Developmental Delay

DEVELOPMENTAL DELAY

Developmental delay is seen at any age and involves a lack of ability to reach milestones. It can be seen in behavior, cognition, motor skills, vision, speech, and hearing. Delays that are common in each category include the following:

• Cognition—this includes differing problems with mental retardation or specific learning disabilities in reading and mathematics. • Motor—this includes cerebral palsy, spina bifida, and muscular dystrophy. • Vision—this includes refraction disorders, night blindness, and juvenile cataracts. • Hearing—this includes sensorineural or conductive hearing loss. • Speech—this includes specific problems with articulation, expressive language disorder, and receptive language disorder. • Behavior—this includes autism and ADHD.

Cognitive delays are evaluated with IQ testing. Mild mental retardation is most common and affects the child’s school performance and vocational skills. More severe cognitive impairment can affect all of the other areas of life, including behavior, motor skills, vision and hearing, and can lead to seizures in some children, who often need skilled care for basic needs.

Specific learning disabilities do not generally affect global cognitive functioning. They include deficits in speech, language, or the ability to read, spell, write, or do arithmetic. Children with these deficits are generally discovered in primary school when the child’s skills are tested independently. Most of these children do well with certain educational accommodations.

Motor disabilities can involve the trunk, the ability to speak and swallow, and the movement of the extremities. Cerebral palsy is usually discovered in infancy, while muscular dystrophies, polio, and spinal muscle atrophies can be diagnosed later in life. Cerebral palsy is not progressive but is permanent. It can affect any area of the body. Most patients have spasticity, although cerebellar involvement can be seen as hypotonia. Other disabilities are possible, including epilepsy, learning disabilities, mental retardation, and language delays. Other motor disorders, such as muscular dystrophy,

are progressive but may also show cognitive delays. Polio and spinal cord deficits generally involve just motor skill problems.

Vision and hearing deficits are generally seen in adults but certainly could be a neurodevelopmental disorder. Refractive errors are the most common of these and are easily fixed with glasses. Speech and hearing are intricately involved so that the child who does not hear at the age of two often cannot later form speech well, even when their hearing is improved at a later time. Hearing screening is done in the newborn period so that modifications can be made as early as possible.

Behavior disorders are under-diagnosed unless the child is carefully monitored. Things like war, poverty, famine, and natural disasters can affect the child’s mental health. Behavior problems are not necessarily linked to known disorders like ADHD or autism and can be environmentally-based. You should screen for behavior issues at every well child visit.

Developmental disabilities come often from damage or developmental anomalies of the immature nervous system. Many are inherited or genetic in nature. Other causes to consider are nutritional deficiencies, infections, or toxic exposures at critical developmental time periods. The timing of the insult is important because, for things like rubella, the infection is most serious in the first trimester.

Genetic aspects to development include the different hemoglobinopathies like thalassemia and sickle cell disease. Most children with sickle cell disease have some degree of mental retardation. Chromosomal abnormalities, such as Down syndrome, greatly affect learning and cognition. Marriages that are consanguineous have an increased risk of cognitive deficits in the child. There are also numerous inborn errors of metabolism and genetic diseases like Duchenne muscular dystrophy that contribute to developmental delays.

Nutritional deficiencies can affect the child’s morbidity and mortality; it occurs all over the world. Iodine-deficiency states lead to cretinism, which can be something the child is born with and can affect all developmental areas. Vitamin A deficiency usually leads to ocular disease, which can be permanent. It also contributes to an increased risk of infectious diseases.

Iron-deficiency anemia is a widespread health problem, especially in low-income parts of the world. It lowers the infection resistance and affects vitamin A and fat absorption. In infants, it leads to low birth weight. Low iron intake in childhood leads to cognitive delays, attention deficits, and learning disabilities.

Folate deficiency is problematic in early pregnancy. It contributes to an increase in neural tube defects like spina bifida, which affects motor function of the lower extremities. For this reason, it is recommended that a woman take folate prior to conception in order to reduce the risk of a neural tube defects.

Protein-calorie malnutrition can affect sensory integration, the development of language, behavior, and learning. There are specific neuropathies that can develop because of nutritional deficiencies. The effect on the developing brain is often permanent. It is unclear if the problem is with energy deficits in total or with specific nutritional deficiencies.

Infections can lead to developmental delays. The things you will most associate with these types of problems include congenital rubella, congenital syphilis, congenital cytomegalovirus, and congenital toxoplasmosis. Each of these will lead to specific symptoms along with mental retardation. Herpes simplex can be gotten in utero by the baby or at the time of birth and can lead to microcephaly, calcifications of the brain, and eye abnormalities. HIV disease is prevalent in low-income parts of the world and can lead to marked impairment of the CNS, movement disabilities, microcephaly, and cognitive delays.

After birth, infections can also cause developmental delays as well. Common infections that can lead to this include malaria, viral encephalitis, bacterial meningitis, polio, tetanus, trachoma, and measles. Malaria of the brain can cause seizures and coma. If the mother has it during pregnancy, there can be intrauterine growth restriction and maternal death from anemia.

Environmental toxins that can affect the fetus, infant, or child, include lead exposure, which can lead to lead encephalopathy. Heavy alcohol use in pregnancy leads to fetal alcohol syndrome, which involves cognitive impairment, microcephaly, facial abnormalities, and low birth weight. Salicylates and streptomycin can cause ototoxicity.