Development Milestones

Function

The assessment of developmental disorders is guided by the processes of surveillance and screening: 

• Surveillance: The process by which children who are at risk or who have developmental delay are identified. [2] It is done at every well-child care visit, and it can be performed by using an age-appropriate checklist of milestone records. Special attention must be had at the 4 to 5-year visit prior to the start of school. 
• Screening: The process by which asymptomatic children who may be at risk of developing a disorder are identified via standardized testing.[1] Once a child screens positive, he or she should undergo a subsequent developmental-behavioral evaluation.[2] The American Academy of Pediatrics recommends screening at ages 9, 18, and 30 months. Some of the tools used are the Denver Developmental Screening Test, Ages, and Stages Questionnaires.

When evaluating a child, it is important to take into consideration the gestational age at birth, as premature infants have a higher risk of long-term neurodevelopmental disabilities. In order to assess the normal growth and development of an infant born premature, the clinician must adjust the chronological age to the appropriate gestational age, and adjust the milestones to the corrected gestational age. For example, a baby is born at 32 weeks, and they are 8 weeks premature based on a full-term baby born at 40 weeks gestation. One would expect this 32-week old baby to reach their milestones 2 months behind their chronological age. 

The implementation of both surveillance and screening enhances early identification, enabling more prompt intervention, which promotes improved outcomes.[3] 

Issues of Concern

The developmental milestones evolve with the child as he or she ages. It is imperative for clinicians to develop familiarity with the normative dynamic process of maturation so that delays can be promptly identified. Responsiveness to intervention is most prominent in early childhood. The later the developmental aberration is identified, the more pronounced the risk becomes for developing emotional, social, and academic dysfunction.[2] 

Delays in development can be overlooked for a multitude of reasons. Sometimes the delay is subtle and undetectable on a brief exam. Furthermore, parents may negate the existence of a perturbation and not report any abnormalities to providers. Because delays can be missed, it is important to maintain routine surveillance.

Developmental delays can be specific (present in one area), or global (present in greater than 2 areas). Children can present initially with only a specific delay but can go on to develop subsequent delays in additional areas of functioning, thus advancing to a global delay.[1] Of the 5 areas of development, language may be considered the most salient to assess, as it is an important predicting factor for literacy level and cognitive skills, and benefits the most from earlier interventions.[4][5]

Clinical Significance

Children with delays qualify for Early Intervention, which are programs that can help the child catch up to development typical for their age. These interventions may include speech therapy, physical therapy, and occupational therapy. The earlier delays are identified and addressed, the more positive the prognosis.[6][7]

Once a delay in development is identified, the clinician must try and find the etiology for the delay. A child with a speech delay may have an underlying hearing problem, whereas, children with visual problems may have delays in motor development. Genetic and metabolic conditions can also precipitate developmental delays, often global in nature. Children with cerebral palsy will also present with global delays. A thorough workup should include hearing screening, thyroid function testing, lead testing, and a microarray.[8][9]

In disorders such as autism, one may begin to see deviations in development, especially in the social/emotional and verbal areas, as early as six months of age. The importance of detecting this early on is that the earlier a child has interventions in place the more likely a child is to become more functional. The older a child gets without the detection of these delays, the therapies, while still useful and worth the effort, may become less effective. Unfortunately, many children with an autism spectrum disorder do not receive a diagnosis until after age 5. Many pediatric offices use screening tools, the most well-studied of which is the Modified Checklist for Autism Screening in Toddlers (M-CHAT), and subsequent variations of this screening tool.[10] Other examples include intellectual disability, attention deficit hyperactivity disorder, hearing impairment, and cerebral palsy. Regardless of the disorder, developmental milestones will help uncover the developmental aberration and promote prompt intervention.

Enhancing Healthcare Team Outcomes

The way a child's development progresses in the first years of life can dictate the individual's lifelong development and level of success they could potentially achieve in adulthood. The role of the primary care physician is crucial in the recognition of normal development and identification of developmental delays. The provider should outline appropriate anticipatory guidance to the caregiver and educate them on what they should expect their child to be achieving as they grow. Developing a strong relationship with parents is important to ensure that when any abnormality in the child's development is identified, the parents will acknowledge the perturbation and acquiesce to recommended intervention strategies and treatment plans. 

Developmental delays, such as speech and language delay, can be a presenting feature of conditions such as autism spectrum disorder (ASD), and also serve as a prognostic factor.[10] Therefore the recommendation of the American Academy of Pediatrics is to screen at 9, 18, and 30 months; and the screening for ASD at 18 and 24 months.[1] A child with motor delay should have a thorough physical examination, including a complete neurological exam; laboratory testing should include creatine kinase and thyroid function, and brain imaging should be considered. 

Whenever screening results are concerning for developmental delay, a further, complete evaluation is necessary. Evaluations ideally performed by developmental specialists (neurodevelopmental pediatricians, developmental-behavioral pediatricians, pediatric neurologists, pediatric psychiatrists), and they can occur at home or medical centers. Early childhood professionals such as educators, psychologists, social workers, and therapists must be included as part of the multidisciplinary team, which will ensure the child is receiving appropriate care. 

Referral to early intervention programs as early as possible is valuable to ensure more positive outcomes. These programs not only provide complete evaluations but connect families with the services required, provide them with service coordinators and social workers that can assist families with issues such as transportations, home visits, counseling, insurance. It is essential to recognize that a specific diagnosis is not required to refer to Early Intervention and to educate parents that they can also request the referral.[2] [Level 5]