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Daisuke Akiba
HIGH RISK INFANTS
A developmental delay is diagnosed when a child
does not reach a developmental milestone (for exam-
ple, sitting, walking, or combining words) at the ex-
pected age, despite allowing for individual variation
in the rate of development. Each year, many children
are born at increased risk of a developmental disabili-
ty or delay. Infant and preschooler development is a
complex, dynamic process that begins at birth and
evolves as infants interact with their caregivers and
environment. Approximately 10 percent of infants
will reflect developmental delay.
The key to intervention and rehabilitation lies in
identifying those infants at significant risk of develop-
mental disability. However, early identification re-
mains difficult. The normal variation in development
among children is broad. Also, development must be
monitored in several areas (motor, cognitive, psycho-
social) simultaneously, and it can be easy to overlook
a small delay in only one area. Parents and pediatri-
cians may be reluctant to discuss their fears that a
child may have a developmental delay. Lastly, the age
at which developmental difficulties manifest, often
depends on the developmental stage of the child. It
is common for hyperactivity, language delays, and
emotional disorders to be diagnosed at about three to
four years of age. However, learning disabilities and
mild mental retardation are frequently not diagnosed
until a child enters school. Assessment of develop-
mental risk includes medical and social history, physi-
cal examination, and developmental observation of
the child. Often developmental surveillance tools,
such as standardized tests that screen several or all
areas of development, are used to help identify the
child with delay.
Not all children with developmental disability
have known risk factors at birth and many times the
cause of delay is not known. An infant with an estab-
lished risk typically has a diagnosed medical condi-
tion known to be associated with a high probability of
developmental disability. Examples of conditions
with established risk are chromosomal abnormalities
(such as Trisomy 21), sensory impairments (such as vi-
sual or hearing impairment), and neurological de-
fects.Risk Factors
There are many influences that can affect devel-
opment. These influences are termed risk factors and
are often divided into biological risk and environ-
mental risk. However, it is recognized that there is
often significant overlap and influence between the
two categories. Biological and environmental stresses
are interactive and together have an additive effect on
developmental outcome. Therefore, infants with mul-
tiple risk factors typically have a greater risk of dis-
ability than infants with single risk factors.
Biological risk factors tend to be associated with
more severe developmental disability, mental retar-
dation, and multiple handicaps. Included in this cate-
gory are prenatal influences such as chromosomal
disorders, congenital infections, congenital malfor-
mations (both of the brain or other organs), and intra-
uterine growth retardation. Maternal substance abuse
during the pregnancy is also a significant prenatal,
and often ongoing, risk factor. Then there are the
perinatal (around birth) influences on development.
Infants born prematurely are at increased risk of de-186 HIGH RISK INFANTS