Joe Palca - Annoying

A year after that visit, when Chris was twenty-nine, he decided to get tested for Huntington’s. “I just felt like I needed to know what direction to go in my life. I felt like I was stuck. I felt like the best thing to do was to find out if I had inherited the gene. I’m working on this documentary, and I’m about ready to find out my test results. I thought, ‘I hope I get some good news, but it would be great for the film if I got bad news.’” It was bad news.

Now, at age forty-three, Chris is showing mild chorea and says he’s a little more forgetful and words are harder to retrieve. His documentary is almost entirely shot, and he’s holding annual fund-raisers to bankroll the production of the rest of it. He makes regular speaking appearances to educate people about Huntington’s. For the last nine years, he’s been working with mentally ill adults—mainly, schizophrenics—who live in something like an assisted-living home, only it is for people with mental illness. The residents can come and go as they please, but there are always caretakers like Chris around. Chris says that he would like to see the same model of care for people with Huntington’s disease.

Care of HD patients is a challenge that often falls on family members, until the burden becomes too much. One of the main reasons people with Huntington’s are put into nursing homes, according to some studies, is irritability.

Psychiatrists such as Karen Anderson say that they spend a lot of time educating the families of HD patients. “A lot of it is teaching people that this loved one or this patient who used to be a reasonable person five or ten years ago is not the same,” Anderson says. “You can’t reason things out anymore because that part of the brain is not working the way it should.”

Although the symptoms can’t be traced to exact circuits, general brain regions are implicated in regulating irritability. Psychiatrist Jon Silver points to the frontal lobes. “Data have shown that irritability and aggression are correlated with frontal lobe lesions,” Silver says.

Silver specializes in treating patients with traumatic brain injury (TBI). The most commonly injured parts of the brain are the frontal and temporal lobes (mostly due to car accidents and falls)—which means there is some overlap between the brain areas affected in TBI patients and Huntington’s patients.

Irritability in Huntington’s patients and TBI patients manifests in a similar way: a short fuse that ends in a giant explosion. This is how Silver describes it: “If you’re crossing the street in Manhattan, and a car comes close to you as a pedestrian, what do you do? What do you do to the driver or the car? You don’t scream at him, you don’t hit the car. Right? My patients do.”

Your frontal lobes are thought to be the brakes for your most basic wants. Think of the frontal lobes as the gatekeeper for your limbic system. The limbic system—which includes the hippocampus, the amygdala, the anterior thalamic nuclei, and the limbic cortex—is your primal urge center. Do you feel hungry? It’s your limbic system telling you. Do you want to have sex? It’s your limbic system knocking. The idea is that without your frontal lobes to regulate your desires, you’d simply do these things without worrying about the consequences.

When you have a disease that affects your frontal lobes, Silver says, “You can’t inhibit your responses and deal with the stressors as well as you can when your frontal lobes are working well. What we’re saying is that the frontal lobe is in charge of inhibiting the limbic system.” Although many areas of the brain can play a role in anger and aggression, Silver believes that the frontal lobes play perhaps the most important role in regulating irritability.

If true, this suggests that getting annoyed over minor provocations is an inhibition problem. In other words, we all have this capacity for extreme responses, but most of us have frontal lobes that tamp down the annoyed reaction. Mark Groves puts it simply: “Our frontal lobes help inhibit inappropriate responses or impulsive responses. And our patients who have damage to these circuits lose their ability to inhibit those behaviors.”

Irritability is one of the earliest symptoms of Huntington’s, according to a study conducted by David Craufurd. {44} 44 1. Camille L. Julien, Jennifer C. Thompson, Sue Wild, et al., “Psychiatric Disorders in Preclinical Huntington’s Disease,” Journal of Neurology, Neurosurgery, and Psychiatry 78 (2007): 939–943. He found that HD patients were irritable five to ten years before motor symptoms appeared. As the HD progresses and more of the brain dies, however, irritability is overcome by indifference. Groves says, “One symptom that you see in basal ganglia disease is apathy. The more damage, the more apathy in Parkinson’s and Huntington’s.” One interpretation is that the basal ganglia—which is primarily associated with motor function—also helps us decide between different actions. In any given moment we’re faced with a huge array of behavioral choices, and it’s thought that this region of the brain helps you select the best one. When it’s not functioning, decisions are harder to make. Your brain can’t choose, so it chooses nothing.

One interesting symptom of Huntington’s that may shine light on the nature of irritability is that HD patients are apt to misconstrue situations, researchers say. Craufurd was the coauthor of a study that tested the ability of Huntington’s patients to read social cues by asking the participants to interpret cartoons. Identifying the humor in the cartoons required the viewer to infer the mental state of another person. Here’s the description from the paper in Neuropsychologia :

In one cartoon, for example, a man is shown cuddling a young woman who is sitting on his lap, while with his free hand, he is tapping a ping-pong ball with a bat. The humor lies in the fact that an older woman sitting in the adjacent room, within earshot but out of view of the couple, is deceived into believing that the man is playing table tennis, whereas in reality he is otherwise occupied. {45} 45 2. J. S. Snowden, Z. C. Gibbons, A. Blackshaw, et al., “Social Cognition in Frontotemporal Dementia and Huntington’s Disease,” Neuropsychologia 41(6) (2003): 688–701.

Huntington’s patients were asked to describe why the cartoon was funny. Here’s a misread that one HD patient made: “They’re having a bit of nooky while the wife’s sat [ sic ] in there. She’s thinking, ‘At least, he’s leaving me alone. Peace!’”

The interpretation isn’t like the paranoid delusion of a schizophrenic; it’s within the realm of possible reality, but it is not supported by the information presented. The authors of the study write, “HD patients did draw inferences that went beyond the physical contents of the cartoon. They abstracted and formulated hypotheses, including hypotheses about a character’s feelings or belief. However, those inferences deviated from the conventional interpretation.”

This tendency to misconstrue seems to exacerbate the irritability problem. We have all met someone who takes things the wrong way. Let’s say you tell your husband that his suit makes him look trim, and he responds, “Are you saying I’m fat?” People who are prone to reading too much into a statement or a situation also seem prone to getting annoyed. Kevin Craig said that many of his depressed patients are irritable, and it seems to be related to their tendency to assume the worst, even if there’s no evidence for the assumption. “They take things the wrong way,” he says. “Neutral comments become upsetting.” In the case of Huntington’s patients, the combination of being likely to misconstrue and having a short fuse because your mental brakes aren’t working well can result in disaster.