According to the National Center on Birth Defects and Developmental Disabilities & Centers for Disease Control and Prevention, USA, developmental disabilities are a group of conditions due to an impairment in physical, learning, language, or behaviour areas. These include but not limited to: Hearing Loss, Visual Impairment, Cerebral Palsy, Kernicterus, Autism Spectrum Disorder, Intellectual Disability, and Attention-Deficit/Hyperactivity Disorder. These conditions may begin prior to, at birth, or shortly thereafter and usually last throughout a person’ s lifetime. Children who experience delay in reaching expected developmental milestones as they grow are often distinguished as having developmental delays rather than disabilities, which is permanent. A developmental delay may improve with intervention and can disappear altogether once the child catches-up in his or her development. It is possible for a developmental delay to develop into a developmental disability if left untreated.

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The first global estimates of developmental disabilities among children younger than five years were first published by the Global Research on Developmental Disabilities Collaborators (GRDDC) in 2018 based on the Global Burden of Disease (GBD) 2016 database from the Institute for Health Metrics and Evaluation (IHME), USA. Globally, 53 million children younger than 5 years had developmental disabilities in 2016 and about 95% of these children lived in low-income and middle-income countries. Vision loss was the most prevalent disability, followed by hearing loss, intellectual disability, and autism spectrum disorder. In 2021, UNICEF estimated that 28.9 million (4.3%) children aged 0–4 years, 207.4 million (12.5%) children aged 5–17 years and 236.4 million (10.1%) children aged 0–17 years have moderate-to-severe disabilities based on household surveys of child functional status. Using the UNICEF estimated prevalence of 10.1%, approximately 266 million children aged 0–19 years are expected to have moderate-to-severe disabilities. In contrast, GBD 2019 estimated that 49.8 million (7.5%) children aged under 5 years, 241.5 million (12.6%) children aged 5–19 years and 291.3 million (11.3%) children younger than 20 years have mild-to-severe disabilities. In both databases, Sub-Saharan Africa and South Asia accounted for more than half of children with disabilities.

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Prevention is always better than cure. A good understanding of the factors associated with developmental disabilities is essential in curbing the incidence. In Sub-Saharan Africa, these typically will include genetic factors such as sickle cell disease and consanguinity; perinatal factors such as preterm birth, birth asphyxia, rubella, meningitis, HIV/AIDS, cytomegalovirus and neonatal jaundice; nutritional deficiencies such as protein-energy malnutrition and micronutrient deficiencies; exposure to environmental toxins such as ototoxic drugs; and poverty. The dominant causes or risk factors for specific developmental disabilities may vary from country to country and across communities in a single country. Epidemiological studies are therefore, necessary to define priorities for action in each population.

Yes. There are three levels of prevention: primary, secondary and tertiary. Primary prevention entails actions to effectively control the underlying cause or risk factor for a developmental disability. This level of prevention is the most preferred because of the substantial life-time monetary and non-monetary costs of providing support a child with developmental disability which are well beyond the means of an average household in low- and middle-income countries.However, not all developmental disabilities are completely preventable. For such conditions, secondary prevention through systematic screening programmes to identify the affected infants at the earliest possible time becomes a priority. Children that are detected through developmental screening will require prompt enrolment into an appropriate intervention or rehabilitation programme, which constitutes tertiary prevention. The goal of this level of prevention is to minimise the adverse consequences associated with the disability, as far as practicable. This intervention typically entails life-long coordinated, interdisciplinary medical and non-medical services, and supports.

Children with disabilities face a dire and uncertain future in low and middle-income countries (LMICs) compared to their peers in high-income countries. They require life-time support. However, early detection and intervention services for developmental disabilities before the age of 5 years are critical to the health and future well-being of the affected children. Children with developmental disabilities deserve timely and priority attention in any global, regional or national initiative on early childhood development. The best available evidence from developmental science suggests that the most effective period to help children with sensory disabilities, especially hearing loss, is from the third month to the first year of life, unlike most other childhood disabilities. The work at HSI-Centre is firmly grounded on this incontrovertible evidence, tagged ‘ Early Help, Better Future’ .

Sources:

• Shonkoff JP, Phillips DA, eds. From neurons to neighborhoods: the science of early childhood development. Washington, DC: National Academies Press (US), 2000.
• Thompson RA, Nelson CA. Developmental science and the media: early brain development. Am Psychol 2001;56:5–15.
  Center on the Developing Child (2007). The Science of Early Childhood Development (In Brief). Retrieved from  www.developingchild.harvard.edu.
• Grantham-McGregor S, Cheung YB, Cueto S, Glewwe P, Richter L, Strupp B; International Child Development Steering Group. Developmental potential in the first 5 years for children in developing countries. Lancet. 2007;369(9555):60-70.