A developmental delay describes the behavior of young children whose development in moving, talking, or playing is slower than other children of the same age. The delay can be in any area(s) of development, such as movement (motor), speech, thinking, or self-care skills. About 10% of all toddlers and preschoolers in the United States are classified as having developmental delay. 

What is Developmental Delay?

The term "developmental delay" may be used to describe any type of delay dealing with motor, speech, or thinking abilities that may or may not result from a specific condition. A child with Down syndrome, for example, would be identified at birth as having the syndrome (or even before birth with prenatal tests) and also, as it becomes apparent, with having developmental delay in several areas, including motor, speech, and thinking skills. Similarly, a child with autism could be described as having autism and developmental delay, meaning that the child’s behaviors can be described as autistic, but the child also exhibits delays in developmental skills. Other children have developmental delay without having a specific diagnosis, or maybe just a motor developmental delay, where they're reaching movement milestones at a slower rate. 

Although all states provide early intervention services for children with developmental delay, each state individually defines “developmental delay” (see Resources). Thus, the term may mean different things to different people and can result in differing services to help a family with a child who has developmental delay.

Signs and Symptoms

If a child has developmental delay, he or she might play with toys for younger children or interact with people like a younger child. When children's motor skills are delayed, they might not run, skip, or jump with other children because they have not yet developed age-appropriate skills and cannot keep up with their peers.

Because the term is such a broad and general one, developmental delay often looks different from one child to the next.

In infancy, a child is first suspected to have developmental delay if common milestones are delayed, such as:

  • Holding the head steadily up by 4 months (symmetry is strong here - kiddo should be able to hold their head in midline) 
  • Unsupported sitting by about 6 months (normal range is 5-7 months)
  • Walking by about 12 months (normal range is 9-15 months)

A child who has a general lack of movement or does not move in a lot of different ways to explore movement, might have a motor developmental delay. Some infants with a motor developmental delay have hypotonia, or low muscle tone, which contributes to their movement difficulties.

Although delays in motor milestones often are the most obvious behavior that caregivers notice, other delays might be related to a child not moving. For example, learning about objects or producing speech sounds can be affected if a child does not learn to sit or change positions. In infancy, all developmental areas are closely connected and influence each other's progress.

Some children have sensory problems adding to movement difficulty, such as hypersensitivity to touch or an inability to plan and problem-solve movement activities. Children who have some or all of these problems also might develop social or emotional problems, such as a fear of trying new motor skills.

How Is It Diagnosed?

You first should talk to your pediatrician about any concerns you have regarding your child's development. Medical problems can have an impact on overall development that your doctor can identify, such as chronic ear infections that reduce hearing and affect the child’s speech development or balance.

Developmental delay is diagnosed by using tests designed to score a child's movement, communication, play, and other behaviors compared with those of other children of the same age. These tests are standardized, or scored on hundreds of children, in order to determine a normal range of scores for each age. If children score far below the average score for their age, they are at risk for developmental delay.

A pediatrician usually will perform a screening test during infancy to determine if a child is progressing normally, often at the request of a parent who suspects the child is not performing the same skills as other children of the same age. A screening test helps to identify which children would benefit from a more in-depth evaluation. A physical therapist, who has knowledge of movement development, coordination, and medical conditions, will perform an in-depth examination to determine if a child’s motor skills are delayed and, if so, by how much they are delayed.

How Can a Physical Therapist Help?

A physical therapist will first evaluate your child, including having a conversation with you and conducting an appropriate and detailed test to determine the child's specific strengths and weaknesses. If the child has motor developmental delay, the therapist will problem-solve with you about your family's routines and environment to find ways to enhance and build your child's developmental skills.

In addition to evaluating your child and the environment in which the child moves, the physical therapist can give detailed guidance on building motor skills 1 step at a time to reach established goals. The therapist may guide the child’s movements or provide cues to help the child learn a new way to move. For example, if a child is having a hard time learning to pull herself up to a standing position, the therapist might show the child how to lean forward and push off her feet; or if a child cannot balance while standing, the therapist may experiment with various means of support so the child can safely learn ways to stand.

The therapist will also teach the family what they can do to help the child practice skills during the child’s everyday activities. The most important influence on the child is the family, because they can make sure the child has the opportunities needed to achieve each new skill.

The therapist will explain how much practice is needed to help achieve a particular milestone. A child learning how to walk, for example, covers a lot of ground during the day, and the therapist can provide specific advice on the amount and type of activities appropriate for your child at his/her stage of development.

Can this be prevented?

Once developmental delay has been diagnosed, there are steps to take to prevent further delay or to help the child "catch up." However, because this diagnosis has so much variability, the outcomes of intervention vary quite a bit. The important thing to remember is that the earlier you intervene, the more likely it will be that your child can improve and not continue to fall behind.

TRUTH IS: Some babies are more prone to developmental (physical) delay. Babies who are larger, quite frankly, tend to develop their motor skills at a slower rate than do some of the smaller kiddos. Why? Because they have more load to lift, and when you're first learning how to lift a load, it's easier if it's lighter. How long would you see a delay like this? Not long. Up to a couple years, maybe. Most kiddos catch up with the other kids their age without a problem. 

CAUTION: Babies who have little or no active "tummy time" play may be prone to developmental delay. The American Academy of Pediatrics (AAP) has recommended that all infants sleep on their backs to reduce the incidence of sudden infant death syndrome (SIDS). As a precaution, many parents have avoided placing infants on their tummies altogether. However, research has shown that avoiding tummy time can slow the rate of accomplishment of motor-skill (movement) milestones. Evidence also indicates that infants who are kept in baby equipment (infant chairs, carriers, sling seats at activity centers) for long periods of time are at a higher risk of motor delays than infants who have sufficient opportunities for active movement.

AAP's new recommendation, "Back to Sleep, Tummy to Play" (see Resources), encourages parents to let a child be on the floor to play in many different positions. This allows the child to learn how to move, and stimulates the brain and muscles so that rolling, reaching, crawling, and eventually walking can be achieved. Experiencing lots of different positions allows children to experiment with their bodies and build new movements. And exploring new movements helps them learn to think differently, and may even stimulate speech and social skills.