Tension headache may actually be temporomandibular muscle and joint disorder

People whose recurrent headaches have been diagnosed as tension-related actually may be suffering from temporomandibular muscle and joint disorder, or TMJD, a study headed by a researcher from the University at Buffalo's School of Dental Medicine has shown.

Results showed that examiners could replicate tension-headache symptoms in 82 percent of subjects by performing the clinical examination of the temporalis muscle, which is involved in TMJD.

Richard Ohrbach, D.D.S., Ph.D., UB associate professor in the Department of Oral Diagnostic Sciences, presented the study results at the American Association of Dental Research meeting held recently in Orlando, Fla.

The temporalis muscle is responsible for closing the jaw and is involved in chewing, but these core functions of that pair of muscles often are ignored when the presenting complaint is "headache," as opposed to jaw pain, Ohrbach said.

"Because headache is so incredibly common, it often is regarded as inevitable, and if sufferers label the pain as 'headache,' they may not seek help," he said. "Or if they do seek help, the label of 'headache' typically will propel the individual to a physician or neurologist for consultation.

"Knowledge about the intersection between jaw pain and headache is not well established, and consequently, jaw pain may be ignored in the differential diagnosis," Ohrbach added. "This can be most unfortunate for the individual, because TMJD can be very treatable, but if a jaw disorder is ignored, then treatment for the headache may not address all of the factors contributing to the headache."

The current study is part of an $8 million project to establish valid and reliable TMJD diagnostic criteria. Results will advance the field of TMJD research and aid clinicians in their practices.

Researchers at the University of Minnesota and the University of Washington, in addition to UB, are involved in the project.

An estimated 5-10 percent of the U.S. population suffer from TMJD severe enough to warrant treatment. These patients experience debilitating pain that can destroy quality of life. Diagnosing the disorder is problematic, however, due to overlap with other conditions, Ohrbach said.

TMJD usually involves more than a single symptom, rarely has a single cause and frequently involves multiple factors, including behavioral and emotional responses. Lacking a firm set of diagnostic tools, physicians and dentists often depend on their individual judgment to decide if a patient does or does not have the disorder, he noted.

The diagnostic criteria for TMJD being tested in this project are part of the established Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Headache diagnosis is based on the International Headache Society (IHS) guidelines. All examiners were been trained to use the "gold-standard" criteria for tension-type headache established by the IHS.