Employment, Social Affairs & Inclusion

Screening for language delay in toddlers

Evidence level:
Evidence of effectiveness:
? - 0 + ++
? - 0 + ++
Enduring impact:
? - 0 +

Project overview

This National Department of Health screening program in the Netherlands applied a diagnostic questionnaire (the VroegTijdige Onderkenning Ontwikkelingsstoornissen Language Screening instrument; VTO) for language delays to parents and their toddlers aged 15-18 months and again at 24 months. Children with positive screening indications were sent to speech and hearing centres for further assessment. The speech and hearing centres then referred children to standard early treatment services as necessary.  55 child health centres in six geographic regions participated. The child health centres provide free services from the Department of Health and are available to all Dutch children.

Practice Category

  • Helping Vulnerable Children

Recommendation pillars

  • Improve the responsiveness of health systems to address the needs of disadvantaged children

Countries that have implemented practice

  • Netherlands

Age groups

  • Young Children (age 0 to 5)
  • Middle Childhood (age 6 to 12)

Years in operation

  • 1995  - 1996

The VroegTijdige Onderkenning Ontwikkelingsstoornissen screening tool is still available but is not in use at the national level.

Scope of practice

  • National level

Rationale of practice

Not available

Type of organisation implementing practice

  • National Government

Mode of delivery

  • Diagnostic questionnaires
  • Face-to-face

Delivery dosage

Not available

Location of practice

  • Institutionalised

Evidence of effectiveness

Van  Agt, H., van der Stege, H., de Ridder-Sluiter, H., & Verhoeven, L.,(2007.) A Cluster-Randomized Trial of Screening for Language Delay in Toddlers: Effects on School Performance and Language Development at Age 8. Pediatrics, 120; 1317.

In this study, authors assessed the screening program’s impact on a range of academic outcomes. The study authors randomly assigned child health centre physicians to apply the VTO instrument or to give normal developmental diagnosis procedures.  In all, 9419 Dutch children aged 15-24 months were assigned to the treatment and control groups.  Assessment of academic outcomes occurred when the children were age 8 via school assignment, grade 2 testing and teacher evaluation.

Summary of Results for Evaluation 1


Treatment Group

Control Group

Outcomes improved (statistically significant p<0.1)

Per cent of children

Per cent of children

Attending special school

Below 10th percentile of spelling in grade 2

Teacher assessment of normal development







Outcomes with no effect



Repeating a grade

Repeating a grade due to language problems*

Below 10th percentile of oral language

Below 10th percentile reading tests in grade 2










This particular screening intervention has not been replicated or studied in other locations, although other language-related screening tools have been used and studied elsewhere.

Practice Materials

  • Practice materials are not available 

Cost information

  • Implementation cost information is not available

Enduring impact

Van Agt et al., 2007 examined the effects of using the VTO screening tool on children in the Netherlands six years after the screening process occurred.  They found positive impacts: fewer children in the screening group attended special schools, fewer children in the screening group scored below the 10th percentile in spelling in grade 2, and fewer of the children’s teachers thought they would not develop normally in the future.  They also found no statistically significant negative outcomes.

Evaluation details

The study authors recruited physicians serving children between 15 and 24 months old from 55 child health centres in six geographic regions of the Netherlands.   Physicians were randomized to using the VTO screening tool as a language diagnostic intervention, or to the control group using standard developmental diagnosis procedures.  The final sample sizes were 3118 children in the intervention group and 2288 children in the control group.  Before the start of screening, there was no difference in the percentage of reported language-related treatments between the control and treatment groups.  The VTO screening process included two five minute interviews between the physician and the child’s parents, one when the child was between 15 and 18 months and the other at age 24 months.

Data was collected via a parent survey, standardized assessment tests given to the children at age 8 and a teacher survey.  Outcomes of interest at age 8 included whether the child was attending a special school, the child’s grade level, scores on standardized tests, teacher predictions of future performance, and the number of instances of language development treatment for the child as reported by the parent.  The study authors conducted intent-to-treat analysis and effect-of-treatment-on-the-treated analysis, reporting the intent-to-treat results as the main outcomes of the study.

Issue to consider

While the VTO screening was shown to lead to fewer children in the intervention group attending special schools, fewer children scoring poorly in spelling and fewer teachers reporting a concern for a child’s future normal development, it had no effect on oral language or reading skills. Additionally, sociodemographic and other information about the children was collected at the age 8 follow-up rather than at baseline, so it is impossible to analyse the characteristics of study drop-outs. In analysis of only children who received the complete, multi-stage VTO screening, the authors found that the full screening led to highly significantly fewer (p<0.01) children in special schools and scoring poorly on oral language tests, but the other results lost significance. This suggests that incomplete VTO screening could be only partially more effective at identifying children with language delays than standard diagnosis procedures. It also may indicate that the services received by the children who had been identified by the VTO screening might not be sufficient to help them reach normal language levels in all assessment categories.

Available resources

Not available


  • van Agt, H., van der Stege, H., de Ridder-Sluiter, H., & Verhoeven, L.,(2007.) A Cluster-Randomized Trial of Screening for Language Delay in Toddlers: Effects on School Performance and Language Development at Age 8. Pediatrics, 120; 1317.

Last updated

December 2018

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