Dubious Use of Surface Electromyography (SEMG)

Samuel Homola, D.C.

In surface electromyography (SEMG), the electrical activity of individual muscles or muscle groups is detected, amplified, and analyzed by a computer [A, B]. The most basic information obtainable from an EMG signal is whether the tested muscle was used during a period of exertion. The test has legitimate use for analyzing certain types of performance in the workplace. However, chiropractors who market a commonly used SEMG device claim that it provides an objective measurement of overall spinal health by detecting electrical activity in the muscles along the spine (paraspinal electromyography), enabling them to screen patients initially and to follow the progress of their treatment [1]. They further claim that this electrical activity is "associated with vertebral subluxations" and therefore that "to third party payers and attorneys, the test is invaluable for determining the need for chiropractic care, the response of the patient to chiropractic care, and the presence or absense of residual abnormalities." [2] They even claim that the test is useful for "improving patient relations" by helping to "make the concepts of vertebral subluxation and nerve interference 'real' to them." [3]

Some SEMG devices enable the chiropractor to interpret the results while the patient observes various markings on a schematic representation of the body on a computer screen. One such device was endorsed by a prominent chiropractor who said it was marvelous for demonstrating the vertebral subluxation complex to the patient and that it helps the patients realize that when their symptoms are gone, there is still correction to be made [4]. The picture on the right illustrates one system which reports that higher readings indicate greater "severity."

 

The key questions in judging whether a diagnostic test is appropriate are:

In 2000, after reviewing more than 2,500 original articles, reviews, and books, an American Academy of Neurology subcommittee concluded that SEMG was "unacceptable as a clinical tool" for diagnosing low back pain or neuromuscular disease [5].

For these reasons, routine chiropractic use of SEMG should be regarded as a money-making scheme.

In 1995, a Boston-area chiropractor was convicted of defrauding automobile and workers' compensation insurers by overstating patients' injuries and by running up patients' bills with unnecessary tests and treatments. During the early 1990s, all automobile accident and workers' compensation patients at his clinics were subjected to a battery of high-technology tests that included SEMG, but uninsured patients were not tested. Most of the clinic's patients were managed by associate chiropractors who were employees. The prosecutors also noted that these chiropractors did not use the test results to guide their diagnosis or treatment [6].

In 2001, the Massachusetts Board of Registration of Chiropractors issued a policy guideline that criticized routine use of paraspinal electromyography:

The use of advanced technologies, such as Paraspinal Electromyography (paraspinal EMG), Electronic Muscle Testing, Thermography, Sonography, Videofluoroscopy, Plethesmography and others not specified, would generally be presumed to be clinically unnecessary if: (a) such procedures are being used during the initial trial phase of a condition, and (b) the relevant information available from these tests could typically be determined through standard testing procedure(s). Furthermore, the use of advanced technology of any type would be considered clinically unnecessary if the ultimate potential benefit of using the advanced technology would have no significant effect on the overall outcome for the patient when compared to the outcome obtained without utilization of the advanced technology [7].

References

  1. Kent C, Gentempo P Jr. Paraspinal surface EMG: Its role in chiropractic practice. Today's Chiropractic 22(3):14-16, 1993.
  2. Kent C, Gentempo P Jr. The role of the paraspinal EMG scanning in managing the vetrtebral subluxation complex. The American Chiropractor 12(3):7-10, 1990.
  3. Kent C, Gentempo P Jr. Improving your practice with the state-of-the-art EMG.
  4. Gregg RJ. Endorsement in ad from Precision Technology, Inc., Today's Chiropractic 21(3):51, 1992.
  5. Pullman SL and others. Clinical utility of surface EMG: Report of the therapeutics and technology assessment subcommittee of the American Academy of Neurology. Neurology 55:171-177, 2000.
  6. Boston area chiropractor and wife sentenced in fraud case. Article adapted from U.S. Department of Justice news release of Sept 7, 1995.
  7. The use of advanced technology in a chiropractic office. Massachusetts Board of Registration of Chiropractors. Policy guideline, July 12, 2001.

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Dr. Homola, who lives in Panama City, Florida, retired in 1998 after practicing chiropractic for 43 years, wrote Inside Chiropractic: A Patient's Guide (Prometheus Books., 1999).

This page was revised on April 15, 2005.