SynonymsSenility,[1] senile dementia
Alzheimer's disease brain comparison.jpg
Comparison of a normal aged brain (left) and the brain of a person with Alzheimer's disease (right). Differential characteristics are pointed out.
SpecialtyNeurology, psychiatry
SymptomsDecreased ability to think and remember, emotional problems, problems with language, decreased motivation[2][3]
Usual onsetGradual[2]
DurationLong term[2]
CausesAlzheimer's disease, vascular dementia, Lewy body dementia, frontotemporal dementia[2][3]
Diagnostic methodCognitive testing (mini mental state examination)[3][4]
Differential diagnosisDelirium[5]
PreventionEarly education, prevent high blood pressure, prevent obesity, no smoking, exercise, social engagement[6]
TreatmentSupportive care[2]
MedicationCholinesterase inhibitors (small benefit)[7][8]
Frequency46 million (2015)[9]
Deaths1.9 million (2015)[10]

Dementia is a broad category of brain diseases that cause a long-term and often gradual decrease in the ability to think and remember that is great enough to affect a person's daily functioning.[2] Other common symptoms include emotional problems, difficulties with language, and a decrease in motivation.[2][3] A person's consciousness is usually not affected.[2] A dementia diagnosis requires a change from a person's usual mental functioning and a greater decline than one would expect due to aging.[2][11] These diseases also have a significant effect on a person's caregivers.[2]

The most common type of dementia is Alzheimer's disease, which makes up 50% to 70% of cases.[2][3] Other common types include vascular dementia (25%), Lewy body dementia (15%), and frontotemporal dementia.[2][3] Less common causes include normal pressure hydrocephalus, Parkinson's disease dementia, syphilis, and Creutzfeldt–Jakob disease among others.[12] More than one type of dementia may exist in the same person.[2] A small proportion of cases run in families.[13] In the DSM-5, dementia was reclassified as a neurocognitive disorder, with various degrees of severity.[14] Diagnosis is usually based on history of the illness and cognitive testing with medical imaging and blood tests used to rule out other possible causes.[4] The mini mental state examination is one commonly used cognitive test.[3] Efforts to prevent dementia include trying to decrease risk factors such as high blood pressure, smoking, diabetes, and obesity.[2] Screening the general population for the disorder is not recommended.[15]

There is no known cure for dementia.[2] Cholinesterase inhibitors such as donepezil are often used and may be beneficial in mild to moderate disorder.[7][16][17] Overall benefit, however, may be minor.[7][8] There are many measures that can improve the quality of life of people with dementia and their caregivers.[2] Cognitive and behavioral interventions may be appropriate.[2] Educating and providing emotional support to the caregiver is important.[2] Exercise programs may be beneficial with respect to activities of daily living and potentially improve outcomes.[18] Treatment of behavioral problems with antipsychotics is common but not usually recommended due to the little benefit and side effects, including an increased risk of death.[19][20]

Globally, dementia affected about 46 million people in 2015.[9] About 10% of people develop the disorder at some point in their lives.[13] It becomes more common with age.[21] About 3% of people between the ages of 65–74 have dementia, 19% between 75 and 84, and nearly half of those over 85 years of age.[22] In 2013 dementia resulted in about 1.7 million deaths up from 0.8 million in 1990.[23] As more people are living longer, dementia is becoming more common in the population as a whole.[21] For people of a specific age, however, it may be becoming less frequent, at least in the developed world, due to a decrease in risk factors.[21] It is one of the most common causes of disability among the old.[3] It is believed to result in economic costs of US$604 billion a year.[2] People with dementia are often physically or chemically restrained to a greater degree than necessary, raising issues of human rights.[2] Social stigma against those affected is common.[3]

Signs and symptoms

A drawing of a woman diagnosed as having dementia.
An old man diagnosed with senile dementia

The symptoms of dementia vary across types and stages of the diagnosis.[24] The most common affected areas include memory, visual-spatial, language, attention and problem solving. Most types of dementia are slow and progressive. By the time the person shows signs of the disorder, the process in the brain has been happening for a long time. It is possible for a patient to have two types of dementia at the same time. About 10% of people with dementia have what is known as mixed dementia, which is usually a combination of Alzheimer's disease and another type of dementia such as frontotemporal dementia or vascular dementia.[25][26]

Neuropsychiatric symptoms that may be present are termed Behavioural and psychological symptoms of dementia (BPSD) and these can include:[27]

  • Balance problems
  • Tremor
  • Speech and language difficulty
  • Trouble eating or swallowing
  • Memory distortions (believing that a memory has already happened when it has not, thinking an old memory is a new one, combining two memories, or confusing the people in a memory)
  • Wandering or restlessness
  • Perception and visual problems[28]
  • Behavioral and psychological symptoms of dementia almost always occur in all types of dementia and may manifest as:[29][30]

When people with dementia are put in circumstances beyond their abilities, there may be a sudden change to crying or anger (a "catastrophic reaction").[31]

Psychosis (often delusions of persecution) and agitation/aggression also often accompany dementia.[32]

Mild cognitive impairment

In the first stages of dementia, the signs and symptoms of the disorder may be subtle. Often, the early signs of dementia only become apparent when looking back in time. The earliest stage of dementia is called mild cognitive impairment (MCI). 70% of those diagnosed with MCI progress to dementia at some point.[11] In MCI, changes in the person's brain have been happening for a long time, but the symptoms of the disorder are just beginning to show. These problems, however, are not yet severe enough to affect the person's daily function. If they do, it is considered dementia. A person with MCI scores between 27 and 30 on the Mini-Mental State Examination (MMSE), which is a normal score. They may have some memory trouble and trouble finding words, but they solve everyday problems and handle their own life affairs well.[33]

Early stages

In the early stage of dementia, the person begins to show symptoms noticeable to the people around them. In addition, the symptoms begin to interfere with daily activities. The person usually scores between a 20 and 25 on the MMSE. The symptoms are dependent on the type of dementia a person has. The person may begin to have difficulty with more complicated chores and tasks around the house or at work. The person can usually still take care of him or herself but may forget things like taking pills or doing laundry and may need prompting or reminders.[34]

The symptoms of early dementia usually include memory difficulty, but can also include some word-finding problems (anomia) and problems with planning and organizational skills (executive function). One very good way of assessing a person's impairment is by asking if they are still able to handle their finances independently. This is often one of the first things to become problematic. Other signs might be getting lost in new places, repeating things, personality changes, social withdrawal and difficulties at work.

When evaluating a person for dementia, it is important to consider how the person was able to function five or ten years earlier. It is also important to consider a person's level of education when assessing for loss of function. For example, an accountant who can no longer balance a checkbook would be more concerning than a person who had not finished high school or had never taken care of his/her own finances.[11]

In Alzheimer's dementia the most prominent early symptom is memory difficulty. Others include word-finding problems and getting lost. In other types of dementia, like dementia with Lewy bodies and fronto-temporal dementia, personality changes and difficulty with organization and planning may be the first signs.

Middle stages

As dementia progresses, the symptoms first experienced in the early stages of the dementia generally worsen. The rate of decline is different for each person. A person with moderate dementia scores between 6–17 on the MMSE. For example, people with Alzheimer's dementia in the moderate stages lose almost all new information very quickly. People with dementia may be severely impaired in solving problems, and their social judgment is usually also impaired. They cannot usually function outside their own home, and generally should not be left alone. They may be able to do simple chores around the house but not much else, and begin to require assistance for personal care and hygiene other than simple reminders.[11]

Late stages

People with late-stage dementia typically turn increasingly inward and need assistance with most or all of their personal care. Persons with dementia in the late stages usually need 24-hour supervision to ensure personal safety, as well as to ensure that basic needs are being met. If left unsupervised, a person with late-stage dementia may wander or fall, may not recognize common dangers around them such as a hot stove, may not realize that they need to use the bathroom or become unable to control their bladder or bowels (incontinent).[33]

Changes in eating frequently occur. Caregivers of people with late-stage dementia often provide pureed diets, thickened liquids, and assistance in eating, to prolong their lives, to cause them to gain weight, to reduce the risk of choking, and to make feeding the person easier.[35] The person's appetite may decline to the point that the person does not want to eat at all. They may not want to get out of bed, or may need complete assistance doing so. Commonly, the person no longer recognizes familiar people. They may have significant changes in sleeping habits or have trouble sleeping at all.[11]

Other Languages
Alemannisch: Demenz
العربية: خرف
Avañe'ẽ: Tarova
azərbaycanca: Demensiya
беларуская: Дэменцыя
беларуская (тарашкевіца)‎: Дэмэнцыя
български: Деменция
bosanski: Demencija
català: Demència
čeština: Demence
Cymraeg: Gorddryswch
dansk: Demens
Deutsch: Demenz
eesti: Dementsus
Ελληνικά: Άνοια
español: Demencia
Esperanto: Demenco
euskara: Dementzia
فارسی: زوال عقل
français: Démence
Frysk: Demintens
Gaeilge: Néaltrú
galego: Demencia
ગુજરાતી: ડિમેન્શિયા
한국어: 치매
հայերեն: Մարազմ
hrvatski: Demencija
Bahasa Indonesia: Demensia
italiano: Demenza
עברית: שיטיון
қазақша: Алжу
Kiswahili: Dimenshia
kurdî: Demenza
Latina: Dementia
latviešu: Plānprātība
Lëtzebuergesch: Demenz
lietuvių: Silpnaprotystė
Limburgs: Verkiensje
magyar: Demencia
македонски: Деменција
മലയാളം: മേധാക്ഷയം
Malti: Demenzja
Bahasa Melayu: Demensia
Nederlands: Dementie
日本語: 認知症
norsk: Demens
norsk nynorsk: Demens
پښتو: عقل زوال
polski: Otępienie
português: Demência
русский: Деменция
Scots: Dementia
shqip: Demenca
sicilianu: Demenza
Simple English: Dementia
slovenčina: Demencia
slovenščina: Demenca
Soomaaliga: Xusuusla'aanta
српски / srpski: Деменција
srpskohrvatski / српскохрватски: Demencija
Basa Sunda: Déménsia
suomi: Dementia
svenska: Demens
Tagalog: Demensiya
தமிழ்: மறதிநோய்
Türkçe: Demans
українська: Деменція
اردو: زوال عقل
Vahcuengh: Binghfatmwnh
Tiếng Việt: Suy giảm trí nhớ
粵語: 痴呆
Zazaki: Demans
中文: 失智症