Chronic tension-type headache: Muscle overactivity versus deficient pain controls

Abstract

Objective: The oscillating school of thought between the peripheral and central mechanisms of pain origin hinders the selection of appropriate therapy for chronic tension-type headache (CTTH). The aim of this study was to assess the role of central and peripheral pain mechanisms together in CTTH. Methods: In the present study, we compared surface electromyography (sEMG) amplitudes and nociceptive flexion thresholds in patients diagnosed with CTTH (n=30) with age-matched healthy controls (n=30). For central pain modulation with spinal and supraspinal influences on nociception, we recorded nociceptive flexion reflex (NFR) by stimulating the sural nerve and observing the biceps femoris muscle response. sEMG was done for the temporalis and trapezius muscles at rest, during mental activity and during maximum voluntary contraction to assess contribution from peripheral pain. Results: We observed a decreased NFR threshold in CTTH patients as compared to healthy controls, suggesting a hyperalgesic state due to central factors. Electromyographic activity of trapezius muscle was increased at rest in CTTH while both temporalis and trapezius showed an overactivity in patients during mental task. Conclusion: Central factors are important in the pathogenesis of CTTH while, peripheral factors, such as stress-related muscle spasm may also contribute to pain state.