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: 10.2174/1874350100801010011Abstract:
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.
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Helmer Myklebust
Helmer R. Myklebust, one of the pioneering figures in Learning Disabilities, died 26 February 2008. Predicated on his work on differentiating among speech disorders, Professor Myklebust emphasized the language-based aspects of Learning Disabilities. He theorized that there were different types of Learning Disabilities and that these types required different treatments. Throughout his career, Professor Myklebust promoted empirical study of language disorders and Learning Disabilities.
Professor Myklebust came to the study of Learning Disabilities after extensive work in hearing and speech disorders. In the 1940s he studied deafness and in the 1950s he focused on aphasia. In 1967, with his collaborator Doris Johnson, Professor Myklebust published one of the first books focused on Learning Disabilities: Learning Disabilities: Educational Principles and Remedial Approaches and later he edited a series of volumes presenting research and theory about Learning Disabilities under the title Progress in Learning Disabilities.
Professor Myklebust sought to differentiate among different variants of Learning Disabilities. He thought that Learning Disabilities could be separated into disorders of auditory language (generalized auditory disorders, auditory receptive disorders, and auditory expressive disorders), disorders of written language (auditory dyslexia, visual dyslexia, and written expression), disorders of arithmetic, and disorders of a non-verbal type. Professor Myklebust proposed that the problems children experienced were a consequence of difficulties in “interneurosensory learning.”
Professor Myklebust, who was born 2 august 1910 in Lester (IA, US), was among a small group of educators and psychologists who generally credited with founding the study of Learning Disabilities. Along with Samuel Kirk, William Cruickshank, Marianne Frostig, Newell Kephart, and perhaps a few others, Myklebust pursued the recognition of the difficulties experienced by these children and their families.
He received a bachelors degree from Augustana College, a masters degrees from Gallaudet College and Temple University, and a doctoral degree from Rutgers University. He taught and conducted research at several institutions, including Northern Illinois University; Northwestern University, where he spent most of his career and where he founded the Children’s Hearing and Aphasia Clinic; University of Illinois, Chicago. Memorial services were held 8 March.
Johnson, D. J., & Myklebust, H. (1967). Learning disabilities: Educational principles and remedial approaches. NY: Grune & Stratton.
Myklebust, H. (1954). Auditory disorders in children: A manual for differential diagnosis. NY: Grune & Stratton.
Myklebust, H. (Ed.). (1968-1975). Progress in learning disabilities (vols. 1-5). NY: Grune & Stratton.
I am late in publishing this note; thanks to Hal McGrady for alerting me to the death of this giant figure in the history or LD.
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