DESCRIPTION

• Developmental delay is a nonspecific description of a child who is functioning below what is expected for his/her age, in the different streams of development such as speech/language, fine and gross motor, personal/social skills, and problem-solving skills.
• Children are expected to attain developmental milestones in these different areas within an age range that is considered normal, following a typical pattern of developmental progress (e.g., the cephalocaudal pattern of gross motor development, ulnar to radial pattern of fine motor development).
• If a child is late in attaining a skill beyond the range of what is considered normal, the child is said to have a developmental delay.
• An important concept in assessing developmental delay is the concept of the 3 Ds of development—delay, dissociation, and deviation. Recognizing these patterns in development aids the clinician in understanding the child’s developmental problem more clearly.
  • Delay is characterized by attaining a skill later than what is expected but still following the pattern of typical development.
  • Dissociation in skills can be recognized by comparing a child’s skills in the different streams of development—a child with isolated gross motor delay would have skills in this area that lag behind skills in other areas such as speech/language, fine motor, and personal/social skills.
  • Deviancy characterizes skills that are not expected in normal development but are important to recognize, such as muscle hypertonicity/spasticity or an atypical pattern of social communication development such as in autism.
• A child may have an isolated delay in a specific area (e.g., gross motor delay or speech/language delay) or may have delays in several areas of development. Speech and language delays associated with social deficits and stereotypic patterns of behavior may indicate an autism spectrum disorder. A child who has delays in several areas of development has what is termed global developmental delay.
• The pediatrician will encounter many patients with developmental delays in their practice. It is important to follow these children over time, monitor their progress, and assess whether they eventually “catch up” or continue to lag behind their peers. Those with more persistent delays would eventually be classified as having a developmental impairment rather than a delay.

EPIDEMIOLOGY

• It is estimated that about 15% of children ages 3 to 17 years have a developmental impairment such as autism spectrum disorder, intellectual disability, language and learning disorders, and cerebral palsy, among other disorders.
• Global developmental delay is estimated to occur in about 1–3% of children, whereas intellectual disability is generally identified in 1% of the population.

ETIOLOGY

• There is a vast list of possible etiologies for developmental delays.
• Specific medical disorders may lead to specific delays in development. This includes hearing loss as a risk factor for speech/language delay and neuromotor disorders as risk factors for motor delay.
• There are conditions associated with more global developmental delays such as genetic disorders, malformations in brain development, and central nervous system (CNS) infections, among other disorders.
• Global developmental delay that persists beyond 5 years of age likely indicates an intellectual disability, which is defined by deficits in cognitive and adaptive skills with onset in the developmental period. The more severe the delay or impairment, the higher is the possibility that there is an identifiable cause for the delay. For a significant number, the cause of developmental delay is unknown.
• Causes of global developmental delay/intellectual disability include the following:
  • Genetic syndromes (e.g., Down, fragile X, Williams, Angelman, Rett)
  • Environmental causes: teratogens including alcohol, prenatal infections, early childhood CNS infections, traumatic brain injury
  • CNS disorders and malformations
  • Metabolic disorders
  • Nutritional
  • Unknown

RISK FACTORS

Risk factors for developmental delay include various genetic, biologic, environmental, and socio-demographic factors, such as:

• Prematurity
• Low birth weight
• Genetic disorders
• Congenital malformations
• Neurologic disorders
• Hearing loss
• Visual problems
• Traumatic brain injury
• Maternal prenatal use of alcohol
• Early adverse childhood events

GENERAL PREVENTION

• Newborn metabolic screening and universal hearing screen can identify disorders that can lead to developmental delays if they are left untreated (e.g., congenital hypothyroidism and phenylketonuria). Universal hearing screen has been key in identifying children with significant hearing loss at birth, a risk factor for developmental problems especially speech/language delays.
• Beyond the newborn period, the pediatrician has an important role in identifying developmental delays in children. The American Academy of Pediatrics (AAP) recommends developmental surveillance at every well-child visit whereby the pediatrician elicits concerns from parents, identifies risk and protective factors, and makes developmental observations of the child. The Centers for Disease Control and Prevention (CDC) through their “Learn the Signs. Act Early.” Program and the AAP recently released updated recommendations on developmental surveillance.
• The AAP recommends general developmental screening using formal screening instruments at the 9-month, 18-month, and 30-month visits and autism-specific screening at the 18-month and 24-month visits as well as at any visit when there is a concern raised by the parent or observed by the clinician. Studies have shown that relying solely on developmental surveillance without the aid of formal developmental screening misses about 50% of children with developmental issues before kindergarten.
• Children with conditions with a high probability of developmental delay may be referred to early intervention for services early on (even before a delay is identified). Among these conditions are certain genetic disorders, extremely low birth weight, central nervous system malformations or dysfunction, visual and ocular problems, and hearing loss, among other conditions. In addition, for certain at-risk conditions, developmental monitoring can be offered. Health care providers can refer to their state’s early intervention website for a list of conditions with automatic eligibility for early intervention services and for those who qualify for developmental monitoring. Audiologic and vision screenings are also recommended during specific pediatric well-child visits.

HISTORY

• Current developmental function of the child
• Review of the attainment of developmental milestones (see Appendix IV, Table 1)
• Summary of previous and current evaluations and therapies
• History of regression in skills
• Prenatal, perinatal, and postnatal history
• Past medical history to review possible risk factors for developmental delay (such as prematurity, CNS infections, brain injury)
• A three-generation family history of developmental problems, mental health conditions, consanguinity
• Social history

PHYSICAL EXAM

• Measurement of growth parameters including head circumference
• General physical examination to include dysmorphic features and other pertinent physical findings
• Skin examination (e.g., neurocutaneous syndromes)
• Neurologic examination with emphasis on muscle tone, reflexes, or asymmetry

DIFFERENTIAL DIAGNOSIS

The differential diagnoses for the different types of delays include the following:

• Gross motor delay
  • Normal variant
  • Neuromuscular disorders
  • Congenital hypotonia
  • Cerebral palsy
  • Global developmental delay
  • Neurodegenerative disorders
• Speech/language delay
  • Normal variant
  • Hearing impairment
  • Autism spectrum disorder
  • Global developmental delay
  • Language regression
  • Seizures
• Global developmental delay (children age <5 years)/intellectual disability
  • Borderline intellectual functioning
  • Learning disorders
  • Language disorders
  • Autism spectrum disorders
  • Sensory impairment
  • Neurodegenerative disorders

DIAGNOSTIC TESTS & INTERPRETATION

GENERAL MEASURES

• The mainstay of treatment of developmental delays is nestled on the Individual with Disabilities Education Act (IDEA), a law that mandates free and appropriate education in the least restrictive environment for all children 0 to 21 years of age with developmental or academic problems.
• Through IDEA, early intervention (age 0 to 3 years) and the board of education (age 3 to 21 years) may perform evaluations and identify children who qualify for educational and developmental services such as speech/language therapy, occupational therapy, physical therapy, special instruction (including applied behavioral analysis) as well as offer placement in specialized classroom settings as mandated in the child’s Individualized Family Service Plan (IFSP) and Individualized Education Plan (IEP), respectively.
• Aside from these developmental and educational services provided by early intervention and the board of education, medical treatment is focused on any treatable etiology of the problem. For example, a child with hearing loss that has led to language delay should be evaluated by an ENT for further management.

FOLLOW-UP RECOMMENDATIONS

PROGNOSIS

• There are various factors that influence the eventual outcome in children with developmental delay, foremost of which is the etiology of the problem (e.g., a genetic syndrome or a neuromuscular disorder).
• Factors such as the severity of the delay and the provision of appropriate therapies may influence the course of the problem.
• For autism spectrum disorder, cognitive and language skills have been found to correlate with the prognosis.
• Children with a history of speech/language delays are at risk for learning problems (e.g., reading problems) in school-age years. Those with receptive language delays tend to have a poorer prognosis than those with an isolated expressive language delay.
• Among those with global developmental delay, about two thirds go on to be diagnosed to have an intellectual disability.

ICD 10

• F89 Unspecified disorder of psychological development
• F82 Specific developmental disorder of motor function
• F80.9 Developmental disorder of speech and language, unspecified
• F88 Other disorders of psychological development
• F81.81 Disorder of written expression
• F81.89 Other developmental disorders of scholastic skills
• F81.0 Specific reading disorder
• F80.4 Speech and language development delay due to hearing loss
• F80.89 Other developmental disorders of speech and language
• F80.1 Expressive language disorder
• F80.0 Phonological disorder
• F81.2 Mathematics disorder
• F80.81 Childhood onset fluency disorder
• F80.2 Mixed receptive-expressive language disorder
• F81.9 Developmental disorder of scholastic skills, unspecified