Etiology and Characteristics of Intellectual Disabilities

Comprehensive vocabulary terms regarding the causes, biological conditions, behavioral characteristics, and prevention strategies for intellectual disabilities.

Prenatal

Occurring before birth.

Perinatal

Occurring around the time of birth.

Postnatal

Occurring after birth.

Down Syndrome

A chromosomal abnormality known as trisomy 21, suspected to be caused by thyroid problems, drugs, exposure to radiation, or maternal age.

Chorionic villus sampling (CVS)

A diagnostic medical procedure used to detect chromosomal abnormalities, usually conducted in the first trimester of pregnancy between $10$ and $12$ weeks of gestation.

Amniocentesis

A diagnostic medical procedure performed to detect chromosomal and genetic abnormalities in a fetus by sampling amniotic fluid.

Fragile X Syndrome

A deficiency in the structure of the X chromosome of the 23rd pair; believed to be the most common form of inherited intellectual disabilities.

Phenylketonuria (PKU)

An inborn error of metabolism resulting from the inability of the body to convert phenylalanine to tyrosine; it is a recessive trait that can be controlled by diet.

Galactosemia

An inborn error of metabolism that makes infants unable to process galactose (brain sugar), resulting in physical problems and intellectual disabilities.

Rubella

A contagious viral disease (German Measles) that, if contacted in the first trimester of pregnancy, often results in significant impairments.

Rh incompatibility

A condition occurring when an Rh-negative woman carries an Rh-positive fetus, leading the mother's body to produce antibodies that can affect future pregnancies.

Toxoplasmosis

An infection contracted through exposure to cat fecal matter, undercooked meat, or raw eggs; especially devastating if exposure occurs during the third trimester.

Cytomegalovirus (CMV)

A common virus part of the herpes group that can lead to brain damage, blindness, and hearing impairments.

Fetal Alcohol Syndrome (FAS)

A leading, completely preventable cause of intellectual disability resulting from maternal alcohol consumption, characterized by physical deformities and attention disorders.

Fetal Alcohol Spectrum Disorder (FASD)

A term describing a group of conditions that can occur when a woman consumes alcohol while pregnant.

Anencephaly

A condition where the entire brain or a large portion of it fails to develop properly.

Microcephaly

A condition characterized by an unusually small head and severe intellectual disability.

Hydrocephalus

A disorder associated with the blockage of cerebrospinal fluid, resulting in an accumulation of excess fluid and potentially damaging compression on the brain.

Low Birth Weight

A term used to describe babies born weighing less than $2,500\,grams$ ($5\,lbs., 8\,oz.$).

Premature Births

Babies born before $37\,weeks$ of gestation age.

Anoxia

Loss of or inadequate supply of oxygen associated with the birth process, frequently resulting in brain damage.

Hypoxia

An insufficient amount of oxygen to the brain that can result in brain damage.

Breech presentation

A birth position where the fetus exits the birth canal buttocks first rather than headfirst.

Precipitous birth

A birth that occurs in less than $2\,hours$, increasing the risk of tissue damage as the skull does not have time for gentle molding.

Lead poisoning

An environmental toxin formerly used in gasoline and paint; ingestion can cause seizures, brain damage, and impaired central nervous system functioning.

Meningitis

A viral infection causing damage to the covering of the brain (meninges); can result from mumps, measles, or chickenpox.

Encephalitis

An inflammation of the brain that may cause damage to the central nervous system.

Working memory

The ability to remember one thing while performing another task.

Short-term memory

The ability to recall and use information encountered just a few seconds to a couple of hours earlier.

External locus of control

The belief that outcomes of a person's actions are the result of circumstances beyond one's control rather than their own efforts.

Learned helplessness

An individual's expectation of failure, regardless of efforts, based on experiences of repeated failure.

Outer-directedness

A problem-solving approach characterized by a distrust of one's own responses and a reliance on others for assistance and solutions.

Generalization

The ability to transfer newly learned knowledge and skills to settings or situations that differ from the conditions where they were initially learned.

Primary prevention

Efforts aimed at eliminating a problem before its onset, such as prenatal health care, genetic counseling, or heightening awareness about alcohol use during pregnancy.

Secondary prevention

Efforts aimed at minimizing or eliminating a potential risk factor, such as newborn screening for PKU or surgical implantation of a shunt for hydrocephalus.

Tertiary prevention

Efforts seeking to limit adverse consequences of an existing problem and maximize potential, such as early intervention or community-based services.