diagnosed dyslexics and individuals with autism - and found opposite trends in terms of connectivity.

    Best to recognize that these general diagnostic categories still encompass many different children and brain organizations.

    ReplyDelete
  9. Anonymous6:15 PM

    I have DZ twins, one who is autistic and one who is dyslexic and they couldn't be more different so this information made perfect sense to me.

    ReplyDelete
  10. Hi quote from article.. referred to above..

    The considers the development of the brain in the first 4 years.so could be a developmental consequence of sensory difference.
    just a thought.

    The major relation of our study with the early development of the brain is
    that abnormal postnatal retractive events happening during the maturation of
    the corpus callosum and other long cortico-cortical projections could account
    for the natural history of some autistic patients that manifest normal develop-
    ment followed by loss of skills and onset of symptomatology. Experience with
    hemispherectomies suggests that this time frame may be the rst 4 years of
    life. During this period of time the hemispheres are equipotential with regards
    to linguistic abilities and a postnatal reorganization of its long corticocortical
    projections establishes cerebral dominance.

    Analyzing the Development and the Functionality of
    Dyslexic and Autistic Brains by Investigating the
    Relationship between the Micro Structures and Macro
    Structures
    Noha El-Zehiry
    1
    , Adel Elmaghraby
    1
    , and Manuel Casanova
    2
    1
    Department of Computer Engineering and Computer Science, University of Loui

    ReplyDelete
  11. In psychological testing such as NEPSY, could there be an explanation based on the minicolumnar hypothesis for a dyslexic's poor performance in theory of mind that may lead to an Asperger's diagnosis?

    ReplyDelete
  12. I'm not sure this research will prove to reliable. I'm a data point, inconsistent with this research

    ReplyDelete
  13. This comment has been removed by the author.

    ReplyDelete
  14. Interesting to read multiple comments about those with Asperger's who also have Dyslexia. My understanding as a Family Physician (and a dyslexic!) is that some people with Asperger's do indeed also have reading difficulties/dyslexia. However, the neurologic reasons behind the reading difficulties in Asperger's Syndrome are different than those behind classic Dyslexia.

    Others with Asperger's can have the opposite condition of HYPERlexia (reading well above age level without training) --this is especially common in females with Asperger's.

    Hope that distinction helps clarify some of the confusion!

    It is intriguing that Dyslexia and Asperger's/Autism are opposites in terms of the neurologic findings described by Dr. Casanova, yet individuals with either condition can have similarities. Both conditions can be accompanied by dyspraxia, abnormalities in hearing or vision, and increased intensity of experiencing the world around them. It will be interesting to see what further research reveals about these two conditions.

    ReplyDelete
  15. i have been trying to tell people this over and over I wish i could past this on face book so people would understand this concept..

    ReplyDelete
  16. I keep wondering about this issue as well. I do think there is a phenotypic (appearance) overlap. I wonder whether it may be that classic autistic (small percent) is the most extreme opposite to dyslexic wiring - but that what many refer to as Aspergers + Dyslexia is due to starting with a dyslexic genetic inheritance (by percentage it is more common) - and then various environmental or other issues - isolate areas - that then develop compensatory hyper wiring in local areas. Does that make sense? It says why some big picture abilities are possible - but also why some hyper wiring in local areas takes place as well.

    ReplyDelete