Different Types of Dementia
Dementia refers to a condition where functions such as memory and thinking decline due to impairment of the brain and there are difficulties in daily life. The probability of having dementia between the ages of 65 and 69 is 1.5%, and increases to 27% among 85-year-olds; in other words, 1 in 4 people have dementia.
Types of Dementia
There are several types of dementia, among which the four major ones are as follows.
Forgetting recent things
Dementia that occurs when part of the brain has shriveled accounts for nearly 70% of all cases of dementia. Symptoms include being able to remember past events, but easily forgetting recent ones. It starts with mild forgetfulness and gradually progresses; patients eventually lose their sense of time and place.
Losing memory in patches
Dementia that occurs due to brain tissue dying because of a stroke or cerebral hemorrhaging accounts for approximately 20% of all dementia cases. Rather than forgetting everything, this type of dementia is characterized by “patchy” dementia where the patient retains part of their memory. Major progression is not observed as long as new vascular lesions do not occur.
Hallucinations and trembling
Dementia with Lewy bodies
This dementia is observed in approximately 4% of the entire dementia population; it occurs due to special proteins known as “Lewy bodies” accumulating in the brain. Symptoms include seeing things that are not really there, trembling of the limbs, stiffness of muscles, and a tendency to fall due to shortened steps.
Inability to control feelings
This dementia is observed in approximately 1% of the entire dementia population, and is considered incurable. Patients become unable to control their feelings due to atrophy of the frontal and temporal lobes that control feelings and judgment; patients are no longer able to follow rules, and problems with sociability also arise easily.
Memory consists of three stages: (1) studying and remembering, (2) storing as memory, and (3) recalling.
Forgetfulness associated with aging is a state where stage (3) becomes difficult, and it takes time to recall memories.
On the other hand, dementia is a state where stage (1), “studying and remembering”, becomes impossible.
For example, remembering that you made a promise to meet someone, but being unable to remember the meeting place falls under forgetfulness. Forgetting that you made the promise itself falls under dementia.
|Forgetfulness due to aging
||Forgetfulness due to dementia
||Cannot recall partially (Example: You made a promise to meet someone, but cannot remember the location)
||Cannot recall anything (Example: You forget that you made a promise to meet someone)
|Learning something new
||Generally able to lead an ordinary life
||There are interferences with daily life
||Not much of an impact
||Issues arise, such as a change in personality