Can eye movement aid recall and ease trauma?

8/10/2003

It seems silly. How can jiggling your eyes back and forth improve memory?

Stephen Christman, a psychology professor at the University of Toledo, acknowledges the idea is a little wacky.

“The notion that something as simple as eye movement can have systematic effects is highly implausible. That's why I found it so interesting,” he said.

His research showed recall improved 20 to 30 percent when test subjects watched lights flashing from side-to-side on a computer screen.

But wait, it gets wackier.

There's a form of therapy sweeping the field of post-traumatic stress disorder treatment that often involves jiggling the eyes back and forth. Its practitioners say such movements ease people past the painful tyranny of traumatic memories.

The idea sounds so weird that few believe it at first.

Dr. Steven Silver started working with traumatic stress patients in 1972. But until 1989, the psychologist at the Veterans Hospital in Coatesville, Pa., relied on a treatment called exposure therapy. This proven technique required his combat-veteran clients to repeatedly review painful memories until the recall lost its raw immediacy. It's an agonizing process that operates at a glacial pace. No surprise that patients often fled the demanding treatment.

Then Dr. Silver read about Eye Movement Desensitization and Reprocessing - EMDR for short - in the Journal of Traumatic Stress. He was immediately suspicious.

“I didn't believe it. In fact, I called the editor ... and said, either there was some major methodological flaw that reviewers missed, or we're victims of a hoax.”

In the article, psychologist Francine Shapiro presented evidence suggesting that eye movement helped people overcome traumatic memories.

Despite his continuing skepticism, Dr. Silver decided to take a closer look and signed up for EMDR training.

“If it turns out to be crap, I'll just leave,” he thought.

He didn't leave. Instead, the following Monday, he put it to work on a Vietnam veteran he'd been working with for months with only minimal success. The vet was plagued by the death of his commanding officer, a man he liked and admired. He had been the officer's driver.

Dr. Silver described EMDR to this troubled man who agreed to try it. Manual in hand, Dr. Silver induced the rapid eye movements.

After the first set of eye movements, the patient reported the memory was “harder to see.” More eye movements, and he saw the memory “through a fog bank.” A third set followed.

“He looked at me, a little puzzled, and he said, `You know, it's too bad he died. He was a good man. But it wasn't my fault.'”

“This was a major trauma. It had been around for 25 years. I couldn't believe it. I thought something had gone wrong.” But since that first EMDR session, the man never again struggled with this memory.

Dr. Silver's work hasn't been the same since. “I hate this phrase - but it's a paradigm shift.”

wDr. Christman in Toledo wasn't trying to further the cause of EMDR when he conducted his memory experiments. His earlier research focused on the memory differences between right-handers and left-handers.

That work showed that left-handers and mixed handers have better episodic memory than right handers. Episodic memory refers to our recall of events.

He theorized that left-handers and mixed-handers benefit from better communication between the brain's two halves. They have a larger corpus callosum, a structure that connects the brain's hemispheres.

This wider roadway may provide a natural memory advantage due to the way memory is initially encoded and later recalled. University of Toronto researcher Endel Tulving showed that we capture memories in our left brain, but we retrieve them from our right.

“There must be some interhemispheric interaction,” Dr. Christman said. Could he enhance it? He decided to try eye movement.

Some 280 research subjects watched 36 words appear on a computer screen. Thirty minutes later, they watched the screens again. On some, subjects saw 30 seconds of alternating flashing lights to the left and right. Others saw the flashes at the top and bottom of the screens. A third group followed a light moving across the screen. A fourth group saw nothing.

Memory tests followed. Subjects received a list of 72 words and circled any they remembered from the earlier memorization task. This tests something called “recognition memory,” part of the episodic memory that Dr. Christman hoped to boost.

People who saw side-to-side lights performed significantly better on memory tests than any of the other subjects. They not only recalled about 25 percent more words; they also were less likely to circle words not on the original list.

In a second study, subjects recorded two events daily in a diary.

Two weeks after subjects turned in their journals, they were tested on its contents. But first, some were shown side-to-side flashes on a computer screen. Others watched a computer-generated dot change colors.

“The results were even more dramatic,” Dr. Christman said.

Those who saw lights flash from side to side scored 30 percent higher on the memory test.

In a paper published in the journal Neuropsychology, Dr. Christman proposed his discovery as a clue to the mechanism behind EMDR. Here was evidence of a relationship between eye movement and memory.

In an earlier memory paper, he had attempted to make a similar point. That time, scientists who reviewed the paper before publication liked his data, but they hated EMDR.

“They were unanimous in telling us to get rid of all mention of EMDR. One reviewer said, `It lowers the credibility of this fine paper' by referring to this `suspect therapy.'”

eFor some, EMDR is more than suspect, it's charlatanism. In scientific articles remarkable for their vitriol, a group of determined critics keep up a chorus of complaint about EMDR and its creator, Francine Shapiro.

In one blistering 25-page critique published in Clinical Psychology Review in 2000, James D. Herbert, of MCP Hahnemann University in Philadelphia, and six others called EMDR a pseudo-science, a charge generally leveled at things like reading bumps on the head or perpetual-motion machines.

The therapy's popularity “appears to have greatly outstripped the evidence for its efficacy,” the authors wrote. The group said studies showing positive results for EMDR were conducted improperly. Subjects were not assigned randomly to experimental groups. Statistical analysis was wrong-headed or otherwise inappropriate. In other instances, the group writes, EMDR practitioners tested their practice against unproven therapies.

“Indeed, there is little evidence to support the extraordinary claims of the most vocal promoters of EMDR, or the enthusiasm of some mental health practitioners who believe in its unique efficacy,” the authors wrote.

eThe edge in Dr. Shapiro's voice grows sharper the longer she talks about what she calls the “cottage industry” of criticism directed toward EMDR. She heads the EMDR Institute in Pacific Grove, Calif.

“There is more controlled research on EMDR than any other treatment,” she said. Studies found the therapy effective among veterans of Desert Storm, Vietnam, Korea, and World War II. Other studies show results among people suffering from panic attacks and a variety of phobias, although a few studies showed little benefit in some phobias. Additional research showed EMDR effective among crime victims, police officers, and victims of sexual assault.

Positive studies have done little to pursude her critics. Even the details of how Dr. Shapiro discovered EMDR are hashed over in the psychological literature.

It is an unusual story. Sometime in the 1980s she was walking in a park in Los Gatos, Calif., looking at the scenery, and chewing on a personal problem. As she walked, her disturbing thoughts disappeared.

“I hadn't done anything to shut them off,” she said. But she noticed her eye movements, and the shift in attention they entailed. So she tried it deliberately. It worked.

“Then I gathered every warm body I could lay my hands on,” and tested the eye-movement impact. It held up.

The insight lead her to a doctorate in psychology and the creation of EMDR.

e“In some ways, I think it's unethical not to use EMDR, it gives so much relief,” said Jeanne Dennler, a Toledo child psychologist who's used EMDR with her young patients for five years.

“It just changed the whole flavor of my practice, in terms of how much quicker things can be, and less distressing for the child.”

People who try EMDR report strange results.

“I was quite stunned by the way my mind leapt from topic to associated topic in a way that felt bizarre and unpredictable, as things in a dream,” said Harvard's Robert Stickgold. “At the same time, there was this uncanny sense of connectedness, like in a dream.”

Perhaps it's not too surprising that Dr. Stickgold, who studies sleep and cognition, drew the dream parallel, considering what he theorizes is behind EMDR's reported efficacy.

Dr. Stickgold sees a relationship between the eye movement of this treatment, and the rapid eye movement that gives its name to REM sleep.

REM sleep plays a critical role in learning, Dr. Stickgold's research shows. Studies demonstrate that learning suffers when we don't sleep.

“It's not just time, and it's not that you won't remember it. It's that you won't master it,” he said.

It has to do with how we process memories.

“Think of what you had for lunch yesterday,” Dr. Stickgold said. To recall that roast beef sandwich, you drew from the short-term, it-just-happened memory bank, located in a horseshoe shaped organ in the middle of your brain called the hippocampus.

But other memories are stored within a network of your life's experiences in the brain's neocortex. These memories have context; allowing you to compare yesterday's greasy lunch at the diner with that dinner you had in Paris on your honeymoon.

REM sleep appears to play a role in moving memories into the neocortex network. But for those who suffer from post-traumatic stress disorder, the transition never takes place. The trauma stays in short-term memory, complete with its heart-pounding terror.

“The memories can't get from the hippocampus to the neocortex. It never gets incorporated into the associated network that is their understanding of their life,” Dr. Stickgold said.

EMDR may move the traumatic memories into the neocortex. The memory is still sad, or tragic, but it is no longer immediate, weighted with all of the sights, smells, sounds, and emotions of a hippocampal memory.

Dr. Stickgold said he doesn't have proof that this is what's occurs in EMDR. And it may be only part of the story, he said.

Dr. Christman's research may reveal another window into the mysterious world of the brain.

“He's got some data that I think is fascinating,” Dr. Stickgold said. “At this point, I'm at the `Let 1,000 flowers bloom' stage. His work could be a piece of this.”'