Archive for the 'Causes' 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.

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.

Head trauma

Adrienne Edwards of Dyslexia Tutor: News-Resources posted an entry about the potential influence of head trauma on learning and behavior.

According to an article in the Wall Street Journal, by Thomas M Burton, researchers at Mt. Sinai School of Medicine in New York believe they have found a common thread running through many cases of seemingly unrelated social problems: a long- forgotten blow to the head.

The US Centers for Disease Control and Prevention estimates 5.3 million Americans suffer from mental or physical disability due to brain injury.

But what is new in this research is the contention that there are many other cases where a severe past blow to the head, resulting in unconsciousness or confusion, is the unrecognized source of such problems.

Link to Ms. Edwards’ post.

Dysfluent reading in disorganized brains

Bernard Chang and colleagues, who study a rare genetic disorder called periventricular nodular heterotopia (PNH), have found evidence that points to a specific relationship between certain brain structures and dysfluent reading. People with PNH have difficulty reading fluently and their genetic disorder causes a known aberration in neural structure. Their fluency in reading is correlated with the degree of disorganization in their brains.
Continue reading ‘Dysfluent reading in disorganized brains’

Blue babies

Over on The Clay Experience (AKA: Unintelligent Design) Clark Bartram often has interesting posts about his experiences as a pediatrician. Last April he posted a gripping recounting of one of those experiences. It’s the story of an emergency Cesarean Section delivery that includes this account of his working with the just-deliverd child. He’s working his way through a standardized set of steps to ensure the neonate lives:

I did this for 30 seconds with no response. The heart rate was steady at just over 60 beats per minute [should be 100] and the child lay before me blue, silent, and still. I’ve never wanted to hear a child cry so much in my life.

I know that one can’t predict precisely from birth events, but descriptions such as this one make me apprehensive about the future for children who make it through such events.

Link to Dr. Bartram’s full account of this story.