When a developmental delay is recognized in a child, further testing can help a doctor find out whether the problem is related to autism, another pervasive developmental disorder (PDD), or a condition with similar symptoms, such as language delays or avoidant personality disorder. If your primary care provider does not have specific training or experience in developmental problems, he or she may refer your child to a specialist-such as a developmental pediatrician, a psychiatrist, a speech therapist, a psychologist, or a child psychiatrist-for the additional testing.
Behavioral assessments. Various guidelines and questionnaires are used to help a doctor determine the specific type of developmental delay a child has. These include:2
Medical history. During the medical history interview, a doctor asks general questions about a child's development, such as whether a child shows parents things by pointing to objects. Young children with autism often point to items they want, but do not point to show parents an item and then check to see if parents are looking at the item being pointed out.
Diagnostic guidelines for autism. The American Association of Childhood and Adolescent Psychiatry (AACAP) has established guidelines for diagnosing autism.2 The criteria are designed so a doctor can assess a child's behavior relating to core symptoms of autism.
Clinical observations. A doctor may want to observe the developmentally delayed child in different situations. The parents may be asked to interpret whether certain behaviors are usual for the child in those circumstances.
Developmental and intelligence tests. The AACAP also recommends that tests be given to evaluate whether a child's developmental delays affect his or her ability to think and make decisions.
Physical assessments and laboratory tests. Other tests may be used to determine whether a physical problem may be causing symptoms. These tests include:
Physical exam, including head circumference, weight, and height measurements, to determine whether the child has a normal growth pattern.
Hearing tests, to determine whether hearing problems may be causing developmental delays, especially those related to social skills and language use.
Testing for lead poisoning, especially if a condition called pica (in which a person craves substances that are not food, such as dirt or flecks of old paint) is present. Children with developmental delays usually continue putting items in their mouth after this stage has passed in normally developing children. This practice can result in lead poisoning, which should be identified and treated as soon as possible.
Other lab tests may be done under specific circumstances. These tests include:
Chromosomal analysis, which may be done if intellectual disability is present or there is a family history of intellectual disability. For example, fragile X syndrome, which causes a range of below-normal intelligence problems as well as autistic-like behaviors, can be identified with a chromosomal analysis.
An electroencephalograph (EEG), which is done if there are symptoms of seizures, such as a history of staring spells or if a person reverts to less mature behavior (developmental regression).
MRI, which may be done if there are signs of differences in the structure of the brain.
Early detection
All doctors who see infants and children for well-child visits should watch for early signs of developmental disorders. Developmental screening tools, such as the Ages and Stages Questionnaire or the Modified Checklist for Autism in Toddlers (M-CHAT), can help assess behavior.
If a doctor discovers the following obvious signs of developmental delays, the child should immediately be evaluated:5
No babbling, pointing, or other gestures by 12 months
No single words by 16 months
No 2-word spontaneous phrases by 24 months, with the exception of repeated phrases (echolalia)
Any loss of any language or social skills at any age
If there are no obvious signs of developmental delays or any unusual indications from the screening tests, most infants and children do not need further evaluation until the next well-child visit.
But children who have a sibling with autism should continue to be closely monitored, because they are at increased risk for autism and other developmental problems.
When socialization, learning, or behavior problems develop in a person at any time or at any age, he or she should also be evaluated.
