Neurodevelopmental disorders include a broad set of disorders. Some of the common terms that fall under the umbrella of neurodevelopmental disorders are intellectual disability, language disorders, autism spectrum disorders, and attention-deficit-hyperactivity disorder amongst others. These disorders can often co-occur. These disorders can be present when the child is born or can be acquired when they are young impacting the development of children, they can have long-term effects as well. They can affect motor disorders, learning, intellect as well as communication, and emotions. These disorders are characterised by developmental deficits that may lead to impairment in personal, social, academic, or occupational functioning.
The diagnosis of neurodevelopmental disorders varies according to the child and the disorder but it often takes time to diagnose a neurodevelopmental disorder as it evolves over time and it is not synonymous with a developmental delay. However, it is important to make the diagnosis as early as possible in order to administer interventions. This blog aims to cover a specific neurodevelopmental disorder, intellectual disability, in detail.
What is intellectual disability?
Intellectual disability (ID), also known as an intellectual developmental disorder, is characterised by deficits in general mental abilities like abstract thinking, problem-solving, learning, reasoning, planning, and adaptive functioning. Deficits in these areas may lead to impairments that cause difficulties in meeting daily life challenges like communication, occupational and academic functioning, community and social settings, etc. In 2013, the federal statute in the US replaced mental retardation with the term ID as it often led to a misunderstanding of the nature of the disorder. Individuals with ID often need ongoing support as the adaptive deficits in functioning may hamper their performance in daily activities.
How can one diagnose ID?
The diagnosis of ID is based on both clinical assessments and standardised testing of intellectual and adaptive functions done by a team of professionals that includes a psychologist, special educator, school staff, and a pediatrician. Individuals with ID may have an IQ lower than 70 but it’s important to note that IQ scores are not taken as a diagnostic criterion while assessing ID. The tests to measure intellectual functioning should be culturally appropriate, comprehensive, psychometrically valid, and sound. The levels of the severity (mild, moderate, severe, profound) of the disability are defined on the basis of adaptive functioning and not on the basis of the child’s IQ as adaptive functioning is imperative in determining the level of ongoing support required by the child.
How prevalent is ID?
The prevalence of intellectual disability according to a meta-analysis done including 52 studies across countries like China, Japan, India, Sweden, Sri Lanka, USA, Australia, Netherlands, etc. was 10.37/1000. The research highlighted that the prevalence of ID around the world is around 1%. The study also highlighted that the highest prevalence of ID was in the adolescent and child population, and the prevalence was almost more than twice that in low and middle income countries as compared to high income countries (Maulik et al., 2011).
Risk factors of ID
Approximately 70% of individuals with ID have organic or biological causes (Shree & Shukla, 2016). Genetic and physiological factors of ID include prenatal etiologies like genetic syndromes, inborn errors of metabolism, brain malformations, maternal disease, and environmental influences like alcohol, drugs, toxins, and teratogens. Some prenatal causes include labour and delivery-related events leading to disturbance in neurological functioning in the early life of an infant (neonatal encephalopathy). Postnatal causes may include traumatic brain injuries, infections, seizure disorders, severe and chronic social deprivation, toxic metabolic syndromes, and intoxications like lead and mercury (DSM-5).
Treatment of ID
The main aim of the treatment is to make the individual reach their full potential in terms of adaptive functioning, occupational, social, and life skills in order to be able to require minimum support. This goal could be achieved to some level through occupational therapy, behaviour therapy, counselling, and medication in some cases.
Neurodevelopmental disorders impair brain growth and development that affect cognitive, motor, learning, and behavioural disorders. Early identification and intervention can help the children lead a life requiring minimal support. A crucial starting point for achieving that goal is learning about these disorders and understanding them.
Author,
Simran Premjani
Clinical Associate Psychology, PsychLine.in
References
https://www.sciencedirect.com/science/article/abs/pii/S0891422210003082
https://www.thieme-connect.com/products/ejournals/abstract/10.4103/0976-3147.165392
American Psychiatric Association. (2013). Diagnostic and statistical manual of ental disorders (DSM-5). American Psychiatric Pub.
Maulik, P. K., Mascarenhas, M. N., Mathers, C. D., Dua, T., & Saxena, S. (2011). Prevalence of intellectual disability: a meta-analysis of population-based studies. Research in developmental disabilities, 32(2), 419-436.
Shree, Abha, and P. C. Shukla. “Intellectual Disability: Definition, classification, causes and characteristics.” Learning Community-An International Journal of Educational and Social Development 7, no. 1 (2016): 9.