attention deficit/hyperactivity disorder (ADHD)
Developmental disorder featuring maladaptive levels of inattention, excessive activity, and impulsiveness.
learning disorder
Reading, mathematics, or written expression performance substantially below the level expected relative to the person's age, intelligence quotient score, and education.
reading disorder
Reading performance significantly below the standard for that age level.
mathematics disorder
Mathematics performance significantly below the standard for that age level.
disorder of written expression
Condition in which writing performance is significantly below the standard for that age level.
stuttering
Disturbance in fluency and time patterning of speech (for example, sound and syllable repetitions or prolongations).
expressive language disorder
An individual's problems in spoken communication, as measured by significantly low scores on standardized tests of expressive language relative to nonverbal intelligence test scores. Symptoms may include a markedly limited vocabulary or errors in verb ten
selective mutism
Developmental disorder characterized by the individual's consistent failure to speak in specific social situations despite speaking in other situations.
tic disorder
Disruption in early development involving involuntary motor movements or vocalizations.
pervasive developmental disorder
One of several wide-ranging, significant, and long-lasting dysfunctions that appear before the age of 18.
Rett's disorder
Progressive neurological developmental disorder featuring constant hand-wringing, mental retardation, and impaired motor skills.
childhood disintegrative disorder
Pervasive developmental disorder involving severe regression in language, adaptive behavior, and motor skills after a 2- to 4-year period of normal development.
autistic disorder
Pervasive developmental disorder characterized by significant impairment in social interactions and communication and restricted patterns of behavior, interest, and activity. Also known as autism.
Asperger's disorder
Pervasive developmental disorder characterized by impairments in social relationships and restricted or unusual behaviors but without the language delays seen in autism.
mental retardation
Significantly subaverage intellectual functioning paired with deficits in adaptive functioning such as self-care or occupational activities, appearing before age 18.
Down syndrome
Type of mental retardation caused by a chromosomal aberration (chromosome 21) and involving characteristic physical appearance. Sometimes known as trisomy 21.
amniocentesis
Prenatal medical procedure that allows the detection of abnormalities (for example, Down syndrome) in the developing fetus. It involves removal and analysis of amniotic fluid from the mother.
fragile X syndrome
Pattern of abnormality caused by a defect in the X chromosome resulting in mental retardation, learning problems, and unusual physical characteristics.
cultural-familial retardation
Mild mental retardation that may be caused largely by environmental influences.
delirium
Rapid-onset reduced clarity of consciousness and cognition, with confusion, disorientation, and deficits in memory and language.
dementia
Gradual-onset deterioration of brain functioning, involving memory loss, inability to recognize objects or faces, and problems in planning and abstract reasoning. These are associated with frustration and discouragement.
agnosia
Inability to recognize and name objects; may be a symptom of dementia or other brain disorders.
facial agnosia
Type of agnosia characterized by a person's inability to recognize even familiar faces.
Alzheimer's disease
Disease of the cerebral cortex that causes an atypical form of senile dementia, discovered in 1906 by German psychiatrist Alois Alzheimer.
dementia of the Alzheimer's type
Gradual onset of cognitive deficits caused by Alzheimer's disease, principally identified by a person's inability to recall newly or previously learned material. The most common form of dementia.
vascular dementia
Progressive brain disorder involving loss of cognitive functioning, caused by blockage of blood flow to the brain, that appears concurrently with other neurological signs and symptoms.
human immunodeficiency virus type 1 (HIV-1)
Disease that causes AIDS.
aphasia
Impairment of loss of language skills resulting from brain damage caused by stroke, Alzheimer's disease, or other illness or trauma.
head trauma
Injury to the head and, therefore, to the brain, typically caused by accidents; can lead to cognitive impairments, including memory loss.
Parkinson's disease
Degenerative brain disorder principally affecting motor performance (for example, tremors and stooped posture) associated with reduction in dopamine. Dementia may be a result as well.
Huntington's disease
Genetic disorder marked by involuntary limb movements and progressing to dementia.
Pick's disease
Rare neurological disorder that result in presenile dementia.
Creutzfeldt-Jakob disease
Extremely rare condition that causes dementia.
deterministic
In genetics, genes that lead to nearly a 100% chance of developing the associated disorder. These are rare in the population.
susceptibility
In genetics, genes that only slightly increase the risk of developing the disorder, but in contrast to the deterministic genes, these are more common in the population.
amnestic disorder
Deterioration in the ability to transfer information from short- to long-term memory in the absence of other dementia symptoms, as a result of head trauma or drug abuse.