Dr. von Hahn: First, learning disabilities, as defined by the DsM, are slightly different from learning disabilities as defined by education law, which are different again from learning disabilities as defined by researchers. You can get a different opinion about whether or not an LD is present depending upon who conducted the evaluation. Pediatricians and child psychiatrists mostly rely on the school evaluation as the first way to figure out if a kid has learning disability or not.
CCPR: What would you say are the most common learning disorders?
Dr. von Hahn: Traditionally, we consider reading disability to be the most common learning disability, but recent research suggests that writing disability may be more frequent. Math disability appears to be lower than the first two. One of the reasons why it’s hard to come up with good numbers is because each of these three disabilities actually consist of different sub-types. For example, you could say that there are two types of reading disorders. One is reading/decoding, or dyslexia, which is based on phonics—for example, do you understand the sounds that letters make and can you sound them out? The second is reading comprehension. If you can’t decode fluently you are going to have a hard time with reading comprehension because you just can’t read quickly enough. But if you have a language impairment, you can also have difficulty with reading comprehension (Mayes SD et al, school Psychology International 2007;28(4):437-448).
CCPR: So how does the process for diagnosis work?
Dr. von Hahn: Very often it is not difficult to figure out if a kid has a learning disability. We, the developmental pediatricians, have an extensive questionnaire that a teacher fills out and another questionnaire that the parents fill out before they ever do a visit with us. It asks specific questions about the student’s performance in various academic tasks. The qualitative information provided by the teacher is quite accurate. You can get the same information by looking at the child’s report card, or by asking the teacher to fill out the Vanderbilt scales for ADHD.
CCPR: Please tell us a little bit about formal learning assessments.
Dr. von Hahn: The most common way to get a formal learning assessment is to ask the school to do it. There are two reasons for doing it that way. One is because, under the Individuals with Disabilities Education Act, the family is legally entitled to the assessment. In the case of LD, this usually involves a psychological evaluation (a cognitive assessment), and then an academic achievement evaluation, which looks at reading, writing, and math. The other reason for asking the school to do the testing is because the school is responsible for providing services if the child qualifies. LD interventions are not covered by a child’s health insurance plan.
CCPR: So the school does the testing. Then what comes next?
Dr. von Hahn: The quality of testing and the identification of LD are very dependent on local and state standards. There are a couple of issues to consider. For example, most schools use the Woodcock Johnson, which is a good test with national norms. However, it is not very sensitive at detecting LD in young children. In any case, you can miss a diagnosis of LD if you don’t check and compare the results of testing with the child’s performance in the classroom. Another issue is what standard scores the school team uses to define the presence or absence of a disability. In Massachusetts, typically a standard score below 85 or 1 standard deviation below the mean is considered to be learning impaired. But pediatricians from other parts of the country tell me that they sometimes see a standard score as low as 70 as the cut-off. There are kids that are performing below a standard score of 85 all across the country; some of them get services and some of them don’t.
CCPR: Let’s say the child is deemed to have a learning disability. How do we proceed?
Dr. von Hahn: Hopefully, remediation comes next. Which services are provided for remediation is highly variable, regardless of what the research says. For example, the educational treatment for reading disability/dyslexia is quite well researched. It involves phonics-based instruction, three to five hours a week, in a group setting of three or fewer students per adult with a properly trained teacher. Not all schools provide this service. When you get into the other kinds of LD, such as reading comprehension or reading fluency, the research is a little less clear, but treatment should usually involve one-on-one to one-on-three instruction by a trained teacher with a quality reading program. I usually recommend the same intensity of services for writing disability, but there are no scientific data to support this recommendation. What’s important to know is that not all school districts offer evidence-based instruction, either because of lack of information or because of lack of funding.
CCPR: Is there anything special for math-related disabilities?
Dr. von Hahn: The math disabilities are the least well-studied. Kids who don’t have a good sense of numbers, for example, need concrete manipulatives to show them differences in quantity. You might remember when you first learned about numbers in kindergarten that you had number rods that you could manipulate that were carefully titrated in size to give you a sense of numbers. And then they were taken away some time in grade one because by then you are supposed to be able to judge numbers mentally. children with math disabilities may continue to need a visual representation of the numbers for longer before they really nail that number sense. The next level is math facts; how do you quickly retrieve answers to addition, multiplication, division, and subtraction problems? A lot of memorization, drilling, and practicing really helps here, because when kids have to perform higher order math problems they have to have those math facts under their belts.
CCPR: How can we as child psychiatrists know that a child is getting proper treatment for a learning disability?
Dr. von Hahn: That is a really thorny question. Most individualized education programs are supposed to have measurable annual goals. But a huge number of the IEPs that are written only have general, but not measurable, objectives. If you have a research-based reading intervention for either general or special education, there are ways in which progress is tracked. Unfortunately, accurate measurement of progress in writing or math are less reliable. You and the parents will have to rely on information provided by the school to document progress.
CCPR: It sounds like writing and math are the two areas where there is still a lot to be done.
Dr. von Hahn: Yes, and reading comprehension is a bit of a can of worms, too. By grade three you are supposed to be reading paragraphs and understanding them. But it’s hard to measure comprehension. Writing can get complicated, too. Writing a five paragraph compare/contrast essay is not the same as writing a poem, but both are included in English Language Arts programs. Measurement in these areas varies by school district.
CCPR: Has the research shown any neurobiological basis for learning disabilities?
Dr. von Hahn: There is a high heritability for reading disability. If your patient has dyslexia, then there is a 40 percent chance that a first-degree family member also has a reading disability. In identical twins it jumps up to 60 or 66 percent (see for example, Monogr Soc Res Child Dev 2007;72(3):vii-l44). To read, the brain has to make connections between the language center and the visual perceptual center, mapping sounds and symbols. There are some MRI studies that show where dyslexia is located, but a child’s brain is so plastic that even if you have atypical brain development, other parts of the brain can take over. So why certain kids have dyslexia and others don’t is not clear. The neurobiological basis for writing and math disabilities is not researched very well.
CCPR: What about comorbidity with psychiatric disorders?
Dr. von Hahn: The research is unclear about the numbers, but it’s clear that comorbidity is really high. For example, children with ADHD have a up to a 70% percent chance of LD (Mayes SD et al, Learning Individual Differences 2006;16(2):145-157). There is high comorbidity between disruptive behavior disorders and learning disabilities. There is a slightly lower correlation with depression and anxiety, but the incidence of LD is still higher than what you would expect for the population as a whole.
The quality of testing and the identification if LD are very dependent on local and state standards.
~ Erik von Hahn, MD
CCPR: How do you think we should approach treatment of psychiatric comorbidity like ADHD in children with learning disabilities?
Dr. von Hahn: If a child has bona fide ADHD, it is likely that he or she is going to perform better in school with stimulants. so, go ahead and treat the ADHD. The child will probably socialize better and follow instructions more successfully. What is not clear is whether the stimulants actually enable a child to learn more. I respect the parents’ preference if they choose not to use medications. In any case, it’s important to provide good LD instruction and really good instruction on organization skills if a learning disability is present.
CCPR: What else do you think we as child psychiatrists can contribute?
Dr. von Hahn: You should be aware that school teams may or may not always provide the identification services or the educational interventions that the child needs. So you really have to understand local practice and point families in the direction of other resources if you think the child is going to be underserviced by the school. Education in general, and special education in particular, is underfunded. A lot of kids really could get to a high school level diploma by the end of grade 12 if they were given the right services.
CCPR: Thank you, Dr. von Hahn.