Pressure Pain Threshold
Pressure Pain Threshold (PPT) was determined using a digital algometer (Lafayette Manual Muscle Test Systemâ„¢, Model 01163, Lafayette Instrument Company, Indiana, USA) which consists of a padded disc attached to a microprocessor control unit that measures peak force (Newton). The PPT of the masseter, trapezius (anterior, posterior, occipital) and temporalis muscles was assessed via the algometer. During PPT assessment, the researcher positioned the algometer on the trigger points of the respective muscles and increase the amount of pressure applied until the participant verbally informed the researcher when the sensation of pressure became pain. The applied pressure was read from the digital screen after each assessment. A lower score indicates a lower pain threshold whereas, a higher score indicates a higher pain threshold.