Des Moines, Iowa-The recent investigation into episodic tension-type headache (ETTH) conducted in Denmark and published in the Journal of the American Medical Association (JAMA), volume 280, pages 1576-1579, by Geoffrey Bove, D.C., Ph.D., and Niels Nilsson, D.C., M.D., Ph.D., is admirable in its careful design and simplicity and it is especially laudable in the precise and sensitive interpretation of its data. In short, it is exactly the kind of research that one would hope is conducted throughout the health professions.

The study essentially points out that, between two types of interventions carried out by the same chiropractor in response to ETTH, there is no significant clinical difference in terms of the improvements observed in both treatments. These recoveries refer specifically to the number of hours of headache experienced and the use of analgesics. Both treatments involve soft tissue treatment in the form of deep friction massage and trigger point therapy if indicated. In addition, the manipulation group received joint manipulation in the form of diversified and/or toggle-recoil techniques; while the additional component in the remaining patient group consisted of low-power laser light, shown previously¹ to produce no consequences other than placebo effects.

One might conclude from a casual reading of this study that chiropractic intervention produces no salutary effect in the management of headaches. This particular interpretation, however, is egregiously incorrect because:

The investigation examines the effect of a manipulative technique (diversified and/or toggle-recoil) only. It actually demonstrates a positive effect produced by other protocols which are integral to the practice of chiropractic (deep friction massage and trigger point therapy). The study scrupulously avoids glossing over the clinical improvement observed in the control group of patients and does not conclude (or even insinuate) that the addition of chiropractic "provided no benefit"--errors which have flagrantly compromised the integrity of another recent study addressed to the efficacy of chiropractic in the management of asthma.²

The authors point out that the results for ETTH are in "stark contrast" to those that they previously published for cervicogenic headache. In the latter condition, the same manipulative techniques published in the current JAMA article produced clinically significant improvements in headache duration, headache intensity, and the use of analgesics in comparison to the control (massage and trigger point therapy) group:

This study therefore achieves the distinction of stimulating further inquiry into the entire realm of the etiology and classification of headache, as it demonstrates a major difference in response (and presumably causative) mechanisms.

It also emphasizes the importance of performing an accurate clinical diagnosis of headache patients, well within the training and practice of chiropractors as well as medical practitioners.

These observations provide a rationale for our current classification of ETTH and cervicogenic headache by emphasizing the effectiveness of soft-tissue techniques in the management of ETTH (presumably of muscular origin) and of manipulative procedures which are more germane to what are possibly osseous contributions to the origins of cervicogenic headache.

This study is to be applauded for its inclusion of a survey of patient expectations of treatment in order to correct for any difference between the treatment regimens in their ability to generate a placebo effect (none were detected). This important control was conspicuously absent in two recent chiropractic studies involving both low-back pain³ and asthma² which appeared in The New England Journal of Medicine and were unfortunately over-interpreted by their respective authors--to say nothing of the media.

Placebogenic effects also were minimized by the fact that interventions of both experimental groups were conducted by the same chiropractor. In addition, eligibility criteria were such that more typical--rather than mild or extreme--cases were admitted into the study.