Part I: A Closer Look
Developmental Surveillance and Screening
What are developmental surveillance and developmental screening?
The AAP recommends developmental surveillance be performed at every health supervision visit. Developmental surveillance is the ongoing process of identifying children who may be at risk for developmental delays. It is a “flexible, longitudinal, continuous, and cumulative process” consisting of 5 components:
- Eliciting and attending to parents’ concerns about their child’s development
- Documenting and maintaining a developmental history
- Making accurate observations of the child
- Identifying risk and protective factors
- Maintaining an accurate record and documenting the process and findings
By incorporating developmental surveillance and screening into primary care visits, the pediatrician can provide anticipatory guidance to the family to support their child’s development and to facilitate early detection of a disorder.
Elements of Surveillance
Elements of surveillance relevant to ASD include:
- Eliciting parental concerns about the child’s hearing or unusual responsiveness, temperamental variations (irritability, passivity), unusual sensitivities (e.g., clothing, food preferences), or resistance to transitions
- History of developmental milestones, particularly in the domains of communication and social-emotional development
- Observations of impaired relatedness (e.g., poor eye contact), lack of joint attention (e.g., gaze monitoring, pointing), lack of response to name, more interest in objects than people, repetitive behavior or play patterns
- Obtaining family member history, especially about siblings diagnosed with ASD, indicating a greatly increased risk as compared to the general population
Concerns raised during surveillance should be addressed with standardized developmental screening tools. Screening refers to the use of measures with proven reliability and validity that are administered in a standardized way. General screening tests are recommended by the AAP at the 9-, 18-, and 30-month visits (or at the 24- month visit if a 30-month visit is not routinely scheduled).
When should you start screening for ASD?
In Identification and Evaluation of Children with Early Warning Signs of Autism Spectrum Disorder, AAP also recommends administering a standardized autism-specific screening tool on all children at the 18-month well-child visit. In 2007, the recommendation was expanded to screen at 24 to 30 months of age to identify those who may regress after 18 months of age.
A standardized screening tool should be used at any point that concerns about ASD are raised by a parent. It should also be used as a result of clinician observations or if there are suspect answers to surveillance questions about social, communicative, and play behaviors.
What screening tool should be used?
Choosing a Screening Tool
The choice of a screening instrument depends on a variety of factors. Screening tools vary with respect to sensitivity, specificity, reliability, and validity.
- Sensitivity is the ability of a test to identify correctly those who have the condition [i.e., true positives over all positives (true positives and false negatives)].
- Specificity is the ability of a test to identify correctly those who do not have the condition [i.e., true negatives over all negatives (true negatives and false positives)].
- Reliability is the repeatability of a test; ability of a test to obtain consistent results.
- Validity is the ability of a test to measure a certain criterion; strength of conclusion.
Screening tools should have strong sensitivity and specificity. Additional factors must be considered, such as cost, availability in multiple languages, reading level required, and whether the test relies on parent report or screener’s observations.
An example of a widely used screening test for ASD is the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F).
The M-CHAT-R is a parent-completed questionnairethat is valid for screening toddlers for ASD between 16–30 months of age. The M-CHAT-R includes a Follow-Up Interview, in which the parent is asked questions to help clarify answers and obtain additional information for at-risk items. The Follow-Up questions improve the ASD detection rate and reduce the number of screen positive when compared to the M-CHAT alone. The estimated sensitivity of the M-CHAT-R with Follow-Up is 85% and Specificity is 99%.
Even with the Follow-Up questions, a significant number of children who score at risk on the M-CHAT-R will not be diagnosed with ASD. However, these children are at higher risk for other developmental disorders or delays, and therefore, evaluation is warranted for any child who screens positive.
Other Screening Tools
Other measures that may help detect early behavioral indicators of autism include:
- Infant Toddler Checklist (ITC), a test designed to screen for communication delays.
- Screening Tool for Autism in Two-Year Olds (STAT), a tool previously designed to assess children between 24 and 36 months which may also be informative in children 12-23 months (Sensitivity and specificity estimated at 95% and 73%, respectively, in a sample of 71 toddlers aged 12–23 months and at high risk).
- Childhood Autism Spectrum Test (CAST), a 37-item, parent-completed questionnaire can be used in children ages 4–11 years old. This has a reported sensitivity and specificity of 88%–100% and 97%–98%, respectively.
Communicating to parents
How should information be communicated to parents about screening and screener results?
Communication with parents is one of the most important tasks a pediatrician has during the visit. When undertaking ASD screening, the pediatrician has the opportunity to discuss the parents’ concerns about their child, talk about the child’s strengths and weaknesses, and consider future steps.When discussing ASD screening, a physician may discuss the following:
- There is a high prevalence of developmental problems in infants and young children. 1 in 6 children ages 3-17 have some type of developmental “issue” (this includes everything from mild speech problems to more significant disorders like ASD and Intellectual Disability).
- If a developmental concern should be found, there are many potential interventions.
- Intervening earlier in a child’s developmental course can lead to improved outcomes.
- Screening involves using a standardized tool to identify and describe a child’s risk for developmental delay (in this case, ASD).
- Screening for ASD is done routinely at the 18- and 24- month visits, or when any concerns are raised during surveillance.
- Screening is not diagnostic. A positive screening test identifies a child at higher risk than one with a negative screen, but does not provide a diagnosis. Further diagnostic evaluation is warranted.
Responding to parents
How would you respond to the parents attributing Matthew’s language delay to being raised in a bilingual household?
At 18 months, you expect a child to say at least several words, and some children say many more.
Growing up in a bilingual household should not be used as a reason to explain away a child’s speech or language delay. Sometimes, initially, children may have a short-lived delay in expressive language, but their receptive language should not be affected by being spoken to in two different languages. The delay in expressive language should be no more than 1-2 months. It is important when assessing a child’s speech to count words in both languages to come up with the total number of words that a child is speaking.