Global developmental delays are a subset of developmental disabilities defined as a significant delay in 2 or more of the following developmental domains;
- Gross/fine motor
- Hearing, speech/ language
- Activities of daily living.
GDD usually follows the usual pattern of development, but with a delay. According to DSM 5, Diagnosis of GDD is limited to children under 5 years of age. GDD is a common problem with wide etiology. A selective investigation is useful for finding the cause. Finding the exact cause is important for further rehabilitation.
Causes of GDD (adapted from Forsyth & Newton, 2007)
- Genetic or syndromic- eg; Down’s syndrome, fragile X syndrome
- Metabolic – eg; urea cycle disorder
- Traumatic- acquired brain injury
- Environmental causes- eg; poor stimulation at home
- Cerebral malformation – eg; neuronal migration disorder
- Cerebral palsy and developmental coordination disorder
- Infections – eg; perinatal rubella, CMV, Neonatal meningitis
- Toxins – eg; maternal alcohol in pregnancy, childhood lead toxicity
A comprehensive history and physical examination are the basic investigation procedures. Laboratory testings can be considered after conducting proper basic evaluations.
Recommended laboratory investigations are,
- Metabolic screening
- Cytogenic testing
- Fragile X testing
- Rest syndrome testing
- Thyroid screening
- Lead screening
- EEG evaluation
- Hearing and visual testing