Dementia (from Latin demens) is 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, although dementia, by definition, is irreversible and will eventually result in death. Probably less than 5% of all dementias are reversible. Dementia is a non-specific term that encompasses many disease processes, just as fever is attributable to many etiologies.
Affected persons may also show signs of psychosis, depression and are at greater risk of developing delirium. It is important to be able to differentiate between delirum and dementia, as both refer to different clinical scenarios that can overlap.
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.
Diagnosis
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 (MR 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).
Types
The most common types of dementia are as follows and vary according to the history and the presentation of the disease:
Alzheimer's disease
Multi-infarct dementia (also known as vascular dementia), including Binswanger's disease
Dementia with Lewy bodies (DLB)
Frontotemporal lobar degeneration (FTLD), including Pick's disease and dementia lacking distinctive histology (DLDH)
Frontal variant frontotemporal dementia
Semantic dementia
Progressive non-fluent aphasia
It can also be a consequence of:
Head trauma
Parkinson's disease
Huntington's disease
Creutzfeldt-Jakob disease
AIDS
Less than 5% of a sample of dementia cases have a potentially treatable cause. These include:
Depressive pseudodementia (note: dementia and depression can coexist in many patients and can be difficult to differentiate.)
Hypothyroidism
Normal pressure hydrocephalus
Vitamin B12 deficiency
Vitamin B1 (thiamine) deficiency
Tumour
People with Down's syndrome have an increased risk of developing dementia of the Alzheimer's type. This risk increases as the person ages.
There is no cure to this illness although scientists are progressing in making a type of medication thatwill slow down the process
Common Neurological Disorders
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