Chapter05 allen7e

©2012 Cengage Learning.
All Rights Reserved.
Chapter 5
Developmental Disabilities: Causes and
Classifications

Causes of Developmental Differences
• Biological factors
– Biological insult refers to interference with or
damage to an individual’s physical structure
or functioning.
– Genetic disorders resulting in abnormal
biological development may be caused by
deviations in chromosomal structure or by
abnormal single genes.

(continued)
– Chromosomal abnormalities are usually
biological accidents; that is, they are one-time
occurrences and do not affect future
pregnancies.

(continued)
• Down Syndrome
– This condition is caused by three number 21
chromosomes.
– It is recognizable by a flat face, upturned
eyes, small ears, short stature, and the simian
crease.
– Heart and intestinal abnormalities are
common.

(continued)
• Fragile X Syndrome
– Caused by a break on the X chromosome
present in males
– Sex-linked disorder given to sons by their
mothers
– Characterized by large ears, language delays,
autism-like behaviors, hyperactivity, and
delayed motor development

(continued)
• Metabolic disorders
– These cause a breakdown somewhere in the
complex chemical activities needed to
metabolize food.
– The breakdown can destroy, damage, or alter
cells.
– Metabolic disorders are single-gene defects,
such as PKU.

(continued)
• Abnormal gene disorders
– Tay-Sachs, an accumulation of fatty tissues
around the brain that eventually leads to
death.
– Cystic fibrosis, a buildup of mucus in the
lungs, which makes it difficult to breathe.
– Breakthrough medical treatments are now
helping these individuals live longer and more
productive lives.

(continued)
• Abnormal gene disorders (continued)
– Sickle-cell anemia, the red blood cells are not
formed correctly, making it difficult to navigate
the bloodstream. It is often accompanied by
joint pain and ulcers.
– Duchenne muscular distrophy, present in
males where the muscles deteriorate.

(continued)
• Prenatal infections and intoxicants
– Rubella—can lead to devastating lifelong and
severe disabilities.
– CMV—at birth these children appear normal.
Later in life, they develop mental retardation,
deafness, and diseases of the eye.
– Herpes simplex—results in inflammation of
the brain and spinal cord.

(continued)
(continued)
– AIDS—passed to the unborn child through the
birth canal or breast milk—leaves a child’s
immune system helpless to fight off disease.
– Diabetes—maternal diabetes can leave
devastating effects on the child.
– Toxemia—women who experience toxemia
often deliver the baby prematurely, leading to
later complications.

(continued)
(continued)
– Alcohol and other drugs have been proven to
lead to birth defects such as fetal alcohol
syndrome and fetal alcohol effect.

(continued)
• Maternal malnutrition and protein
deficiency
– Lack of protein during the first trimester can
lead to immature development of the brain
and nervous system.
– It can also lead to small babies that are born
prematurely.

(continued)
• Birth complications
– Lack of oxygen to the brain—anoxia can
occur.
– Premature babies can suffer hemorrhaging.
– C-sections may need to be performed if the
life of the mother or infant is in danger.

(continued)
• Complications following birth
– Meningitis—a virus or bacterial infection that
causes inflammation of the protective
covering of the brain and the spinal column—
can lead to brain damage.
– Encephalitis—swelling of the brain—can also
lead to brain damage.
– Lead poisoning—poisoning from lead found in
lead-based paint and older homes.

Poverty
• Nutritional deficiency
– Children living in poverty have inadequate
nutrition.
– WIC was designed to eliminate some of the
counter effects of poverty.
– WIC provides funds to pregnant mothers and
then their newborn to purchase healthy foods.

Poverty (continued)
• Inadequate health care and education
– Living in poverty, many women do not seek
out prenatal care, leaving themselves open
for premature labor and other complications.
– Regular medical checkups are also good for
the newborn child.
– Without health insurance, good care is not
always possible, so immunizations fall behind.

Poverty (continued)
• Homelessness and substandard housing
– Living in these conditions can cause health
problems by being exposed to contaminants
in the environment.
• Single-Parent Families
– Single mothers in particular tend to work
multiple jobs, leaving their children
unattended or with little supervision.

Poverty (continued)
• Child Care
– Quality child care can combat the effects of
poverty, but people living in poverty cannot
often afford quality.
– Centers need to offer the best with what they
have, making quality available to all.

Poverty (continued)
• Combating poverty
– Early intervention and care can eliminate
some of the effects of poverty and give
children the chance to be successful in life.

Classification of Developmental
Disabilities
• To receive funding, children must be
categorized. The following are categories
approved by the federal government:
– Specific learning disabilities, having a deficit
between IQ and ability
– Speech and language disorders, having
difficulty with receptive or expressive
language

Disabilities (continued)
– Mental retardation—IQ is 70 or below, and
there are significant delays in other areas of
development as well.
– Emotional disorders—children have difficulty
controlling behavior and reading emotional
cues.
– Multiple disabilities—a combination of one or
more disabilities.

– Hearing loss—a hearing loss so severe that
individuals cannot process spoken language,
even with hearing aids or other forms of
amplification.
– Orthopedic impairments—a child has limited
use of the limbs.
– Health impairments—the child has difficulty
maintaining developmental milestones due to
health problems.

– Visual impairments—the children’s vision is
so poor that they cannot use that sense to
learn from their environment.
– Combined vision and hearing loss—a child
has loss of both vision and hearing and incurs
learning difficulties form them.
– Autism—a child retreats into “his or her own
world,” language often stops, and the child
begins to turn inward.

– Traumatic brain injury—this category of
injuries (either open- or closed-wound) to the
head cause tearing of the nerve fibers,
bruising of the brain against the skull, or
bruising of the brain stem.

Chapter05 allen7e

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