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Dementia is a syndrome that involves memory loss and decline in intellectual functioning that is severe enough to interfere with an individual’s ability to perform routine tasks. More specifically, it involves:

  • impairment in two or more areas of thinking and mental ability, for example chronic forgetfulness, planning, organizing and decision making, and confusion.
  • a decline from prior levels of function that interferes in daily life, such as work duties, driving, organizing tasks and preparing meals.

Common symptoms of dementia

  • memory changes that disrupt daily life
  • problems with planning or problem solving
  • difficulty completing familiar tasks
  • confusion with time or place
  • trouble understanding visual images and spatial relationships
  • new problems with words in speaking or writing
  • misplacing things and losing ability to retrace steps
  • decreased or poor judgment
  • withdrawal from work or social activities
  • changes in mood and personality.

Dementia is detected through a multi-step process that includes the patient’s medical history, as shared by both the patient and a knowledgeable informant such as a family member, and an objective assessment by a healthcare professional including a mental status evaluation, a clinical examination and laboratory tests.

Types of Dementia

Alzheimer’s disease is the most common cause of dementia, accounting for between 60 and 80 percent of all cases. For more information, see the Alzheimer’s disease page. However, there are more than 80 different disorders that cause dementia or simulate dementia. Dementia is sometimes the result of degenerative diseases that are progressive and cannot be stopped. However, some causes of dementia may be treated and reversed.

Vascular Dementia (VaD)
Vascular dementia (VaD) may arise as a result of cerebrovascular disease in which the flow of blood to the brain is limited or non-existent to certain areas of the brain. VaD is often the result of multiple strokes; it is estimated that nearly a fifth of people who suffer a stroke will develop problems involving their mental abilities. VaD is responsible for approximately 20 percent of dementia cases. Approximately 10 to 20 percent of Americans over age 65 experiencing dementia have VaD, making it one of the leading causes of dementia, along with Alzheimer’s disease.

Lewy body dementia (LBD)
LBD affects an estimated 1.3 million individuals and their families in the United States alone. Because LBD symptoms may closely resemble other more commonly known diseases like Alzheimer’s and Parkinson’s, it is widely under-diagnosed.

LBD is an umbrella termfor two related diagnoses. It refers to both Parkinson’s disease dementia and dementia with Lewy bodies. The earliest symptoms differ but reflect the same underlying biological changes in the brain. Over time, people with both diagnoses will develop very similar cognitive, physical, sleep and behavioral symptoms.

Early diagnosis and treatment of LBD may extend quality of life and independence. Many people with LBD enjoy significant lifestyle improvement with a comprehensive treatment approach and some may even experience little change from year to year. 

LBD symptoms

  • Dementia is the primary symptom and includes problems with memory, problem solving, planning and abstract or analytical thinking. Cholinesterase inhibitors, medications originally developed for Alzheimer’s, are the standard treatment today for cognitive LBD symptoms.
  • Cognitive fluctuations involve unpredictable changes in concentration and attention from day to day.
  • Parkinson’s-like symptoms include rigidity or stiffness, shuffling gait, tremor and slowness of movement. Sometimes a Parkinson’s medication called Levodopa is prescribed for these symptoms.
  • Hallucinations and seeing or hearing things that are not really present. If the hallucinations are not disruptive, they may not need to be treated further. However, if they are frightening or dangerous, physicians may recommend a cautious trial use of a newer antipsychotic medication.
  • Information on Lewy Body Dementia has been provided by the Lewy Body Dementia Association (LBDA).

Dementia-Related Disorders

Medication-induced and systemic disorders 
Medication-induced dementia and systemic disorders are two common causes of dementia that are potentially reversible. A thorough drug history and a review of all medications being taken by a patient is used to rule out a medication-induced dementia. Metabolicendocrine or nutritional system disorders, such as hypothyroidism, can be diagnosed with routine laboratory tests and most respond favorably to treatment.

Depression is another common cause of reversible dementia in older adults. Depression may cause elderly patients to experience symptoms such as confusion, loss of memory disturbance and inattention deficits, all of which can be mistaken for dementia. A medical history and mental-status examination helps determine the need for a treatment plan to address depressive symptoms.

Frontotemporal disorders
This form of dementia is caused by a family of brain diseases known as frontotemporal lobar degeneration (FTLD). Scientists estimate that FTLD may cause up to 10 percent of all cases of dementia and may be about as common as Alzheimer’s among people younger than age 65.

Frontotemporal disorders can be grouped into three types, defined by the earliest symptoms physicians identify when they examine patients.

  • progressive behavior/personality decline—characterized by changes in personality, behavior, emotions, and judgment.
  • progressive language decline—marked by changes in language ability, including speaking, understanding, reading and writing.
  • progressive motor decline—characterized by various difficulties with physical movement, including shaking, difficulty walking, frequent falls and poor      coordination.

Molecular Imaging and Dementia

PET/CT scans are highly useful in:

  • detecting types of dementia,
  • evaluating ongoing cognitive decline
  • evaluating the effectiveness of new therapies in clinical trials.

SPECT is used to differentiate disease processes that produce dementia.