Pressure-controlled palpation: a new technique which increases the reliability of manual palpation

The objective of the present study was to investigate whether the reliability of tenderness evaluation can be increased by using a new technique called "pressure-controlled palpation" (pcp). The technique has been made possible by a newly invented piece of equipment called a palpometer, with which a pressure-sensitive plastic film attached to the index finger records the pressure exerted. In 15 patients with chronic tension-type headache and in 15 healthy volunteers, 2 investigators studied myofascial tenderness using conventional palpation and pressure-controlled palpation. Tenderness was scored on a 4-point scale in each of the examined pericranial regions. The sum of tenderness scores recorded by two observers using conventional palpation differed significantly (p = 0.0003), while results did not differ between observers using pressure-controlled palpation (p = 0.89). During palpation with seven different pressure intensities a positive and linear relation between pressure and pain intensity was found (p = 0.00006). Pain intensity reported by the subjects correlated highly with tenderness scored by the observer (rs = 0.95, p < 0.0001). These results demonstrate for the first time that tenderness scores can be compared between observers if palpation pressure is controlled. Pressure-controlled palpation represents a major improvement on current palpation techniques and should be standard in future research on myofascial pain disorders.