NeuroSENse – Intellectual disability

Written by Dr Jo Van Herwegen

Intellectual disability (ID), which may also be referred to as learning disability (LD), is a developmental condition that is diagnosed when a child has significant difficulties in both intellectual functioning (what might be considered in terms of low IQ scores) and adaptive behaviour (including conceptual, social and self-care abilities) that impact on their day-to-day lives. Psychologists assess intellectual skills using cognitive tests, which produce an overall IQ score. The IQ score of the ‘average child’ is 100, and the ‘normal’ range is from 85 to 115. Psychologists often use categories of intellectual disability based on IQ scores, using the following labels: There are four levels of intellectual disability: mild (50-55 to 70), moderate (35-40 to 50-55), severe (20-25 to 35-40) and profound (below 20-25). The utility of IQ measures for people with intellectual disabilities has been questioned, especially those with lower needs1. There are also broader issues with using measures such as IQ and other ‘norm-referenced’ tests as, many will have a ‘floor’ level below which a test is unable to provide a useful measure. Establishing a floor for an individual’s cognitive ability flattens the profile of test scores among people with intellectual disability. This in turn may eliminate the opportunity to fully appreciate actual strengths and weaknesses that an individual may have. Sometimes, ID is also identified as ‘other’ or ‘unspecified’ or referred to as learning difficulties in the UK. It is estimated that about 1.5 million people in the UK have an ID, with about 25 per 1000 people having mild to moderate learning difficulties2.


There are a number of causes for ID: genetic causes (e.g. Down Syndrome), complications during pregnancy (e.g. fetal alcohol syndrome, Zika virus) and birth (e.g. lack of oxygen) or after birth (e.g. meningitis). These various causes all have an impact on the developing brain. The development of the brain is a highly organised process in terms of specialisation, maturation and survival of neurons (optimisation of brain connectivity) but genes and environmental factors can impact these processes leading to altered or damaged brain structures and functions. Indeed, neuroscience studies have shown that individuals with ID can often have altered neuronal configurations (e.g. Down syndrome3, Fetal Alcohol Syndrome4; Zika Virus5).

Common misconceptions about learning and individuals with ID

In this blog we consider three neuromyths (i.e., misunderstandings of cognitive neuroscience) that can affect the learning experience of children with intellectual disabilities. These are:

Neuromyth 1: The learning outcomes of those with ID cannot be improved by education
Neuromyth 2: Those with ID cannot learn anything complex
Neuromyth 3: What a child with learning difficulties can understand can be measured by what that child can say

All three of these statements are incorrect, and in this blog we consider why that is so.

Neuromyth 1: The learning outcomes of those with intellectual disability cannot be improved by education

It is commonly believed that: the learning outcomes of those with ID cannot be improved by education (neuromyth 1) or that those with ID cannot learn anything complex (neuromyth 2) (see6). For example, in the past, individuals with Down syndrome or other types of learning disabilities were not usually taught to read because of low expectations concerning their developmental potential7. Indeed, reading is a complex cognitive process that requires the decoding of symbols in order to construct or derive meaning (reading for comprehension). Yet, recent studies have shown that 70% of people with ID do develop at least functional reading levels and that reading abilities are often in line with their overall cognitive abilities8.

Neuromyth 2: Children with intellectual disability cannot learn anything complex

The misconceptions that individuals with ID cannot learn anything complex or would not benefit from education relates to the belief that the brain is static, and thus, once particular areas of the brain are affected there cannot be any learning or compensation taking place. Secondly, as learning tends to be slower in those with ID, their learning will be limited as some learning might need to take place outside any sensitive period of neuroplasticity. Sensitive periods of neuroplasticity are developmental periods during which developing brains can be altered in a profound and permanent way by specific experiences. For example, during the first few months of life, many synaptic connections are created in the brain, far more than exist in adulthood. During the ensuing years, many of these connections are eliminated (pruning), suggesting that the first few years of life are important for learning and brain stimulation (e.g. early years education programmes)9. Current evidence for sensitive periods and the importance of the first three years of life comes from a number of studies in various fields. For example, visual experience during specific sensitive periods impacts the way the brain processes information from each eye and the development of binocular vision. Kittens who had their eyes closed during particular times in early development showed atypical visual cortex structures and showed irrevocable visual processing difficulties. Similarly, a number of studies focused on first language development have shown that, if language input is not optimal during the first few years of life, either because of social deprivation or because of hearing impairments, children will show syntactic impairments in their language10.


However, sensitive periods can be impacted by many factors, including exposure and experience, and it has been shown that the brain is plastic and able to form new connections and learn new things throughout the lifespan. For example, London taxi drivers obtain a very detailed map of London in their mind through experience, and studies have shown that London taxi drivers have enlarged hippocampi (an area of the brain that is important for spatial memory)11. So, although early childhood experiences are very important for ongoing development and it is clearly imperative to support all children in having the best possible early childhood experiences, the capacity to form synapses, i.e. plasticity, is not limited to the first three years of life. In addition, sensitive periods are properties of low level sensory and motor skills, not of cognitive abilities. You can read more about the myths related to early years sensitive periods here:

Neuromyth 3: What a child with an intellectual disability can understand can be measured by what that child can say

Another issue that impacts on the endorsements of neuromyths relates to the attitudes and low expectations one might have in general of people with ID. Parents often complain that their child with ID is being underestimated by teachers12. This might be caused by the fact that it is often believed that  “What a child with learning difficulties can understand can be measured by what that child can say” (neuromyth 3). Indeed, many individuals with ID have communication difficulties in comparison to typically developing peers. However, numerous studies have shown that individuals with ID often have uneven cognitive profiles, with some abilities being stronger or better developed than others. For example, individuals with Down syndrome have significant expressive language difficulties compared to better language comprehension skills13, meaning that a child with Down syndrome is likely to understand far more than what they can say, for example, in the complexity of the sentences that they produce. As learning is often assessed in a way that depends heavily on expressive language skills (e.g. answering questions verbally or in written format), children with ID with expressive language difficulties (e.g., Down syndrome) are often underestimated in their ability to learn complex cognitive tasks.

So how can learning in individuals with ID be supported?

Academic outcomes in students with ID can be improved by a number of teaching practices and interventions. For example, a recent review has shown that systematic and explicit instruction with feedback and the use of manipulatives are effective instructional approaches and strategies to improve mathematical outcomes for students with ID14. In addition, it has been suggested that providing even brief information that emphasises the capabilities of individuals with intellectual disabilities can result in more positive attitudes15.


Other reviews have shown that students with ID benefit from cognitive and metacognitive strategies (for example, see systematic review16) and scaffolding (see EEF review March 2020). For example, when solving a mathematical problem, students with ID benefit from breaking the problem down into smaller steps or sub-problems and from being guided through the various strategies they could use to solve the problem at hand. Such a strategy can, in fact, be beneficial for many students.

As many individuals with ID have uneven cognitive profiles, regular assessments of these profiles and focusing on strengths to overcome areas of difficulty have been recommended. For example, individuals with Williams syndrome (a rare genetic disorder that causes mild to moderate learning difficulties) are often very interested in music and are motivated to participate in musical activities. Music stimuli have been shown to aid memory, attention and mathematical outcomes in pupils with Williams syndrome17.

Furthermore, differentiation between groups and alternative assessments should be considered for those with ID. For example, although read-aloud strategies have been successfully used to teach a variety of subject areas in different settings, for both students with and students without disabilities18, silent reading may facilitate better reading outcomes compared to oral reading for certain groups, including those with Down syndrome12.

In sum, when provided with the right opportunities and training, people with ID are able to learn new skills and improve their educational outcomes. As such, dispelling neuromyths around ID is a first step to enabling children with ID to reach their full educational potential.


1DiStefano, C., Sadhwani, A., & Wheeler, A. C. (2020). Comprehensive assessment of individuals with significant levels of intellectual disability: challenges, strategies, and future directions. American Journal on Intellectual and Developmental Disabilities, 125(6), 434-448.

2 [last accessed 8th of August 2021].

3Pinter, J. D., Eliez, S., Schmitt, J. E., Capone, G. T., & Reiss, A. L. (2001). Neuroanatomy of Down’s syndrome: a high-resolution MRI study. The American Journal of Psychiatry, 158(10), 1659–1665.

4Wozniak, J. R., Riley, E. P., & Charness, M. E. (2019). Clinical presentation, diagnosis, and management of fetal alcohol spectrum disorder. The Lancet. Neurology18(8), 760–770.

5Rasmussen, S. A., Jamieson, D. J., Honein, M. A., & Petersen, L. R. (2016). Zika Virus and Birth Defects–Reviewing the Evidence for Causality. The New England Journal of Medicine374(20), 1981–1987.

6Gini, S., Knowland, V., Thomas, M.S.C. & Van Herwegen, J. (in press). Neuromyths about neurodevelopmental disorders: Misconceptions by educators and the general public. Mind, Brain & Education.

7Næss, K. A., Melby-Lervåg, M., Hulme, C., & Lyster, S. A. (2012). Reading skills in children with Down syndrome: a meta-analytic review. Research in Developmental Disabilities33(2), 737–747.

8Ratz, C., & Lenhard, W. (2013). Reading skills among students with intellectual disabilities. Research in Developmental Disabilities34(5), 1740–1748.

9Bailey, D. B., Jr., Bruer, J. T., Symons, F. J., & Lichtman, J. W. (Eds.). (2001). Critical thinking about critical periods. Paul H Brookes Publishing.

10Friedmann, N., & Rusou, D. (2015). Critical period for first language: the crucial role of language input during the first year of life. Current Opinion in Neurobiology, 35, 27–34.

11Maguire, E. A., Woollett, K., & Spiers, H. J. (2006). London taxi drivers and bus drivers: a structural MRI and neuropsychological analysis. Hippocampus16(12), 1091–1101.

12Cologon, K. (2013). Debunking Myths: Reading Development in Children with Down Syndrome. Australian Journal of Teacher Education, 38(3).

13Dykens, E. M., Hodapp, R. M., & Evans, D. W. (1994). Profiles and development of adaptive behavior in children with Down syndrome. American Journal of Mental Retardation98(5), 580–587.

14Schnepel, S., & Aunio, P. (2021). A systematic review of mathematics interventions for primary school students with intellectual disabilities: European Journal of Special Needs Education. European Journal of Special Needs Education, 1-16.

15MacDonald, J. D., & MacIntyre, P. D. (1999). A rose is a rose: Effects of label change, education, and sex on attitudes toward mental disabilities. Journal on Developmental Disabilities, 6(2), 15–31.

16Harris, P., Partanen, P., & Van Herwegen, J. (in prep). The Effectiveness of Feuerstein’s Instrumental Enrichment Programme: A Systematic Review.

17Thakur, D., Martens, M. A., Smith, D. S., & Roth, E. (2018) Williams syndrome and music: A systematic integrative review. Frontiers in Psychology, 14,

18Alquraini, T.A. & Rao, S.M. (2020). Developing and sustaining readers with intellectual and multiple disabilities: A systematic review of literature. International Journal of Developmental Disabilities, 66(2), 91-103, DOI: 10.1080/20473869.2018.1489994


Leave a Reply

Your email address will not be published. Required fields are marked *