dementia
de·men·tia
D0120200 (dĭ-mĕn′shə)dementia
(dɪˈmɛnʃə; -ʃɪə)de•men•tia
(dɪˈmɛn ʃə, -ʃi ə)n.
dementia
| Noun | 1. | dementia - mental deterioration of organic or functional origin |
| 单词 | dementia | |||
| 释义 | dementiade·men·tiaD0120200 (dĭ-mĕn′shə)dementia(dɪˈmɛnʃə; -ʃɪə)de•men•tia(dɪˈmɛn ʃə, -ʃi ə)n. dementia
dementianoundementiadementia(dĭmĕn`shə) [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 insanityinsanity,mental disorder of such severity as to render its victim incapable of managing his affairs or of conforming to social standards. Today, the term insanity is used chiefly in criminal law, to denote mental aberrations or defects that may relieve a person from the legal ..... Click the link for more information. , and the term dementia praecox was used in the 19th cent. to describe the condition now known as schizophreniaschizophrenia , group of severe mental disorders characterized by reality distortions resulting in unusual thought patterns and behaviors. Because there is often little or no logical relationship between the thoughts and feelings of a person with schizophrenia, the disorder has ..... Click the link for more information. . 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. Frontotemporal dementia, resulting from the atrophy of the frontal and temporal lobes of the brain, is the most common form of dementia, however, in persons under the age of 60. It was formerly known as Pick's disease; that term is now reserved for a specific subtype of frontotemporal dementia. Individuals who have experienced cerebrovascular disease (particularly strokes) may develop similar brain tissue deterioration, with symptoms similar to various forms of dementia. Other diseases that cause dementia include Huntington's disease and Parkinson's disease. Some forms of familial Alzheimer's disease are caused by specific dominant gene mutations. BibliographySee L. L. Heston and J. White, The Vanishing Mind (1991). Dementiairreversible deterioration of mental activity, manifested mainly by a decreased ability to acquire knowledge, loss of previously acquired knowledge, emotional apathy, and behavioral changes. Dementia may be congenital (oligophrenia) or acquired. The concept of dementia usually refers to acquired dementia, that is, dementia resulting from mental disease. Clinically, dementia may be total or partial. Total dementia is characterized by an impairment of the ability to make judgments and arrive at conclusions, a sharply decreased critical attitude toward one’s condition, a loss of individual personality features, and a predominance of a complacent attitude (as in the case of senile psychosis). The main symptom of partial (dysmnestic) dementia is a disturbance of memory accompanied by emotional instability, helplessness, and a weakening of mental activity (as in the case of vascular disease of the brain). In partial dementia, however, consciousness of one’s own incompetence is retained, and the personality does not lose its individuality to the degree that it does with total dementia. The irreversibility of dementia is to some extent conditional, as is demonstrated by the results of treatment for patients with Bayle’s disease. In addition, there is a special form of acute transitory dementia associated with certain febrile, toxic, and other psychoses. The characteristics of dementia depend on the disease that produces the mental deterioriation; among the diseases are epilepsy, schizophrenia, and alcoholism. M. I. FOM’IANOV dementia[də′men·chə]dementiadementiaDementiaDefinitionDementia is a loss of mental ability severe enough to interfere with normal activities of daily living, lasting more than six months, not present since birth, and not associated with a loss or alteration of consciousness. DescriptionDementia is a group of symptoms caused by gradual death of brain cells. The loss of cognitive abilities that occurs with dementia leads to impairments in memory, reasoning, planning, and behavior. While the overwhelming number of people with dementia are elderly, dementia is not an inevitable part of aging; instead, dementia is caused by specific brain diseases. Alzheimer's disease (AD) is the most common cause, followed by vascular or multi-infarct dementia. The prevalence of dementia is difficult to determine, partly because of differences in definition among different studies and partly because there is some normal decline in functional ability with age. The prevalence of dementia roughly doubles for every five years of age beginning at age 60. Dementia affects about 1% of people between ages 60 and 64, 5-8% of all people between ages 65 and 74, up to 20% of those between 75 and 84, and between 30% and 50% of those age 85 and older. About 60% of nursing home patients have dementia. The Alzheimer's Association estimates that in 2007, 5.1 million Americans were living with a diagnosis of AD. That number expected to grow substantially as the population ages. The cost of dementia can be considerable. While most people with dementia are retired and are not affected by income losses from their disease, the cost of care often is enormous. Financial burdens include lost wages for family caregivers, medical supplies and drugs, and home modifications to ensure safety. Nursing home care may cost several thousand dollars a month or more. The psychological cost is not as easily quantifiable but can be even more profound. The person with dementia loses control of many of the essential features of his life and personality, and loved ones lose a family member even as they continue to cope with the burdens of increasing dependence and unpredictability. Causes and symptomsCausesDementia usually is caused by degeneration in the cerebral cortex, the part of the brain responsible for thoughts, memories, actions, and personality. Death of brain cells in this region leads to the cognitive impairment that characterizes dementia. The most common cause of dementia is AD, accounting for one-half to three-fourths of all cases. The brain of a person with AD becomes clogged with two abnormal structures called neurofibrillary tangles and senile plaques. Neurofibrillary tangles are twisted masses of protein fibers inside nerve cells (neurons). Senile plaques are composed of parts of neurons surrounding a group of proteins called beta-amyloid deposits. Why these structures develop is unknown. Current research indicates possible roles for inflammation, blood flow restriction, and molecular fragments known as free radicals. Several genes have been associated with higher incidences of AD, although the exact role of these genes still is unclear. Discovered by researchers at Duke University in the early 1990s, potentially the most important genetic link to AD is on chromosome 19. A gene on this chromosome, called APOE (apolipoprotein E), codes for a protein involved in transporting lipids (fats) into neurons. Certain variations of this gene appear to increase the chance for developing AD and/or lower the age at which symptoms occur. Researchers believe that as many as seven other AD risk-factor genes exist. In 2007, scientists identified a possible risk factor in four new AD-related regions in the human genome. In these regions, one out of several hundred genes may be a risk factor. One gene called SORL 1 has drawn particular research attention. This gene is involved regulating the transport of certain proteins in the cell. As of 2009, the role SORL 1 in the development of AD remained under study. Vascular dementia is estimated to cause from 5-30% of all dementias. It occurs from decrease in blood flow to the brain, most commonly due to a series of small strokes (multi-infarct dementia). Other cerebrovascular causes include vasculitis from syphilis, Lyme disease, or systemic lupus erythematosus (SLE); subdural hematoma; and subarachnoid hemorrhage. Because of the usually sudden nature of its cause, the symptoms of vascular dementia tend to begin more abruptly than those of Alzheimer's dementia. Symptoms may progress stepwise with the occurrence of new strokes. Unlike AD, the incidence of vascular dementia is lower after age 75. Other conditions that may cause dementia include:
SymptomsDementia is marked by a gradual impoverishment of thought and other mental activities. Losses eventually affect virtually every aspect of mental life. The slow progression of dementia is in contrast with delirium, which involves some of the same symptoms, but has a very rapid onset and fluctuating course with alteration in the level of consciousness. However, delirium may occur with dementia, especially since the person with dementia is more susceptible to the delirium-inducing effects of may types of drugs. Symptoms of dementia include:
DiagnosisSince dementia usually progresses slowly, diagnosing it in its early stages can be difficult. However, prompt intervention and treatment has been shown to help slow the effects of some dementias, so early diagnosis is important. Office visits over several months or more may be needed. Diagnosis begins with a thorough physical exam and complete medical history, usually including supplemental information from family members or caregivers. A family history of either AD or cerebrovascular disease may provide clues to the cause of symptoms. Simple tests of mental function, including word recall, object naming, and number-symbol matching, are used to track changes in the person's cognitive ability. Depression is common in the elderly and can be mistaken for dementia; therefore, ruling out depression is part of the diagnosis. Distinguishing dementia from the mild normal cognitive decline of advanced age also is critical. The medical history should include a complete listing of drugs and dosages and being taken, since a number of drugs can cause dementia-like symptoms in the elderly. Determining the cause of dementia may require a variety of medical tests, chosen to match the most likely etiology. Cerebrovascular disease, hydrocephalus, and tumors may be diagnosed with x rays, CT or MRI scans, and vascular imaging studies. Blood tests may reveal nutritional deficiencies or hormone imbalances. TreatmentTreatment of dementia begins with treatment of the underlying disease, where possible. The underlying causes of nutritional, hormonal, tumor-caused, and drug-related dementias may be reversible to some extent. Treatment for stroke-related dementia begins by minimizing the risk of further strokes through smoking cessation, aspirin therapy, and treatment of hypertension, for instance. Alzheimer's disease is, as of 2009, incurable; however, early diagnosis and prompt intervention can slow decline from AD and extend the period during which people the disease can maintain independent functioning. As of 2009, the United States Food and Drug Administration (FDA) had approved five prescription drugs for the treatment of AD symptoms. Four of these are used to treat mild to moderate AD. They are galantamine (Razadyne formerly known as Reminyl), rivastigmine (Exelon), donepezil (Aricept), and tacrine (Cognex). Tacrine, however, is rarely prescribed because of safety issues. These drugs all act by increasing the level of chemical signaling molecules (neurotransmitters) in the brain to help compensate for decreased communication ability among nerve cells. The fifth drug, memantine (Namenda), is used to treat moderate to severe AD. It acts by regulating a chemical in the brain called glutamate. None of these drugs cure or stop AD. In some individuals, they do slow the progression of symptoms by modestly increasing cognition and improving the individual's ability to perform normal activities of daily living. Slowing or reversing dementia is an area of active research. Clinical trials of new drugs and therapies are ongoing. A list of current clinical trials that are enrolling volunteers can be found at http://www.clinicaltrials.gov. Participation in a clinical trial is free to qualified volunteers. Psychotic symptoms, including paranoia, delusions (false beliefs), and hallucinations (seeing things that are not there), may be treated with antipsychotic drugs such as haloperidol (Haldol), risperidone (Risperdal), quetiapine (Seroquel) and olanzapine (Zyprexa). Side effects of these drugs can be significant. Antianxiety drugs such as buspirone (BuSpar) may improve behavioral symptoms, especially agitation and anxiety. Depression is treated with antidepressants, usually selective serotonin reuptake inhibitors (SSRIs) such as sertraline (Zoloft) or paroxetine (Paxil). Sleep disturbances can also be treated with drugs, although many drugs for insomnia are recommended for short-term use only. In order to minimize side effects,medications generally should be administered cautiously and in the lowest possible effective doses to an individual with dementia. Caregivers generally must actively supervise the administration of all medications. Alternative treatmentAntioxidants, which act to protect against oxidative damage caused by free radicals, have been shown to inhibit toxic effects of beta-amyloid in laboratory tissue cultures. Vitamin E, an antioxidant, is thought to delay AD onset. However, it is not yet clear whether this is due to the specific action of vitamin E on brain cells or to an increase in the overall health of those taking it. Research is being conducted to determine if vitamin E or other antioxidants may delay or prevent AD. Ginkgo extract, derived from the leaves of the Ginkgo biloba tree, appeared to be one of the more promising alternative treatments for AD. A 1997 study of patients with dementia seemed to show that ginkgo extract could improve their symptoms, although the study was criticized for certain flaws in its method. Unfortunately, a large-scale, well-designed, follow-up study released in 2008 showed that Ginkgo extract neither prevented nor delayed AD. Some alternative practitioners advise people with AD to take supplements of phosphatidylcholine, vitamin B12, gotu kola, ginseng, St. John's Wort, rosemary, saiko-keishi-to-shakuyaku (A Japanese herbal mixture), and folic acid. As of 2009, none of these alternative therapies met the safety and effectiveness standards of conventional Western medicine as a treatment for AD. Supportive careCare for a person with dementia can be difficult and complex. The individual with dementia must cope with functional and cognitive limitations, while family members or other caregivers assume increasing responsibility for the person's physical needs. In progressive dementias such as AD, the person may ultimately become completely dependent. Education of the patient and family early in the disease progression can help them anticipate and plan for inevitable changes. Behavioral approaches may be used to reduce the frequency or severity of problem behaviors, such as aggression or socially inappropriate conduct. Problem behavior may be a reaction to frustration or overstimulation; understanding and modifying the situations that trigger it can be effective. Strategies may include breaking down complex tasks, such as dressing or feeding, into simpler steps, or reducing the amount of activity in the environment to avoid confusion and agitation. Pleasurable activities, such as crafts, games, and music, can provide therapeutic stimulation and improve mood. Modifying the environment can increase safety and comfort while decreasing agitation. Home modifications for safety include removal or lock-up of hazards such as sharp knives, dangerous chemicals, and tools. Childproof latches or Dutch doors may be used to limit access as well. Lowering the hot water temperature to 120°F (48.9°C) or less reduces the risk of scalding. Bed rails and bathroom safety rails can be important safety measures, as well. Confusion may be reduced with simpler decorative schemes and presence of familiar objects. Covering or disguising doors (with a mural, for example) may reduce the tendency to wander. Positioning the bed in view of the bathroom can decrease incontinence. Long-term institutional care may be needed for the person with dementia, as profound cognitive losses often precede death by a number of years. Early planning for the financial burden of nursing home care is critical. Useful information about financial planning for long-term care is available through the Alzheimer's Association (see resources). Family members or others caring for a person with dementia often are subject to extreme stress, and may develop feelings of anger, resentment, guilt, and hopelessness, in addition to the sorrow they feel for their loved one and for themselves. Depression is an extremely common consequence of being a full-time caregiver for a person with dementia. Support groups can be an important way to deal with the stress of caregiving. The location and contact numbers for caregiver support groups are available from the Alzheimer's Association; they may also be available through a local social service agency or the patient's physician. Medical treatment for depression may be an important adjunct to group support. PrognosisThe prognosis for dementia depends on the underlying disease. Alzheimer's disease is incurable and often fatal. When AD is not be the direct cause of death, the generally poorer health of a person with AD increases the risk of life-threatening infection, including pneumonia. In addition, other diseases common in old age such as cancer, stroke, and heart disease often have more severe consequences in a person with AD. Vascular dementia usually is progressive, with death from stroke, infection, or heart disease. PreventionAs of 2009, there was no way to distinguish between people who will develop dementia as they age and those who will not. There currently is no known way to prevent Alzheimer's disease, although several drugs may slow its progression. Various studies have reported that people over age 75 who actively participated in leisure activities such as playing board games, reading, dancing, and playing musical instruments were less likely to have dementia after five years than others their age. The risk of developing multi-infarct dementia may be reduced by reducing the risk of stroke. Key Terms
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Dementia dementia[dĕ-men´shah]de·men·ti·a(dĕ-men'shē-ă),dementia(dĭ-mĕn′shə)dementiaImpairment of previously attained occupational or social functioning, due to development of acquired and persistent memory impairment associated with impairment of intellectual function in one or more of the following domains: language, visuospatial, skills, emotion or personality of cognition, in the presence of normal consciousness.Frequency At age 60 to 69, 1% are demented; at age 90-95, 40% are demented. Aetiology Alzheimer’s, dementia with Lewy body formation, vascular dementia, frontotemporal dementia. Rare causes of dementia Degenerative disease, prion disease, metabolic/nutrition/toxic infections, hydrocephalus, neoplasia, head injury, demyelination. Treatable causes of dementia Endocrine and metabolic disease, thyroid or parathyroid disease, pituitary/adrenal dysfunction, hepatic encephalopathy, Wilson’s disease, chronic renal failure. Infections Cryptococcal meningitis, neurosyphilis. Intracranial disorders Hydrocephalic dementia, tumours. Vasculitis SLE, periarteritis nodosa, temporal arteritis. Vitamin deficiency Thiamin, nicotinic acid, folic acid, vitamin B12. Others Drugs and/or toxins, heart failure, “respiratory” encephalopathy, sarcoidosis, functional psychiatric disorders. dementiaChronic brain failure, chronic brain syndrome, chronic organic brain syndrome, cortical and subcortical dementia, organic mental disorder, presbyophrenia, senility Neurology A general term for a diffuse irreversible condition of slow onset seen in older Pts, due to dysfunction of cerebral hemispheres; it is an end stage of mental deterioration, and is characterized by a loss of cognitive capacity, leading to ↓ social &/or occupational activity Prevalence Age-linked–affects ± 10.5% of those 80-85; 12.6-47.2% ≥ 85 Etiology 47% Vascular-type–potentially treatable; 44% Alzheimer's type Clinical ↓ mental ability, memory loss, often with emotional disturbances, personality changes Imaging MRI, PET, SPECT DiffDx Alzheimer's disease, multi-infarct–vascular dementia, Pick's disease, diffuse Lewy disease, Wernicke-Korsakoff syndrome, frontal lobe-type dementia, progressive supranuclear palsy, progressive subcortical gliosis, corticobasilar degeneration; other causes of dementia include alcohol, schizophrenia, subdural hematoma, normal pressure hydrocephalus, vitamin B12 deficiency and repeated trauma–'punch-drunk' syndrome, torture victims. See Dialysis dementia, Lewy body dementia, Multiinfarct dementia, Pseudodementia, Vascular dementia.de·men·ti·a(dĕ-men'shē-ă)Synonym(s): amentia. dementiaA syndrome of failing memory and progressive loss of intellectual power due to continuing degenerative disease of the brain. About half are believed to be due to ALZHEIMER'S DISEASE and about one third to small repeated STROKES. A small proportion are due to PRION DISEASE (spongiform encephalopathy). It has been shown that participation in leisure activities such as playing music, games and reading, are associated with a significantly lower risk of dementia, but it is not clear whether such activities reduce the risk.de·men·ti·a(dĕ-men'shē-ă)Patient discussion about dementiaQ. how is dementia and alcoholism related Q. Is obesity a risk factor for Dementia? Q. discussing my father situation with the doctor My 82 years old dad has dementia, and currently lives with us at my home. For the last few weeks he's very nervous and sometimes yells and screams at us. I want to take him to the doctor and see if he can get any help, but I'm afraid that if I'll try to speak with doctor about this subject in front of my dad he'll take offense. What can I do?Thank you very much! dementiadementia is not available in the list of acronyms. Check:
dementia
Synonyms for dementia
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