Why do HD behaviors occur?

The Prefrontal Cortex (PFC) is slowly damaged in HD

  • The PFC is a uniquely human part of the brain.
  • It is a “simulator” that creates an internal vision of goals and possible actions.
  • It organizes planning, sequencing and initiating tasks.
  • This brain area stops the flow of unimportant information into consciousness.
  • When changes in the environment occur, the PFC organizes a change in behavior. This is why people with HD have “rigid” routines.
    • I can’t get started, and when I do, I do everything slower than I used to, and the links between steps are missing.
    • I need more alarms to prompt me that something needs to be done; I depend on a rigid system of reminders.
    • Change makes me very anxious.
    • I sometimes can’t figure out what I need to pay attention to, and get overwhelmed.

The Prefrontal cortex is involved in interpersonal
reactions and relationships

  • This brain area recognizes social cues and nonverbal communication
  • Anticipating social consequences of behavior, the prefrontal cortex initiates socially acceptable behavior or inhibits damaging social reactions
  • The PFC stops the flow of unimportant information into awareness
  • Controlling behavior activation, the PFC controls exaggerated behavioral expression or highly inhibited, apathetic behavior
    • I don’t know what to expect from other people, I am often perplexed by how others react to me.
    • I blurt out rude comments, even if I hurt the people I care about
    • I can’t read emotions or sometimes misread emotions in the face of others.
    • Being around new people is overwhelming.
    • Noise, colors, what people say to me or say to each other – flood my brain, and I get overwhelmed.

The Prefrontal Cortex manages behavior at an unconscious level

You don’t know that you have the ability to do these things. When someone loses these abilities, it can be very perplexing because:

  • If you aren’t aware you have these abilities, you don’t know how to help the person with HD replace the ability lost.
  • The affected person is unaware they have lost these abilities, and may be unwilling to receive help for missing skills.
  • How can you relate to someone who has lost an ability you don’t even know you have? This is one of the most difficult to understand aspects of HD related behavior. It’s hard to empathize with this loss of function.

Other problems:

  • Thinking slows down. It may take longer for the person with HD to understand and process what you say and do. There may be several seconds or even minutes before the person with HD can respond to you.
  • It becomes more difficult to learn. It takes more repetitions to consolidate a new memory.
  • Language is impaired, both because of the muscle coordination required for speech, but also because speech production is impaired.
    • My thinking is slow, and distracted.
    • I have to work really hard to keep on task.
    • Interpersonal interactions with others are fraught with struggle. I don’t feel understood, and I don’t understand the reactions I get from others.
    • I can’t trust myself.

“Having HD is hard work.”
Vickie Hunt, RN
Wake Forest University