Active Trigger Points in the Cervical Musculature Determine Altered Activation of Superficial Neck and Extensor Muscles in Women with Migraine

Objective: Previous studies have demonstrated the presence of active TrPs in women with migraine reproducing their headache attacks. No study has investigated if these TrPs can alter muscle function in the cervical spine in migraine. Our objective was to analyze differences in activation of superficial neck flexor and extensor muscles in women with migraine considering the presence of active trigger points (TrP) in splenius capitis (SC), upper trapezius (UT), and sternocleidomastoid (SCM) muscles. Methods: Surface EMG was recorded from superficial flexor (SCM and anterior scalene) and extensor (SC) muscles bilaterally as subjects performed a staged task of cranio-cervical flexion (CCF; 5 contractions representing a progressive increase in CCF range of motion) in 70 women with migraine. They were stratified according to presence or absence of active TrPs in SCM, SC or UT musculature. Comparison of normalized root mean square (RMS) values was conducted with 2x5 ANCOVA with task level as the within-subject variable, group stratified by active TrPs as the between-subjects variable and the presence of neck pain as a co-variable. Results: All patients exhibited active TrPs in their cervical muscles which reproduced their migraine. Women with migraine exhibiting active TrPs in the SCM (P<0.01), UT (P<0.05) or SC (P<0.05) muscles had lower normalized RMS values of their superficial neck flexors than those without active TrPs in the same muscles. In addition, subjects exhibiting active TrPs in the SC and UT (both, P<0.05) muscles had higher normalized RMS values in the SC muscle than those without active TrPs in the same muscles. Conclusion: The presence of active TrPs in the cervical musculature determines altered activation of superficial neck and extensor muscles during low-load, isometric CCF contractions in women with migraine.