age effects

The consequences of being a given chronological

age.

Alzheimer’s disease

A dementia involving a progressive atrophy of cortical tissue and marked by memory impairment, intellectual deterioration, and, in more extreme cases, involuntary movements of limbs, occasional convulsions, and psychotic behavior.

cohort effects

The consequences of having been born in a given year and having grown up during a particular time period with its own unique pressures, problems, challenges, and opportunities.

delirium

A state of great mental confusion in which consciousness is clouded, attention cannot be sustained, and the stream of thought and speech is incoherent. The person is probably disoriented, emotionally erratic, restless or lethargic, and often has illusions, delusions, and hallucinations.

dementia

Deterioration of mental faculties—memory, judgment, abstract thought, control of impulses, intellectual ability—that impairs social and occupational functioning and eventually changes the personality.

dementia with Lewy bodies (DLB)

Form of dementia recently categorized as distinct from Parkinson’s disease; characterized by shuffling gait, memory loss, and hallucinations and delusions.

disorientation

A state of mental confusion with respect to time, place, identity of self, other persons, and objects.

frontal-temporal dementia (FTD)

Dementia that begins typically in the mid to late 50s, characterized by deficits in executive functions such as planning, problem solving, and goal-directed behavior, as well as recognition

and comprehension of emotions in others.

neurofibrillary tangles

Abnormal protein filaments present in the cell bodies of brain cells in patients with Alzheimer’s disease.

plaques

Small, round areas composed of remnants of lost neurons and beta-amyloid, a waxy protein deposit; present in the brains of patients with Alzheimer’s disease.

selective mortality

When people are no longer available for follow-up because of death

social selectivity

The late-life shift in interest away from seeking new social interactions and toward cultivating those few social relationships that matter most, such as with family and close friends.

time-of-measurement effects

A possible confound in longitudinal studies whereby conditions at a particular point in time can have a specific effect on a variable that is being studied over time.