Dyslexia and Autism: Differing Ends of Brain Connector Spectrum

Evidence about some key differences in the brain structures of people with dyslexia and those on the Autism Spectrum (ASD) has been highlighted by Dr. Manuel Casanova, a neuroscientist in the University of Louisville, in the Department of Psychiatry. He’s been focusing on certain types of cortical cell connectors, called mini-columns, which are strands of brain fibers important in connecting brain cells to other brain cells. Apparently and to me not surprisingly, people with dyslexia show an opposite pattern of connectivity than people with Autism Spectrum. Pardon the expression, but “dyslexic brains” favor longer connections at the expense of shorter ones.

People on the autism spectrum have brains that favor shorter connectors. The longer ones seen in the brains of people with dyslexia indicate an easier time with big picture thinking and abstraction. The short connectors, conversely, makes short and more localized connections. Other studies also indicate that brains of people with ASD are inefficient with making the larger generalized connections between more distant areas of the brain. This helps explain that while people with this short connector type of brain structure may see small details easily, might not quickly put together the social meaning.

People with dyslexia also have longer fibers in parts of the brain involved in language processing. The researchers believe this leads to differences in the way their brains develop early in life and that their brains don’t adapt as efficiently to the process of learning to read. These adaptations have been shown in studies of early brain development in children without any learning disabilities.

In short, no pun intended, dyslexic brains are structured so that they are more likely to develop a less efficient reading circuit Casanova said. This explains why children with dyslexia have difficulty sounding out words despite normal or superior cognitive skills.

About Sanford

Learning Disabilities specialist and Educational Consultant
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24 Responses to Dyslexia and Autism: Differing Ends of Brain Connector Spectrum

  1. Pingback: LD Resources » Blog Archive » Dyslexia and Autism: Differing Ends of Brain Connector Spectrum | The Reading, Learning, and Attention Clinic, LLC

  2. Dyslexic says:

    Many people get confused between these days, after reading this post its clear now that how these are different.

    • Sanford says:

      Dyslexic: Are you saying that many people get confused between dyslexia and autism? I wouldn’t have thought so, but glad the article helped clear up any confusion.

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  4. O.Frank Turner says:

    I think there is something more going on. I am 71 and have be clearly dyslexia all my life, but knew I had a host of other neurological difficulties. Recently my mother told me that she believes I was ASD as a child, based on children she saw on TV, and looking at it I still today have many of the clear patterns of ASD. I took a on line test that said I did have clear ASD treats. Thus I would have to be a acceptation to what the brain research is showing.

    • Sanford says:

      O. Frank. Agreed. There’s always more going on with people, as they can show more variety in how they process, than studies that are dependent on clear lines of diagnosis and description. That said, online screenings only offer a hint at clarity and I’d be careful of those too.

    • Christina says:

      There is an overlap between symptoms of ASD and those of Sensory Processing Disorder. Have you looked at SPD? My son is both dyslexic and has SPD.

      • Sanford says:

        Yes, thanks Christina. Sensory issues is often an overlooked part of understanding and treatment. Sometimes they’re “stand-alone” co-occurring issues and sometimes they are an inherent part of the overlapping condition such as with ASD.

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    • Sanford says:

      Good point. I would imagine some folks get to big picture thinking in different ways. For some, the may be their initial starting point from which to ponder the details and for others, perhaps the reverse.

  7. Chelsea Duff says:

    Can you have dyslexia and autism at the same time?

    • Sanford says:

      Chesea, thanks for your question; it’s a good one.

      The short answer is yes. In different ways, autism snd dyslexia are both brain-based differences related to the language system. To drill down further however, Dyslexia is more about inefficiencies with the mechanics of processing speech sounds, aka spoken language in thee alphabetic system. This results in struggles decoding when reading and encoding spell (putting sounds tougher to write). Because of those struggles, issues of reading comprehension will necessarily follow.

      On the other hand, autism is based on social language struggles, and includes non-verbal as well as verbal language components of communication.

      Both of these conditions can occur together in the same person but it’s really important to get a good thorough and differential diagnosis to tease them apart if indeed they’re coexisting.

      Let me know if that makes sense and if you have any follow up questions.

  8. Katherine Steele-Dantin says:

    My son, 7.6 years old, has both Autism and Dyslexia (DD). I’ve been working on getting a “thorough and differential diagnosis to tease them out” but even in an area like Boston that is difficult to do as the professionals to handle it are limited. He also has an incredibly high IQ. Do you have any suggestions?

  9. Sanford says:

    Hi Katherine. I would contact Caryl Frankenberger at www.frankenbergerassociates.com
    She’s a fantastic LD evaluator and also is one of the more knowledgeable professionals in the northeast including knowing “who’s who” as relates to your question.

    Best of luck. Keep us informed as you continue this process.

  10. Bernadette Littlewood says:

    I am curious if there is a connection with autism spectrum disorder and dyslexia. I have
    Two children we are currently having assessed for ASD and my third is very different but we suspect he may have dyslexia or a similar specific learning difficulty. Do you find it is common for families with ASD to also have other children with dyslexia?

    • Sanford says:

      Hi Bernadette. From my experience, what’s not common is for the two conditions/profiles to co-exist int he same person. In terms of the type of high functioning autism previously called Asperger’s syndrome, people with that profile have strong auditory, phonological, decoding and spelling skills. More classic autism involves social language deficits but also more generalized language delays and struggles. So I can see the overlap in how that autism profile could be mistakenly seen as dyslexia.

      All that said, what you ask is about the commonality of the two different types of developmental and learning profiles to exist in the same family. From what I’ve tracked int the literature, neurological and developmental gene pools, including ADHD, ASD and Dyslexia seem to congregate within family trees.

  11. Rory says:

    I still don’t understand how autism and dyslexia can be comorbid in the same person when the structural and connective brain conditions are nearly completely different ?
    Is it dyslexia and ASD or is it ASD with dsylexia like symptoms in reading and comprehension?

  12. Sanford says:

    Rory, great question and well-put.

    I must admit I’ve changed my opinion over time. Each condition is an umbrella term so the structural brain differences will always have some variations to one degree or another in individual brains. So in that sense comorbidty of the two can exist. For example, a brain (person) can have neuronal differences in structure and activity in the area involved with phonological processing. The same brain could also have differences in other areas that lead to difficulty or even disability in social language and pragmatics.

    No matter what the cause (gestational/pre-birth/genetic) and/or trauma, Adverse Childhood events) can lead to injury or impact in more than one area and so, two conditions.

    That said I’m pretty clear that there are mistakes made in these types of multiple diagnoses. For example someone with ASD who consequently struggles to understand motivation of character (social reasoning) and who has poor prosody, will show comprehension struggles when reading certain types of text. That’s not the same as Dyslexia.

    I will still contend that even though the two conditions can exist in the same person it would not be common at all. Though I have no data to back that up.

    Thanks again for your inquiry. It got me thinking.

  13. Rachelle Barrett says:

    I find it very intriguing. I have a mother and brother who appear to be on the autism spectrum who have dyslexia, a sister with dyslexia but no autism traits and a son wgo had autism but no dyslexia. Are there many neurological studies available?

    • Sanford says:


      There’s so much variation in the neurological make-up of people. All sorts of conditions and combinations seem to occur. In my 30 plus years in this professional field it doesn’t seem common to have both ASD and Dyslexia but have never seen any articles on prevalence.

  14. Lauren says:

    Hello, Very interesting thread to me as my 6 yo daughter has recently been privately diagnosed with ADHD and SLD-Dyslexic Pattern, while the school has assessed her as having ASD and appears to disagree with dyslexia. I can see both and don’t understand why it necessarily has to be either/or, I just want her to learn to read! I’m trying to advocate that she needs support for both Dyslexia and Autism as we continue to “tease” these out over the next year or so, given that this last year has been so hard on all kids not to mention kids social communication issues, and returning to a semi-normal school environment next year will be very informative. Please do continue to post any updated research on co-occurrence and prevalence.

  15. Jonah Ryder says:

    Hi. I’m dyslexic and I also find it strange that anyone could be Autistic and Dyslexic at the same time. Personally I think that people that don’t have dyslexia are stuck in a small picture type of thinking. What if they don’t know what to test for, because they can’t think of things outside of their closed minded thinking. Lol I mean the majority of the population are always the best, and have no interest in finding out a smaller number of the population might have gifts they don’t hav..so let’s only look at the negatives, and ignore all the positives. Lol maybe there’s test’s to prove dyslexia, that don’t involve Numbers, letters, words or reading. That’s probably what you should be figuring out. I’m sorry but really when you use the same test’s to prove dyslexia and autism, you with probably end up with autistic, Dyslexic people! Try again!

  16. Sanford says:

    Jonah, thanks for writing in.

    I used to feel pretty much as you do about the idea of being dyslexic and at the same time “having” autism (spectrum). At that time it seemed like the strengths of one segment of ASD–being “book smart,” good spellers and decoders, are the basics of the weaknesses of those with dyslexia. But that’s just one segment (Aspergers). In addition, the primary struggle with Autism is social communication and that can be a strength of many dyslexics. So on those surfaces it seems odd to have them in the same person.

    BUT we’ve been wrong. Though not very common, the two conditions can be co-occuring in the same person. Statistically rare but quite possible. There are many neurological reasons why it’s not common but for the folks who do have both it’s quite impactful.
    To one of your other points; the specifics and process of diagnosing the two conditions is quite different. While in a comprehensive evaluation SOME of the tests might be given to each, it’s quite a different deal.

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