Development is a broad term that encompasses a great number of progressive achievements and abilities. For a child to develop normally they must attain physical milestones like sitting and walking. They must acquire the expression and the comprehension of language. They must be able to retain old knowledge and use it as the foundation for new knowledge. They must learn to relate effectively to the people and the environment around them. Development is a global process where no domain exists in isolation of another. It is rare to find a task that relies solely on one skill which is why if one area is lagging or dysfunctional, the entire process of development is compromised. When these areas of cognition or function are delayed, an individual may be said to be experiencing a developmental delay.
Developmental delay refers to a pervasive problem that affects one or more areas of a child’s development. It usually takes time to make a clear diagnosis to be sure that the delay is not temporary or due to a treatable condition. Development in children is measured against the usual timeline for certain skills and abilities to appear; these benchmarks are known as developmental milestones and are achieved within a period of time defined as normal. It cannot be expected that every child will progress at the same rate, but there needs to be an age-range that allows parents or professionals to differentiate between children who are slightly behind and those who require attention and intervention.
Because children do not acquire language immediately and cannot be tested for cognitive ability, developmental milestones can be recognized as physical accomplishments such as crawling, sitting without support and standing unassisted. Also, there are speech and language milestones such as monosyllabic and polysyllabic babbling, recognizing common words and combining words and gestures. If these milestones are achieved only slightly later than reasonably expected, the child may catch up eventually and suffer no academic consequences. However, late development and ongoing problems may also indicate a more severe form of developmental delay which can have a limited or overall effect on a child’s life.
Children with developmental delay do not fail to develop – they just develop at a slower rate than most children of the same age. The progressions still occur and milestones can be eventually reached. Development ceases for all people at a certain stage but the end point for developmentally delayed adults tends to arrive before they have acquired enough skills to allow them to function without impairment. The prognosis for children with developmental delay depends entirely on the severity of their symptoms and has no conclusive or single cause. Some types of developmental problems are inherited and can be predicted or tested such as in the case of Down’s syndrome or dyslexia. Most developmental problems are suspected or found to occur in the critical period of a child’s growth before, during, or soon after birth, either because of infection, nutritional issues, exposure to toxins or a variety of other disruptions or abnormalities.
Children with developmental delay commonly display unusually extreme reactions to neutral stimuli (e.g.. withdrawing from soft touch) or unusually unresponsive reactions to painful stimuli (e.g.. not reacting to a very loud noise). This reflects a problem with sensory integration, the way sensory information is interpreted by the brain. Any neurological problem such as developmental delay can impact the acquisition of language and the ability to communicate effectively, and learning difficulties may become apparent when the child begins to attend school.
Global delay is used to describe the condition of a child who suffers impairments in all developmental domains. Motor delay may be characterized by clumsiness, poor balance and coordination, inability to manipulate objects and poor gross and fine motor skills. Language disorders may be evident through the child’s inability to use and deliver language signals at the expected age, and this may progress into poor reading and language comprehension and limited vocabulary.