Dementia 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. Dementiais a group of symptoms caused by gradual death of brain cells. Dementia is usually 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 which characterizes dementia.
The loss of cognitive abilities that occurs with dementia leads to impairments in memory, reasoning, planning, and personality. While the overwhelming number of people with dementia are elderly, it is not an inevitable part of aging. Instead, dementia is caused by specific brain diseases. Alzheimer's disease is the most common cause, accounting for three quarters of all cases, followed by vascular or multi-infarct dementia. 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, or neurons. Senile plaques are composed ofparts of neurons surrounding a group of proteins called beta-amyloid deposits. Why these structures develop is unknown.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).
Dementia is marked by a gradual impoverishment of thought and other mental activities. Losses eventually affect virtually every aspect of mental life. Theslow 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.
- Symptoms include:
- Memory losses
- Impaired abstraction and planning
- Language and comprehension disturbances
- Poor judgment
- Impaired orientation ability
- Decreased attention and increased restlessness
- Personality changes and psychosis
Treatment of dementia begins with treatment of the underlying disease, wherepossible. 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.There are no therapies which can reverse the progression of Alzheimer's disease. Aspirin, estrogen, vitamin E, and selegiline are currently being evaluated for their ability to slow the rate of progression.
Care for a person with dementia can be difficult and complex. The patient must learn to 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 Alzheimer's disease, the personmay ultimately become completely dependent. Education of the patient and family early on in the disease progression can help them anticipate and plan forinevitable changes.
Symptoms of dementia may be treated with a combination of psychotherapy, environmental modifications, and medication. Drug therapy can be complicated by forgetfulness, especially if the prescribed drug must be taken several times daily.
Two drugs, tacrine (Cognex) and donepezil (Aricept), are commonly prescribedfor Alzheimer's disease. These drugs inhibit the breakdown of acetylcholine in the brain, prolonging its ability to conduct chemical messages between brain cells. They provide temporary improvement in cognitive functions for about40% of patients with mild-to-moderate AD. Hydergine is sometimes prescribed as well, though it is of questionable benefit for most patients.
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.
Family members or others caring for a person with dementia are often subjectto extreme stress, and may develop feelings of anger, resentment, guilt, andhopelessness, in addition to the sorrow they feel for their loved one and forthemselves. 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 togroup support.
The prognosis for dementia depends on the underlying disease. On average, people with Alzheimer's disease live eight years past their diagnosis, with a range from one to twenty years. Vascular dementia is usually progressive, withdeath from stroke, infection, or heart disease.