Archive for the 'Research' Category

Language development: Speechome Project

Here’s an interesting research project: Equip a house with a host of highly sensitive audio-video recording devices that pipe the data into cluster of high-powered computers which have an array of very capacious storage devices. Using this system, document the language environment in which a child is raised and record the child’s language development. Pretty nifty, hunh? A petabyte of developmental data!

This is, in fact, what a couple of parents—Deb Roy (Massachusetts Institute of Technology; Cambridge, MA, US) and Rupal Patel (Northwestern; Boston, MA, US)—have been doing for the past few years.

The high-powered academic couple—he directs of the Cognitive Machines Group at the Massachusetts Institute of Technology (MIT) Media Lab, and she directs the Communication Analysis and Design Laboratory at Northeastern University—scrambled to convert their suburban Boston home into a state-of-the-art research center that would host the most ambitious study ever conducted on how children acquire language. They named the linguistic data-mining odyssey the Human Speechome Project (HSP), a marriage between “Speech” and “Home.”

Why’s this relevant for LD Blog? Well, other research (especially Hart and Risley’s excellent work as summarized in Meaningful Differences, but note that there are many related studies in the research literature) has shown that differences in language environments have substantial effects on children’s language (e.g., vocabulary). Many Learning Disabilities are associated with problems in language (e.g., low phonological awareness, atypical syntax, problems in morphology, poor pragmatics). Understanding the language environment in which children develop their language skills might help explain some of the problems we see among children with Learning Disabilities.

Am I blaming parents? Nope. Language experiences that some children have may actually have protective effects. But, some experiences apparently are predictive of later outcomes. It would be good to know.

Am I saying that Learning Disabilities are environmental, that they have no biological components? Nope. I’m not saying that they do or do not have biological features. But, imagine that there are biological predispositions and that some language environments prevent or mitigate the manifestation of disability. That would be worth knowing, I’d say.

To complete a project examining the contribution of language environments to Learning Disabilities would require a prospective longitudinal study of substantial size. Supposing that Learning Disabilities appear in 5% of the population, then to get a enough children with Learning Disabilities to make the study reasonably sensitive, one would need 2000 families; at 5 per 100, that would yield about 100 children with Learning Disabilities. Now, if one were clever, she would look for families where there were siblings so that one could also examine the shared and non-shared environments, and start to factor in the contribution of genetic factors.

Imagine the financial cost of such a study….

If you could have a switch that would stop the recording at any time, would you agree to have such a system record your interactions with your newborn all the way through toddlerhood?

Meanwhile, to learn more about the Human Speechome Project, check these resources:

ADHD in families

Dr. M. Romanos and colleagues examined the genetic make-up of several families and found that there are common elements that appear to be associated with ADHD. Although these findings point toward a genetic contribution to ADHD, it is important to note the caveat implied by the final sentence of the abstract: So many factors contribute to ADHD, that these results should not be construed as identifying the precise cause of the disorder. In the full article, the authors are circumspect about this: “The identification [in this study] of several novel linkage regions as well as replication of previously reported loci provides further evidence for the highly heterogeneous genetic etiology of ADHD.”

Genome-wide linkage analysis of ADHD using high-density SNP arrays: Novel loci at 5q13.1 and 14q12

M Romanos, C. Freitag, C. Jacob, D. W Craig, A. Dempfle, T. T. Nguyen, R. Halperin, S. Walitza, T. J Renner, C. Seitz, J. Romanos, H. Palmason, A. Reif, M. Heine, C. Windemuth-Kieselbach, C. Vogler, J. Sigmund, A. Warnke, H. Schäfer, J. Meyer, D. A. Stephan, & K. P. Lesch

Molecular Psychiatry (2008) 13, 522–530; doi:10.1038/mp.2008.12; published online 26 February 2008

Abstract

Previous genome-wide linkage studies applied the affected sib-pair design; one investigated extended pedigrees of a. genetic isolate. Here, results of a. genome-wide high-density linkage scan of attention-deficit/hyperactivity disorder (ADHD) using an array-based genotyping of approx ~50 K. single nucleotide polymorphism (SNPs) markers are presented. We investigated eight extended pedigrees of German origin that were non-related, not part of a. genetic isolate and ascertained on the basis of clinical referral. Two parametric analyses maximizing LOD scores (MOD) and a. non-parametric analysis for both a. broad and a. narrow phenotype approach were conducted. Novel linkage loci across all families were detected at 2q35, 5q13.1, 6q22-23 and 14q12, within individual families at 18q11.2-12.3. Further linkage regions at 7q21.11, 9q22 and 16q24.1 in all families, and at 1q25.1, 1q25.3, 9q31.1-33.1, 9q33, 12p13.33, 15q11.2-13.3 and 16p12.3-12.2 in individual families replicate previous findings. High-resolution linkage mapping points to several novel candidate genes characterized by dense expression in the brain and potential impact on disorder-relevant synaptic transmission. Our study provides further evidence for common gene effects throughout different populations despite the complex multifactorial etiology of ADHD.

Differential drug effects in arithmetic

Professor Orly Rubinsten and colleagues found that methylphenidate affects the arithmetic performance of children in different ways, but its effects are not only on children with ADHD. When they received methylphenidate, the active ingredient in Ritalin, children had higher correct responding on problems requiring them to follow a series of steps than when they didn’t receive the drug; in contrast, there were no differences between drug and no-drug conditions on simpler tasks. The effects occurred for children with dyscalculia, less math problems, or no math problems.

Methylphenidate has Differential Effects on Numerical Abilities in ADHD Children with and without Co-Morbid Mathematical Difficulties
Authors: Orly Rubinsten, Anne-Claude Bedard, Rosemary Tannock
doi: 10.2174/1874350100801010011

Abstract:
Objective. To investigate effects of methylphenidate (MPH) on numerical performance in children with Attention- Deficit/Hyperactivity Disorder (ADHD) with and without concurrent math difficulties. Method. Data were analyzed from three groups of children with ADHD, who varied in arithmetic abilities. Groups were matched for IQ and reading abilities and classification was based on ICD-10 criteria, using scores on a standardized arithmetic achievement test. Thus, we identified one group with severe difficulties in arithmetic (ADHD+Developmental Dyscalculia; DD), second group with more general and less severe difficulties in arithmetic (ADHD+Mathematical Disabilities; MD), and a third group with good arithmetic abilities (ADHD). All children completed a 10-minute arithmetic task involving subtraction problems, during an acute, randomized, placebo-controlled cross-over trial with three dose levels of methylphenidate (10mg, 15mg, 20mg). Results. (1) Both ADHD+MD and ADHD+DD were impaired in using strategies that implicate working memory (i.e., borrowing). However, only the ADHD+DD were impaired in using implicit knowledge of quantities (i.e., doing simple subtractions). (2) MPH improved all children’s performance of arithmetic procedures (borrowing) that involves working memory, but had no effect on basic numerical skills that involves understanding of quantities. Conclusions. We show clear dissociation of MPH functions: it improves working memory functions but does not improve specific cognitive functions such as quantity manipulation. Moreover, MPH shows decreased efficacy for arithmetic performance in ADHD+DD, highlighting the need for additional intervention in this subgroup.

Keywords: Methylphenidate, developmental dyscalculia, ADHD
Affiliation: Neurosciences and Mental Health Research Program, Research Institute, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario, Canada.

The study appeared in The Open Psychology Journal and the entire article is available for free via the Open Journal initiative.

Brain Gym (Skeptic’s Dictionary)

Wheeeheee! Over on the Skeptic’s Dictionary, Robert T. Carroll has a take-down and pin of Brain Gym. The contemporary incarnation of some ideas that were thoroughly discredited in Learning Disabilities in the 1970s, Brain Gym is making something of a splash. Shoot, it even appeared in one of my Curry School colleague’s classes for a while, as I understand.

Professor Carroll’s indictment of Brain Gym presents a good opportunity to make an important point. The problem with Brain Gym and many of its siblings is not that the activities might not be worthwhile, it’s that the advocates over-reach so substantially. Shoot, I’m glad to advocate that we teach kids who might fit the clumsy category how to walk, move, dance, play basketball, and etc. I just don’t want people to be sold a bill of goods about how doing so will improve those children’s reading, etc.

Read Professor Carroll’s analysis. Need info on the research about the benefits of perceptual-motor training? Here’s a link to a meta-analysis.

DYX1C1: How genetic variation affects proteins and thus dyslexia

Although the paper was published several years ago, it is worth noting. It may not be news, but it forms part of the fabric one has to consider in thinking about the nature of dyslexia. Read this in the context of other stories (e.g., this one) about genetic bases for dyslexia.

A candidate gene for developmental dyslexia encodes a nuclear tetratricopeptide repeat domain protein dynamically regulated in brain

Mikko Taipale, Nina Kaminen, Jaana Nopola-Hemmi, Tuomas Haltia, Birgitta Myllyluoma, Heikki Lyytinen, Kurt Muller, Minna Kaaranen, Perttu J. Lindsberg, Katariina Hannula-Jouppi, and Juha Kere

Communicated by Albert de la Chapelle, Ohio State University, Columbus, OH, June 24, 2003 (received for review December 23, 2002)

Approximately 3–10% of people have specific difficulties in reading, despite adequate intelligence, education, and social environment. We report here the characterization of a gene, DYX1C1 near the DYX1 locus in chromosome 15q21, that is disrupted by a translocation t(2;15)(q11;q21) segregating coincidentally with dyslexia. Two sequence changes in DYX1C1, one involving the translation initiation sequence and an Elk-1 transcription factor binding site (–3G A) and a codon (1249G T), introducing a premature stop codon and truncating the predicted protein by 4 aa, associate alone and in combination with dyslexia. DYX1C1 encodes a 420-aa protein with three tetratricopeptide repeat (TPR) domains, thought to be protein interaction modules, but otherwise with no homology to known proteins. The mouse Dyx1c1 protein is 78% identical to the human protein, and the nonhuman primates differ at 0.5–1.4% of residues. DYX1C1 is expressed in several tissues, including the brain, and the protein resides in the nucleus. In human brain, DYX1C1 protein localizes to a fraction of cortical neurons and white matter glial cells. We conclude that DYX1C1 should be regarded as a candidate gene for developmental dyslexia. Detailed study of its function may open a path to understanding a complex process of development and maturation of the human brain.

Link to the PNAS materials.

Posts from the West

Last week, Liz Ditz teased us with notices about her whereabouts: She was attending an annual conference about brain research and learning. Don’t think I’ve flipped a wig; she wasn’t hearing the pablum that we usually get on this topic. This is a scholarly event, with presentations by eminent authorities (Is that redundant? Nope.) who are invited to discuss their work. I wrote to Liz that I envied her opportunity to attend.

Liz posted these entries: What I Am Doing This Week: Learning and the Brain Conference and Cognitive Neuroscience and Education: A Ways to Go. Go read them and then monitor her site for updates from her conference adventures. I shall do so, and mayhaps she’ll send LD Blog a heads up when there are going to be new entries!