Dementia is a decline in intellectual capacity that reduces a person’s ability to carry out everyday activities. The mental skills affected by dementia may vary. They can include memory, language, visual perception, spatial reasoning, judgment, attention, and behavior. Dementia is more common among the elderly. It is uncommon before about age 60. Physicians use the term mild cognitive impairment for intellectual decline that is not yet severe enough to affect daily living.
Dementia is not a disease in itself. It results from another underlying condition. Alzheimer’s disease is the most common cause of dementia. Other causes, such as Huntington’s disease, result from an inherited genetic mutation. The risk of developing dementia may increase with cardiovascular disease, severe head injury, and family history.
A form of dementia called vascular dementia is caused by multiple small strokes. Infections—including syphilis and HIV—and autoimmune diseases, such as multiple sclerosis, can also cause dementia. Rarer causes include tumors, hormone abnormalities, vitamin deficiencies, and alcohol or drug misuse. Physicians usually diagnose dementia based on a patient’s symptoms. Further testing and treatment depend on the suspected cause.
See also Chronic traumatic encephalopathy (CTE).
