Normal child development, hearing and vision

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Normal child development, hearing and vision

Children acquire functional skills throughout childhood. The term ‘child development’ is used to describe the skills acquired by children between birth and about 5 years of age, during which there are rapid gains in mobility, speech and language, communication and independence skills. During school age, evidence of developmental progression is predominantly through cognitive development and abstract thinking, although there is also some further maturation of early developmental skills.

Normal development in the first few years of life is monitored:

The main objective of assessing a young child’s development is the early detection of delayed or abnormal development in order to:

This chapter covers normal development. Delayed or abnormal development and the child with special needs are considered in Chapter 4.

Influence of heredity and environment

A child’s development represents the interaction of heredity and the environment on the developing brain. Heredity determines the potential of the child, while the environment influences the extent to which that potential is achieved. For optimal development, the environment has to meet the child’s physical and psychological needs (Fig. 3.1). These vary with age and stage of development:

Fields of development

There are four fields of developmental skills to consider whenever a young child is seen (Fig. 3.2):

Gross motor skills are the most obvious initial area of developmental progress. As fine motor skills require good vision, these are grouped together; similarly, normal speech and language development depends on reasonable hearing and so these are also considered together. Social, emotional and behavioural skills are a spectrum of psychological development.

The acquisition of developmental abilities for each skill field follows a remarkably constant pattern between children, but may vary in rate. It is like a sequential story. Thus, the normal pattern for acquisition of skills:

A deficiency in any one skill area can have an impact on other areas. For instance, a hearing impairment may affect a child’s language, social and communication skills and behaviour. As a child grows, additional skills become important, such as attention and concentration and how an individual child manages to integrate their skills.

Developmental milestones

Chronological age, physical growth and developmental skills usually evolve hand in hand. Just as there are normal ranges for changes in body size with age, so there are ranges over which new skills are acquired. Important developmental stages are called developmental milestones.

When considering developmental milestones:

Median and limit ages

The difference between median and limit ages is shown by considering the age range for the developmental milestone of walking unsupported. The percentage of children who take their first steps unsupported is:

The median age is 12 months and is a guide to the common pattern to expect, although the age range is wide. The limit age is 18 months (2 SDs from the mean). Of those not achieving the limit age, many will be normal late walkers, but a proportion will have an underlying problem, such as cerebral palsy, a primary muscle disorder or global developmental delay. A few may be understimulated from social deprivation. Hence, any child who is not walking by 18 months should be assessed and examined. Thus, 18 months can be set as a ‘limit age’ for children not walking. Setting the limit age earlier may allow earlier identification of problems, but will also increase the number of children labelled as ‘delayed’ who are in fact normal.

Variation in the pattern of development

There is variation in the pattern of development between children. Taking motor development as an example, normal motor development is the progression from immobility to walking, but not all children do so in the same way. While most achieve mobility by crawling (83%), some bottom-shuffle and others crawl with their abdomen on the floor, so-called commando crawling (creeping) (Fig. 3.3). A very few just stand up and walk. The locomotor pattern (crawling, creeping, shuffling, just standing up) determines the age of sitting, standing and walking.

The limit age of 18 months for walking applies predominantly to children who have had crawling as their early mobility pattern. Children who bottom-shuffle or commando crawl tend to walk later than crawlers, so that within those not walking at 18 months there will be some children who demonstrate a locomotor variant pattern, with their developmental progress still being normal. For example, of children who become mobile by bottom-shuffling, 50% will walk independently by 18 months and 97.5% by 27 months of age, with even later ages for those who initially commando crawl.

Is development normal?

When evaluating a child’s developmental progress and considering whether it is normal or not:

This will enable you to decide if the child’s developmental progress is normal or delayed. Normal development implies steady progress in all four developmental fields with acquisition of skills occurring before limit ages are reached. If there is developmental delay, does it affect all four developmental fields (global delay), or one or more developmental field only (specific developmental delay)? As children grow older and acquire further skills, it becomes easier to make a more accurate assessment of their abilities and developmental status.

Pattern of child development

This is shown pictorially for each field of development, including key developmental milestones and limit ages:

• Gross motor development (Fig. 3.4 and Table 3.1)

Table 3.1

The primitive reflexes present at birth gradually disappear as postural reflexes develop, which are essential for independent sitting and walking

Primitive reflexes Postural reflexes
Moro – sudden extension of the head causes symmetrical extension, then flexion of the arms
Grasp – flexion of fingers when an object is placed in the palm
Rooting – head turns to the stimulus when touched near the mouth
Stepping response. – stepping movements when held vertically and dorsum of feet touch a surface
Asymmetrical tonic neck reflex. – lying supine, the infant adopts an outstretched arm to the side to which the head is turned
Labyrinthine righting. – head moves in opposite direction to which the body is tilted
Postural support. – when held upright, legs take weight and may push up (bounce)
Lateral propping. – in sitting, the arm extends on the side to which the child falls as a saving mechanism
Parachute – when suspended face down, the arms extend as though to save themself
 

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• Vision and fine motor (Fig. 3.5)

• Hearing, speech and language (Fig. 3.6)

• Social, emotional and behavioural (Fig. 3.7).

In order to screen a young child’s development, it is necessary to know only a limited number of key developmental milestones and their limit ages.