1. Chapter 5 Developmental Disabilities: Causes and Classifications

2. Objectives After reading this chapter, you will be able to:
specify several possible causes of developmental differences and give examples of causes both prior ro and after birth.
describe and understand the classifications of developmental disabilities.

3. Causes of Developmental Differences
Biological factors
Biological insult refers to interference with or damage to an individual’s physical structure or functioning.
May occur at time of conception, during pregnancy (usually within first trimester), and may be related to health problems in the mother
Genetic disorders resulting in abnormal biological development may be caused by deviations in chromosomal structure or by abnormal single genes.
Syndromes are groupings of similar physical characteristics known as stigmata.

4. Causes of Developmental Differences (continued)
Down Syndrome (aka Trisomy 21)
This condition is caused by three number 21 chromosomes (usually contributed by the egg).
It is recognizable by a flat face, upturned eyes, small ears, short stature, and the simian crease.
Heart and intestinal abnormalities are common.

5. Causes of Developmental Differences (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.
An estimated 5-7% of intellectual disabilities in males may be due to Fragile X syndrome.

6. Causes of Developmental Differences (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 (phenylketonuria), which can result in brain damage if not detected early and treated.

7. Metabolic Disorders

8. Causes of Developmental Differences (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.

9. Causes of Developmental Differences (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 dystrophy
Present in males where the muscles deteriorate.

10. Causes of Developmental Differences (continued)
Prenatal infections and intoxicants
Rubella
Leads to devastating lifelong and severe disabilities.
CMV Virus
Children appear normal at birth. Later in life, they develop intellectual disabilities, deafness, and diseases of the eye.
Herpes simplex
Inflammation of the brain and spinal cord.
Even in remission, mother can pass to her newborn

11. Causes of Developmental Differences (continued)
Prenatal infections and intoxicants (continued)
AIDS
Can be passed to the unborn child through the birth canal or breast milk and leaves a child’s immune system helpless to fight off disease.
Maternal diabetes
High risk for developmental problems in child.
Preeclampsia (toxemia)
Usually occurs after 20 weeks of preganancy
Characterized by high blood pressure and excess protein in the urine
Complications that can lead to death in mother and infant.

12. Causes of Developmental Differences (continued)
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.
Poor nutrition including lack of protein can lead to low birth weight, illness and higher risk of death in first year of infant’s life. Poor nutrition can also damage the developing brain and nervous system.

13. Causes of Developmental Differences (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.

14. Causes of Developmental Differences (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 lead to brain damage.
Lead poisoning
Poisoning from lead found in lead-based paint and older homes can damage nervous system.

15. Causes of Developmental Differences (continued)
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.

16. Causes of Developmental Differences (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.

17. Causes of Developmental Differences (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.

18. Causes of Developmental Differences (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.

19. Classification of Developmental Disabilities
Categories of disability under IDEIA
Specific learning disabilities
A disorder in one or more of the basic psychological processes involved in using language, spoken or written.
Speech and language disorders
Difficulty with receptive or expressive language.

20. Classification of Developmental Disabilities (continued)
Developmental delay
Delay in one or more of the developmental domains.
Intellectual disability
Sub-average general intellectual functioning along with deficits in adaptive behavior.
Emotional disturbance
Behavioral or emotional responses that are different from age, ethnic or community norms.

21. Classification of Developmental Disabilities (continued)
Multiple disabilities
A combination of one or more disabilities.
Hearing impairment and deafness
Hearing impairment is a hearing loss that adversely affects educational performance.
Deafness is a hearing loss so severe that individuals cannot process spoken language, even with hearing aids or other forms of amplification.

22. Classification of Developmental Disabilities (continued)
Orthopedic impairments
Developmental problems that interfere with walking or other body movements.
Other health impairments
Limited strength, vitality, and alertness.

23. Classification of Developmental Disabilities (continued)
Visual impairments
A range from partially sighted to blind.
Individuals who are partially sighted read large print or possibly regular print.
Individuals who are blind have a severe enough vision loss that they cannot read print.
Combined deafness and blindness
A child has loss of both vision and hearing.

24. Classification of Developmental Disabilities (continued)
Autism
Developmental disability significantly affecting verbal and nonverbal communication and social interaction.
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.

26. A Final Thought on Categories
Each category describes a condition that makes a student eligible for a free and appropriate public education.
To meet the definition, a child’s educational performance must be adversely affected by the disability.
Category does not prescribe the services for a child but a program should be planned based on individual needs.

27. Objectives Revisited After reading this chapter, you will be able to:
specify several possible causes of developmental differences and give examples of causes both prior ro and after birth.
describe and understand the classifications of developmental disabilities.