Development is a continuous process that begins at conception and progresses stage by stage in a sequential manner. There are specific milestones within each of the six areas of development — cognitive skills, gross motor skills, fine motor skills, language skills, social skills, and self-help skills — that must be achieved before moving on to the next stage. Children are expected to achieve one skill at a time, and the timing of each milestone is measured in weeks, months, or years.
Infants with Down syndrome may experience delays in certain developmental stages due to the challenges associated with the condition. This means they will achieve all developmental milestones just as other children do, but on their own individual timelines. For this reason, when monitoring the development of a child with Down syndrome, it is more meaningful to focus on the milestones achieved rather than the age at which they were achieved.
Developmental Milestones Comparison
| Skill | Children with Down Syndrome | Typical Development |
|---|---|---|
| Gross Motor Skills | ||
| Sits independently | 6 – 30 months | 5 – 9 months |
| Crawls | 8 – 22 months | 6 – 12 months |
| Stands | 1 – 3.25 years | 8 – 17 months |
| Walks independently | 1 – 4 years | 9 – 18 months |
| Language | ||
| Single-word sentence | 1 – 4 years | 1 – 3 years |
| Two-word sentence | 2 – 7.5 years | 15 – 32 months |
| Social Development and Self-Help Skills | ||
| Responsive smile | 1.5 – 5 months | 1 – 3 months |
| Finger feeding | 10 – 24 months | 7 – 14 months |
| Drinks from cup unassisted | 12 – 32 months | 9 – 17 months |
| Uses a spoon | 13 – 39 months | 12 – 20 months |
| Bladder and bowel control | 2 – 7 years | 16 – 42 months |
| Dresses without assistance | 3.5 – 8.5 years | 3.25 – 5 years |
Source: The information in this article has been reproduced under an exclusive agreement with the National Down Syndrome Society. Available at: ndss.org
