In a study released in February 2006, the United States Preventive Services Task Force20 concluded that the evidence is insufficient to recommend for or against routine use of brief, formal screening instruments in primary care to detect speech and language delay in children up to 5 years of age. The Canadian Guide to Clinical Preventive Health Care21 recommended against screening with the Denver Developmental Screening Test and stated evidence was insufficient to support either the inclusion or exclusion of other screening tools. No studies have randomized children to screening versus no screening with contemporary screening tools.
Developmental screening is reliable
Screening tests can identify children with developmental delay with reasonable accuracy, and, as noted, such children may benefit from early intervention.
Developmental screening instruments fall into 1 of 2 categories: those that require the direct elicitation of developmental skills from children in conjunction with parental report, and those that rely solely on parental report.
Researchers in developmental screening regard a sensitivity of 70% to 80% as acceptable.22 Though this sensitivity is relatively low compared with other common screens used in medicine, it is in part unavoidable given the brevity of screens and the dynamic nature of child development. No screening tests have been shown to maintain sensitivity much greater than this without an unacceptable trade-off in specificity.
The specificity for a good developmental screen should also be in the range of 70% to 80%, ideally closer to 80%.22 Though this relatively low specificity will result in false-positive results, research has questioned whether this is problematic. Glascoe, in a study23 involving a geographically representative sample of 512 children, found that though false positives on validated screening instruments did not reflect disabilities, these children nevertheless scored substantially lower than peers in intelligence, language, and academic achievement—the 3 best predictors for school success. Thus, many children who do not qualify for special educational services on subsequent testing may still have substantial risk factors for academic failure and may benefit from other services such as Head Start, Title 1 services, private speech-language therapy, and quality day care.
Suitable tests convenient for a busy office practice
The following 2 screening instruments rely on parental input. Research has shown that parental questioning is a valid means of screening for developmental delays, and that standardized instruments have a sensitivity and specificity similar to that of screens that require direct elicitation of a child’s skills, such as the Brigance and the BDSI (discussed later).24
PEDS
PEDS (Parents’ Evaluation of Developmental Status) consists of 2 open-ended questions and 8 yes/no questions. It is written at a fifth-grade reading level and takes approximately 5 minutes to administer if an interview is needed—and even less time if parents can complete it independently. It need not be administered by a professional, and can be completed by a parent while waiting to see the doctor or even at home before a well-child visit.
PEDS was published in 1997 as a developmental screen entirely dependent on one kind of parental report—their concerns. The instrument was standardized and validated with 771 children representative of the 1996 US Census.25 Twenty-five percent of the children used in standardization lived in poverty, 30% had unmarried parents. This questionnaire has a sensitivity of 74% to 79% and a specificity of 70% to 80% across ages 0 to 8 years in the detection of developmental delays and behavioral problems. It maintains its psychometric properties across various levels of parental education, socioeconomic status, and child-rearing experience.26 The sensitivity and specificity for all ages combined was 75% and 74%, respectively.
Validity was determined through comparison with a battery of tests including the Woodcock-Johnson Psychoeducational Battery: Tests of Achievement, Stanford-Binet Intelligence Scale, and the Bayley Scales of Infant Development–II.
Scoring stratifies risk as low, medium, and high. Children at high risk require referral for more comprehensive assessment; validity studies found approximately 70% to possess disabilities or substantial delays on further evaluation. Children at intermediate risk require further screening, as approximately 30% were found to have disabilities or substantial delays on in validation studies.25
The Ages and Stages Questionnaires
The Age and Stages Questionnaire (ASQ) system (formerly known as the Infant Monitoring Questionnaires) was developed by Bricker, Squires, and colleagues at the University of Oregon.27 It is a low-cost and easily administered screening instrument relying on parental report.28 Items are written at a fourth- to sixth-grade reading level; illustrations and examples are often provided. This self-administered assessment can be completed in 10 to 20 minutes and scored in 1 to 5 minutes.