Neurodevelopmental disorders are emerging as a big health threat and may be more prevalent among India’s children than previously thought. A recent study has shown that almost one in eight children below the age of 10 years have at least one neurodevelopmental disorder.
Researchers assessed 3,964 children from five geographically different regions – Palwal in Haryana, Kangra in Himachal Pradesh, Dhenkanal in Orissa, Hyderabad in Telangana and North Goa. They found at least one neurodevelopmental disorder in 475 children out of 3,964, or nearly 12% of the children evaluated.
Neurodevelopmental disorders or NDDs are disabilities arising out of impairments in the development of the neurological system including the brain. The brain starts to form in the initial months of the foetus but most of its development occurs from between six months as a foetus till three years after birth. Any damage or genetic abnormality during this time can permanently impact brain function. These impacts manifest as NDDs like autism, cerebral palsy or epilepsy and also affect learning ability, memory, psychological and emotional development.
Globally, nearly 200 million children develop NDDs in the first five years of their lives. According to the 2011 census, more than 6 million children below the age of nine are afflicted by all kinds of disabilities in India. The census divides disabilities into eight categories – seeing, hearing, speech, movement, mental retardation, mental illness, multiple disabilities and others – and probably underestimates number of children suffering from NDDs.
The new study published in PLOS Medicine projects that more than 23 million children below nine years have NDDs alone.
“Our study provides the first population-base [the number of people in a given area for a particular section of the population as estimated by the census] on the burden of NDDs in two-year-old to nine-year-old children from India,” said Dr Narendra K Arora, executive director of International Clinical Epidemiology Network who led the study that involved a team of around fifty medical practitioners, clinicians and researchers. “The study highlights NDDs in children as an important public health challenge for India.”
Dr Anjana Thadani, developmental pediatrician and director of Niramaya Hospitals who was not part of the study said, “At present it is the most comprehensive data available with regards to neurodevelopmental disabilities in India.”
Suffering more than one disorder
The researchers evaluated children between the ages of two and six for vision impairment, epilepsy, neuromotor impairments including cerebral palsy, hearing impairments, speech and language disorders, autism spectrum disorders. They checked for two additional NDDs – attention deficit hyperactivity and learning disabilities – among older children between the ages of six and nine.
Almost one-fifth of the children who were diagnosed with NDDs had more than one NDD. According to Arora these children suffered the worst. More than 100 children had two or more disorders. Autism spectrum disorders, intellectual disability, neuromotor impairments and epilepsy mostly occurred together in the children.
“This was a very important observation,” said Arora. “A possible explanation for this could be that several NDDs share common risk factors.”
Across the five sites, hearing impairment, intellectual disability, speech and language disorders, epilepsy and learning disabilities were the most commonly occuring NDDs. These different conditions are considered as NDDs “because they occur in the developmental period of the child and due to malfunctioning of the brain,” said Dr Sheffali Gulati, head of child neurology in the department of pediatrics at the All India Institute of Medical Sciences, Delhi, and the coordinator of the study.
Development of the brain occurs in three parts. One is motor development, which concerns movement of limbs; the second is sensory, which involves development of senses; and the third is cognition. “Anything that hampers these three parts can cause NDDs,” said Dr Pradnya Gadgil, paediatric neurologist at Kokilaben Dhirubhai Ambani hospital in Mumbai.
She went on to explain how a hearing impairment, for example, can lead to other NDDs. “The way humans develop speech is by imitation,” she said. “A child hears people around talk and sees them move their mouth and learns to speak. So if the child’s hearing is impaired, the child develops speech and language disorders like stuttering or apraxia [an acquired oral motor speech disorder affecting an individual’s ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability].”
Gulati pointed out that all NDDs last through the life of the patient. Epilepsy can be controlled by medication but other disorders are treated with behavioural, social or educational interventions. For example, a person with a hearing impairment might use a hearing aid for life.
Conditions of birth
The conditions in which is baby is born can determine whether it grows up with an NDD. One of the factors that contributes to NDDs is non-institutional delivery of newborns. Most hospitals are or should be equipped to handle complications at the time of the delivery but homes, most often, are not. If the baby gets stuck during labour, it could asphyxiate due to lack of oxygen. This insufficient oxygen supply could cause epilepsy or cerebral palsy.
Cleanliness can also be a problem. Studies have shown that sepsis can lead to NDDs like cerebral palsy in infants.
“People don’t wash hands and handle babies,” says Gadgil. “In some places there is no running water, so there always aren’t clean cloths to wraps babies and this can cause infections like meningitis or sepsis.”
Although there have been considerable decline in infant mortality rates and about 26 million children are born every year, nearly 40% of births still do not happen in hospitals or maternity clinics.
According to Gadgil, NDDs prevalent in urban and rural populations are different. She finds autism, intellectual disability and Down syndrome more in urban children, while NDDs such as cerebral palsy and, conditions like neonatal encephalopathy and polyneuropathy that are caused due to asphyxia during birth, sepsis and malnutrition are more in rural populations. “This is a reflection of the kind of public health care that exists,” says Gadgil. “Mothers in rural areas normally don’t receive antenatal or postnatal care.”
Other studies show that NDDs can be due genetic birth defects caused by inbreeding due to consanguineous marriages in some communities. Inbreeding narrows the pool of gene selection and chances of passing on genes carrying NDDs increases.
The study also finds higher prevalence of NDDs in the older age group of six to nine years could be attributed to nutritional deficiency and stunted growth in the initial years. “For development of the brain and body, nutrition is required,” says Gulati. Inadequate nutrition could weaken a child’s immune system and make it vulnerable to infections.
Differences by geography
Odisha’s Dhenkanal recorded the lowest prevalence of NDDs in the study with only 2.9% of children between ages two and six with disorders. But this could be due to high mortality rate in the region that is endemic for hemoglobinopathies and cerebral malaria. As a result fewer children with NDDs may have actually survived.
Palwal in Himachal Pradesh had the highest prevalence with 18.7% of children with NDDs. Hyderabad was the only fully urban site and it recorded 8% prevalence of intellectual disability, the highest amongst the sites, in the children between six and nine years old.
Speech and language disorders were most common in children from North Goa. Dr Maria Silveria of Goa Medical College said that differences in medium of instruction in schools and language spoken at home could contribute to exacerbating such problems in children who have these type of NDDs. “If they speak Konkani at home and learn in English at school and do not understand, this causes lot of language problem,” she said. “This disparity of not understanding makes them little more susceptible to language disorders.”
According to Silveria, pediatricians now are picking up NDDs earlier in children’s lives. Early detection can be crucial for treatment as the brain is developing in the initial years of life and is not set in its ways. For example, detection of autism has increased while early interventions are helping reduction in effects of cerebral palsy.
The study points to the government’s Rashtriya Bal Swasthya Karyakram, which was launched in 2013 for the early detection of birth defects, diseases, deficiencies, development delays including disability in children all over India upto eighteen years of age.
“The scheme has identified 40 birth defects as NDDs along with functional traits like eyesight, hearing, congenital heart disease along with metabolic diseases,” said Dr Arun K Singh of the Ministry of Health and Family Welfare.
The program has targeted 27 crore children to be screened for developmental delays. Nearly 20 crore children have been screened out of which over 30 lakh children were detected to have birth defects and developmental delays. The programme, the study says can benefit from the trends shown in the study, the authors say .
Most of the causes for NDDs that this study identifies can be addressed by investments in public health and improving child nutrition. Improvements in public health care will reduce medical complications during pregnancies, infections like chorioamnionitis which can lead to cerebral palsy and sepsis that can cause neuromotor impairments can be avoided. Institutional deliveries can lower the cases of perinatal asphyxia, serious neonatal illness and infections like meningitis and encephalitis that can cause NDDs. Improvements in nutrition of children and can reduce the prevalence of stunting and low birth weights that can harm the cognitive abilities.