Dementia

Dementia is not a specific disease; rather, it is a descriptive term for a collection of symptoms related to the loss of intellectual ability. Dementia can be caused by a number of disorders that affect the brain, some of which are reversible and some of which are progressive. When dementia results from damage to particular areas of the brain, careful observation and examination can often localize the site(s) of the damage with considerable accuracy.

The emotional and financial impact of dementia on families is difficult to overstate, and the costs increase with the time an individual is demented and with the severity of the cognitive impairment.^[1] Alzheimer disease, one form of dementia, was estimated to cost more than $100 billion in the US in 1998.^[2]

Types

• Alzheimer dementia is the principal manifestation of Alzheimer Disease, also known as senile dementia of the Alzheimer Type (SDAT). This is the most common cause of dementia.
• Arteriosclerotic Dementia results from atherosclerosis of blood vessels supplying the brain.
• Boxer's Dementia results from repeated traumatic injuries to the brain
• Multi-infarct Dementia is caused by multiple, usually widely dispersed injuries (infarctions) caused by interrupted blood flow. It is commonly referred to as Vascular Dementia. Binswanger's disease is a sub-type of multi-infarct dementia that is characterized by brain atrophy, multiple lacunar infarcts in the white matter, subcortical arteriosclerosis, and appearance of leukoaraiosis on brain imaging studies.
• Dementia with Lewy Bodies is caused by accumulation of bits of alpha-synuclein protein -- inside the nuclei of neurons in areas of the brain that control particular aspects of memory and motor control.
• Frontotemporal Dementia, also known as Pick's Disease, is caused by a shrinking and frontal and temporal areas of the brain.
• Normal Pressure Hydrocephalus is dementia caused by excessive accumulation of cerebrospinal fluid in the brain, causing hydrocephalus being observed as enlarged ventricles on the brain scan (CT or MRI). Dementia associated with normal pressure hydrocephalus is also accompanied by gait difficulty with tendency to fall backwards, and by bladder incontinence.
• While some patients have a single, well defined dementia, many others have an ill-defined form which may be caused by a mixture of several types of dementia. Mixed dementia is often more complicated, with a greater number of behavioral symptoms that are harder to treat.

Signs and Symptoms

People with dementia have significantly impaired intellectual functioning that interferes with normal activities and relationships. They also lose their ability to solve problems and maintain emotional control, and they may experience personality changes and behavioral problems, such as agitation, delusions, and hallucinations. While memory loss is a common symptom of dementia, memory loss by itself does not mean that a person has dementia.

Diagnosis

The diagnosis of dementia is often based on observations gathered from family members or caregivers and evaluation of signs and symptoms from a health professional. According to the Diagnostic and Statistical Manual of Mental Disorders, (DSM-IV),the criteria for dementia include evidence of impairment in memory and either (a) impairment in one other intellectual function (abstract thinking, judgment or higher cortical functions) or (b) a personality change. These disturbances must be sufficient to interfere with work, usual social activities or relationships with others. The tenth edition of the International Classification of Diseases (ICD-10) also require a decline in memory and other cognitive abilities sufficient to impair normal everyday personal activities. Another popular definition proposes that 'dementia is the decline of memory and other cognitive functions in comparison with the patient's previous level of function as determined by a history of decline in performance and by abnormalities noted from clinical examination and neuropsychological tests'.^[3] The diagnosis of dementia remains a clinical diagnosis, however blood tests, neuropscyhological testing and brain imaging are all valuable tools to aid in the diagnosis. Presently, neuroimaging includes either a CT scan of the head or MRI of the brain ( if one suspects a vascular component to the cognitive complaints). Although over the years, many new neuroimaging techniques have been approved for evaluating someone with a suspected dementia, their use, and approval based on various healthcare providers, varies across the country. Thus, specialists often reserve the use of brain PET imaging (positron emission tomography) scan to aid in the diagnosis of different types of dementia including Alzheimer's disease, Frontotemporal dementia or multi infarct dementia.[[Category:|Category:]]

Causes

Some of the diseases that can cause symptoms of dementia are Alzheimer disease, vascular dementia, Lewy body dementia, frontotemporal dementia, Huntington’s disease, Creutzfeldt-Jakob disease, and AIDS. Doctors have identified other conditions that can cause dementia or dementia-like symptoms including reactions to medications, metabolic problems and endocrine abnormalities, nutritional deficiencies, infections, poisoning, brain tumors, anoxia or hypoxia (conditions in which the brain’s oxygen supply is either reduced or cut off entirely), and heart and lung problems.

Epidemiology

Dementia is highly prevalent, and its prevalence increases with age. One estimate is that 5.7% of people in the US over 65 years of age have dementia.^[4]

Treatment

Medications

Drugs to specifically treat Alzheimer Disease and some other progressive dementias are now available. Although these drugs do not halt the disease or reverse existing brain damage, they can improve symptoms and slow the progression of the disease. This may improve an individual’s quality of life, ease the burden on caregivers, or delay admission to a nursing home. Many researchers are also examining whether these drugs may be useful for treating other types of dementia.

To date there are five agents that clinicians use to treat Alzheimer's disease. Four of these drugs work to enhance cholinergic transmission in the brain by reducing the degradation of acetylcholine through enzyme inhibition of acetylcholinesterase ( AchE). ^[5]

The very first drug used to treat AD was tacrine, but due to liver toxicity is no longer being used in clinical practice. The drugs that are commonly used in clinically practice, that are in the AchE class include, Donepezil, Galantamine and Rivastigmine. All of these drugs have shown similar results for the symptomatic treatment of mild to moderate Alzheimer's disease. It is important to note that none of these drugs reverse the underlying progression of AD but rather aim to slow down the clinical progression of the disease.

Typically donepezil is given one a day starting at 5 mg /day and then increased to 10 mg/day after 4 to 6 weeks. Many clinicians who do not see many patients with Ad, fail to increase the dose to 10 mg/day and keep their patients at 5 mg/day. It is important to note that all of the clinical trials that have evaluated the use of donepezil, have used the 10 mg/day dose and thus 10 mg /day is the desired dose for treatment. If side effects ( see below) occur with the higher dose of Aricept, then experts suggest to switch to another AchE such as Galantamine or Rivastigmine.

Galantamine is typically started at 4 mg twice a day for four weeks and then increased to 12 mg twice a day. Some clinicians have opted to start their patients on an extended release form of Galantamine, and various formulations include, 8mg, 16 mg, and 24 mg doses that can be taken once daily.  Rivastigmine is typically given twice daily at 1.5 mg starting dose and then increased to 3 mg twice a day  and then maintained at 6 mg twice a day. 

These medications are not without side effects and specific contraindications. Patients who have serious liver disease or have alcohol abuse should not be treated with these medications. AchE also increase gastric secretions and bronchial secretions and thus should not be used in patients with peptic ulcer disease or asthma. Finally, patients who have pre existing bradycardia, sick sinus syndrome or AV blocks, should not be given AchE. Common side effects of AchE in varying degrees are: diarrhea, leg cramps ( seen with donepezil), nausea, weight loss ( rivastigmine), vivid dreaming ( donepezil).

Over the years, a new class of medication, partial glutamate antagonists, have been used for the treatment of AD. The most commonly used medication is a N methly-D-aspartate ( NMDA) drug called memantine. The mechanism of action of memantine is to block the excitatory effects of glutamate. Memantine is normally given 5 mg once daily to 10 mg twice a day. Similar to AchE, the titration should occur over 4 weeks. Typically memantine is used as an add on therapy for mild to moderate AD, however many clinicians are using memantine as the first line medication when their initial assessment suggests a moderate to severe stages of the disease. The main side effects of memantine are constipation, excitability or sleepiness. To date, there are no drug to drug interactions.

Cognitive interventions

Many people with dementia, particularly those in the early stages, may benefit from practicing tasks designed to improve performance in specific aspects of cognitive functioning. For example, people can sometimes be taught to use memory aids, such as mnemonics, computerized recall devices, or note taking. Some types of dementia can be halted or reversed with appropriate treatment.

Caring for someone with Dementia

People with moderate or advanced dementia typically need round-the-clock care and supervision to prevent them from harming themselves or others. They also may need assistance with daily activities such as eating, bathing, and dressing. Caring for someone with dementia can be a stressful experience, and caregivers often need respite.

Clinical Trials

A list of clinical trials related to dementia that are currently enrolling volunteers is available here.

Related Videos

An eye-to-eye interview to help understand Alzheimer's disease (video donated by NIH):


Scientists think that as many as 4.5 million Americans suffer from Alzheimers disease. With November being Alzheimers Disease Awareness Month, were featuring an interview with an expert on the subject. Dr. Laurie Ryan is with the National Institute on Aging. We start by asking what exactly is Alzheimers disease?

References

1. ↑ Jönsson L, Berr C. Cost of dementia in Europe. Eur J Neurol. 2005 Jun;12 Suppl 1:50-3. Citation
2. ↑ Meek PD, McKeithan K, Schumock GT. Economic considerations in Alzheimer's disease. Pharmacotherapy. 1998 Mar-Apr;18(2 Pt 2):68-73 Abstract
3. ↑ McKhann G, Drachman D, Folstein M, Katzman R, Price D, Stadlan EM. Clinical diagnosis of Alzheimer's disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease. Neurology. 1984 Jul;34(7):939-44. Abstract
4. ↑ Rice DP, Fillit HM, Max W, Knopman DS, Lloyd JR, Duttagupta S. Prevalence, costs, and treatment of Alzheimer's disease and related dementia: a managed care perspective. Am J Manag Care. 2001 Aug;7(8):809-18. Abstract | PDF
5. ↑ Hitzeman N. Cholinesterase inhibitors for Alzheimer's disease. Am Fam Physician. 2006 Sep 1;74(5):747-9. Citation | Full Text

External Links

The Alzheimer's Foundation of America is dedicated to improving the quality of life for individuals confronting dementia and their caregivers and families.