Denver Developmental Screening Test

The Denver Developmental Screening Test© (DDST) is a widely used assessment for examining the developmental progress of children from birth until the age of six devised in 1969. There were concerns raised from that time about specific items in the test, and coupled with changing normal values, it was decided that a major revision of the test was necessary in 1992.¹
It was originally designed at the University of Colorado Medical Center, Denver USA.

Developmental delay occurs in up to 15% of children under 5 years of age.² This includes delays in speech and language development, motor development, social-emotional development, and cognitive development.

• It is has been estimated that only about half of the children with developmental problems are detected before they begin school.³
• Parents are usually the first to pick up signs of possible developmental delay, and any concerns parents have about their child's development should always be taken seriously. However, the absence of parental concern does not necessarily mean that all is well.
• Parental recall of their child's developmental milestones has been demonstrated in a number of studies to be inaccurate, but it is generally more accurate when milestones are significantly delayed.⁴

The main purpose of developmental assessment depends on the age of the child:

• Tests may detect neurological problems such as cerebral palsy in the neonate.
• Tests may reassure parents or detect problems in early infancy.
• Testing in late childhood can help detect academic and social problems early enough to minimise possible negative consequences.(Although parental concern may be just as good a predictor for some problems.⁵)

The move to targeted examinations at ages 2 and 3.5 years, rather than routine, has raised concerns that some conditions e.g. pervasive developmental disorder may be missed.⁶
No developmental screening tool can allow for the dynamic nature of child development. A child's performance on one particular day is influenced by many factors. Development is not a linear process - it is characterised by spurts, plateaus and, sometimes regressions. Gradually screening has been replaced by the concept of developmental surveillance.⁷ This is a much broader concept. It involves parents, allows for context and should be a flexible, continuous process.

Test design

The test consists of up to 125 items, divided into four parts:

• Social/personal: aspects of socialisation inside and outside the home
• Fine motor function: eye/hand co-ordination, and manipulation of small objects
• Language: production of sounds, ability to recognise, understand, and use of language
• Gross motor functions: motor control, sitting, walking, jumping, and other movements

Application

• No special training is required.
• The test takes approximately 20 minutes to administer and interpret.
• There may be some variation in time taken, depending on both the age and co-operation of the child.
• Interviews can be performed by almost anyone who works with children and medical professionals.
• The 125 items are recorded through direct observations of the child plus for some points, the mother reports whether the child is capable of performing a given task.
• Younger infants can sit on their mother's lap.
• The test should be given slowly.

Interpretation of the test

• The data are presented as age norms, similar to a growth curve.
• Draw a vertical line at the child's chronological age on the charts; if the infant was premature, subtract the months premature from chronological age.
• The more items a child fails to perform (passed by 90% of his/her peers), the more likely the child manifests a significant developmental deviation that warrants further evaluation

Concerns should prompt referral to a general or developmental paediatrician.

• Most paediatricians would prefer to see children early rather than late.
• If development appears normal, then reassuring anxious parents is always rewarding. On the other hand if there is developmental delay, intervention at the earliest possible time can make a significant difference to outcome.⁸

Sensitivity rates are reported between 56-83% for the Denver II©, but specificity may be as low as 43%, rising to 80%.⁹ There is a danger of unnecessary referral.
However, research has shown that children over-referred (false positives) because of developmental screens perform substantially lower on measures of intelligence, language, and academic achievement - the 3 best predictors of school success - than children with true negative scores. These children may also carry more psychosocial risk factors, such as limited parental education and minority status. Thus, children with false-positive screening results are an at-risk group for whom diagnostic testing may not be an unnecessary expense, but can serve as a sign post to focus necessary interventions e.g. Head Start programmes - intensive, supported nursery places.¹⁰

• It enables the tester to compare a child's development with that of over 2,000 children who were in the standardised population, like a growth curve.
• It consists of items in which a sub-sample (race, less educated parents, gender and place of residence) which varied a clinically significant amount from the composite sample, are identified and their norms are provided in the Denver II© Technical Manual.
• It provides a broad variety of standardised items to give a quick over-view of the child's development.
• It also contains a behaviour rating scale.

These include:

• Bell
• Glass bottle
• Set of 10 blocks
• Rattle
• Pencil
• Tennis ball
• Wool
• Raisins
• Bag with zip top
• Cup
• Doll
• Baby bottle
• Interpretation card

• When prone lifts head up, using forearm support (with or without hands).
• Throws balls overhand 3 feet to within your reach.
• Bounce a ball. He must catch it. Allow up to three tries.
• Child grasps raisin between thumb and index finger
• "Copy this" (circle). Do not name or demonstrate
• "Give the block to Mum". "Put it on the table". No gestures
• Answer 3/3: "What is a spoon/shoe/door made of?" (no others).
• While he plays with a toy, pull it away. Pass if he resists.