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Understanding Behavior in HD.final.8-18-05 - Huntington's Disease ...

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diagnosis or keep the diagnosis from the affected <strong>in</strong>dividual because they are concerned that he/she “cannot<br />

handle it.” Some people <strong>in</strong>terpret the unawareness as a sign that the <strong>in</strong>dividual “does not want to know” or<br />

will “get depressed” if he/she receives the diagnosis of <strong>HD</strong>. There is no evidence to suggest, however, that<br />

talk<strong>in</strong>g about <strong>HD</strong> to a person with unawareness will cause negative consequences.<br />

POSSIBLE CAUSES<br />

• Damage to circuits connect<strong>in</strong>g the caudate nucleus and the frontal and parietal lobes.<br />

• Normal psychological response to an overwhelm<strong>in</strong>g situation.<br />

• The circuit that relays <strong>in</strong>formation from other centers <strong>in</strong> the bra<strong>in</strong> to the frontal lobes (where appropriate<br />

actions are considered and <strong>in</strong>itiated) is <strong>in</strong>terrupted by caudate degeneration secondary to <strong>HD</strong>.<br />

In the f<strong>in</strong>al case, although the person with <strong>HD</strong> may still be able to see and hear accurately, the <strong>in</strong>formation<br />

seen and heard is often not available to the boss or decisionmaker of the bra<strong>in</strong>. Consider the example below.<br />

The eyes see that the person has two different shoes on and the visual <strong>in</strong>formation gets sent to the occipital<br />

cortex, which has cells to read shape, color, and movement. This <strong>in</strong>formation then travels toward the frontal<br />

lobes, where the boss will <strong>in</strong>struct the “motor controller” to change shoes. When an <strong>in</strong>dividual has <strong>HD</strong>,<br />

however, the cells <strong>in</strong> the caudate are break<strong>in</strong>g down and the <strong>in</strong>formation never gets relayed back to the frontal<br />

lobes.<br />

EXAMPLES<br />

Miles cont<strong>in</strong>ues to say that he will live with his wife and she will care for him, even though she has filed<br />

for divorce.<br />

Bob bathes and shaves only when asked, due to his difficulty recogniz<strong>in</strong>g how he smells or when his<br />

hygiene is poor.<br />

Claire will not go to the doctor. She says, “Noth<strong>in</strong>g is wrong with me, I’m not sick.”<br />

Steve will not say he has <strong>HD</strong>.<br />

When asked, Beverly says she has no change <strong>in</strong> her speech or walk<strong>in</strong>g and no uncontrollable movements,<br />

although she has severe chorea and slurred speech.

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