dementia

dementia

[dih-men-shuh, -shee-uh]
dementia [Lat.,=being out of the mind], progressive deterioration of intellectual faculties resulting in apathy, confusion, and stupor. In the 17th cent. the term was synonymous with insanity, and the term dementia praecox was used in the 19th cent. to describe the condition now known as schizophrenia. In recent years, the term has generally been used to describe various conditions of mental deterioration occurring in middle to later life. Dementia, in its contemporary usage, is an irreversible condition, and is not applied to states of mental deterioration that may be overcome, such as delirium. The condition is generally caused by deterioration of brain tissue, though it can occassionally be traced to deterioration of the circulatory system. Major characteristics include short- and long-term memory loss, impaired judgement, slovenly appearance, and poor hygiene. Dementia disrupts personal relationships and the ability to function occupationally. Senility (senile dementia) in old age is the most commonly recognized form of dementia, usually occurring after the age of 65. Alzheimer's disease can begin at a younger age, and deterioration of the brain tissue tends to happen much more quickly. Individuals who have experienced cerebrovascular disease (particularly strokes) may develop similar brain tissue deterioration, with symptoms similar to Alzheimer's disease and senile dementia. Other types of dementia include Huntington's disease, Parkinson's disease, and Pick's disease. Some forms of familial Alzheimer's disease are caused by specific dominant gene mutations.

See L. L. Heston and J. White, The Vanishing Mind (1991).

Any of a group of severe mental disorders that have in common symptoms such as hallucinations, delusions, blunted emotions, disorganized thinking, and withdrawal from reality. Five main types are recognized: the paranoid, characterized by delusions of persecution or grandeur combined with unrealistic, illogical thinking and frequent auditory hallucinations; the disorganized (hebephrenic), characterized by disordered speech and behaviour and shallow or inappropriate emotional responses; the catatonic, characterized by motor inflexibility or stupor along with mutism, echolalia, or other speech abnormalities; the simple or undifferentiated type, which conforms to basic definitions of schizophrenia but does not exhibit particular behaviours in the aforementioned types; and the residual type, which is a chronic stage indicating advancement toward later-stage schizophrenia. Schizophrenia seems to occur in 0.5–1percnt of the general population, and more than half of those so diagnosed will eventually recover. There is strong evidence that genetic inheritance plays a role, but no single cause of schizophrenia has been identified. Stressful life experiences may help trigger its onset. Treatment consists of drug therapy and counseling.

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Chronic, usually progressive deterioration of intellectual functions. Most common in the elderly, it usually begins with short-term-memory loss once thought a normal result of aging but now known to result from Alzheimer disease. Other common causes are Pick disease and vascular disease. Dementia also occurs in Huntington chorea, paresis (see paralysis), and some types of encephalitis. Treatable causes include hypothyroidism (see thyroid gland), other metabolic diseases, and some malignant tumours. Treatment may arrest dementia's progress but usually does not reverse it.

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Dementia (from Latin de- "apart, away" + mens (genitive mentis) "mind") is the progressive decline in cognitive function due to damage or disease in the body beyond what might be expected from normal aging. Although dementia is far more common in the geriatric population, it may occur in any stage of adulthood. This age cutoff is defining, as similar sets of symptoms due to organic brain dysfunction are given different names in populations younger than adulthood (see, for instance, developmental disorders).

Dementia is a non-specific illness syndrome (set of symptoms) in which affected areas of cognition may be memory, attention, language, and problem solving. Higher mental functions are affected first in the process. Especially in the later stages of the condition, affected persons may be disoriented in time (not knowing what day of the week, day of the month, month, or even what year it is), in place (not knowing where they are), and in 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 percent of cases of dementia are due to causes which may presently be reversed with treatment. Causes include many different specific disease processes, in the same way that symptoms of organ dysfunction such as shortness of breath, jaundice, or pain are attributable to many etiologies. Without careful assessment of history, the short-term syndrome of delirium can easily be confused with dementia, because they have many symptoms in common. Some mental illnesses, including depression and psychosis, may also produce symptoms which must be differentiated from both delirium and dementia.

Diagnosis

Proper differential diagnosis between the types of dementia (cortical and subcortical - see below) will require, at the least, referral to a specialist, e.g. a geriatric internist, geriatric psychiatrist, neurologist, neuropsychologist or geropsychologist. However, there exist some brief tests (5-15 minutes) that have reasonable reliability and can be used in the office or other setting to screen cognitive status for deficits which are considered pathological. Examples of such tests include the abbreviated mental test score (AMTS), the mini mental state examination (MMSE), Modified Mini-Mental State Examination (3MS), the Cognitive Abilities Screening Instrument (CASI), and the clock drawing test.. An AMTS score of less than six (out of a possible score of ten) and an MMSE score under 24 (out of a possible score of 30) suggests a need for further evaluation. Scores must be interpreted in the context of the person's educational and other background, and the particular circumstances; for example, a person highly depressed or in great pain will not be expected to do well on many tests of mental ability.

Mini-mental state examination

The U.S. Preventive Services Task Force (USPSTF) reviewed tests for cognitive impairment and concluded:

  • MMSE

sensitivity 71% to 92%
specificity 56% to 96%

A copy of the MMSE can be found in the appendix of the original publication.

Modified Mini-Mental State examination (3MS)

A copy of the 3MS is online. A meta-analysis concluded that the Modified Mini-Mental State (3MS) examination has:
sensitivity 83% to 94%
specificity 85% to 90%

Abbreviated mental test score

A meta-analysis concluded:
sensitivity 73% to 100%
specificity 71% to 100%

Other examinations

Many other tests have been studied including the clock-drawing test (example form). Although some may emerge as better alternatives to the MMSE, presently the MMSE is the best studied. However, access to the MMSE is now limited by enforcement of its copyright.

Another approach to screening for dementia is to ask an informant (relative or other supporter) to fill out a questionnaire about the person's everyday cognitive functioning. Informant questionnaires provide complementary information to brief cognitive tests. Probably the best known questionnaire of this sort is the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE).

Further evaluation includes retesting at another date, and administration of other (and sometimes more complex) tests of mental function, such as formal neuropsychological testing.

Laboratory tests

Routine blood tests are also 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. The problem is complicated by the fact that these cause confusion more often in persons who have early dementia, so that "reversal" of such problems may ultimately only be temporary.

Chronic use of substances such as alcohol can also predispose the patient to cognitive changes suggestive of dementia.

Imaging

A CT scan or magnetic resonance imaging (MRI scan) is commonly performed, although these modalities (as is noted below) do not have optimal sensitivity for the diffuse metabolic changes associated with dementia in a patient who shows no gross neurological problems (such as paralysis or weakness) on neurological exam. CT or MRI 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. However, the functional neuroimaging modalities of SPECT and PET have shown similar ability to diagnose dementia as clinical exam. The ability of SPECT to differentiate the vascular cause from the Alzheimer disease cause of dementias, appears to be superior to differentiation by clinical exam.

Types

Cortical dementias

Subcortical dementias

Dementia and early onset dementia have been associated with neurovisceral porphyrias. Porphyria is listed in textbooks in the differential diagnosis of dementia. Because acute intermittent porphyria, hereditary coproporphyria and variegate porphyria are aggravated by environmental toxins and drugs the disorders should be ruled out when these etiologies are raised.

Treatment

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. Cholinesterase inhibitors are often used early in the disease course. Cognitive and behavioral interventions may also be appropriate. Educating and providing emotional support to the caregiver (or carer) is of importance as well (see also elderly care).

A Canadian study found that a lifetime of bilingualism has a marked influence on delaying the onset of dementia by an average of four years when compared to monolingual patients. The researchers determined that the onset of dementia symptoms in the monolingual group occurred at the mean age of 71.4, while the bilingual group was 75.5 years. The difference remained even after considering the possible effect of cultural differences, immigration, formal education, employment and even gender as influences in the results.

Medications

Tacrine (Cognex), donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon) are approved by the United States Food and Drug Administration (FDA) for treatment of dementia induced by Alzheimer disease. They may be useful for other similar diseases causing dementia such as Parkinsons or vascular dementia.

  • N-methyl-D-aspartate Blockers. Memantine (Namenda) is a drug representative of this class. It can be used in combination with acetylcholinesterase inhibitors.

Off label

  • Amyloid deposit inhibitors

Minocycline and Clioquinoline, antibiotics, may help reduce amyloid deposits in the brains of persons with Alzheimer disease.

  • Antipsychotic drugs

Haloperidol (Haldol), risperidone (Risperdal), olanzapine (Zyprexa), and quetiapine (Seroquel) are frequently prescribed to help manage psychosis and agitation. Treatment of dementia-associated psychosis or agitation is intended to decrease psychotic symptoms (for example, paranoia, delusions, hallucinations), screaming, combativeness, and/or violence.

Depression is frequently associated with dementia and generally worsens the degree of cognitive and behavioral impairment. Antidepressants may be helpful in alleviating cognitive and behavior symptoms by reuptaking neurotransmitter regulation through reuptake of serotonin, noradrenaline and dopamine.

  • Antianxiety drugs

Many patients with dementia experience anxiety symptoms. Although benzodiazepines like diazepam (Valium) have been used for treating anxiety in other situations, they are often avoided because they may increase agitation in persons with dementia or are too sedating. Buspirone (Buspar) is often initially tried for mild-to-moderate anxiety.

Selegiline, a drug used primarily in the treatment of Parkinson's disease, appears to slow the development of dementia. Selegiline is thought to act as an antioxidant, preventing free radical damage. However, it also acts as a stimulant, making it difficult to determine whether the delay in onset of dementia symptoms is due to protection from free radicals or to the general elevation of brain activity from the stimulant effect.

Prevention

Since there is no cure for dementia, the best an individual can do is to prevent it from developing in the first place.

The main method to prevent dementia is to live an active life, both mentally and physically. It appears that the regular moderate consumption of alcohol (beer, wine, or distilled spirits) may reduce risk.

Furthermore, there are medications which might contribute to prevent the onset of dementia, including hypertension medications, anti-diabetic drugs, and NSAIDs. A study has shown a link between high blood pressure and developing dementia. The study, published in the Lancet Neurology journal July 2008, found that blood pressure lowering medication reduced dementia by 13%.

Studies published in US journals suggested that a Mediterranean diet or long-term beta-carotene supplements could ward off dementia.

Risk to self and others

Driving with dementia could lead to severe injury or even death to self and others. Doctors should advise appropriate testing on when to quit driving.

Florida's Baker Act allows law enforcement and the judiciary to force mental evaluation for those suspected of suffering from dementia or other mental incapacities.

Services

Adult daycare centers as well as special care units in nursing homes often provide specialized care for dementia patients. Adult daycare centers offer supervision, recreation, meals, and limited health care to participants, as well as providing respite for caregivers.

See also

References

Notes

External links

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