Dementia (from Latin de- "apart, away," + mens (genitive mentis) "mind") is the progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal aging. Particularly affected areas may be memory, attention, language and problem solving, although particularly in the later stages of the condition, affected persons may be disoriented in time (not knowing what day, week, month or year it is), place (not knowing where they are) and person (not knowing who they are). Symptoms of dementia can be classified as either reversible or irreversible depending upon the etiology of the disease. Less than 10% of all dementias are reversible. Dementia is a non-specific term that encompasses many disease processes, just as fever is attributable to many etiologies.
Early symptoms of dementia often consist in changes in personality, or in behavior. Often dementia can be first evident during an episode of delirium. There is a higher prevalence of eventually developing dementia in individuals who experience an acute episode of confusion while hospitalized.
Dementia can affect language, comprehension, motor skills, short-term memory, ability to identify commonly used items, reaction time, personality traits, and executive functioning. Even without signs of general intellectual decline, delusions are common in dementia (15-56% incidence rate in Alzheimer's type, and 27-60% incidence rate in multi-infarct dementia). Often these delusions take the form of monothematic delusions, like mirrored self-misidentification.
Elderly people can also react with dementia-like symptoms to surgery, infections, sleep deprivation, irregular food intake, dehydration, loneliness, change in domicile or personal crises. This is called delirium, and many if not most dementia patients also have a delirium on top of the physiologial dementia, adding to the symptoms. The delirium can go away or greatly improve when treated with tender care, improved food and sleeping habits, but this does not affect the alterations in the brain. Affected persons may also show signs of psychosis or depression. It is important to be able to differentiate between delirium and dementia.
Proper differential diagnosis between the types of dementia (see below) will require, at the least, referral to a specialist, e.g. a geriatric internist, geriatric psychiatrist or neurologist. However, there are some brief (5-15 minutes) tests that have good reliability and can be used in the office or other setting to evaluate cognitive status. Examples of such tests include the abbreviated mental test score (AMTS) and the mini mental state examination (MMSE).
An AMTS score of less than six and an MMSE score under 24 suggests a need for further evaluation. Of course, this must be interpreted in the context of the person's educational and other background, and particular circumstances. Routine blood tests are usually performed to rule out treatable causes. These tests include vitamin B12, folic acid, thyroid-stimulating hormone (TSH), C-reactive protein, full blood count, electrolytes, calcium, renal function and liver enzymes. Abnormalities may suggest vitamin deficiency, infection or other problems that commonly cause confusion or disorientation in the elderly. Chronic use of substances such as alcohol can also predispose the patient to cognitive changes suggestive of dementia.
A CT scan or magnetic resonance imaging (MRI scan) is commonly performed. This may suggest normal pressure hydrocephalus, a potentially reversible cause of dementia, and can yield information relevant to other types of dementia, such as infarction (stroke) that would point at a vascular type of dementia. Sometimes neuropsychological testing is helpful as well.
The final diagnosis of dementia is made on the basis of the clinical picture. For research purposes, the diagnosis depends on both a clinical diagnosis and a pathological diagnosis (ie, based on the examination of brain tissue, usually from autopsy).
The most common types of dementia are as follows and vary according to the history and the presentation of the disease: (Where available the ICD-10 codes are provided. The first code refers to the dementia, and the second to the underlying condition.)
Most common causes
- (F00/G30) Alzheimer's disease
- (F01) Vascular dementia (also known as multi-infarct dementia), including Binswanger's disease
- (F02.3/G20) Dementia with Lewy bodies (DLB)
- (F02.0/G31.0) Frontotemporal lobar degeneration (FTLD), including Pick's disease
Less common causes
It can also be a consequence of:
- (F02.1/A81.0) Creutzfeldt-Jakob disease
- (F02.2/G10) Huntington's disease
- (F02.3/G20) Parkinson's disease
- (F02.4/B22.0) HIV infection (leading to AIDS dementia complex)
- (F07.2) Head trauma
- (Q90) People with Down's syndrome have an increased risk of developing dementia of the Alzheimer's type. This risk increases as the person ages.
Less than 5% of a sample of dementia cases have a potentially treatable cause. These include:
- (F02.8/E01-E03) Hypothyroidism
- (F02.8/E51) Vitamin B1 (thiamine) deficiency
- (F02.8/E53.8) Vitamin B12, Vitamin A deficiency
- (F03/F32-F33) Depressive pseudodementia (note: dementia and depression can coexist in many patients and can be difficult to differentiate.)
- (G91.2) Normal pressure hydrocephalus
Except for the treatable types listed above, there is no cure to this illness, although scientists are progressing in making a type of medication that will slow down the process.
Snoezelen rooms that provide patients with a soothing and stimulating environment of light, color, music and scent have been used in the therapy of dementia patients.
- Dementia - new research, news reports, new books, web sites
- The Dementia Services Development Centre, University of Stirling
- Dementia tutorial for U.K. practitioners by the Alzheimer's Society
- Getting Started in Telecare for Patients with Dementia