An experimental test of the muscle tension hypothesis of tension-type headache.

The present study employed an experimental design to provide a direct test of the classic etiological account of tension-type headaches, that these stem from elevated levels of muscle tension. Twenty-eight female subjects with relatively frequent headaches were divided into 4 groups, according to a 2 x 2 design. The independent variables were (1) Target response (to maintain elevated levels of either frontalis EMG or digital temperature for 40 min), and (2) Expectation (either specifically of a headache or of some unspecified discomfort). Dependent variables included headache as well as a number of other possible symptoms. Results showed that subjects were successful in complying with their assigned tasks. However, there were no main effects of Target response or Expectation and no interactions of these factors with respect to headache or any other symptom. These data provide strong evidence against the classic etiological account of muscle-contraction headaches.