Faculty Interview: Dr. Denckla Discusses Learning Disabilities

tags: Center for Innovation and Leadership in Special Education Linking Research to Classrooms: A Blog for Educators

January 12, 2016


The current fellows at the Center for Innovation and Leadership in Special Education (CILSE), Jessica Grow, Rachel Eversole, Martine Philippe-Auguste, and Anne Marie Tagliaferri, interviewed Kennedy Krieger Institute’s Dr. Martha Bridge Denckla to find out more about learning disabilities.

Martha Bridge Denckla, M.D. is a research scientist and director of the Developmental Cognitive Neurology Clinic at the Kennedy Krieger Institute. She is also a professor of neurology at the Johns Hopkins University School of Medicine.

Fellows: Dr. Denckla, can you explain what a learning disability is to our readers?

Dr. Denckla: I am not going to answer that in an official school system way; I am going to answer it from the point of view of my own neurological training and research. My definition of a learning disability is a specific [brain] system or circuit that is relatively weak in relation to the demands of a specified task. Conventionally, we use learning disability (LD) for school subjects. Basically, you’re trying to show that there are established neurocognitive abilities that are in a direct causal relationship to a specific skill. You have to be very specific, making it basic reading skills, or reading comprehension skills. When you talk about written expression you have to talk about creative or divergent expression compared to convergent, such as essay or factual. And because math changes so much, really we should be talking about arithmetic disability rather than math disability, because algebra is not the same thing as learning your basic addition and subtraction, or even long division. But that’s the basic definition of a learning disability; you have to show a selective weakness, and the question is “how weak is weak?” Again, it’s going to be a sliding scale depending on how high the hurdle of the demand. The height of the demand has changed in my over forty years of experience.

Fellows: What should teachers be on the look-out for in order to identify students with LD as early as possible?

Rather than being so fast to identify a student with a learning disability, I think we should reinstitute readiness testing. I think we're going to have many false positive identifications if we look to see who is not meeting our demands since our demands are now way beyond what they used to be. I think we should start with identifying readiness for writing and pre-reading as a certain track. We should seriously entertain what sounds very counterintuitive, which is, holding back from even engaging in doing academic teaching if standards are not age-grade aligned. I think we have to have a massive reexamination of the developmental status of children before putting into effect our curriculum, which expects much greater skill development much sooner, sometimes years ahead of what has been previously expected. I think I'm answering [this question] very differently from how I would have ten years ago. What I would have said then is, when you have readiness testing, you should look for those children who are not at that level and immediately see whether you can get them into an intervention program. That would not be my recommendation now. I would first ask whether we should consider a transitional class. These days, we might consider it being transitional between Pre-Kindergarten and Kindergarten.

Fellows: Are there evidence-based interventions for students with an SLD?

I would prefer to say that there are principles of interventions. Dr. Frank Vellutino has a very well validated approach called the “interactive strategy approach.” It’s a balanced diet. The basic principles are:

  • Don’t get “hooked on phonics” - do some phonics, but also, don’t get so doctrinaire and exclude sight words. Sometimes the sight words are not only valuable in the progress but they are valuable for keeping up the morale of the student who has a “tin ear” for phonics.
  • Early on, delve into some actual text that the student can work on with the remedial intervener directly.
  • Then, what Dr. Vellutino means by interactive strategy is saying, well okay, if you don’t know that word, let’s draw out some ideas on how we could we figure it out. Does it look like another word you know? How far will your phonics take you?

Dr. Vellutino has these basic principles within each lesson. You have some direct instruction in phonics, you have some sight words, and then you have some actual text. That theme also emerges in Mary Ann Wolfes’ RAVE-O program. Her program also has a lot of use of text, building up fluency, etc. There are a lot of clinicians that will swear by the Wilson method or the original Orton Gillingham, but they always have the same basic principles; they are systematic, they are structured, and they are step-wise; they use phonics but they don’t have an exemption on bringing in sight words. I don’t know of as many well-researched remedial math programs. The NIH [National Institute of Health] has just put out a request for centers to work on the thorny issue of written expression. We still have a long way to go on developing interventions for reading comprehension as well.

Fellows: How do specific learning disabilities impact school performance?

Over time, even when well recognized and well remediated, [SLD] keeps cropping up in different disguises as you go along. If you have a specific neurocognitive weakness based upon something different about your brain, it’s going to impact basic skills. Interestingly enough, for example, you can be remediated and look like you have met benchmark for the basic skills, and then reading comprehension will show up as a problem perhaps 2-3 years after everybody thought you were good to go. And then written expression is such a multi-faceted assembly line, including everything from organizing your thoughts, putting those thoughts into appropriately retrieved words, and then having to organize all of this into a sequence that makes some kind of sense. Then you have the mechanics of moving a writing implement motorically. So you have this assembly line and so many places along the way. Written expression is really full of pitfalls.

We often find that those who are remediated for reading problems at a young age have a shadow of word retrieval problems later on. It’s not typically bad enough to call it specific language impairment, but reading is just the tip of a language iceberg with all of this language under it. I remember working with a little girl who had always done brilliantly in arithmetic, even word problems, and then she got to high school and was flunking Algebra. I didn’t understand what was going on until I had conversation with a very wise language pathologist who explained, “Algebra is naked syntax; it’s grammar without nouns.” It’s probably what you saw as mild reading or language disorder now coming up as a challenge in algebra. If you follow kids for years, you will see that kind of thing happen.

So you will find that what you thought was a circumscribed reading disability usually comes with this neurocognitive weakness in expressive language that surfaces, and almost catches you by surprise. Unfortunately, we really don’t have research studies of kids in kindergarten who are followed through years of school, so we just understand that things that just look like subtle reading and language weaknesses, may turn into other difficulties with subjects that have a lot of language maneuvers in other areas or latter in school.

Fellows: How does executive dysfunction contribute to learning disabilities?

Working memory is a big part of executive functioning. My favorite example is one little boy who could recite the “silent E rule” to me but said, “When I start doing my reading I forget to look ahead!” You can see baby steps of executive functioning in the fact that you have to have a strategy and look ahead. We can remediate that by doing something that catches the eye, like circling or underlining the final word in red. There is a problem that students with language impairment and students with executive functioning impairment share, and it’s in the domain of verbal working memory. When you're given a verbal instruction, you're supposed to keep that in mind to complete even a five or ten minute period of seatwork in the classroom. You use working memory in reading comprehension, because, if you don't hold enough of a sentence in your working memory, even though you are decoding every single word, you have to keep going back and rereading things. Your verbal working memory highlights a big overlap between the traditional language-based learning disability and students who are okay when it comes to the language system, per se, but when information has to be fed into that frontally based working memory system, both students will look very similar.

Most children with executive dysfunction are children with ADHD, and most of those children also have trouble with handwriting, so they have problems with written expression right from the get-go. They may have lots of ideas and they may not even have difficulty with word retrieval, but they have a whole bunch of floating words that they have trouble capturing, organizing, and sequencing. Students may do much better in creative writing and poetry. For instance, one child said to me, “I like poetry because there are no rules.” A person who has very good images and use of language can put out lovely things for poetry or even for story writing. Although the story might be rambling or tangential, certainly they're going to look a lot better than when it's an essay and you have to have a topic sentence that everything supports, and you have to follow a much more convergent kind of written expression.


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