Biofeedback and Vulvovaginal Pain: Summary of a Lecture

Biofeedback, as the name suggests, involves the electronically-assisted measurement of physiologic processes such as heart rate, blood flow, and muscle contraction. Through the use of highly specialized computers, a specific physiologic process is translated into an auditory or visual signal, which the patient learns to control by modifying the physiologic response. For example, a light turns off when the patient relaxes a particular muscle. After the initial training sessions in a biofeedback practitioner's office, practice typically takes place at home using portable equipment. Over time, the patient achieves some control of the underlying process, e.g., increasing blood flow to the extremities or relaxing neck muscles. This article focuses on the use of a specific type of biofeedback, surface electromyography (sEMG), in the treatment of vulvodynia and vulvar vestibulitis.

History of Biofeedback

Biofeedback had its origins in principles of learning, an area of experimental psychology. It was developed in the late 1960s in the laboratories of Dr. Neal E. Miller, a psychologist at Rockefeller University. (Glazer was his post-doctoral student.) In Dr. Miller's laboratory, biofeedback was used to demonstrate the capacity of animals and humans to self-regulate certain physiologic systems which were not previously thought to be under voluntary control. At the time, for example, it was widely held that gastrointestinal and cardiac responses were completely involuntary. Dr. Miller hypothesized that voluntary control of such responses offered great potential in the treatment of many disorders. For example, he proposed that learning to exert direct control over vascular constriction (narrowing of blood vessels) could reduce or eliminate migraine headaches. The ultimate success of biofeedback in teaching patients to regulate physiologic processes has led to applications in the treatment of many disorders, including irritable bowel syndrome, heart disease, and chronic pain.

Some years later, Dr. Catherine Burgio first applied biofeedback technology to the pelvic floor muscles in the treatment of urologic conditions such as urinary urge incontinence and stress incontinence. Urge incontinence refers to the involuntary loss of urine resulting from abrupt urinary urge. Stress incontinence involves the loss of urine when laughing, coughing, sneezing, standing quickly, or experiencing other acute intra-abdominal pressure events; it is associated with a weakened external urethral sphincter. Both the external urethral and anal sphincters are the continuation of fibers from the pelvic floor muscle. Compromised or weakened pelvic floor muscles and sphincters may result from surgery, trauma, decrease in estrogen, normal muscle deterioration, or neurologic degeneration.

To correct both types of urinary incontinence, Dr. Burgio used a biofeedback combination. Activity of the urethra, pelvic floor musculature, and detrusor muscle (bladder muscle) were measured. The treatment worked as follows: sEMG readings of the external urethral sphincter enabled the patient to exert control over the contraction of the sphincter, turn off activity of the detrusor muscle, and there by prevent involuntary urine loss associated with abrupt urge or acute intra-abdominal pressure.

One drawback of Dr. Burgio's incontinence treatment was the invasive nature of the procedure. Treatment required that tubes be inserted in the bladder and urethra, and external surface patches be applied to the perineal area. Another limitation was the need to conduct the treatment in a hospital setting. Subsequently, Dr. John Perry developed a less invasive office procedure, requiring the patient to insert a small tampon-like sensing device into the vagina to measure the electrical activity of the pelvic floor muscle. Dr. Perry's procedure is still in use today. The patient privately inserts the sensing device and then re-enters the office fully clothed, with the sensor wire pulled through the clothing. The wire is then plugged into a computer, which reads and analyzes the electrical activity of the pelvic floor muscle.

Application to Vulvovaginal Pain

In 1991, Dr. Glazer was approached by a group of specialists working exclusively with patients suffering from vulvovaginal pain conditions such as vulvodynia and vulvar vestibulitis syndrome (VVS). This group had identified, upon digital vaginal examination of their patients, high levels of tension and instability in the pelvic floor muscle. This was not surprising since it was well-known that in any area of the body where soft tissue pain is experienced, the local muscle becomes tense as part of a natural guarding process intended to protect the area from pain. Dr. Glazer hypothesized that the muscle tension was a consequence of the vulvar pain. If this hypothesis were true, working with the pelvic floor muscle would not relieve the pain, because the underlying cause of the vulvodynia or VVS would not be addressed.

At the time, however, commonly used treatments for vulvodynia and VVS were not very effective. Topical palliatives (e.g., Aveeno solution), low dose tricyclics, and antihistamines provided minimal pain relief. Surgery, an option for some patients, was rarely pursued as a first line treatment. Given these limited alternatives, Dr. Glazer and the group of vulvar pain specialists decided to try biofeedback. Dr. Glazer treated approximately 50 patients with diagnoses ranging from pure VVS (i.e., sharp vaginal entry pain only) to combinations of subtypes of vulvodynia. Many patients also had associated conditions such as interstitial cystitis, irritable bowel syndrome, and fibromyalgia. Surprisingly, the strengthening, relaxation, and stabilization of the pelvic floor muscle in many of these patients resulted in pain relief. Unlike the rapid relief experienced by urologic patients, however, the vulvar pain patients needed many months of diligent daily practice to achieve symptomatic relief.

Research Findings

The results of Dr. Glazer's first 35 patients were reported at the 1993 Congress of the International Society for the Study of Vulvovaginal Disease, and published in the April 1995 Journal of Reproductive Medicine. In summary, 83 percent reported overall improvement in vulvar pain symptoms. Slightly over 50 percent of the 35 patients were asymptomatic at the end of treatment, and remained pain-free at six-month follow-up. Subsequent to publication of the study, Dr. Glazer continued to follow the progress of these asymptomatic patients, all of whom were still pain-free after two or more years. This study is currently being replicated by a Canadian research group, with Dr. Glazer's participation. Preliminary data appears consistent with the results of the initial study.

These findings have led to a change in some health care professionals' understanding of vulvovaginal pain. Originally, it was believed that muscle activity was a secondary process intended to protect the area from pain. The observation that decreasing pelvic floor muscle instability leads to symptomatic vulvar pain relief, however, suggests that muscle instability plays an integral part in the maintenance of the pain. Clearly more research is needed, but one explanation for these findings may stem from a chronic pain condition known as reflex sympathetic dystrophy (RSD). The typical response to injury or trauma is as follows: histamine is released and causes swelling; vasoconstriction occurs and leads to proliferation of blood vessels and redness; and guarding of the tissue takes place and results in muscle tension. These natural responses usually protect and help resolve the injury. As the tissue heals, these responses dissipate. When RSD occurs, however, these protective responses do not dissipate. Instead, the mechanisms which are intended to promote healing persist, and the pain condition is maintained rather than resolved. In other words, swelling, redness, and guarding are only helpful in the early stages of the healing process following an injury or trauma. Prolonged swelling, redness, and guarding actually maintain the pain condition.

In the April 1995 issue of the Journal of Reproductive Medicine, Dr. Glazer and his colleagues, Gae Rodke, M.D., Charles Swencionis, Ph.D., Alexander Young, M.D., and Ronny Hertz, M.D., hypothesized that instability of the pelvic floor muscle maintained VVS. The authors speculated that a hyperactive and unstable pelvic floor muscle might cause a reflex, or signal, from the nerves of the pelvic floor to the nerves of the local spinal cord. Thus, VVS might be a variation of RSD.

There is no strong scientific evidence that VVS is a variation of RSD, but the theory does provide a descriptive understanding of what may be happening in VVS. According to this theory, the nerves of the local spinal cord activate the sympathetic nervous system, which in turn causes the release of histamine and vasoconstriction. When inflammation and increased blood vessel growth occur in an area of densely packed nerve endings (as is the case in the soft tissue area of the vulva), pressure applied to the soft tissue produces a burning sensation as experienced in vulvodynia, and sharp pain and tissue tenderness as reported in VVS.

Another finding with important treatment implications for vulvovaginal pain conditions emerged from the 1995 study. The researchers were interested in determining which characteristic(s) of the pelvic floor muscle were associated with pain relief. They discovered that the stability of the muscle at rest was the only characteristic that predicted pain relief. Whereas the goal for incontinent patients was to increase control by strengthening the pelvic floor muscle, simply strengthening the muscle did not relieve pain in VVS patients. Rather, the results of this study indicated that the stabilization or reduction of variability of the pelvic floor muscle at rest was the key factor in alleviating vulvar pain.

It should be noted that biofeedback equipment and protocols for the pelvic floor muscle were originally designed for the treatment of incontinence. To treat vulvovaginal pain conditions, it is essential to have software that also measures pelvic floor muscle stability. In addition to this requirement, the other important component of treatment is the protocol, i.e., the method of scientific measurement in which the same procedures are followed at each session, so that changes in the muscle can be monitored over time.
A second study at Cornell University is currently in the process of completion and publication. The purpose of this study, by Romanzi, Polenewski, and Glazer, is to investigate the accuracy and reliability with which physicians diagnose patients with pelvic floor muscle tension. Currently, physicians identify pelvic floor muscle tension by palpation. This research is important to determine whether physicians are correctly identifying and referring vulvovaginal pain patients for sEMG biofeedback treatment. In this study, pelvic floor muscle tension was measured in two ways: by physicians' examinations and with sEMG biofeedback. Findings indicated that physicians' measurements were not consistent with sEMG biofeedback readings. In addition, the consistency with which physicians accurately identified muscle tension varied greatly among practitioners. Generally, physicians' accuracy improved when identifying muscle tension within the same patient, in repeated sessions over time. Overall, these findings suggested that physicians do not assess pelvic floor muscle tension with sufficient reliability, and that an initial sEMG biofeedback assessment is a more reliable diagnostic tool.

Another biofeedback study by White, Jantos, and Glazer was published in the Journal of Reproductive Medicine in April 1997. The purpose of this study was to differentiate subtypes of vulvodynia patients from normals, based on readings of pelvic floor muscle stability. Consistent with the results of the 1995 study, the stability of the muscle at rest proved to be 92 percent accurate in identifying vulvodynia patients. Additional characteristics that reliably differentiated vulvodynia patients from normals included: the speed of on set of contractions, the amplitude of the muscle contraction, the speed with which the muscle returned to rest, the post-contraction resting baseline, and the muscle fibers used during contraction.

These results have important diagnostic implications. To date, vulvodynia and VVS have been diagnosed based on a description of symptoms, rather than physical findings or etiology. If it turns Out that vulvodynia or VVS can be accurately diagnosed with sEMG biofeedback, this would be the equivalent of having a blood test that reveals a positive or negative result.

Additionally, the White, Jantos, and Glazer paper discussed the case of a vulvodynia patient who was referred for sEMG biofeedback, but upon evaluation presented with a normal pelvic floor muscle. Further medical testing revealed that the patient had an infectious condition. When treated for this condition, the patient's vulvar symptoms disappeared. Dr. Glazer has seen several patients diagnosed with vulvodynia and referred for sEMG biofeedback whose pelvic floor muscle appeared normal during evaluation. He has referred all of these patients back to their gynecologists for a more detailed workup. Although not empirically studied, in each case, a gynecological abnormality or external irritating factor that had not been addressed was determined to be the source of the patient's problem.

The ongoing Canadian study is producing other interesting findings. This is the first study to demonstrate controlled comparisons of surgery, biofeedback, and psychological/psychosexual approaches to the treatment of vulvodynia. Pure VVS patients, i.e., those with sharp vaginal entry pain only, were randomly assigned to one of three groups: vestibulectomy, biofeedback, or talk therapy with a combination of group and sex therapy. By the three-month follow-up, surgery produced the best results, with biofeedback a close second. Talk therapy produced little or no positive results. At six month follow-up, the effectiveness of surgery remained the same, the biofeedback group showed additional improvement, and talk therapy continued to show little or no benefit.

At the September 1997 meeting of the International Society for the Study of Vulvovaginal Disease, Glazer, Jantos, Hartmann, and Swencionis presented a poster comparing sEMGs of vulvodynia patients and normals. This current research demonstrates that, in addition to pelvic floor muscle stabilization measures, muscle fiber readings are emerging as a key factor in predicting pain reduction. These' readings specify which type of muscle fiber the patient is contracting during training exercises.

Summary

In summary, these research findings indicate that sophisticated analysis of the pelvic floor muscle using sEMG biofeedback equipment is helpful in the diagnosis and treatment of vulvovaginal pain. Pelvic floor muscle changes must not only include stabilizing the muscle, but strengthening the correct muscle fibers, to alleviate pain. Repeating the identical assessment procedure at each session allows for comparison over time to assure that rehabilitation is occurring. Some patients achieve pelvic floor muscle strengthening or relaxation, but not pain relief. A more detailed analysis may indicate that the patient is contracting the wrong fibers or that the pelvic floor is more relaxed, but still unstable.

Selecting a biofeedback specialist

In selecting a biofeedback practitioner, it is necessary to keep in mind that the treatment of vulvovaginal pain with sEMG biofeedback is new. First, look for a specialist with specific training in sEMG biofeedback for the pelvic floor; ideally this will include training in the treatment of vulvovaginal pain conditions. Second, ask the practitioner if the office equipment and protocols include readings of muscle fibers, as well as muscle stability.

Insufficient practitioner training, or inadequate equipment and protocols, are likely to affect the quality of the biofeedback results. Only sEMG biofeedback can measure thestability of the pelvic floor muscle at rest and specify which muscle fibers are used during contraction. Dr. Glazer has heard patients say, "I've tried biofeedback and it didn't work," or "it had limited value." Frequently, these patients used instruments involving electrical stimulation of pelvic floor muscles, or alternative measurement devices such as manometers, instruments used for pressure readings. Vulvar pain patients, who have had unsuccessful experiences with biofeedback, but did not use sEMG biofeedback, may want to consider trying it again with a practitioner who has appropriate training and equipment.

References:

References

1. Glazer, H.I., Rodke, G., Swencionis, C., Hertz, R., Young, A. Treatment of vulvar vestibulitis syndrome with electromyographic biofeedback of pelvic floor musculature. J. Reprod. Med. 1995; 40:283-90.

2. Romanzi, L., Poloneczky, M., Glazer, H. A simple technique for assessment of pelvic muscle function as a part of routine pelvic examination; validation by surface electromyography. Manuscript in preparation.

3. White, G., Jantos A., Glazer, H. Establishing the diagnosis of vulvar vestibulitis. J. Reprod. Med. 1997; 42:157-60.