Learning Disabilities

Learning disorders can have a big impact on a child’s development and participation in today’s world. In our previous article, we saw that children can benefit from cognitive training, specifically working memory training. In this article we will go into detail which diseases can cause learning disorders and if children with learning disorders can benefit from cognitive training.

But first, let us introduce the term learning disorders to you. Because, what is meant by ‘learning disorders’? Following Mayoclinic, a ‘learning disorder’ is a problem in the information-processing that will prevent a person from learning a skill and using it effectively. A child who doesn’t match the level of for example reading of fellow children of his age and intelligence is considered having a learning disorder. The term learning disorder can be further divided into several subcategories being:

  • Reading disorders
  • Written language disorders
  • Mathematics disorders
  • Disability of nonverbal skills

Within the sub-category reading disorder, we find the subset dyslexia. And within the sub-category mathematics disorder, we find the subset dyscalculia. Both are well-known disorders.

These disorders have neurobiological and environmental causes. Factors that influence the development of those disorders are among others: genetics, prenatal and neonatal risks, psychological trauma, physical trauma, and other environmental exposure.

In some cases the learning disorder is an isolated problem, in other cases, it is accompanied by another disease or disorder, which we also call a comorbidity. This last option is something we see in learning disorders together with attention deficit with hyperactivity disorder (ADHD). The co-occurrence rate of ADHD and reading disorders is somewhere between 25-48%. That is pretty high, don’t you think? But we haven’t even talked about the co-occurrence rate of ADHD and written language disorder, which is even higher. The co-occurrence rate of those are ranged from 55-64%. The last one, comorbidity of mathematics disorder and ADHD is found in 11-30% of the cases. Overall, it is found that the co-occurrence rate of ADHD and learning disorders is around 31-45%. These high co-occurrence rates give us the idea that the presence of or SLD or ADHD increases the risk of developing the other disorder in individuals.

There are more diseases that have a comorbidity with learning disorders. It is found that a remarkable part of children with Duchenne Muscular Dystrophy (DMD) have difficulties reading and writing. Before we start explaining where the learning disabilities in DMD might come from, let’s first find out what DMD is. DMD is a recessive X-linked genetic disease that develops because of a mutation in the dystrophin gene. Mutations in the dystrophin gene result in less production of the dystrophin protein and therefore loss of the myofiber membrane integrity. When the membrane integrity is affected, cells basically cannot survive and go into necrosis. Normally regeneration occurs, but as patients age, the regenerative capacity of the muscles gets lower and lower and therefore myofibers are replaced by fat and connective tissue. The dystrophin gene is mostly expressed in the striated muscles but also in the cardiac muscle, retina, and even in the brain. Although the distribution in the brain is less than in the muscles, it does explain some manifestations of DMD related to the central nervous system. Astrea et. Al. stated that children with DMD frequently have difficulty mastering academic material and that this may be due to specific learning disabilities such as dyslexia. They think problems in higher-order level cognitive, executive functions, could interfere with learning basic skills, such as reading, writing, math, and psychological health. To specify executive functions, mainly the working memory is affected in children with DMD compared to regular children.

Is there already proof that cognitive training could be beneficial in children with ADHD or DMD? Not much is known about cognitive training in children with DMD to improve their working memory level. However, more research is being done on whether we can improve cognitive functioning in ADHD. Bigorra et al. examined the long-term far-transfer effects of computerized working memory training in children with ADHD conducting a randomized controlled trial. They examined these effects using executive functions (EF) rating scales. The assessments were conducted at baseline, 2 weeks post-training, and 6 weeks post-training. For the primary outcome measure, they found significant improvement in the experimental group compared to the control group. These improvements were seen in the WM subscale, plan/organize subscale, metacognition index of the EFs scales assessed by parents. When assessed by teachers they did find improvements in the subscales: shift, initiate, metacognitive index, WM subscale, and the monitor. 

Figuur 1: 2 Effect size on subscales of BRIEF parent and teacher version. Negative effect sizes indicate a greater reduction of raw score in the experimental group compared to the control group; hence, a greater improvement in EF scales in the experimental group. Small effect size: 0.2; moderate effect size: 0.5; large effect size: 0.8.*p ≤ 0.05 in the adjusted analysis with score changes using a general linear model, controlling for age, sex and the presence of disruptive behaviour disorders [Bigorra et al.]

In conclusion, we saw that there is already proof that cognitive training induces a significant improvement of cognitive functioning in children with ADHD. Besides, Bigorra et al. also showed some reduction in symptoms of ADHD after cognitive training. This shows us that cognitive training can contribute to improving the quality of life of these children. Hopefully, in the future, we can further explore the beneficial effects of cognitive training in children with other diseases such as DMD. 

References

  • Astrea, G., Battini, Rb., Lenzi, S., Frosini, S., Bonetti, S., Moretti, E., Perazza, S., Santorelli, F.M., Pecini, C. (2016). Learning disabilities in neuromuscular disorders: a springboard for adult life.35(2): 90-95.
  • Bigorra, A., Garolera, M., Guijarro, S., Hervás, A. (2016). Long-term far-transfer effects of working memory training in children with ADHD: a randomized controlled trial. European Children Adolescents Psychiatry. 25: 853-867.
  • Mayo Clinic. (2021). Learning disorders: Know the signs, how to help. Healthy Lifestyle Children’s health. URL:https://www.mayoclinic.org/healthy-lifestyle/childrens-health/in-depth/learning-disorders/art-20046105
  • Pham, A.V., Riviere, A. (2015). Specific Learning Disorders and ADHD: Current Issues in Diagnosis Across Clinical and Educational Settings. Current Psychiatry Rep. 17(38).
  • Ricotti, V., Mandy, W.P.L., Scoto, M., Pane, M., Deconinck, N., Messina, S., Mercuri, E., Skuse, D.H., Muntoni, F. (2015). Neurodevelopmental, emotional, and behavioural problems in Duchenne Muscular Dystrophy in relation to underlying dystrophin gene mutations. Developmental Medicine % Child Neurology. 58(1):77-84.