Northwestern University Feinberg School of Medicine

Northwestern University Feinberg School of Medicine

About Dementia

Overview

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There is a type of dementia called "frontotemporal" which typically affects patients at a very early age. In this type of dementia, there is no true memory loss in the early stages of the type that is seen in Alzheimer's dementia. Instead, there are changes in personality, ability to concentrate, social skills, motivation and reasoning. Because of their nature, these symptoms are often confused with psychiatric disorders. There are gradual changes in one's customary ways of behaving and responding emotionally to others. Memory, language and visual perception are usually not impaired for the first two years, yet as the disease progresses and spreads to other areas of the brain, they too may become affected. Typically, the disorder affects females more than males.

The symptoms reflect the fact that the brain degeneration is not initially widespread and settles in the parts of the brain that are important for social skills, reasoning, judgement and the ability to take initiative.

When the brains of individuals with frontal lobe dementia are studied after death, the types of microscopic abnormalities that are seen are typically of two kinds. The first type is called Non-specific focal degeneration and the second is labeled Pick's disease. Non-specific focal degeneration accounts for 80% of cases of frontal lobe dementia. It is called "non specific" because there are no abnormal particles that are identifiable-only evidence that brain cells have been eliminated. Pick's disease, which accounts for 20% of cases of frontal lobe dementia, is identified under the microscope by abnormal particles called "Pick bodies", named after the neurologist who first observed them.

How Does it Affect the Brain?

Frontotemporal dementia affects the part of the brain that regulates comportment, insight and reasoning. "Comportment" is a term that refers to social behavior, insight, and "appropriateness" in different social contexts. Normal comportment involves having insight and the ability to recognize what behavior is appropriate in a particular social situation and to adapt one's behavior to the situation. For example, a funeral is a solemn event requiring certain types of behavior and decorum. Similarly, while it may be perfectly natural and acceptable to take one's shoes and socks off at home, it is probably not the thing to do while in a restaurant. Comportment also refers to the style and content of a person's language. Certain types of language are acceptable in some situations or with friends and family, and not acceptable in others.

Insight, an important aspect of comportment, has to do with the ability to "see" oneself as others do. Insight is necessary in order to determine whether one is behaving in a socially acceptable or in a reasonable manner. Insight is also necessary for the patient to recognize his/ her deficits and illness. Changes in comportment may be manifested as "personality" alterations. A generally active, involved person could become apathetic and disinterested. The opposite may also occur. A usually quiet individual may become more outgoing, boisterous and disinhibited. Personality changes can also involve increased irritability, anger and even verbal or physical outbursts toward others (usually the caregiver). Comportment is assessed by observing the patient's behavior throughout the examination and interviewing other people (family and friends) who have information about the patient's "characteristic" behavior.

Individuals with frontotemporal dementia frequently have executive function and reasoning deficits. "Reasoning" refers to mental activities that promote decision-making. Being able to categorize information and to move from one perspective of a problem to another are examples of reasoning. "Executive functions" is a term that refers to yet another group of mental activities that organize and plan the flow of behavior. A good example of executive functions is what might happen if one were driving a car, talking with the passenger and suddenly having to respond to a child running into traffic. The ability to handle all the stimulation and to quickly plan a course of action is accomplished via executive functions. Individuals with frontal lobe dementia often lack flexibility in thinking and are unable to carry a project through to completion. Failure of executive functions may increase safety risk since they may not be able to plan appropriate actions or inhibit inappropriate actions.


This page last updated Jun 18, 2012

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