Archive for the 'Dyscalculia' Category

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Dyscalculia videos

Under the title “Famous Dyscalculics!” on YouTube, readers can find a video composed of images of famous people who are said to have dyscalculia. There’s lots of repetitive music and text bubbles to help explain the pictures. Here’s the link. That’s one of several on YouTube; the others are called “Dyscalculia” and “Dyscalculia – Not Only Troubles with Math.”

Flash of the electrons to long-time blogger Maria Angala of Special Education Teacher in Washington DC for tipping me to the video.

Ultrasound and dyslexia

Some reports of research showing ultrasound’s effects on neurological development of mice fetuses are generating interest in the popular press. Working in the lab of Pasko Rakic, Eugenius Ang and colleagues found that a “small but statistically significant number of neurons fail to acquire thier proper position” within the cerebral cortex among fetal mice exposed to 30 or more minutes of ultrasound waves during the period of time when these neurons develop.
News reports such as one by Randolph E. Schmid (Associated Press science writer) include a quotation from Dr. Rakic (Yale University) mentioning a possible connection to dyslexia and other disorders.

Rakic’s paper said that while the effects of ultrasound in human brain development are not yet known, there are disorders thought to be the result of misplacement of brain cells during their development.

“These disorders range from mental retardation and childhood epilepsy to developmental dyslexia, autism spectrum disorders and schizophrenia,” the researchers said.

The reasons for caution in extrapolating to human fetal development are many. Mr. Schmid also interviewed Joshua Copel, president-elect of the American Institute of Ultrasound Medicine and another professor at the Yale Medical School, getting additional interpretation of the findings.

Copel… did point out that there are large differences between scanning mice and scanning people.

For example, because of their size, the distance between the scanner and the fetus is larger in people than mice, which reduces the intensity of the ultrasound. In addition, he said, the density of the cranial bones in a human baby is more than that of a tiny mouse, which further reduces exposure to the scan.

The paper noted that the developmental period of these brain cells is much longer in humans than in mice, so that exposure would be a smaller percentage of their developmental period.

However, it also pointed out that brain cell development in people is more complex and there are more cells developing, which could increase the chances of some going astray.

Furthermore, previous research directly testing the hypothesis that prenatal exposure to ultrasound increases the risk of dyslexia has provided mixed-but-mostly-null results. According to the abstract of one study, Stark and colleagues found “no biologically significant differences between exposed and unexposed children,” however, some folks (e.g., here and here) say that there was a significant correlation between exposure and dyslexia; I have requested the original article so that I can review it and shall report on it once I’ve read it. Salvesen and colleagues found (1992) “that those [children] whose mothers received diagnostic ultrasound screening while pregnant did just as well on reading, spelling and arithmetic tests as those whose mothers had not” but they reported (1993) that “the odds of non-right handedness were higher among children who had been screened in utero than among control children…. No clear differences were found between the groups with regard to deficits in attention, motor control, and perception or neurological development during the first year of life” but cautioned that the findings were inconsistent.

Link to the abstract of the article by the Rakic team; there are additional links on this page from which one can see supporting material and download a PDF of the full article. Link to Mr. Schmid’s story, as carried by LiveScience. Link to an HTML page for Dr. Rakic’s lab.

  • Ang, E. S. B. C Jr., Gluncic, V., Duque, A., Schafer, M. E., & Rakic, P. (2006). Prenatal exposure to ultrasound waves impacts neuronal migration in mice. Proceedings of the National Academy of Science, 2006 Aug 10 [Epub ahead of print]. Retrieved 14 August 2006 from http://www.pnas.org/cgi/doi/10.1073/pnas.0605294103.
  • Stark, C. R., Orleans, M., Haverkamp, A. D., & Murphy, J. (1984). Short- and long-term risks after exposure to diagnostic ultrasound in utero. Obstetrics & Gynecology, 63, 194-200.
  • K. A. Salvesen, K. A., Bakketeig, L. S., Eik-nes, S. H., Undheim, J. O., & Okland, O. (1992). Routine ultrasonography in utero and school performance at age 8-9 years. The Lancet, 339(8785), 85(5).
  • Salvesen K. A., Vatten L. J., Eik-Nes S. H., Hugdahl K., & Bakketeig, L. S. (1993). Routine ultrasonography in utero and subsequent handedness and neurological development. British Medical Journal, 307(6897), 159-

LD regs and RtI

The New York Times lead for its news story about the release of regulations for implementing the US Individuals with Disabilities Education Improvement Act (IDEA) featured response to intervention or instruction (RtI). Although the “regs” apply to the entire law, the Times story by Diana Jean Schemo emphasized the permission that the regs grant to states on identifying students with Learning Disabilities.

For more than 25 years, federal law had required that schools nationwide identify children as learning disabled by comparing their scores on intelligence tests with their academic achievement. This meant that many students had to wait until third or fourth grade to get the special education help they needed.

In regulations issued today after changes to the law, the federal Education Department said states could not require school districts to rely on that method, allowing districts to find other ways to determine which children are eligible for extra help.

The RtI concept, which has mostly focused on early reading achievement (hence the connection to Learning Disabilities; most students who are identified as having Learning Disabilities have problems in reading, i.e., “dyslexia”) requires that schools employ powerful, evidence-based instructional procedures in general education classrooms and monitor students’ academic progress regularly and systematically. For students who are not progressing rapidly enough, the schools shoudl provide supplement that instruction with at least one level or tier of supplemental instruction incorporating procedures and methods that are likely to overcome the problems; typical recommendations are additional time devoted to reading instruction, instruction in smaller groups, use of additional specialized materials, and so forth. Schools should continue to monitor students’ progress during tier two or three instruction, providing additional supplements or removing them depending on individual learners’ outcomes. Formal determination of eligibility for special education services because of Learning Disabilities would be undertaken only when a child continued to experience difficulties after receiving the first tiers of evidence-based instruction.

Those who advocate employing RtI models, which are close to the underlying recommendations from the Reading First part of the No Child Left Behind legislation, hope that infusing effective early instructional practices into general education classrooms and systematically monitoring progress will make it possible to catch and correct—prevent—reading problems. To the extent that such RtI efforts are successful, there should be reduced financial costs for schools and personal costs for children and their families.

I know of no one among my colleagues in special education who hopes that RtI (and Reading First) efforts fail. It will be wonderful for those students who benefit by having their problems addressed early and using the most effective methods available. One important consequence for those of us who study Learning Disabilities will be that we will have a purer group of children identified by the schools as having Learning Disabilities; as it stands now, we have a group that is a combination of instructional casualties (those whose problems stem from dysteachia) and students with more fundamental problems (disabilities).

However, I harbor little hope that RtI and Reading First will eliminate the achivement problems that charcterize Learning Disabilities. Among the reasons (this is not an exhaustive list):

  1. Not all students with Learning Disabilities have reading problems; some have reading, writing, and arithmetic problems or other unique combinations of those (and other problems). Our understanding of instructional procedures at tiers 1, 2, and 3 is not as highly developed in these other areas as in the reading aspect of literacy. Estimates vary, but it’s probably safe to say that at least 25% of children with Learning Disabilities have difficulties with arithmetic and mathematics; given that ~5% of children are currently identified as having Learning Disabilities in the US, that amounts to > 1% of children who will still need Learning Disabilities Services.
  2. Some children still do not learn to read, even when experts in reading who have access to tremendous resources provide what they consider optimal literacy instruction—even when we throw all we have in reading teaching at them—. Rollanda O’Connor and Joe Torgesen (among others prominent researchers) have separately verified that we can anticipate a percentage of “treatment resistors.” The percentage of students who fall into this category is not known precisely, but even if it is 2-4% of the bottom quarter of readers, a conservative estimate, that amounts to as many as 1% of the students.
  3. The task of getting schools and teachers to employ the most effective instructional practices is a daunting one. Even when there is no resistence to the methods that work the best (and there is resistence among some in education to employing those methods), there are mistakes in implementation. Deviations from optimal RtI models (slips in fidelity) are inevitable and will result in deviations from optimal outcomes. If a 10% deviation in fidelity results in only a 1% slip in outcome, that 1% is still going to be a lot of children.

So hip-hip-hooray for RtI, but don’t expect Learning Disabilities to disappear. And, while we’re at it, let’s not let this issue overshadow the provision of appropriate needs of children with disabilities. RtI may be the lead for the story in the New York Times, but there is much more to regs than RtI (fair reporting on my part: The Times article does refer to the contentious matter of eliminating short-term objectives) and there is much more to special education than the methods for determining eligibility of students with Learning Disabilities.

Link to Ms. Schemo’s story. Link to the US Department of Education press release about the regs. Link (2.2 MB PDF) to the preliminary version of the regs (full version due in the Federal Register later this month).