As we mentioned in the first part of our series, we defined dementia broadly to describe a condition which is characterized by cognitive decline. As we said, there’s many different types of dementia of which we will describe below:
Alzheimer’s disease
This is the most common type; it accounts for an estimated 60 to 80 percent of cases. Difficulty remembering names and recent events is often an early clinical symptom; apathy and depression are also often early symptoms. Later symptoms include impaired judgment, disorientation, confusion, behavior changes, and difficulty speaking, swallowing, and walking.
Hallmark abnormalities are deposits of the protein fragment beta-amyloid (plaques) and twisted strands of the protein tau (tangles).
Vascular dementia (also known as multi-infarct or post-stroke dementia or vascular cognitive impairment)
Vascular dementia is considered the second-most common type. Impairment is caused by decreased blood flow to parts of the brain, often due to a series of small strokes that block arteries. Symptoms often overlap with those of Alzheimer’s, although memory may not be as seriously affected.
Mixed dementia
Mixed dementia is a condition in which abnormalities characteristic of more than one type occurs simultaneously. Physicians may also call mixed dementia “Dementia-multifactorial.”
In the most common form of mixed dementia, the abnormal protein deposits associated with Alzheimer’s disease coexist with blood vessel problems linked to vascular dementia. Alzheimer’s changes to the brain also often coexist with Lewy bodies. In some cases, a person may have brain changes linked to all three conditions: Alzheimer’s disease, vascular dementia, and dementia with Lewy bodies.
Dementia with Lewy bodies
Dementia with Lewy bodies (DLB) is a type of progressive dementia that leads to a decline in thinking, reasoning, and independent function because of abnormal microscopic deposits that damage brain cells over time.
From my many years of observation, I strongly believe that dementia with Lewy bodies is among the most common causes of dementia after Alzheimer’s disease and vascular dementia. This belief is also supported by the Alzheimer’s Association.
Parkinson’s disease
Parkinson’s disease (PD) belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. Some people with Parkinson’s disease will develop dementia, usually after the age of 70 or as late as during the early 80s. The four primary symptoms of PD are tremor, or trembling in hands, arms, legs, jaw, and face; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance and coordination. As these symptoms become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. PD usually affects people over the age of 50 from my observation (early stage). Early symptoms of PD are subtle and occur gradually. In some people the disease progresses more quickly than in others. As the disease progresses, the shaking or tremor, which affects the majority of PD patients, may begin to interfere with daily activities. Other symptoms may include depression and other emotional changes; difficulty in swallowing, chewing, and speaking; urinary problems or constipation; skin problems; and sleep disruptions.
