Tuesday, May 15, 2007

Visual Processing Problems: When It's Hard for the Brain to See

Most people don't understand how primitive our understanding of vision is. Medical science does pretty well with refractive errors of the eye, but it often drops the ball when it comes to recognizing brain-based disorders of visual perception or processing.

The problem is, we don't really know what other people see - and because it is subjective, it is also hard to study "higher order vision" in animal models. Too often we see children with brain-based visual processing problems who have been unrecognized or misdiagnosed for years because no one knew that an eye chart was a poor way to identify problems with brain-based or central visual impairment.

In studies of young adults with a perinatal injury to the corpus callosum, researchers (see right) found that these individuals had to work much harder to visually match figures than age-matched or normal callosum controls. Interestingly, this study also showed extra "work" that these test subjects needed to perform when listening and matching sounds. No wonder that for many children, it's difficult to both listen and look at the same time.

For an excellent recent paper detailing some of the practical (school and home life) challenges facing children with brain-based visual problems check out Gordon Dutton's recent review here.

Some Highlights:

- Clarity of vision often varied (affecting reading) and worsened with fatigue
- Children often preferred pictures with clear color boundaries
- Increasing the font (and the spacing between letters) often improved reading ability
- Teachers had to be instructed that children with visual problems might appear to look past them because they could see better out of the sides of their vision.
- For some kids, reading vertically was easier.
- Some children struggle with visual movement and this may impact the playground as well as the TV - a preference for stationary subjects (for instance prefer watching the news instead of cartoons)
- Errors with direct copying improved if the children verbalized what they saw as they copied
- Visual crowding and complexity were a big obstacle - so reducing the visual distractions or complexity of school materials would help. Interestingly, visual crowding also contributed to food issues and social difficulties (hard to look and listen at the same time).
- Problems and tips about visual recognition, spatial orientation, and social and emotional issues are also discussed.

Children with visual processing problems often have a history of premature birth, birth stress, or a condition such as dyslexia. Because of the importance of visual cues in normal human interactions, many children with brain-based visual impairments are misdiagnosed as having Asperger Syndrome, PDD-NOS, or an attention deficit disorder.

If you have a child you suspect may have central visual impairment or CVI, you may need to look carefully for professionals with specific expertise in this area; for special glasses (prisms) or therapeutic intervention, often a fellow of the COVD will also be needed.

Perinatal Corpus Callosum Damage in Young Adults pdf
Recent advances in central visual impairment pdf

Technorati tags: , , , , , ,

15 comments:

  1. Anonymous8:29 AM

    Great point. One of the best things I got from your book was to take my child to a developmental optometrist if testing indicated problems with VMI. I guess you know this is somewhat controversial advice, and rarely heard from an MD. My daughter was far higher (gifted range) on verbal IQ and far lower on performance (below the mean), with visual motor integration problems. I have to say my pediatrician adamantly opposed this idea and suggested a pediatric ophthalmologist. I took her anyway, and she was diagnosed with convergence insufficiency. Still skeptical, I took her to the one the doctor recommended-- same diagnosis! The ophthalmologist recommended pencil pushups rather than vision therapy, but considering all we're paying to get my daughter up to speed, vision therapy is *nothing,* so we're back with the optometrist to begin therapy this summer. I wouldn't have had the guts to buck the MD establishment without your book. Thanks.

    ReplyDelete
  2. After I had been in practice for many years, I happened to get three patients who had suffered different types of injury that made it difficult for them to read (one a young man in a whiplash car injury, another an older woman with a stroke, and the third a middle age person with a head injury). All three had been to the ophthalmologist and been told "good news, your vision is fine." Only problem was, their vision was still such a problem they were unable to read.

    I fully informed these three about the controversy from the medical community about vision therapy, but as these three were highly motivated, and they felt they had nothing to lose, but everything to gain (they wanted to read again) - they wanted to try. I sent them to Dr. Nancy Torgerson...and all three regained the ability to read.

    I remembered when I started my neurology training, I heard some of my professors tell me that neurorehabilitation wasn't necessary because it took time for the brain to heal. Therapy, according to them, mainly made people "feel" better because the recovery took so long. It couldn't have been more wrong.

    The brain is like a muscle. Many people just need to find out to pinpoint the problem better - and then focus their energies so that it will bring them the most benefit.

    ReplyDelete
  3. Finding a reading curriculum with an increased font size was the only way our homeschooled 1st grader made any progress in reading this year. We used The Reading Lesson program (by Levin and Langton, readinglesson.com).

    But, having gotten past the initial learning to read portion, we are struggling to find more extra-large print stuff at the second grade level. When I talk to other parents, they say page magnifiers were a lifeline, but they haven't helped in our case. The issue seems to be, she can't tell if things are out of focus because her eyes are tired or because she's not holding the magnifier at the correct distance from the page. Thus, she tries to correct with her eyes and fatigues more quickly instead of less with the magnifier.

    Since anything above 16 or 18 point is considered "large print", the regular "I Can Read" books are considered "large print" already. Unfortunately, my kid can barely read at that font size. Even the state library for the visually impaired does not catalog it's collections by font size!

    I'd love to hear if you have any resources to share for finding large print resources for little kids. I've been reduced to sitting in the children's section of the library, randomly flipping open picture books to see the font inside. I can't be the only parent in this situation.

    ReplyDelete
  4. Anonymous12:15 PM

    You're not the only parent-- we were there. I'm the poster from above, and that's why it was not really surprising to me to hear from the developmental optometrist that my daughter has several visual issues, none of them picked up on vision screening for acuity (she has 20/20 vision). In fact, that's the main clue to me-- my daughter has trouble moving to the harder to read books because the print gets smaller. If you haven't gone to a developmental optometrist (fellow of COVD), definitely give it a try.

    ReplyDelete
  5. It would be great if publishers could catch onto this. Font and spacing really does matter, and many children would be farther along in reading chapter books if there were more options open to them.

    We've had some children start into Geronimo Stilton books as their first chapter books just because of the variation in fonts and increased spacing. Some books like the Bunnicula series are also generous with font size and spacing.

    If you like classical stories, you might also consider a site like Baldwin Online Children's Literature that allows you to download / copy the entire book so that you can reprint it in a larger and more easily readable font (like Comic Sans).

    ReplyDelete
  6. Anonymous4:00 PM

    Sheet magnifiers are a good resource for those who need bigger print!

    And I second, third, and fourth the Eides' comment on the plasticity of the brain and the importance of therapy.

    ReplyDelete
  7. Thanks for the various suggestions!

    Yes, we have seen a COVD optometrist. We are still waiting to see whether we will need vision therapy. So far, she has improved with just the reading glasses. We recheck every 6 months, and therapy will come if she plateaus in her progress.

    The website with stories to print at my own font size will be very helpful, and I'll check out the other books on my next trip to the library.

    ReplyDelete
  8. Helen8:53 PM

    My daughter was diagnosed with binocular dysfunction, convergence insufficiency and accommodative infacility by a COVD along with 20/20 vision 2 months ago. Last week her pediatrician did an informal eye test and said she was 20/30. This increased my husband's doubt's about the visual processing issues. Additionally, our health insurance categorically rejects vision therapy. My husband is very reluctant to spend the money on the vision therapy when it is viewed so skeptically. Is there anything I can do to help my daughter at home? Thank you!

    ReplyDelete
  9. There is a lot that you can do at home, but it sounds like your daughter might have a number of visual coordination issues going on.

    Perhaps you can talk to your optometrist, tell him / her your situation and see whether you can be given some recommendations re: home exercises, then follow up at some point in the future. There are books like Developing Your Child for Success, but you want her to be doing the best types of eye exercises for her condition.

    ReplyDelete
  10. Anonymous8:32 PM

    Great article! I'm curious though, how do you differentiate between dyslexia and composite visual issues like these along with auditory processing or working memory problems? If you have a child with very impaired auditory working memory and the kinds of visual processing problems in the article who is having difficulties reading and spelling, are they dyslexic? Or are they just suffering from two difficulties that happen to get in the way of reading?

    ReplyDelete
  11. Sometimes it can be hard to sort this out - and that's why we see many of these decisions as being clinical decisions rather than checklist ones.

    When it's practiced well, a clinician knows the different patterns that exist in normal variations and disease. He or she also gets to know a person's personal story, experience, symptoms, and family history - and then after weighing different factors, makes a diagnosis.

    Dyslexia can be acquired or inherited, and visual problems that can cause problems reading can be due to either.

    Sometimes the boundary is murky (lets see...is that a little bit of inherited dyslexia, or a little visual problem from that stressful birth)...but often it's more likely one than the other.

    Dyslexia is a clinical diagnosis - and so it is often found with other neurological findings like mirrored movements, finger confusion, reversals, etc. The same goes for visual disturbances due to central (brain) or peripheral (eye) causes.

    ReplyDelete
  12. Anonymous11:56 PM

    Thanks for the reply, very interesting! So you're saying a child can very well have reading difficulties due to a combination of neurological visual processing difficulties and auditory processing/memory difficulties and not be dyslexic? (And another child with both problems could very well be dyslexic) I've sometimes wondered if dyslexia isn't both underdiagnosed and overdiagnosed at the same time, much like ADHD. What I found truly amazing about your book was the way in which is was able to broke down the cognitive and sensory processes involved in different elements of learning, but even at the end I still find myself something unsure of how to differentiate between dyslexia and combination sensory processing difficulties, or of whether there was indeed a differentiation to make! I guess that just speaks to the murkiness of of diagnosis and symptoms.

    ReplyDelete
  13. Anonymous1:39 PM

    My son has been diagnosed with auditory processing, dyslexia and also ADD. What is the best way to help him. He is in the 7th grade and is struggling with reading, writing, memory skills, organization, etc. Are there any programs out there that can help him at home? I have a hard time trying to figure out what to work on first, or does it make a differene.

    ReplyDelete
  14. I'm glad that this is a legitimate site with good information, and not just another platform to sell something, but in this case I would like a little advertising! Several posters have mentioned "your book" however I see no mention of an author or title, and nobody pushing the book ... who is the author and what is the title of this book? I'd love to read it!

    ReplyDelete
  15. Hi Judy, Thanks! We have a chapter on Visual Processing in our first book, The Mislabeled Child. Our second book is The Dyslexic Advantage.

    ReplyDelete