Child development is exciting. In the first year children change from individuals in flexed, fetal positions who are entirely dependent, into people who are mobile, inquisitive, exploratory and able to partly modify their environment to meet their demands. A knowledge of normal developmental patterns will allow the doctor to recognise those patterns which are a variation on the normal or within the normal range so that guidance about child management and accident prevention can be given. For example, a nine month old child will be starting to crawl and will be beginning to develop finger-thumb grip.
This will enable the infant to pick up small objects. At this age all objects will still be automatically tested by putting them into the mouth. In addition, there will be interest in exploring the environment with this new-found mobility, so that the danger of accidents significantly increases.
A developmental assessment shows how far the infant has progressed in relation to average developmental milestones for children of that age. If development is uniformly slow, then the child has a developmental age which is behind his or her chronological age. If other confounding factors such as prematurity, illness, prolonged hospitalisation, environmental or emotional deprivation are not present, one may predict that the child is likely to have continuing developmental delay.
It is much more difficult to make predictions of high intelligence on advanced developmental milestones. Advanced gross motor milestones have little useful correlation with high intelligence, and while early speech development shows some correlation, it is extremely difficult, and probably of little value, to forecast high intelligence in an individual case.
Specific delays in some areas with normal development in other areas raise the question of isolated defects. For example, delayed speech in a child who is normal in other milestones suggests a hearing loss. Delayed motor development with normal social relationships and speech suggests a neuromuscular disorder.
There are many factors which affect a child's development. If the child was premature, allowance has to be made. If birth was at 32 weeks gestation, eight weeks should be subtracted from the chronological age when assessing development. Environmental factors may also influence development. Emotionally deprived children, who receive little verbal stimulation or who do not have the opportunity to practise walking or crawling when they are ready to achieve these milestones will be delayed in their development.
Similarly, children from a stimulating environment, who receive good quality language stimulation and opportunities for a wide variety of play experiences may develop in advance of average milestones. Genetic factors also play a part so that family history and assessment of the development of the parents and siblings should also be considered.
Developmental milestones can be conveniently grouped into 4 main areas:
It is daunting to try to learn all of the developmental milestones but it is important to try to learn one or two in each of these four main categories at key ages. A summary of some of the main milestones is included here. It is important to remember that lists of when milestones are achieved represent the average of a range. Many normal children may be somewhat earlier, while others may be slower in reaching these milestones. However, the sequence in which the milestones are reached is usually the same.
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Oates, K. "What's Normal?" in, Child health: a practical manual for general practice, K Oates, K Currow and W Hu (editors) Maclennan and Petty, Sydney, 2001 pp 6-11
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Hu W, Currow K and Oates K "Is development normal?" in Child health: a practical manual for general practice, K Oates, K Currow and W Hu (eds) Maclennan and Petty, Sydney, 2001, pp66-80
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Developmental and behavioral pediatrics, 3rd Edition. M Levine W Carey and A Crocker, (eds) W B Sunders, Philadelphia, 1999
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The Cambridge encyclopedia of child development. B Hopkins (ed) Cambridge University Press, Cambridge, 2005