- Developmental delay is a descriptive term, not a specific diagnosis, comprising many disorders and encompassing a broad category of etiologies.
- The term describes any situation where a child is not meeting age-appropriate milestones as expected in one or more streams of development. These streams of development include gross motor, fine motor, receptive and expressive language, adaptive, and social (Appendix, Table 1).
- The key feature is that the rate of progress has been slow over time in the area(s) of delay.
- Children with behavioral problems may also be masking developmental delays.
- Children with delays in one stream of development may also have delays in other areas of development. For example, language delay may be an indication of general cognitive delays.
- Hearing impairment may present as a delay in development.
Found in both sexes and all racial and socioeconomic groups
This is a heterogeneous group of disorders with different prevalence rates.
There is no known prevention of developmental delays, although prevention of some of the underlying causes is possible.
- This is highly variable depending on etiology, which can include genetic, familial, metabolic, infectious, endocrinologic, traumatic, anatomic brain malformations, environmental toxins, and degenerative disorders as causes. These disorders often result in some neurologic or neuromuscular injury causing the delay. In many cases, the etiology is never determined.
- Prevalence of this group of disorders may vary depending on the inclusiveness of the definition. The milder delays are quite common and can be found in any pediatric practice. Some disorders in this grouping are more prevalent in boys. The long-term outcome depends on the severity and type of delay, with the more involved children usually having lifelong disability.
Specific etiologies are too numerous to list completely, but a partial list of the more common causes includes the following:
- Fragile X syndrome
- Trisomy 21 (Down syndrome)
- Other chromosomal abnormalities
- Tuberous sclerosis
- Muscular dystrophy
- Nervous system anomalies
- Spina bifida
- Prenatal cytomegalovirus
- Postnatal bacterial meningitis
- Neonatal herpes simplex
- Congenital hypothyroidism
- Heavy metal poisoning such as lead
- In utero drug or alcohol exposure
- Closed head trauma
- Perinatal cerebral hemorrhages
- There are numerous associated findings including seizures, sensory impairments, feeding disorders, psychiatric disorders (especially depression), and behavioral disorders.
- Having a child with significant developmental delays can also add stress to the family in terms of time, finances, and emotions.
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