What is Dementia?
Dementia is not one disease. Instead, it is an umbrella term that describes a group of symptoms affecting a person’s intellectual and social abilities severely enough to interfere with daily functioning. Different types of dementia exist, but all dementias are in some way caused by conditions or changes in the brain. The most common cause of dementia in people over 65 years of age is Alzheimer disease.
MCI - Mild Cognitive Impairment, DLB - Dementia with Lewy Bodies,
FTD - Frontotemporal Degeneration, PDD - Parkinson Disease Dementia,
PSP - Progressive Supranuclear Palsy, CBD - Corticobasal Degeneration
Click on the dementia names below to find out more information.
Mild Cognitive Impairment (MCI)
Mild cognitive impairment (MCI) is an intermediate stage between the expected cognitive decline of normal aging and the more pronounced decline of dementia. It involves problems with memory, language, thinking, and judgment that are greater than typical age-related changes. By definition, and unlike dementia, the changes associated with MCI aren't severe enough to interfere with day-to-day life and ordinary activities.
Vascular dementia is an alternative term for multi-infarct dementia (MID) and is caused by a number of small strokes or, sometimes, one or several large strokes. Symptoms of vascular dementia are slowed thinking and stroke-like symptoms (e.g., weakness on one side of the body). Notably, strokes often complicate other dementias such as Alzheimer’s disease.
Dementia with Lewy Bodies (DLB)
Dementia with Lewy bodies (DLB) is form of dementia that is closely related to both Alzheimer’s disease and Parkinson’s disease. Dementia with Lewy bodies is accepted as the way to describe patients whose earliest symptoms include a decline in thinking abilities and who later develop such Parkinson’s disease symptoms as tremor, increased muscle tone, slowness of movements, and gait problems. When the brains of these patients are examined, they show clear signs of Lewy body brain cell changes and, over half the time, brain cell changes that are characteristic of Alzheimer’s disease (or the “Lewy body variant of Alzheimer’s disease”). Other symptoms associated with DLB include visual hallucinations, fluctuations in alertness and confusion, and REM sleep behavior disorder (the latter typically characterized by acting out of dreams). Conversely, patients whose difficulties begin with the motor symptoms of Parkinson’s disease and only develop dementia later in their illness are identified as having “Parkinson’s disease dementia.”
Frontotemporal Degeneration (FTD)
Frontotemporal degeneration (FTD) is characterized by the accumulation of pathology in the frontal and temporal lobes of the brain. FTD spectrum diseases are the leading cause of dementia in people under 65 years of age (early onset).
Clinically, FTD can manifest as impairments in language and comprehension (primary progressive aphasia) or behavior and personality changes (behavioral variant FTD). These changes may include inappropriate behaviors (such as eating off other’s plates at dinner or in a restaurant), disinhibition, loss of interest in activities (apathy), and compulsive behaviors. Memory tends to be relatively preserved in FTD, but other areas of thinking such as judgment, organizational skills and speech can become quite impaired as the disease progresses. Some forms of FTD also involve motor symptoms, such as ALS.
Parkinson's Disease Dementia (PDD)
Patients whose difficulties begin with the motor symptoms of Parkinson’s disease and only develop dementia later in their illness are identified as having Parkinson’s disease dementia. In contrast to people with Alzheimer’s disease, people with Parkinson’s disease dementia tend to experience greater difficulty with executive functions such as multi-tasking and organization and with skills requiring spatial function (e.g., finding ones way around town). Many symptoms seen in dementia with Lewy bodies (DLB) such as hallucinations are also often seen in Parkinson’s disease dementia.
Progressive Supranuclear Palsy (PSP)
Progressive supranuclear palsy (PSP) is a rare brain disorder that causes serious, permanent problems with people’s ability to control their walking movements and balance. The most obvious sign of the disease is an inability to aim the eyes properly, which occurs because of lesions in the area of the brain that coordinates eye movements. Affected individuals often show alterations of mood and behavior, including depression and apathy, as well as mild dementia that progresses over time.
Corticobasal degeneration (CBD)
Corticobasal degeneration (CBD) is a rare progressive neurodegenerative disease involving a part of the brain known as the cerebral cortex and gray matter in the brain, which is known as the basal ganglia. The initial symptoms of CBD include stiffness; shaky, slow, or clumsy movements; and difficulty with speech and comprehension. Symptoms that are related to a lack of muscle control usually begin on one side of the body and spread gradually to the other side of the body.
Prion diseases are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished other neurodegenerative disorders by long periods of dormancy and incubation as well as characteristic spongiform changes in the brain that are associated with loss of brain cells. Although prion disease has many different forms, some symptoms are dementia, personality changes, depression and other psychiatric problems, lack of coordination, and/or unsteady walking movements. Most prion diseases in humans, although not all, progress more rapidly, survival of 6 to 12 months, than other dementias such as Alzheimer’s disease. The prion disease include Creutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker disease, fatal familial insomnia, and bovine spongiform encephalopathy ("mad cow disease").