Developmental delay in children is a common and concerning presentation in pediatric primary and specialty care. The identification and evaluation and treatment of children with learning or developmental impairments is of great concern in the clinical, educational, and public health settings. This article reviews core principles of development in children. Appropriate use of screening methods aimed identifying developmental problems in children is discussed. The specialty medical evaluation and management of children with identified developmental disorders will be reviewed, including current recommendations for investigations and treatment.
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• Development proceeds in an orderly, timed, and sequential process that occurs in a predictable fashion.
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• Developmental delay is a common pediatric presentation that can be influenced by all domains of health (biological, psychological, and socioeconomic).
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• The range of underlying diagnoses is broad and assessment of developmental delay requires a comprehensive and longitudinal approach to history and physical exam.
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• Investigations should be targeted based on individual presentations and cooccurring conditions with genetic testing being first line for unexplained cases of global developmental delay.
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• A child with a developmental disability should have an identified medical home as a child with special health care needs with targeted, multidisciplinary interventions.
Historical note and terminology
The study of child development has a longstanding history, with different approaches to cognitive development emerging over time and from different disciplines. The study of development aims to describe how and why people change over the lifetime, how this manifests in individual differences, and what can be done to maximize the growth of function, both in normal development and development that may be impaired by disease or injury.
A psychodynamic perspective of child development was proposed and promoted through Freud and his followers. They put forward the theory that early experiences shaped the adult personality, influencing the 3 components of the personality: the id, the ego, and the superego. They suggested there were stages of development that were discontinuous and required resolution of the previous phase prior to moving to the next phase. These phases consisted of the oral, anal, phallic, latency, and genital phases. Healthy development through these stages culminates in the ability to invest in and derive pleasure from love and work. Fixation on a lower stage may occur if fundamental needs are not met at any particular stage. Although there are many criticisms of this approach to development, and it has limited clinical translation, its emphasis on early experience and emotional relationships added an early contribution to the understanding of early emotional development that was continued through Erik Erikson’s stages of psychosocial development. Erikson conceived of personality development as a series of 8 conflicts (trust vs. mistrust, autonomy vs. shame, initiative vs. guilt, industry vs. inferiority, identity vs. confusion, intimacy vs. isolation, generativity vs. stagnation, ego integrity vs. despair) that extend sequentially throughout life (32).
Another foundational theory of development emerged from Jean Piaget’s constructivist approach that proposed 4 broad stages of cognitive development that arise from the individual actively constructing knowledge based on their own experiences. The stages (sensorimotor, preoperational, concrete operational, and formal operational) each build upon the previous, resulting in increasing sophistication and abstraction of thought across multiple cognitive domains (07). Although Piaget’s theories added understanding of the overview of child learning and found success in some educational models of experiential learning, they oversimplified the consistency and complexity of learning, underestimated the competence of infants and children, and did not account for the contribution of social relationships to learning and development. Albert Bandura described how children could learn through the environment with social learning theory. Bandura expanded on the concepts of classical and operant condition (where a behavior is learned due to association between a stimulus and the response) by describing mediating processes that can occur between stimuli and the response (accounting for individual differences) and how behavior can be learned through observation (50).
Modern approaches to the evaluation of development in children traces back to the work of Arnold Gesell, pediatrician and psychologist at the Yale University School of Medicine, and his collaborator, Catherine Amatruda. Dr. Gesell focused on early child development, leading to popular writings such as The First Five Years of Life (23). He and Amatruda also created a new science of developmental evaluation with the 1941 publication of Developmental Diagnosis - Normal and Abnormal Child Development - Clinical Methods and Pediatric Applications (24). They described developmental examination of the infant and linked problems in development to medical problems, including prematurity, thyroid disorders, seizures, cerebral palsy, visual disorders, and hearing impairments and later emphasized the link between the fetus and postnatal child development in The Embryology of Behavior (25).
In creation of the science of developmental diagnosis, Gesell and Amatruda compared typical developmental patterns with those seen in the child being evaluated. Typical development is based on documented sequences of skill emergence, and the age norms for when these skills are observed. Gesell established the first set of norms by recording the skill acquisition of children seen in his clinic, establishing that an orderly, timed, and sequential process of development occurred in a predictable fashion. This allowed for identification of both normal and abnormal patterns. They also introduced the concept of developmental quotient (DQ), a comparison of a child’s chronologic age and his developmental age, expressed as a ratio.
By combining public health methods of population screening for disease with the methods introduced by Gesell, William Frankenburg aimed for widespread identification of developmental disorders (21). Paul Dworkin further described the process of embedding developmental monitoring into the process of surveillance as recommended by both major British and American pediatric organizations (19). In the American Academy of Pediatrics policy statement on developmental surveillance and screening, surveillance is used to describe the continuous, informal tracking of a child’s development (04). Screening implies the use of a standardized test at discrete age intervals on all children. Developmental evaluation, as introduced by Gesell, describes the more complex process used for establishment of a developmental diagnosis.