Visualization of narrower problems
Chronic brain syndrome
Organic brain syndrome
Cerebral atrophy
Dementing illness
The term "dementia" is used by the medical community to describe people with impaired intellectual capacity. Dementia is not a normal part of the aging process. Dementing conditions are caused by abnormal disease processes, and can affect younger as well as older persons.

Short- and long-term memory impairment is the most prominent symptom of dementia. It ranges from inability to learn new information, to think problems through or to complete complex tasks, to inability to remember past personal history. There may also be impairment in abstract thinking or in judgement. Dementia may disturb higher cortical function affecting language and motor activities. Personality change happens often involving either an alteration or an accentuation of paranoid, inappropriate or bizarre behaviour.

Deteriorating intellectual capacity may be caused by a variety of diseases and disorders. The US National Institute on Aging states that some 100 conditions which mimic serious disorders are actually reversible. These are sometimes called "pseudodementias," and are often treatable. Examples of conditions causing reversible symptoms of dementia are: (1) reactions to medications (sedatives, hypnotics, neuroleptics, antihypertensives and antiarthritic medications); (2) emotional distress ([eg] depression or major life changes); (3) metabolic disturbances ([eg] renal failure, liver failure, electrolyte imbalances, hypoglycemia, hypercalcemia, hepatic diseases or pancreatic disorders); (4) Undetected problems of vision or hearing may result in inappropriate responses, misinterpreted as dementia; (5) nutritional deficiencies; (6) endocrine abnormalities (hypothyroidism, hyperthyroidism, parathyroid disturbances or adrenal abnormalities can cause confusion which mimics dementia) (7) older persons can develop infections which produce a sudden onset of a confusional state; (8) subdural haematoma (blood clot on the surface of the brain); (9) normal pressure hydrocephalus; (10) brain tumours; (11) atherosclerosis, causing a series of small strokes occurs (multi-infarct dementia).

The U.S. Congress, Office of Technology Assessment estimates that 1.8 million Americans have severe dementia and another 1 to 5 million Americans have mild to moderate dementia. According to the Alzheimer's Association, approximately 4 million of these people are afflicted with Alzheimer's disease. By the year 2040, the number of persons with Alzheimer's disease may exceed 6 million.
(E) Emanations of other problems