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Chapter 5Developmental 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.


Causes of Developmental Differences (continued)

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



• 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.



• 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



• 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.



• 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.



• 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.



• 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.



• Prenatal infections and intoxicants (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.



• Prenatal infections and intoxicants (continued)– Alcohol and other drugs have been proven to

lead to birth defects such as fetal alcohol syndrome and fetal alcohol effect.



• 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.



• 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.



• 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


Classification of Developmental 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.

Education

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