Middlebury, Vt -- As senior psychology major Libby Marks leads her research subjects into the interview room, the task seems simple compared with the complexity of the data she is about to collect. They fill out some paperwork, then Marks fits them with an electroencephalography (EEG) cap, which is connected to electrodes that measure brain wave activity. She shows them to a comfortable armchair then leaves to observe the experiment from another room.
Now seated and wired, the subjects watch a computer screen which shows them a sequence of 64 short sentences. The words flash on the screen one at a time and when the final word of each sentence appears, the subject clicks a button marked either "yes" or "no" to indicate whether the sentence makes sense.
|Subjects are fitted with an EEG cap covered in electrodes to measure brain wave activity.|
|During the experiment, subjects read a sequence of 64 sentences, one word at a time.|
|Marks and Kimble are looking at a specific part of the brain wave in each subject to see if there are differences in those suffering from PTSD.|
Marks, who has been working as a senior thesis student for Assistant Professor of Psychology Matthew Kimble says her senior thesis work in the lab has made her understand the urgent need for more information about PTSD. "We need more studies that lend legitimacy to the disorder," says Marks. "I hope our findings will point people in the right direction for further study that will give PTSD the recognition it deserves."
One of the greatest barriers to effective diagnosis and treatment, especially among veterans, is the notion that PTSD is a sign of weakness or that complaints won't be taken seriously.
"The thing I think is valuable about this study," says Kimble, "is that it may provide empirical physiological evidence that's consistent with what the veterans have been telling us." He says this type of information is urgently needed in a field like PTSD that is surrounded with doubt and controversy. "If you can show the neurophysiological correlates of the complaints that these men and women are reporting, then I think you're making headway into establishing the type of sympathy that is required for people to recover."
Marks, Kimble and another student, senior Yanik Bababekov, are exploring whether there are differences between the brain activity of a PTSD sufferer and a normally functioning person. They are looking at a specific part of the brain wave that deals with expectancy - or how your brain fills in the blanks when you hear a spoken sentence.
Theory suggests that people with PTSD symptoms, who commonly suffer from things like hypervigilance or inability to concentrate, would have different neurological responses, which they may not even realize, to the sentences than a normally-functioning person and that this difference would show in their brain waves.
Back in the lab with her subject ready to go, Marks begins the experiment. Each sentence in the sequence will be in one of three categories: expected, unexpected or trauma-related.
For example, they might begin with a sentence that makes perfect sense:
"The field was littered with trash."
Next, they might read something unexpected:
"The field was littered with traffic."
And some of the sentences will be related to trauma:
"The field was littered with bodies."
This kind of testing for expectancy responses is common in neuropsychological research, but it has never been done in the PTSD population until now. Marks says that it's still too early to draw any conclusions, but that she and Kimble have noticed signs that the PTSD subjects have more difficulty with the task than the non-PTSD group, which suggests there could be differences in this group that they will uncover when they analyze the data.
As she reflects on the experience of working in Kimble's clinical psychology lab, Marks realizes what a great opportunity this front line research has given her. "I had no exposure to any clinical population before this," she says. "The stories these people have and their willingness to put themselves out there and say, 'Here's what happened to me and here's how it affected my life,' has moved me to want to pursue clinical psychology."
Kimble says the clinical psychology lab is an excellent teaching opportunity for undergraduate students like Marks. "One of my larger goals here is to expose more students to these types of experiences and get them interested so that really good, smart students become clinical psychologists."
Thanks in part to her clinical research, Marks was recently offered and accepted a two-year staff research position at Massachusetts General Hospital in an anxiety disorders lab where she will work on panic disorder, general anxiety disorder and phobias. It's a position that will immerse her in the type of clinical setting she has come to love. After that, she says a doctorate is the likely next step, but she's keeping her options open.
Soon Marks and Kimble will begin to analyze her thesis data to see what, if anything, they can conclude about the N400 response in PTSD sufferers. Regardless of what they discover in this round of research, they have continual reminders from their participants about the need for this kind of study. "The vast majority of people who participate in the experiment tell us they're really glad they did it," says Kimble. "They tell us, 'Anything I can do to help people who've had experiences like this, I'm willing to do.'"