Pinpointing pain

WHEN Melanie Burke’s infertility treatments went awry a few years back, she came down with constant throbbing muscle aches, searing back pain, insomnia and migraines so severe they affected her vision.

Burke’s doctors wrote off the symptoms as a reaction to the hormones she was taking to help her get pregnant. But the pain persisted long after Burke stopped those treatments. “I saw an orthopedic doctor, a neurologist, two endocrinologists and a physical therapist,” says the 47-year-old Santa Monica psychotherapist. “Nothing helped -- I was beginning to think I had something very serious.”

Finally, after six straight months of pain-racked days and sleepless nights, Burke turned to acupuncture -- and found relief within two treatments. Her pain subsided so quickly that “within five minutes, I was so relaxed I was on the verge of sleep,” she says.

From the traditional Chinese medicine point of view, Burke’s qi, or energy flow, had been out of balance. Needles inserted at specific points in her body redirected the flow of her qi and restored her to good health.

From the modern medicine point of view, Burke may have had an endocrine imbalance caused by fertility treatment. The needles helped her through a combination of hormone production, cell changes, neurons firing -- and possibly a bit of mind over matter.

Hundreds of thousands of Americans attain pain relief through acupuncture each year, according to a recent national survey conducted by the Centers for Disease Control and Prevention -- and many, these days, seek the treatment at their doctor’s suggestion. Mainstream medical interest in acupuncture has grown as the studies pile up: A National Institutes of Health statement, published in 1997, concluded that the procedure appeared most promising in treating nausea, then pain.

Yet despite this growing Western faith in an ancient Chinese practice, scientists and doctors understand remarkably little, in modern medical terms, about how the procedure works to provide lasting pain relief.

In recent years scientists have begun studying the body’s biological responses to the treatment in hopes of shedding light on how a handful of needles and some heat lamps can perform as well as, or better than, Western medicine’s strongest pain-killing drugs. They have come up with an array of theories to explain the technique’s effectiveness, some of them widely accepted, others too new to assess.

“We’re still in the early stages of understanding how it works,” said Dr. Ka-Kit Hui, founder and director of the Center for East-West Medicine at UCLA. Already, he adds, studies on the topic are raising interesting questions about the body’s physical and emotional responses to pain -- and might someday force Western medicine to reassess its understanding of the nauseous sensation.

A philosophical approach

IN traditional Chinese medicine terms, good health depends upon two things: an unobstructed flow through the body of energy, or qi, along 12 major channels, or meridians, and a balance between the two life forces -- cool, passive yin and warm, active yang. Illness or pain occurs when the flow of qi is blocked, or when one life force dominates the other.

Acupuncture is thought to act on meridians. In the form of the treatment most widely practiced in the U.S., hair-thin needles are inserted into the skin at specific points along the meridians to redirect or unblock stagnant qi. (Other types of acupuncture apply pressure, smoldering herbs or electrical currents at the points.) These so-called acupoints correspond (in traditional theory, at least) to different organs or systems in the body.

For example, inserting a needle at a point inside the forearm known as P6 is intended to treat nausea; needling Liv3, on top of the foot, is meant to help with motor function.

Studies suggest that inserting needles into acupoints does affect the body, and in potentially meaningful ways. In a study of 37 subjects published this year in the journal Neuroscience Letters, inserting a needle into acupoint L14 on the hand -- traditionally used to treat pain -- was shown to deactivate parts of the brain that are involved in processing pain.

Indeed, a decade of acupuncture imaging research has shown that “people who get better with acupuncture have clear changes in their brain function,” says Dr. John Farrar, a pain researcher at the University of Pennsylvania School of Medicine. Changes are seen in the thalamus, a brain region that processes information from the senses, including touch and also pain.

But acupuncture also affects activity in the brain region called the cingulate gyrus as well as other brain structures that make up the limbic system, which processes the range of human emotions and memory.

The fact that acupuncture deactivates the brain’s limbic system suggests it “diminishes the emotional part of the pain experience,” such as anxiety or that woe-is-me feeling, says Terry Oleson, a board member of the Society for Acupuncture Research and a director at Emperor’s College of Traditional Oriental Medicine in Santa Monica, which trains acupuncturists and offers degrees in Oriental medicine.

Hormone release could be key to such brain changes. Thirty years ago, about the same time acupuncture started to pique the interest of Americans, Chinese medical researchers began studying it in animals. They showed -- and subsequent Western researchers confirmed -- that acupuncture increased the body’s production of its own natural painkillers, known as endogenous opioids, or endorphins. People experienced no pain relief from acupuncture if they were first injected with a drug that blocked the opioids’ activity.

Today most Western researchers agree that acupuncture’s stimulation of endorphins plays a big part in explaining how the practice works, says Dr. John Longhurst, director of the Susan Samueli Center for Integrative Medicine at UC Irvine.

But some medical acupuncture researchers maintain that this can’t be the whole picture.

Most crucially, they say, endorphins alone cannot explain why individual acupuncture points or meridians would correspond to particular functions or parts of the body -- if, indeed, they do.

The meridian theory

FOR thousands of years, acupuncture has been based on the premise that specific points along the meridians correspond to specific organs, such as the liver, and functions, such as motor control. From the 1970s through the ‘90s, the relationship between acupoints and their related organs was a key focus of acupuncture research. Some early studies supported the idea that the links were real.

For instance, in his work as a graduate student and postdoc at UCLA and UC Irvine in the 1970s, Oleson reported a link between tenderness or sensitivity in ear acupuncture points governing a certain organ or body part, and the corresponding health of that part of the body. For example, if a patient had foot pain (say, from plantar warts or some other condition), a foot-specific acupoint on his ear was likely to be tender and inflamed too.

The same type of finding has been reported for non-ear acupoints. Chinese researchers, for example, found an association between pain or sensitivity at acupoint Li8 during acupuncture and severity of disease in the liver, which Li8 governs.

But such studies are hard to perform objectively, and scientists aren’t sure what to make of them. Recently, focus has shifted to the unique physical properties of acupoints and meridians without attempts to link them to specific organs or functions.

The meridians depicted in Chinese medical charts have no obvious anatomical basis -- though diagrams of them do bring the nervous system to mind, says Farrar.

Meridians and acupoints might also correspond to areas of the body with physiologically distinct properties. In a study published in the scientific journal Anatomical Record in 2002, Dr. Helene Langevin, an associate professor of neurology at the University of Vermont College of Medicine, showed that about 80% of the acupoints on the arm correspond to areas of connective tissue between muscles.

This might be why practitioners and patients alike often notice a distinct feeling when an acupuncture needle is inserted into the skin, says Langevin. Patients sometimes describe the feeling, called de qi in Chinese, as pressure, a nick, something akin to a mosquito bite. To the practitioner, the grip on the needle feels like catching a fish on a line, or a “tightening” of the skin around the needle.

Langevin is now examining what implications this might have for how acupuncture sends messages to the brain. She has published data showing that when needles are inserted into acupoints, the underlying connective tissue winds around the needle “like spaghetti around a fork,” she says. This doesn’t happen when a needle goes into a non-acupoint area.

Langevin has also shown that the winding action causes the cells in the area to change shape, a process that she theorizes might signal the central nervous system. She is testing the theory in a series of animal experiments.

Other, older studies conducted and published in Asia and Europe during the 1970s and ‘80s produced evidence suggesting that acupoints might be areas of very low electrical resistance, might be slightly more sensitive to touch or might lie near major nerve pathways. But scientists don’t know the significance of these characteristics.

In more recent years, brain imaging has been used to clarify the relationship between acupoints and the functions they represent. The practice was pioneered by Zang-Hee Cho, an imaging expert and UC Irvine professor of radiological sciences who, just over a decade ago, took a spill while on a hike in South Korea. Plagued by the pain that later radiated from his back, he eventually gave in to his wife’s suggestion to see a local acupuncturist -- who made his pain disappear in 15 minutes, he says.

Cho showed in a series of imaging experiments, published in 1998 in the Proceedings of the National Academies of Sciences, that needling several acupoints for eye problems -- located near the little toe -- in a group of 12 volunteers increased activity in the visual cortex, the part of the brain governing vision.

Yet when Cho and his colleagues stimulated random points, located a few centimeters away from each acupoint, no activity occurred in the visual cortex.

Dr. Randy Gollub, assistant director of psychiatric neuroimaging at Massachusetts General Hospital, is also investigating the differences in brain activity generated by needling at real and fake (or “sham”) acupoints. In an ongoing study -- Gollub hopes to publish the results next year -- healthy volunteers are subjected to pain (a hot probe applied to the skin) and then given either real or sham acupuncture. So far, both treatments appear to activate or deactivate various regions of the brain involved in controlling the body’s reaction to pain: “They’re a lot more alike than they are different,” Gollub says.

But, she adds, it looks as if the brain’s response is stronger for true acupoints than for sham ones. “Think of it as a mountain range, with the acupuncture points as peaks,” Gollub says. “As long as you’re not in the valley, the acupuncture is probably going to have some effect.”

Competing observations

NOT all scientists are believers in the so-called “point specificity” of acupuncture. They note that many studies have shown that simply inserting needles in the skin can relieve pain -- regardless of whether the needles are placed at random or in the places defined by traditional Chinese medicine.

For example, in studies comparing real, sham and no acupuncture for osteoarthritis of the knee, real and sham acupuncture both offered more relief than no acupuncture at all -- suggesting that acupuncture might be effective regardless of needle placement.

This raises an important question for acupuncture researchers: Does something highly location-specific occur at the point of needle insertion, or does simply inserting a needle, no matter where, trigger a set of pathways that enable patients to “turn on” their brain’s own healing capacity?

Cho, for one, has found in recent studies that inserting needles in real or sham sites produces similar changes in parts of the brain perceiving pain.

In simplified terms, he thinks that inserting a needle at almost any point on the body triggers a series of biochemical messages between the brain’s hypothalamus and the hormone-producing pituitary and adrenal glands. The signals tell the body to alter its production of, for example, certain stress hormones and immune molecules that help the body cope with stressors -- such as bacteria, viruses, emotional trauma or pain.

In fact, Cho believes that acupuncture might someday be refined to the point where the use of a dozen or more needles could be traded in for a single well-placed needle. “One good stimulation may be enough” for lasting pain relief, he says.

As acupuncture research evolves, scientists acknowledge that there might be other effects of the therapy that have little to do with slipping needles into skin. For instance, skeptics have long held that acupuncture helps heal through the power of the mind: that patients feel better because they think they are receiving an effective treatment. The placebo effect, as it’s called, can be powerful.

And the truth, some experts say, is that Burke and other acupuncture patients rarely find relief from needles alone.

According to Burke’s acupuncturist, UCLA’s Hui, Burke’s busy, hectic life had a bit too much yang and not enough yin. The intensity of her work life, the personal stress of trying to conceive and her hard-core exercise regimen left little room for calm and relaxation.

So, along with the acupuncture treatments, Hui prescribed a more modest work schedule, a less rigorous workout routine and smaller, more frequent meals.

“I walked out of his office feeling like I was in control of my healing,” says Burke.

Such an experience might help subjects “turn on” their brain’s own healing pathways.

“If you have a cold or the flu and do something you like, like going to a movie or watching TV, you will experience less of the symptoms than if you just sort of lay around in bed and feel sorry for yourself,” Farrar says. “It’s a very real effect -- you’re turning on something in your brain to help you suppress or turn off the symptoms.”

In other words, when pain patients turn to acupuncture, other simple changes may produce measurable alterations in brain function with real implications for pain relief.

The herbs, dietary shifts and exercise regimens often prescribed by traditional acupuncturists might have as much to do with the treatment’s effectiveness as the needles themselves -- physically as well as psychologically.

But for patients convinced of acupuncture’s effectiveness, it might be of little importance whether the procedure takes one needle or 20, and whether it’s the needles themselves or other aspects of the treatment that provide relief.

What matters is that the treatment helps.

Burke, for one, says her success with acupuncture has brought her back to Hui’s office again and again.

“I go for a treatment as soon as I feel the pain coming back,” she says, “because I know it works.”